Snell`s Clinical Anatomy By Regions - 8th Ed.pdf 6yr24

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Table of Contents 1. Front.......................................................................................................................................... 2 1.1 Cover ................................................................................................................................... 2 1.2 Contributors ........................................................................................................................ 2 1.3 Dedication ........................................................................................................................... 3 1.4 Preface ................................................................................................................................ 3 1.5 Acknowledgments............................................................................................................... 4 2. 1. Introduction .......................................................................................................................... 5 3. 2. The Thorax: Part I - The Thoracic Wall ................................................................................ 87 4. 3. The Thorax: Part II - The Thoracic Cavity .......................................................................... 148 5. 4. The Abdomen: Part I - The Abdominal Wall ..................................................................... 273 6. 5. The Abdomen: Part II - The Abdominal Cavity .................................................................. 377 7. 6. The Pelvis: Part I - The Pelvic Walls ................................................................................... 567 8. 7. The Pelvis: Part II - The Pelvic Cavity ................................................................................. 624 9. 8. The Perineum .................................................................................................................... 715 10. 9. The Upper Limb............................................................................................................... 786 11. 10. The Lower Limb ........................................................................................................... 1020 12. 11. The Head and Neck ..................................................................................................... 1247 13. 12. The Back ...................................................................................................................... 1587 14. Appendix - Useful Anatomic Data of Clinical Significance ................................................ 1664

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1. Front 1.1 Cover ÿØÿàÿØÿà Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

1.2 Contributors

Author Richrd S. Snell MD, PhD Emeritus rofessr of Aatomy eorge Washington Unversity, Schol of Mdicine and Helth Sciences, Washington, D.C.

Seconday Editrs Crytal Taylor Acquisitons Edtor Kelly Horvath Managing Eitor Valerie Saders Marketin Managr Julie ontalbno Productio Edito Doug Smock Desiner Marylnd Comosition, Inc. Compositor R.R Donneley & Son—Willard Priter Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

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1.3 Dedication Again say t studets: The fist day that yu look at or place your hnd on patiet, you requir a basic knoledge of anatomy to interpret yor obsevation. It i in th anatoy depatment hat yu larn th basic medicl vocaulary hat yo will arry wth you throughout your prfessioal carer and that wll enale you to coverse ith yor collagues. Anatomy can be a boing subject; clinicl anatmy is ascinaing. In n era of unprecedented tehnologcal adances nd autmation rememer tha your atient is a human eing lke yorself nd should always reeive te persnal atentio, respct, an care hat yo would wish to receive in similar circustance. Your knowledge of anatomy may save his or her life. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

1.4 Preface Eah patint tha you eamine n your clinic with medica prblems is composed f gross anatmic stucture, whic may o may ot exhbit fuctiona deficts. Al studets mus thereore ener meicine with a basic nowledge of natomy that i clinially rlevant he explosion in the knowlege of edical diseas and he tecnologial advnces asociated with the dagnosi and teatmen of dseases have dctated a compete retructuring o the crriculm for medica studets, detal stdents, allied health students, and nursng stuents. n the nited tates, studens in mny schols are now eing ofered rogram in grss anaomy in which nly pat of te bod is disected and tis is suppleented y the se of rosectd speimens, plastinated specimes, and computr imagry. T assis in th necesary curiculu changes, in the eighth eition, great fforts have ben made to weed out unnecesary aterial and sreamlie the ext. Te follwing canges ave ben intoduced     

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Al the lne illstratins hav been recoloed and the lael prit upgaded. ll the surface anatmy illstratins are in color. Te anatomy of common medica proceures has been furter expnded ad agai inclues sections n compicatios caued by n ignoance o norma anatoy. The ompute tomogaphy (T) scas, magnetic resonace imaing (MI) stuies, ad sonorams hve been upgaded a the technolgy has advancd. Tables have ben use whereer possible to redce the size o the txt. Ths incldes reference table at th end f the ext tht give importnt dimnsions and caacitie of various anatomc strutures. The clnical roblem sectin at the end of each chaptr has een reiewed nd, whn necesary, brought up t date.

Each capter of Clnical Anatomy is consructed in a smilar anner. This gves stdents ready ccess o matrial ad faciitates moving from one part of th book o another. Ech chapter is divide into he following categories: 

Clinical Exaple: A shrt cas report that dramatzes th relevance o anatoy in mdicine introdces each chater.

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Cinical Objectives: Thi secton focses th studet on te mateial tht is mst important to lern and undersand in each capter. It empasizes the baic structures in the area being tudied so tha, once mastered, the student is asily ble to build p his r her knowledge bas. This sectin also points out stucture on which exminers have repeatedly ased quetions. Basc Clincal Antomy: Ths secton proides bsic inormatin on gross aatomic structres tat are of clinical mportace. Nuerous xample of nomal rdiograhs, CT scans, MRI studies, and soograms are alo provded. abeled photogaphs o crosssectioal anaomy of the head, nek, and trunk are icluded to stiulate tudent to thnk in erms o thre-dimenional natomy which is so mportant in the interpretation o imaging stuies. urface Anatomy: This ection provids surfce lanmarks f impotant aatomic structures, many o which are loated sme disance bneath the skin. This secton is important because most prcticing medial peronnel seldo exploe tisses to ny deph beneth the skin. Photogaphs o livig subjcts hae been used etensivly. Clinical Proble Solvig: Examples of clinicl case are gven at the end of each chater. Ech is followed by ultipl-choic questons. Aswers o the roblem are iven a the ed of the section. Review uestios: The prpose f the questions is threefold: to ocus atentio on aras of importance, o enabe studnts to assess their reas o weaknss, ad to povide a form of sel-evalution fr quesions aked uner exminatin condtions. Some f the uestios are entere aroun a clnical roblem that rquires an antomic nswer. Solutions to the problems are prvided t the nd of he secion.

To assist in the quick nderstnding of anatomic facts, the book is hevily ilustraed. Mot figures have been kept simple, and coor has been ued extnsivel. Illutratios summrizing the nrve an blood supply of regions hve bee retaied, as have oerviews of the distribution of cranial nrves. R. S S. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

1.5 Acknowledgments I a greaty indeted to many faculty member of th Depatment f Radilogy a the Gorge Washinton Unversit Schoo of Mdicie and Health Sciencs for he loa of th radioraphs, computd tomograph (CT) cans, nd magnetic resonance imaging (MR) that have een reroduce in diferent sectios of tis boo. I am also gratefu to D. Caro Lee, r. Goron Sze and D. Robet Smit of th Depatment f Radilogy a Yale Univerity Meical Cnter fr suppying xample of mmmogras, CT cans o the vrtebra colum, and MRIs of the limbs. My special thanks ar owed o Dr. ichael Remetz of the Department of Cardology t Yale for prviding exampls of cronary arterograms My special thanks are owd to Lrry Clrk, wh, as a senio techncian in the Department of natomy at Geoge Wasington University, greatl assised me n the reparaion of anatomc spcimens for photograhy and for th prepaation of plastinated specmens o many ifferet orgas. His enthusasm fo the mny prjects as conagious and greatly helped in the final poductin of utstaning spcimens many f whic are ilustrated in the text. I ish also to express my sincere thnks to Terry Dolan, Virginia Childs, Myra Feldman, and Ira Grunther for prparatin of te artork.

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snell Finally, I ish to expres my dep gratitude to the staff of Lippncott illiam & Wilkins for heir geat hep and suppor in th prepaation f this new edtion. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

2. 1. Introduction A 65-year-old man ws ittd to the emergenc departent complaining of the suddn onset f a sevee crushig pain er the font of te chest preading down the left arm nd up into the neck an jaw. On questionng, he sid that h had had several ttacks f pain before and hat they had alwa occurre when he was climng stairs or diging in te garden Previousy, he fond that he discmfort disappeared ith rest after abut 5 mintes. On is occaion, the pain was more sevre and hd occurre spontanously whle he ws sittin in a chir; the pin had nt disappared. The iniial episdes of pin were ngina, a form of ardiac pin that ccurs on exertion and disppears on rest; it is caused by narrowing of the cronary ateries so that th cardiac uscle hs insuffcient blod. The patient ha now exprienced yocardia infarction, in wich the oronary lood flow is suddly reducd or stpped and the cardic muscle degeneraes or dis. Myocarial infrction i the majr cause o death i industralized ntions. learly, knowledge f the blod suppl to the hart and he arranement o the coroary arteies is o paramoun importace in maing the diagnosi and treting this patient.

Chapte Objecties 

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It is esential hat studets undertand th ued for dscribing the struure and function of different regins of grss anatoy. Witho these trms, it s impossible to dscribe i a meanigful way the compsition o the bod. Moreove, the pysician eeds thes s that antomic abormalities found o clinicl examintion of patient can be acurately ecorded. This hapter also introduces som of the asic strctures tat compoe the boy, such s skin, ascia, mcles, bnes, and blood vesels.

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Bsic Anatmy Anatmy is the sciece of the structure and funtion of he body. Cnical atomy s the sudy of te macrosopic strcture an functio of the ody as i relate to the ractice of medicin and othr health sciences Basic anatomy s the tudy of the minmal amout of anaomy consstent wih the unerstanding of th overall structur and function of te body.

Descritive Anaomic Ters 5

snell It is imporant for edical prsonnel o have a sound kowledge and understanding o the basc anatomc . With the aid of medical dictionar, you wil find tat understanding aatomic erminoloy greatl assists you in th learning process. Th accurate use of aatomic erms b medical personnl enabls them to communiate with their coleagues oth nationally and internaionally. Without natomic trms, one cannot acurately discuss or record the abnomal funcions of oints, t actions of muscls, the lteration of positon of orans, or he exact ocation f swelligs or tuors.

Tems Relatd to Postion All desciptions f the humn body ae based n the asumption that the person is standing erect, wth the uper limb by the ides and the face and palm of the ands direted forwrd (Fig. 1-). Ths is the so-calle aatomic psition The varous part of the ody are hen descibed in rlation t certain imaginar planes.

Meian Sagital Plan Thi is a veical plae in through the centr of the body, divding it nto equa right and left hves (Fig. 1-1). Panes sitated to oe or the other sie of the edian plane and prallel t it are ermed paramdian. structure situatd nearer to the mdian plan of the ody than another said to be medial to the ther. Siilarly, a structu that lis farthe away frm the meian plane than anoher is sid to be laeral o the other.

Coroal Plane These planes re imagiary vertcal plans at right angles o the meian plan (ig. 1-1).

Horiontal, o Transvese, Plans Tese plans are at right anles to both the median and the cornal plans (Fig. 1-). he anerior and posteior ar used to indicate the fron and back of the bdy, respectively Fi. 1-1. To decribe the relationhip of to structres, one is said o be anerior or posterio to the ther insfar as it is close to the anterior or posteror body urface. In describing the and, the palmar and doral surfaes are used in lace of nterior nd posteior, and in descrbing the oot, the plantar and dosal surfces ar used intead of ower and upper sufaces (Fig. 1-1). The proxmal ad istal describ the reltive distnces fro the roos of the limbs; for examp, the ar is proxmal to te forearm and the and is dstal to the forem.

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Fiure 1-1 Anatomc sed in relation to position Note th the subjects are standing in the anatomic psition.

Th supeficial and deep denote he relative distaces of sructures from the surface f the boy, and te suprior ad nferior denote levels rlatively high or low with rference o the uper and lwer ends of the body. P.3

Te intrnal nd external are sed to describe th relativ distanc of a stucture fom the enter of an organ or cavity for exaple, the internal carotid rtery is found inide the ranial cvity and the extenal caroid arter is foun outside the cranal cavit. The tem psilaterl refs to th same sid of the ody; for example, the left and and eft foot are ipsiateral. Conralatera refrs to oppsite sids of the body; fo example the left biceps rachii mscle and the righ rectus emoris mscle are ontralatral.

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snell The supne postion of he body s lying n the bak. The pron posiion is lyng face ownward.

Tems Relatd to Movment A site where two or more ones com together is known as a t. Some ts hve no moement (stures of the skul), some hve only slight mvement (uperior tibiofibulr t) and som are frely movale (shouder ). Flexin is a movement that taes place in a sagttal plae. For exmple, flxion of he elbow t aproximats the anerior surace of te forear to the aterior urface o the arm It is uually an anterior movement but it s occasonally poterior, s in the case of he knee oint (Fig. -2). Extnsion means strightenin the joit and usally tak place i a posteior diretion (Fig. -2). Lateral flexn is movement of the runk in he coronal plane (Fig 1-3) Abuction is a moement of a limb away from te midlin of the ody in te coronal plane (Fig. 1-2). Adducion is a movemet of a lmb toward the body in the cronal plne (Fig. 1-). In the fingrs and tes, abdution is pplied t th spreading of thse structures an adduction is appled to th drawing together of these structres (Fig. 1-3). Te movemets of th thumb (Fig 1-3), which are a little more complicated are desribed on page 517 Rotation is the term appled to th movemen of a pat of the body aroud its log axis. Medial rotaton is the moveent that esults i the antrior surace of th part faing medilly. Latera rotatio is te movemet that rsults in the anteror surfae of th part faing lateally. Proation of the forerm is medial otation f the foearm in uch a maner that the palm of the hnd faces posteriory (Fig. 1-). Supinaion of te forear is a ateral P.

rotatin of the forearm rom the ronated osition o that th palm of the hand comes to face antriorly (Fig 1-3).

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Figure 12 Som anatomic sed in rlation to movement Note th differece between flexion of the ebow and hat of the knee.

Circuduction is the ombination in seuence of the movements of lexion, xtension abductin, and aduction Fi. 1-2) 9

snell Prtraction is to ove forwrd; retraction is to move ackward used to describe the forward and bacward movment of he jaw a the temoromandibular s). Invrsion is the movement of the foot so that he sole faces in a meial diretion (Fig. -3). Evesion s the opposite movement of he foot o that te sole fces in a lateral irection (Fg. 1-3.

Baic Strucures kin Th skin is divided nto two arts: th superfical part the epideris, ad the deep part, he dermis (Fg. 1-4). The eidermis is a stratified ephelium wose cell become lattened as P.5

hey matre and rse to the surface. On the plms of te hands nd the oles of te feet, he epidemis is etremely hick, to withstand the wea and tea that occurs in thse regios. In oter areas of the bdy, for example, n the anerior suface of he arm ad forearm it is hin. The dermis is composed of dense connectie tissue containin many bood vessls, lymphatic vessls, and erves. I shows cnsiderabl variaton in thckness i differe parts o the bod, tendin to be thinner on the anteior than on the pterior srface. I is thiner in woen than n men. Te dermis of the sin is conected o the uderlying deep fasia or boes by th superficial fascia, oterwise nown as subutaneous tissue.

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igure 1- Addiional antomic tems used n relatin to movement.

The skin ov ts always fods in th same plce, the ski creases (Fig. 1-). At these sies, the skin is thinner thn elsewhre and i firmly tethered to underying strutures by strong bnds of fbrous tisue. Te appendges of te skin ae the nails hair folicles, ebaceous glands, and swea glands. Th ils ae keratiized plaes on th dorsal urfaces f the tis of the ingers ad toes. he proxial edge f the plte is the rot of th nail Fi. 1-5). With th exceptin of the distal ege of th plate, he nail s surrouned and oerlapped by folds of skin known as nal folds. The suface of kin coveed by th nail is the nail be (Fig. 1-).

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snell Hairs grow out of follicles, which ar invagintions of the epidemis into the derms (Fig. 1-4). The ollicles lie obliuely to the skin urface, nd their expanded xtremitis, called hir bulbs, penetate to te deeper part of he P.6

demis. Each hair bul is concve at it end, an the conavity is occupied by vascuar connetive tisue calle hir papila. A bnd of smoth musce, the arretor pili, connets the udersurfae of the follicle to the sperficia part of the dermi (Fg. 1-4. The mucle is innrvated by sympathetc nerve fbers, and its contraction cases the hir to mov into a re verticl positin; it alo compreses the seaceous glnd and causes it to extrude me of it secretio. The pul of the mscle also causes dipling of he skin urface, s-called gooeflesh Hairs a distriuted in vrious nubers over the whol suface of he body except on the lps, the palms of te hands, the sides of the figers, th glans peis and cltoris, te labia mnora and he interl surfac of the bia major, and the oles and sides of he feet ad the sids of th toes.

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Figure 1-4 Gneral stucture of the ski and its relatinship to the sperficia fasci Note tht hair fllicles extend down into te deeper part of the dermi or even ito the suerficial ascia, wereas swet glands extend deeply nto the superfical fasci.

Sebaceos glands pour thir secrtion, the sebum, onto the shafts of th hairs as they pas up throuh the neks of the follicle. They ar situated on the slping undsurface f the follicles and lie withi the derms (Fig. 1-4). Sebum is an oiy materia that hels preserv the flexbility of the emergng hair It also oils the surface eidermis aound the mouth of the folicle. Sweat glads ae long, spiral, ubular gands disributed ver the srface of the body except on the rd margin of the ips, the nail beds, and the glans peis and litoris Fi. 1-4. These lands exend thrugh

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snell the full thicess of te dermis and ther extremties may lie in the superfcial fasia. The weat glads are therefore te most eeply peetrating structur of all he epidemal appedages. P7

Figur 1-5 The various skin creases on the palmr surfac of the and and he anterior surface of the wrist jont. The elationsip of th nail to other stuctures f the figer is also shown

Clinicl Notes Skin Ifections The nil folds hair folicles, nd sebacous glan are comon site for entance int the undrlying tissues of athogeni organims such as Staphylooccus aueus. Ifection ccurring between he nail nd the nil fold i called pronychia. Infetion of te hair fllicle ad sebaceus gland s responible for the common oil. A cabuncle is a saphylocoal infecion of te superfcial fasia. It fequently occurs i the nae of the neck and usually sarts as n infecton of a air follcle or a group of hair folicles.

Sebaceos Cyst A sebaceou cyst is cause by obsruction f the mouth of a sebaceous duct and may be aused by damage rom a co or by ifection. It occur most frquently n the salp.

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Shck A ptient wh is in a state of shck i pale and exhibits goosefleh as a rsult of veractivty of th sympathetic systm, which causes vsoconstrction of the derma arteriles and ontractio of the arrector ili musces.

Skin Burns he depth of a burn determnes the ethod an rate of healing. A partial-ski-thicknes burn eals fro the cels of the hair folicles, sbaceous lands, a sweat lands as well as rom the ells at he edge f the burn. A burn that exends deeer than te sweat lands hels slowly and fro the edgs only, nd consierable cntracture will be aused by fibrous tissue. o speed p healing and reduce the inidence o contracure, a deep bur should be grafted

kin Grafting Ski graftin is o two main types: split-hickness grafting and full-hickness grafting In a slitthicness grat the grater part of the eidermis, including the tip of the ermal paillae, i removed from the donor sie and plced on the recipnt site. This leaes at th donor ste for rpair puroses the epiderma cells o the sids of the dermal paillae an the cels of th hair folicles ad sweat lands. A ull-thicness ski graft icludes bth the eidermis nd dermi and, to survive, equires apid estblishmen of a ne circultion witin it at the reciient site The donr site i usually covered with a slit-thickness graf. In cerain circmstances the fullthicknes graft is made in he form f a pedile graft, in which a flap f full-tickness sin is tuned and titched n position at the recipien site, laving th base of the flap with its lood supply intat at the donor sie. Later, when the new bloo supply o the graft has ben estabished, te base of the graf is cut cross. P.8

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Figure 16 Secion throgh the mddle of he right arm showing the arangement of the uperficil and dep fascia Note ho the fibous septa extend etween goups of uscles, ividing he arm ino fascia compartents.

Fasciae The fasciae f the body can be ivided ito two tpes—supericial and deep€”and li between the skin nd the uderlying muscles nd bones The supeficial fscia, or subcutaneous tssue, is a mixtur of loos areolar and adipose tissu that untes the ermis of the skin to the uderlying deep fasca (Fig. 1-6). In the scalp, the ba of the neck, the palms of the hand, and th soles of the fee, it conains numrous bunles of collagen fiers that hold th skin fily to th deeper tructure. In the eyelids, uricle f the ea, penis nd scrotm, and citoris, t is devoid of adiose tisue.

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igure 17 Extnsor retnaculum n the poterior surface of he wrist holding he underying tenons of te extensr muscle in posiion.

The dep fascia is a embranou layer o connectie tissue that invsts the uscles ad other eep structures (Fig. 1-6). In the nck, it frms welldefined layers that may pla an impotant roe in detrmining he path aken by athogenic organism during he spred of infction. n the thrax and bdomen, i is merey a thin film of areolar issue coering the muscles nd aponeroses. I the libs, it frms a deinite shath aroud the musles and ther stuctures, holding hem in pace. Fibrous septa extend fom the dep surfce of th membrane between the grous of musles, and in many places diide the nterior f the libs into compartmes (Fig. 1-). In he regio of ts, the dep fascia may be cnsideraby thickeed to for restraiing band called retnacula (Fig. 1-7). Their function is to hold underlying tendos i positio or to srve as plleys around which the tenons may ove.

Clinicl Notes Fascie and Inection A knowedge of he arranement of the deep fasciae ften heps explan the pat taken b an inftion whe it spreds from ts primry site. In the nek, for eample, te variou fascial planes eplain how infection can extend fro the regn of the floor of the mouth to te larynx

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Mscle Te three ypes of uscle ar skeleta, smooth, and carac.

Skeetal Musle Skeletal mucles prouce the movements of the skeleton; tey are smetimes alled volunary musces ad are made up of sriped mucle fibes. A skeetal musle has to or mor attachmnts. The attachmet that mves the east is eferred o as the oigin, nd the oe that mves the ost, the inertion (Fg. 1-8). Unde varying ircumstaces the egree of mobility of the atachment may be reversed; herefore the ters rigin and insertin are interchaneable. The fleshy prt of th muscle is referrd to as ts belly Fi. 1-8. The ends of a mcle are ttached to bones, cartilag, or ligments by cords of ibrous tssue caled tendons (Fig. 1-9). Occaionally, flattene muscles are attaced by a hin but trong shet of fibous tisse called an aponeurois (Fig 19) A raphe is an iterdigittion of he tendinus ends f fibers of flat scles (Fig. 1-9).

nternal tructure of Skeleal Muscl Te muscle fibers ae bound tgether wth delicte areoar tissu, which is condensd on the surface o form a fibrous envelope the epimysim. Th individual fibers of a musle are aranged eiher paralel or oblique to the long xis of te P.9

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musle (Fig. 1-1). Bcause a scle shotens by ne third to one hlf its reting lenth when it contrcts, it ollows tat muscls whose fbers run parallel to the ne of pul will bing about a greate degree f moveme compare with tose whos fibers un obliqly. Examles of mscles wih paralel fer arranements (Fig 1-10 are the sternoclidomastod, the rctus abdoinis, an the sarorius.

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Figure -8 Oriin, inserion, and belly of te gastrocemius musle.

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Figre 1-9 Examples f (A) a tndon, (B an aponerosis, ad (C) a rahe.

Musces whose bers run obliquely to the lie of pull are refered to as penate muscle (the resemble a feathe) (Fig. 1-1). A unipennate muscle s one in which the tendon lis along oe side

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snell of the musce and th muscle fibers obliquel to it (.g., extnsor digtorum lonus). A biennate mscle i one in wich the tedon lie in the enter of he muscle and the uscle fiers to it from tw sides (.g., recus femors). A multpennate muscle may be aranged a a serie of bipenate musles lying alongside one ather (e.g., acromal fiber of the eltoid) r may hae the tedon lyig within its centr and the muscle fibers ing to i from al sides, onverging as they o (e.g., tbialis aterior). For a gven volue of musce substane, pennat muscles have many more fiers compaed to mucles with arallel fber arrngements nd are threfore moe powerfu; in othe words, range of ovement has been sacrificd for strength.

Figue 1-10 Differet forms f the inernal stucture o skeletal muscle. relaxed and a cntracted

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muscle ae also sown; not how the muscle fbers, on contracion, shoren by o third t one haf of thei resting length. Note als how the muscle sells.

Seletal Mscle Acton Al movemets are te result of the cordinate action of many uscles. owever, o undersand a mucle's acion it i necessry to stdy it inividuall. A mscle may work in he folloing four ways: 

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Pri mover: A musle is a rime movr when i is the hief musle or meer of a chief goup of mucles resonsible for a prticular movement For exmple, th quadris femoris is a prime mover in the ovement f extening the nee t (ig. 1-11). Antaonist: Any mucle that opposes he action of the prime mover is an atagonis For exmple, the biceps emoris oposes th action f the qudriceps femoris hen the nee is exteded (Fig. 111). efore a rime mover can cotract, te antagoist musce must b equall relaxed this is brought bout by ervous reflex inhibition. P.1

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Figure 1-11 Dfferent ypes of uscle acion. A. uadricep femoris extendin the kne as a

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prme mover and bis femors acting as an anagonist. B. Biceps femoris lexing te knee a a prime mover, ad quadrieps actig as an ntagonis. . Musces aroun shoulde girdle ixing th scapula so that ovement f abduction can tae place t the shulder jont. D. lexor an extensor muscles f the crpus actng as syergists nd stablizing te carpus so that ong flexr and exensor tedons can flex and extend te finger.





Fixatr: A fixator contracts isometrically (i.., contrction increases te tone but does ot in itself prode movemet) to stbilize te origin of the rime movr so tha it can ct efficently. Fr example, the muscles attaching the shoulr girdle to the trunk contract as ixators to allow he deltod to act on the shoulder oint (Fig. -11). Synerist: n many ocations in the bdy the pime move muscle crosses several jnts befe it reaches the oint at hich its main acton takes place. o preven unwante movemens in an intermedite t, groups f muscl called synergists contrac and stailize th intermeiate jonts. For example, the flexr and exensor P.2

muscles of the arpus cotract to fix the rist joit, and tis allow the lon flexor and extnsor musles of te finger to work efficiently (Fig. 1-1). These trms are pplied t the acton of a articula muscle during a particulr movemet; many uscles cn act as a prime mover, a antagonst, a fiator, or a synergst, depending on the movement to b accomplshed. uscles cn even cntract pradoxicaly, for xample, when the biceps bachii, a flexor o the elbw t, contract and cotrols th rate of extensio of the lbow whe the trieps bracii s.

Nrve Suppy of Skeetal Muscle he nerve trunk to a muscle is a mixd nerve, about 60 is motr and 40 is sensry, and t also cntains some sympathetic aonomic fbers. Th nerve eters the muscle a about te midpoit on it deep suface, ofen near he margi; the plce of entrance is known a the motor oint. his arragement llows th muse to moe with minimum interference with the nerve trnk.

Naming of Skletal Mucles Indivdual musles are named accrding to their shape, size number f heads r bellie, positin, depth attachmnts, or actions. ome examles of mscle nams are shwn in Table 1-1.

Clinical Notes Muscl Tone

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snell Determintion of he tone f a musce is an mportant clinical xaminatin. If a uscle is faccid, then eiher the fferent, the effeent, or oth neurns involed in th refle arc necessary for the prouction o muscle tone have een intrrupted. For examle, if the nerve unk to muscle i severed both nurons wil have ben interupted. I poliomyelitis has involved the motr anterir horn clls at a level in the spinl cord tat innevates th muscle, the effeent moto neurons will not function If, conversely, the muscl is foun to be hpertonic the posibility exists o a lesion involvig higher otor neuons in te spinal cord or brain.

Muscle Atachments The mportanc of knowng the min attacments of all the major mucles of he body eed not e emphaszed. Onl with such knowledge is it possibl to undestand the normal ad abnorml action of indvidual mscles or muscle goups. Ho can one even attmpt to analyze, fr exampl, the abormal gat of a ptient witout this informaton?

Muscle hape an Form The genral shae and form of musles shoud also b noted, since a pralyzed muscle or one that is not usd (such s occurs when a lmb is imobilized in a cast) uickly arophies nd changs shape In the ase of t limbs, t is alway worth rmemberin that a uscle on he opposte side f the boy can be used fo comparison.

Smooth Mscle mooth mucle conssts of lng, spinle-shape cells losely aranged in bundles r sheets In the ubes of he body t provids the motie power fr propelling the cotents though the lumen. In the digestive systm it also causes te ingested food to e thorougly mixed ith the digestive uices. A ave of cotraction f the crcularly rranged fiers s along t tube, mlking the contents onward. B their cotraction the lonitudinal fibers pul the wal of the tbe proxially over the contnts. Thi method f propuion is rferred t as peristalsis. In store organs such as he urinay bladder and the uterus, he fiber are irrgularly rranged nd interlced wit one anther. Ther contration is low and ustained and bring about xpulsion of the cntents o the orgns. In te walls of the blod vesses the smoth musce fibers are arraned circuarly and serve to modify he calib of the umen. epending on the ogan, smoth muscl fibers ay be mad to conract by ocal strtching o the fibrs, by nrve impulses from autonomi nerves, or by homonal stmulation.

Cardac Muscl Cardiac muscle consist of strited musce fibers that brnch and uite with each othr. It foms the mocardium of the hart. Its fibers tnd to be arranged in whorl and spials, and hey have the proerty of pontaneos and rhthmic cotraction. Specialied cardic muscl fibers frm the concting system of te heart.

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snell Cardiac uscle is supplied by autonomic nerv fibers tat termiate in te nodes f the coducting system and in the ocardium

Cliical Notes Necrosis o Cardiac Muscle The crdiac mucle receives its blood supply from te coronry arteres. A suden bloc of one f the large branchs of a oronary rtery wil inevitably lead o necross of the cardiac mscle an often o the death of the patient.

ts A site here two or more ones com togethe whether or not mvement ocurs beteen them, is calle a t ts are clasified acording t the tisses that ie betwen the bnes: fibous s, cartiaginous oints, and synovia ts.

Firous Joits The articulating surfces of te bones re e by fibrus tissu (ig. 1-12), and thus ver little ovement s possibe. The stures of the vault of the kull and the inferior tibioibular jints are examples of fibros t. P.13

Table 11 Namng of Skletal Musclesa

Name

Shap Sze

Deltoid

Trianular

Teres

Round

Recus

Saight

Number f Heads r Bellie Positioepth Attacments Actins

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Major

Lrge

Latissmus

Bradest

Longisimus

Longest

Bis

wo heads

Qadriceps

Four eads

Digastic

Two belies

Pectorlis

Of te chest

Supaspinatu

Above spin of scapa

Brachi

Of the rm

rofundus

Dee

uperficilis

Superfcial

Extenus

Eternal

rom sterum and cavicle t mastoid process

Strnocleidomastoid

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From coracoid process o arm

Coraobrachiais

Extenso

Extend

Flexo

Flex

Constrictor

onstrict

a

Thse name are comonly usd in comination, for exaple, fleor polliis longs (long flexor o the thub).

Cartilaginou ts Cartlaginous ts cn be diided int two typs: primay and seondary. A primary artilagnous joit is ne in wich the bones ar united y a plate or bar of hyalie cartilage. Thus, the unin betwee the epiphis an the diaphsis f a growng bone and that tween th first rb and th manubrim stern are examples of ch a joit. No moement is possible A secodary carilaginou t is one in which the bones are unied by a late of ibrocartlage and the artcular sufaces of the bone are covred by a thin layr of hyline carilage. Eamples are the ts betwen the vrtebral odies (Fig 1-12 and the syphysis pbis. small aount of ovement s possible.

Synovil ts The aticular urfaces f the boes are cvered by a thin lyer of haline cailage separated b a t cavity (Fig 1-12. This arangemen permits a great degree of freedom of movemen. The city of e t is lined by synovial membrane, whic extends from the margins f one aricular srface to those of the othr. The sovial membrane is protecte on the utside b a tough fibrous membrane referred to as th sule of the oint. Th articul surfacs are lubicated y a viscus flui called syovial flid, hich is roduced y the snovial membrane. In certan synovil ts for emple, i the kne t, iscs or edges of fibrocarilage ar interpsed betwen the aticular urfaces f the boes. Thes are referred to as articula discs. Fatt pads are found in some syovial jonts lyin between the synoial membane and he fibros capsue or bone. xamples are foun in the ip (Fig. 1-12) and knee ts.

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snell Te degree of movemnt in a ynovial oint is imited by the shae of the bones paticipatig in the t, te coming together of adjacent anatoic strucures (e.., the tigh agaist the anterior bdominal wall on lexing t hip joit), and he presece of fious ligamets uniing the ones. Mot ligaments lie ouside the t casule, bu in the ee some mportant ligament, the crucite ligamnts, ie withi the capule (Fig 1-13) Synovial ts can be classifid accoring to th arrangment of he articlar surfces and he types of movemnt that are possile. 



Plae ts In lane joits, the pposed aticular urfaces re flat r almost flat, and this permits the bones t slide o one another. Examples of hese joits are te sternolavicula and acrmioclaviular joits (Fig. 1-4). Hinge ts: Hinge t resemble the hinge on a door, so that flexion and extension movement are posible. Exmples of these joits are te elbow knee, ad ankle oints (Fig. 114). P.14

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Figue 1-12 Examples of three types of ts. A. Fibrou t (oronal sture of kull).B. Cartilagious (t etween to lumbar ertebral bodies). C. Synoval t (hip joit).

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

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Pivot ts: In pivt t, a central bony pivot is surrouned by a bony–lgamentous ring (Fig 1-14) and rottion is he only movement pssible. he atlanoaxial ad superir radioulnar t are good examples. Condyloi ts: Condyoid s have to distint convex surfaces that artculate with two ncave srfaces. The movemets of flxion, extension, aduction, and addction ar possibl together with a small amout of rottion. Te metacarpophalngeal jonts or kuckle ts are god exampes (Fig. 1-4). Elipsoid jints: In ellisoid joits, an eliptical convex aticular urface fts into an ellipical conave artilar surfce. The ovements of flexin, extesion, abduction, ad adducton can tke place but rottion is impossibl. The wrst t is a goo example (Fg. 1-14). P.15

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Figure 113 Th three min factos responsble for tabilizing a t . Shap of artiular suraces. B. Ligaments . Musc tone.

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

Saddle ts: In sadle t, the aricular srfaces ae reciprcally cocavoconvx and rsemble a saddle on a horse' back. Tese s permit flexion, extensin, abduction, addution, an rotatio. The bet exampl of this type of oint is he carpoetacarpa t o the thub (Fig. 1-1). Ball-ad-socket ts: In bal-and-soket t, a ballshaped had of on bone fit into a socketle concavity of anther. Ths arrangement permts free movement, including flexio, extenson, abdution, aduction, mdial roation, lteral roation, ad circumuction. The shouldr and hi ts are good examples f this tpe of jont (Fig. 1-4).

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Stabilty of Jonts Te stabilty of a oint depnds on tree main factors: th shape, size, and arrngement of the rticular surfaces the lgaments; and the tone of he musces aroun the jont.

Aticular urfacs The balland-socket arranement o the hip t (Fig. -13) and the mortise rrangemet of the anle are goo example of how bone shape plys an imortant rle in jont sability. Other examples f ts however in whic the shae of th bones cntrbutes litle or nothing o the stbility iclude the acromioclaviculr t, the calcaneocubid t and the knee joit.

Ligamets Fibrus ligaents preven excessie movemet in a t (ig. 1-13), bu if the tress i continued fr an excssively ong perid, then fibous ligaents strtch. For example, the ligaments of the jints beween the bones frming te arches of the feet ill not by themslves the weight of the body. Should the ton of the uscles tat norally the arches bcome impired by fatigue, then the ligamens will stretch nd the aches wil collaps, producing flat feet. Elasic ligamnts, conversely, retun to ther original lengt after sretchin The elastic lgaments of the aditory ssicles lay an ative par in ing he ts and assisting in the retrn of th bones to their original positio after mvement.

Musce Tone In mos ts, muscle tone is the major actor cntrollin stabiliy. For eample, he musce tone o the short musces aroun the shulder jont keeps the hemipherical head of the humus in te shallw glenoi cavity f the sula. Wihout th action of these muscles, very lttle fore would P.16

be required to disloate this t. Te knee jint is ery unstble witout the tonic acivity of the quadiceps feoris musle. The oints etween te small bones foming the arches f the fet are lrgely spported y the toe of the muscles f the le, whose endons re inseted into the bone of the fee (ig. 1-13).

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Figre 1-14 Exampes of diferent tpes of ynovial oints. A. Plane oints (sernoclavicular ad acromiclaviclar s). B. Hnge joit (elbow t). C. Pivo t (tlantoaxal t). D. Codyloid jint (meacarpophlangeal oint). E Ellipsod t wrist jint). F. Saddle oint (capometacapal of the humb). G. Ball-ad-socket t (hi t).

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Neve Suppl of ts The capsue and liaments rceive an abudant senory nere suply. A sensory neve supplying a jint also supplies the muscles movng the jint and the skin overlyin the inrtions f these muscles a fact that has been codified as Hiltn's law.

Clinial Notes Exaination f ts When examinig a patint, the linicia should ssess te normal range o movemen of al ts. When te bones f a are no longer i their nrmal antomic relationshp with one anothr, then the joit is sai to be dilocated. Some ts ae particularly suseptible o disloction because of ack of upport b ligamens, the por shape of the aticular urfaces or the absence f adequae muscuar suppot. The soulder t, emporomandibular t, and acromoclavicuar t are goo exampls. Dislcation o the hip is usually congenital, being cause by inaequate dvelopmen of the socket tat normlly hold the head of the femur firmly in psition. The presence of cartilginous dscs witin t, especially weightbeaing s, as i the ca of the knee, maes them particulrly susceptible o injury in sports. Durin a rapid movement the dis loses its norma relatiship to he bones and becoes crushd betwen the weghtbearig surfacs. In ctain dieases of he nervos system (e.g., syingomyela), he sensation of pain in a t is lost. Ths means at the warning snsations of pain elt when a t moves bend the nrmal range of mvement ae not experienced. This pheomenon rsults in the desruction f the jont. nowledge of the cassificaion of jints is f great value bcause, or exampe, certin diseaes affect only crtain tyes of jints. Gonooccal arhritis affect large sovial ts suc as the nkle, ebow, or rist, wereas tubeculous athritis also afects synovial ts and may sta in the synovial membrane or in th bone. that more tha one joit may rceive th same nrve suppy. For eample, te hip ad knee jints are both supplied by the obtrator nrve. Thu, a patnt with disease imited t one of these jints may experiene pain n both. P.17

Ligamens A lgament is a cor or band of connetive tisue uniing two tructure. Commoly foun in assoiation with s, ligaents are of tw types. Most are compose of dens bundles of colagen fibers and are unsretchabl under nrmal conditions e.g., te iliofeoral ligment of e hip jont and te collatral ligaents of the elbo t). The secod type is composed largely f elasti tissue and can herefore

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snell regain is origial lengt after sretching (e.g., he ligamntum flaum of th vertebrl column and the calcaneonvicular igament f the fot).

Clnical Noes Dmage to igaments ligaments are ver prone t excessie stretcing and even teang and rpture. I possibl, the aposing daaged sufaces of the ligant are bought toether by positionng and mmobilizig the jnt. In severe injries, sugical aproximatin of the cut ends may be rquired. he blood clot at th damaged site is invaded y blood essels ad fibroblsts. The fibroblats lay dwn new ollagen d elastic fibers, which bcome orinted along the lines of mhanical stress.

Bursa A bura is a lubricating device cnsisting of a cloed fibrus sac led with delicat smooth embrane. Its wall are serated by a film o viscous fluid. Brsae are found wheever tenons rub against ones, liaments, r other endons. hey are commonly fund cloe to joits where the skin rubs aganst undelying bony structures, fo example, the preptellar brsa (Fig. 1-15). Occasionlly, the cavity of a bursa communiates wit the cavty of a synovial t. Fr exampl, the suprapatellar bursa communicats with he knee oint (Fig. 1-15) nd the sbscapulais bursa communictes with the shouder t.

Sovial Sath synovia sheath s a tubular bursa that surounds a tendon. The tendon invaginaes the brsa from one sid so that he tendn become suspendd within the burs by a mesotndon Fig. 1-15. The msotendon enables lood vesels to eter the endon alng its ourse. In certain situation, when e range f movemet is extnsive, he mesotndon disppears o remains in the frm of narow threads, the vicula (.g., the long flor tendons of the fingers nd toes) Synovial sheaths ccur whee tendon uner ligaents and retinacua and thrugh ossfibrous tunnels. Their function is to reduc frictio between the tendn and it surrouning strctures.

Clincal Note Trauma and Infection o Bursae nd Synoval Sheats Bursae and synoial sheahs are commonly the site o traumac or infectious dsease. For example, the exensor tedon sheths of te hand my become inflame after excessive r unaccutomed ue; an inlammatio of the repatellr bursa ay occur as the rsult of rauma fom repeated kneelig on a hrd surfae. P.18

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Figure -15 A Four brsae relted to te front f the kne t. Note tha the surapatellr bursa ommunicates with the cavity of the t. B. ynovial heaths around the long tenons of te finger. C. How tendon ndents snovial seath durng develpment, ad how blod vesses reach the tendon through the mesoendon.

Bloo Vessels 37

snell Blood essels ae of thre types: arteries veins, nd capilaries (Fig. 1-16). Arteries transort bloo from th heart ad distribute it to the varius tissus of the body by eans of heir branches (Figs. 1-16 ad -17). The smalest arteies, <0.1 mm n diametr, are referred to as arterioles. The ng of banches o arterie is calld an anasomosis. Arteris do not have vales. natomic nd arteres (Fig. 1-17) are vessls whose terminal ranches o not anstomose with brahes of ateries spplying djacent reas. Functonal end arteries are essels wose termnal branhes do aastomose with thoe of adacent arteries, bu the calber of te anastoosis is sufficiet to kep the tisue aliv should oe of the arteries become bocked. Vein are essels tat transort bloo back to the hear; many o them posess vales. The mallest eins are called venues (Fig. 1-17). The smaler veins or tributaies, nite to orm largr veins, which comonly jon with oe anothe to form veous plexses. Mdium-size deep arteries are ofte accompaied by two veins, ne on eah side, alled venae comitants. Veins leaving the gastroinestinal tract do ot go diectly to the hear but conerge on he portal vein; his vein enters te liver nd break up agai into vens of dminishing size, wch ultimtely capillary-like vssels, trmed sinusods, i the livr (Fig. 1-17). A portl system is ths a systm of vesels interosed beteen two apillary beds. illarie are microscoic vesses in the form of network connectig the arerioles to th venule (Fig. -17) Sinusois resmble caillaries in that they are thin-waled blood vessels, but the have a irregulr cross iameter nd are wder than capillaies. The are fond in th bone marrow, th spleen, the livr, and sme endorine gands. In some aras of the bdy, pricipally he tips of the fngers and oes, direct connctions ccur between the arterie and veins withut the ntervention of apillaries. The sites o such cnnectins are referre to as areriovenous anasomoses (Fig. 1-7).

linical otes Disease of Blood Vessels Diseses of bood vessls are cmmon. The surfac anatom of the ain arteries, espially tose of te limbs, is discssed in the appropiate secions of his book The collaeral cirulation of mot large rteries hould be understoo, and a istinctin should be made between natomic end arteries and fuctional nd arteres. All large arteies that cross or a are liale to b kinked uring moements o the joit. Howevr, the dstal flo of blood is not interruptd becaus an adeqate anasomosis i usually between branches of the artery tht arise th proximal and dstal to the . The alernative blood chnnels, wch dilat under tese cirumstance, form the collateal circuation. Kowledge f the eistence ad positin of suc a circation ma be of vtal impotance sould it e necessry to ti off a lrge artey that hs been damaged by trauma o disease Coronar arterie are funtional ed arteris, and i they become bloed by disease (cronary arterial occlusion is common) the cadiac musle normaly suplied by hat artey will rceive isufficiet blood 38

snell nd undero necross. Blockge of a arge coronary arry resuls in the death of the patint. (See the clinica example at th beginnig of thi chapter.) P.1

Figure 1-16 eneral pan of th blood vscular sstem.

P.20

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igure 117 Different types of bood vesels and heir metods of nion. A. Anastomois betwen the banches o the suprior mesnteric artery. B. capillay netwok and an arteriovenous anastomosis. C. Anatoic end aery and functiona end artry. D. A portal sstem. E. Structure of the bicuspid vlve in a vein.

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Lmphatic ystem The lymhatic sytem conssts of lmphatic issues an lmphatic vessels Fig. 1-8). Lymphatc tissue are type o connectve tissu that cotains large number of lympocytes. Lymphatc tissue is organzed into the follwing orgns or stuctures: the thyus, the ymph nodes, the sleen, an the lymphatic noles. Lyphatic tssue is ssential for the mmunologc defenss of the body aginst baceria and viruses. Lymhatic vesels re tubes that asist the ardiovasular sysem in th removal of tissue fluid from th tissue paces of the body the vesels then return te fluid to P.21

t blood The lymphatic system is essentially a drainage system and thee is no circulaton. Lympatic vesels are ound in ll tissus and ogans of he body xcept the central nervous system, the eyebal the internal ear, the epdermis o the skin, the cartilage, nd the bne. Lymp is te name gven to tssue flud once it has entered a lymphatic vssel. Lymph capillaies ae a netwrk of fie vesses that dain lymph from th tissues The caillaries are in trn draind by smll lymph vessels, which unie to fom large ymph vesels. Lymh vessel have a eaded apearance because f the prence of umerous valves along their course. Befor lymph i returne to the loodstrem, it pases throgh at lest one lymp node and often through several. The lymp vessels that carry lymph to a lymph node ar referre to as affeent vesels (Fig. 1-18); those tt transprt it awy from a node are eferent vessels. The lymp reaches the bloostream a the root of the neck by large lymp vessels called te ight lymhatic dut and the thoraci duct Fig. 118).

Cliical Nots Disease of the Lymphatic Systm Te lymphaic syste is ofte deemphaized by natomist on the grounds hat it is difficult to see on a cadaver. Hower, it is of vital importance to edical prsonnel, since lyph nodes may swel as the result o metastaes, or primary tumor. For is reaso, the lmphatic rainage f all maor organ of the ody, incuding th skin, hould be known. A patient may complain of a swelling produce by the enlargemnt of a lymph node A physician must know th areas of the body that drain lymph to a paricular nde if he or she i to be ale to fnd the pimary sie of the disease. Often th patient ignores he primry disease, which may be a small, panless cncer of he skin. Coversely, the patint may cmplain o a painf ulcer f the togue, for example, and the hysician must kno the lymh drainge of th tongue o be able to detrmine whther the disease has spead beond the limits o the ongue.

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ervous Sstem The nerous systm is divded int two mai parts: the centrl nervou system, which consist of the rain an spinl cord, and the periphral nervus syste, whch consits of 12 pairs of cranial nerves nd 31 pars of spnal neres and teir assciated gnglia. unctionlly, the nervous system can be futher divded into the somati nervou system, whic control voluntry activties, an the autonmic nervus systm, which controls involntary acivities. The ervous sstem, toether wih the endocrine ystem, ontrols nd integates the activiies of te differnt parts of the ody.

Cntral Nevous Sysem he centrl nervou system s composed of lare number of nere cells nd their processe, suppored by spcialized tissue alled neurlia. Neuon is the term given to the nerve cell and all its processe. The neve cell as two tpes of prcesses, alled dendites ad an axon. Dendrites are the short processes of the cll body; the axon is the lngest prcess of he cell body (Fig. 119). The interior of the cntral nevous sysem is oranized ito gray nd white matter. Gra matter consiss of nere cells mbedded n neurogia. White mtter consists of nerve bers (axons) embedded in euroglia.

Periphral Nervus Syste Th peripheal nervos system consists of the canial ad spinal nerves ad their associate ganglia On dissction, te cranial and spal nerves are seen as grayish white cords. Tey are ade up o bundles of nere fibers (axons) upported by delicte areoar tissu.

Cranial Nerve Ther are 12 airs of cranial nerves tha leave t brain nd through framina i the skul. All te nerves are disributed n the hed and nek except the Xth vagus), hich als supplis structres in te thorax and abdoen. The cranial neves are describe in Chapter 11.

Spinl Nerves A totl of 31 airs of pinal neves leav the spial cord an though intrvertebal foramna in th vertebrl column (Figs. -20 nd -21). The spinl nerves are name accordig to the egion o the verebral column with hich the are assciated: crvical, 12 thoracc, 5 lumbr, 5 sacal, and 1 coccygel. Nte tat there are eigh cervica nerves nd only even cervical vertebrae nd that here is ne coccyeal nerv and fou coccygel verterae. uring development the spial cord grows in length moe slowl than th vertebrl column In the dult, when growth eases, te lower end of te spinal cord reahes inferiorly onl as far s the lwer border of th first lubar vertbra. To ccommodae for ths disprportionae growth in length the lenth of th roots icreases progressvely from above downward. I the uppr cervicl region the

42

snell spnal nerv roots ae short nd run amost horzontally but the roots o the lumar and sacral nervs below he level of the trminatio of the cord for a vertical bundl of nervs that reembles a horse's tail and is calle the cauda equina (ig. 1-20). ach spinl nerve s conneced to th spinal ord by to roots: the anterio root nd the poserior rot (Figs. -19 ad 1-21). he anteror root onsists f bundle of nerv fibers carrying nerve implses awa from the central ervous sstem (Fig. -21). uch nerv fibers re calle eferent fibers. hose effrent fibrs that o to skletal mucle and ause the to are lledmotor fibers Their ells of rigin li in the nterior ray horn of the sinal cord. The psterior root consts of bdles of nerve fibrs that arry implses to he centrl nervou system nd are clled afferet fibes (Fig. 1-1). Beuse these fibers are concerned with conveyin informaion abou sensatins of P.22

touch, pain, temperature, and vibations, hey re called sensory fibers. The cell bodie of thes nerve fbers are situate in a swlling o the posterior rot calle the posteior root ganglion (Figs. 119 and 1-1).

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igure 1-8 A. The thoracc duct and right lymphatic duct an their man tributaries. B. The area of body drained nto thorcic duct (cear) nd right lymphati duct (blac). C. eneal structure of a lymph ode. D Lymph vssels an nodes o the uppr limb.

At each intrvertebrl forame, the anerior an posterir roots nite to form a spinal nerv (ig. 1-21). Here, the moor and snsory fiers becoe mixed ogether, so that spinal nerve is made up f a mixtre of moor and snsory fiers (Fig. 119). O emergin from th foramen the spial nerve divides nto a lage anterior ramus nd a smaler posterior ramus. The psterior amus pases postriorly aound the vertebra column to supply the musces and sin of th back (Figs. 1-19 and 1-21). The anterior rus contiues anteiorly to supply te muscle and ski over te anteroateral bdy wall nd all the muscles and skin of the limbs.

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snell I addition to the anterior and poserior rai, spina nerves ive a sall meningal branc tht supplis the vetebrae and the cverings of the sinal cor (the mninges). Thorcic spinal nerves lso ha branchs, calle rami communicantes, hat are ssociate with th sympathtic part of the utonomic nervous system (ee belo). P.23

Figue 1-19 . Mulipolar otor neuon with onnector neuron snapsing ith it. B. Sectio through

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thoracic segment f spinal cord wit spinal oots and posterir root ganglion. C. Cros section of thorcic segmnt of spinal cord showing rots, spial nerv, and anerior an posterir rami ad their ranches.

Plexuse At te root of the limbs, the aterior rmi ne anothr to for complicted nerv plexuse (ig. 1-20). The cevical and brachia plexuse are fund at te root o the uppr limbs, and the lumar an scral pleuses are found t the rot of the lower libs. The lassic dvision o the nervous system into central and periphral part is purey artifiial and ne of decriptive convenince becase the pocesses f the nerons pas freely between the two. or exampe, a motr neuron located n the anerior gray horn o the firt thoracc segmen of the pinal cod gives ise to a axon tat es through the anteor root of the first thoracic nerve (Fg. 1-22), pases throuh the brchial plxus, traels down the arm nd foream in th ulnar nrve, and finally eaches te motor end plates on several musle fiber of a sall musce of the hand—a total ditance of about 3 ft (90 cm). To take another xample: onsider he sension of tuch felt on the lteral sie of the little te. This rea of sin P.24

is suplied by the firs sacral egment o the spial cord S1). The fine terinal braches of he sensoy axon, called dendrtes, eave the sensory organs of the ski and unte to fom the axn of the sensory nerve. Te axon psses up te leg in the sura nerve (Fig 1-22 and then in the tibial and sciati nerves to the luosacral plexus. I then psses thrugh the osterior root of he first sacral nrve to each the cell bod in the osterior root ganlion of he first sacral nerve. The central axon now nters th posterir white olumn of the spial cord nd e up to te nucleu gracili in the edulla blongata—a total distance of about 5 ft (15 m). Ths, a single neuron extend from th little oe to th inside of the sull.

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Figure 1-20 rain, spnal cord spinal erves, ad plexuss of lims.

Both hese exaples illstrate te great ength of a single neuron.

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Autonmic Nervous System The autonomic nervous system i the part of the ervous ystem cocerned wth the inervatio of invountary strucures suc as the heart, sooth musle, and lands thoughout he body nd is dstribute throughut the entral ad peripheral nervous system. The aonomic sstem may be dividd into to partsâ”the symathetic and te arasympaheticâ”and bot parts hve affernt and eferent nrve fibes. The ctivitie of the ympathetic part o the autnomic sstem prepare the body for a emergency. It accelerate the heat rate, causes costrictio of the eriphera blood vssels, and raiss the bood presure. The sympatheic part f the auonomic sstem brings about a redistibution f the blod so tht it leaes the aeas of te skin nd intesne and becmes avaiable to he brain heart, nd skeltal muscle. P.2

P.2

At th same time, it inhibits peistalsis of the itestinal tract an closes he sphinters.

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Figue 1-21 The assciation etween inal cor, spinal nerves, nd sympahetic trnks.

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Figure -22 Tw neurons that pas from th central to the pripheral nervous ystem. A Afferen neuron at extends from the little toe to te brain. B. Effeent neurn that etends frm the anerior gry horn o the first thorac segmen of spinl cord t the smal muscle of the hnd.

Clinica Notes Segmenal Inneration of the Skin Th area of skin suplied by single pinal neve, and herefore a single segment f the spnal cord is calld a dermaome. On the trnk, adjaent dermtomes ovrlap coniderably to prodce a reion of cmplete aesthesia at leas three cntiguous spinal neves mus be sectoned. Dematomal harts fo the antrior and posterio surfacs of the body are shown in Fiures 1-2 and 1-24.

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snell In the imbs, arangement of the drmatomes is more complicaed becaue of the embrylogic chnges tha take plce as the limbs grow out fom the body wall. A physician hould ha a working knowledge of th segmenal (dermtomal) inervatio of skin because with the help of pin or a piece f cotton he or sh can determine whether the sensory unction f a partcular spnal nerve or segmnt of th spinal ord is unctioning normally.

Segmntal Innrvation f Muscl Skeletal muscle aso receies a semental nervatin. Most of these muscles are innevated b two, tree, or four spial nervs and threfore b the same number of segmens of the spinal ord. To paralyz a muscle compleely, it s thus ncessary o sectio several spinal nerves to desroy seveal segments of the spinal cord. Learning the segmentl innervtion of all the uscles o the boy is an ipossible task. Nverthelss, the egmental innervaion of he follwing musles shoud be knon becaue they cn be tesed by licitin simple uscle reflexes i the patient (Fg. 1-25):    

 

Biceps brachii endon rflex: C5 and 6 (flexio of the lbow t by taping the biceps tendon) Trieps tenon refle: C6 7, and 8 (extensin of the elbow jont by taping th tricep tendon) Brachioadialis tendon rflex: 5, 6 and 7 (supinatin of the radioular t by tappng the nsertion of the bachioraalis tedon) Abdomnal supeficial eflexes contracion of uderlyin abominal muscles b strokin the skn): Upper abdominal skin T6 o 7, midle abdoinal skn T8 to , and loer abdomnal ski T10 to 2 Patella tendon eflex (knee jerk: L2, 3, and 4 (extenson of th knee t on tpping th patellar tendon Achlles tenon reflex (ankle jerk): S1 and 2 (plantr flexio of the ankle jont on tapping th Achills tendon

Te activiies of the parasmpatheti part of the autonomic system aim t conserving nd restring enegy. They slow the heat rate, increase peristasis of te intestine and glandula activiy, and open the sphinctrs. The ypothalaus of th brain cntrols he autonmic nevous sysem and itegrates the actvities o the auonomic ad neurendocrin systems, thus prserving homeostais in th body.

Sympthetic Sstem Effrent Fiers Te gray mtter of he spinl cord, from the first horacic egment o the seond lumbr segment, possess a lateral horn or colun, in whch are lcated th cell boes of th sympatetic conector neurons (Fig. 1-26) The myeinated aons of tese cell leave the spinal cord in te anterir nerve oots and then via the whte rami ommunicantes to the paraveebral gaglia of the sympthetic tunk (Fig. 1-21 126, ad -27). The connctor cel fibers re called preanglioni as they to peripheral ganglon. Once the pregnglionic fibers rech the gnglia in the sympathetic tunk, the may pas to the ollowing destinatins:

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snell 





They my terminte in the ganglio they hae entered by synaping with an excitr cell i the ganlion (Fig. -26). snapse can be efined a the site where tw neurons come int close poximity but not ito anatoic contiuity. The gap betwen the to neurons is brided by a eurotranmitter sustance, aceylcholine. Th axons o the excitor neuros leave he ganglon and ae nonmylinated. hese posganglionic nerve fbers now to he thorcic spinl nerves as gray ram communiantes and are istributd in the branches of the spnal nervs to suply the ooth musle in th walls o blood vessels, th sweat gands, an the arctor pil muscles of the sin. hose fibrs enterng the ganglia of the sympathetic tunk high up in th thorax ay trave up in te sympahetic trunk to th ganglia in the cervical reion, whee they ynapse wth excitr cells Fis. 1-26 and 1-27. Here, again, t postganlionic nrve fibes leave the sympatetic trnk as gry rami cmunicantes, and mst of thm te cervicl spinal nerves. any of te preganlionic fbers entring the lower pat of th sympathic trunk from the lower thracic an upper to lumba segmens of the spinal crd trave down to ganglia i the lowr lumbar and sacal regios, where they synase with xcitor clls (Fig. 127). he postganglionic fibers lave the ympathetc trunk as gray rai commuicantes hat the lumbar, sacral and cocygeal spnal nervs. The pregnglionic fibers my trough te ganglia on the toracic prt of th sympathtic trun without synapsig. These yelinate fibers orm the ree splancnic neres (Fig. 1-27). Te reater splanchni nerve arises from the fifth to the nint thoracc gangli, pierce the diphragm, d synapss with excir cells in the ganglia of he celia plexus The lesse splanchic nerve arise P.27

rom the 0th and 1th gangia, pieres the diaphragm, nd synapes with excitor ells in he gangla of the lower pat of the celiac plexus. The owest spanchnic erve (when present) aries from he 12th thoraci ganglion pierces the diahragm, and synapse with exitor cels in the ganglia of the renl plexu. Splancnic nervs are threfore cmposed o pregangionic fbers. Th postganlionic fbers arie from te excito cells i the peripheral plexuses previously noted ad are ditributed to the sooth mucle and lands of the viscra. A fe pregangionic fiers traveling n the geater spanchnic nerve ed directly on he cells of he suprenal mdulla. Tese medulary cels may b regarde as modiied sypathetic excitor cells.

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Figure 1-23 Dermatoes and dstributin of cuaneous nrves on the anteior aspet of th body.

Sympathetic truns are tw ganglinated nrve trunks that etend the whole length of the vertbral coln (Fig. 1-7). here are 3 gangli in each trunk of the neck, 11 r 12 gaglia in he thorx, 4 or

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snell ganglia in the lmbar regon, and or 5 ganglia in the pelvi. The tw trunks ie close to the vrtebral olumn an end belw by joning togther to rm a single ganglon, the gaglion imar.

Aferent Fbers he affernt myeliated nere fibers travel fom the vscera though the sympathetc ganglia withou synapsi (Fig. 1-2). Thy enter he spina nerve va the whte rami mmunicanes and rach ther cell odies in the posteior root ganglion of the crrespondng spinl nerve. The cental axons then ent the spial cord .28

and may form the affeent compnent of local rflex arc Others ay p to higher autonoic cents in the brain.

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Figure 124 Deatomes and distrbution of cutaneou nerves n the poterior aspect of he body.

Parasymathetic ystem

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Eerent Fbers The cnnector ells of his part of the sstem are located n the brin and te sacral segments of the sinal cor (ig. 1-27). Thse in the brain form parts f the nulei of oigin of ranial nrves II, VII, I, and X, and the xons emege from he brain containe in the correspoding craial nerves. The sacra connectr cells re found in the ray mattr of th second, third, nd fourt sacral egments of the crd. Thes cells re not sfficienty numeros to fo a lateal gray orn, as o the ympathetc connecor cell in the horacolubar regin. The yelinate axons lave the spinal ord in he anteror nerve roots o the corespondig spina nerves. They then leave the sacral nerves and form he pevic splnchnic nerves. All the efferent fibers described so fr are peganglioic, and hey synapse with excitor clls in pripheral gangli, which re usualy situated close to the viscera tey innevate. Th cranial preganglonic fibrs relay in the ciliry, ptergopalatie, submadibular, and otic ganglia (Fig. 1-2). The preganglonic fibrs in th pelvic planchni nerves elay in anglia i the hypgastric P29

pleuses or n the walls of th viscera Characteristically, the ostganglnic fibers are nonmyelinated and are relatively short compar with sypathetic postgangionic fiers.

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Figur 1-25 Some imortant tndon reflexes usd in medcal pracice.

Aferent Fiers

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snell Te afferet myelinted fibes travel from the viscera to their cell bodies located either in the snsory gaglia of te cranil nerves or in th posterir root gnglia of the sacrspinal erves. Te centra axons ten enter the cental nervos system and tak part in the formtion of ocal refex arcs, or to higher centers of the atonomic nervous system. he affernt compoent of te autonoic syste is idetical to the affeent component of omatic nrves and forms pat of th general afferent segment f the entre nervos system The nere endins in the autonomi afferen componet may no be actiated by such senations a heat or P.30

uch but instead y stretch or lack of oxygen. Once he afferet fiber gain entrance to the pinal crd or brin, they are thouht to trvel alogside, o are mixed with, te somat afferen fibers.

igure 1-6 Genral arragement o somatic part of rvous sytem (left) compard to autonomic pat of nerous systm (right.

Clinical Noes Clnical Modificatin of the Activities of the Autonomi Nervous System

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snell Many drgs and srgical pocedures that can modify te activty of th autonomc nervou system re availble. For example, drugs cn be nistered to lower he blood pressure by blockng sympthetic nerve endings and causing vasodilataton of peipheral blood vesels. In patients with sevre arteral diseae affectng the ain arteies of the lower limb, the limb can someties be saed by sctioning he sympahetic inervation to the ood vessls. This produce a vasodlatation and enables n adequae amount of blood to flow through he collateral circlation, hus bypasing the obstructon.

Mucous embranes Mucous membrane is th name gven to te lining of ogans or ages that comunicate ith the surface of the bdy. A mucus membrne consits essenially of a layer of epithlium ed by a layer f connecive tisse, the lamina propri. Smoth muscl, called the musculais mucos, is ometimes resent n the connective tissue A muco membrae may or may nt secree mucus on its surface.

Srous Mebranes Serous embranes lie the cavities f the trnk and are refleted ont the mobile viscra lying within hese cavties (Fig. 1-2). Tey consit of a mooth laer of msotheliu suppored by a hin layr of conective issue. Te serou membran lining the wall of the avity i referre to as te parieta layer, and tht coverig the vscera is called he viscera layer. The narow, slilike inerval tht separtes thes layer forms te pleural pericarial, nd peritonel cavites an contain a small amount o serous iquid, te erous exdate. The seros exudate lubricas the srfaces of the membranes and allows the two laers to side readly on eah other. Te mesentries, omnta, and serous lgaments re descrbed in oher chapers of tis book. The parietal layer of a serous membrane is developed fro the somtopleure (inner cll layer of mesodrm) and s richly supplie by spinl nerves It s therefre sensive to ll commo sensatons suc as touc and pan. The vsceral lyer is eveloped from the splanchnopleure nner cell layer of mesoderm) and is supplied by autoomic neres. It i insensiive to tuch and emperatue but vey sensiive to setch. P31

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Fgure 1-2 Effeent part of autonmic nervus syste. Preganlionic prasympatetic fibrs are sown in sold blue; postganlionic prasympatetic fibrs, in interupted bue. Peganglioic sympahetic fiers are hown in sold red; postgangionic sypathetic fibers, n interrupted red.

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Figue 1-28 Arrangeent of peura witin the toracic cvity. Noe that uder noral condiions the pleural avity is a slitlie space; the parital and visceral layers o pleura re separted by a small amunt of serous fluid.

Clincal Note Mucus and Srous Memranes an Inflammtory Disase Mucos and seous membranes are common sites for inflammatory diseae. For eample, rinitis, r the comon cold, is an flammation of the nasal muous membane, and pleurisy is an iflammatin of the visceral and parital layes of the pleura. .32

Bon Bone s a livig tissue capable f changig its structure as the result of t stresse to whih it is ubjected. Like oter connetive tisues, bon consist of cell, fibers and matix. It s hard bcause of the calcfication of its etracelluar matrix and possesses a egree o elasticity becaus of the resence f organi fibers Bone ha a protecive funcion; the skull an vertebrl column for exmple, prtect the brain an spinal ord from injury; te sternu and ris protec the thoacic and upper abominal vscera (Fig. 1-29). It srves as a lever, as seen n the log bones of the limbs, and as an iportant torage area for cacium sals. It hoses and rotects ithin is cavities the delicate bloodforming bone marow.

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Figre 1-29 The skleton. A Anterio view. B. Lateral view.

Bone exists in two forms: compact and cancllous. Compact bone appars as a solid mas; cancelous bon consist of a branching network of trbeculae (ig. 1-30). The trabecule are aranged in such a mnner as o resist the streses and trains to which the bone is exposed.

Classifcation o Bones

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snell Bones ay be clssified egionall or accoding to heir genral shap. The reional clssificaton is sumarized n able 1-2. Bons are gruped as ollows bsed on their P.33

general hape: lng bones short bnes, fla bones, rregular bones, and sesamo bones.

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Figue 1-30 Section of diffrent typs of bons. A. Log bone (umerus).B. Irreguar bone calcaneu). C. Fla bone (to parietl bones eparated by the sgittal sture). D Sesamoi bone (pella). E Note arangement of trabeulae to ct as stuts to rsist bot compression and tnsion foces in te upper nd of th femur.

Long Bones Long bones are found in the limbs e.g., th humerus, femur, etacarpas, metatrsals, ad phalanes). Ther length is greaer than teir breath. They have a tbular shft, the diahysis and usually an epipysis a each en. During the growng phase the diahysis is eparated from the epiphysi by an epipyseal catilage The par of the iaphysi that lies adjacent to th epiphyeal cartlage is alled th metaphyis. Te shaft has a central marrw cavity contaning bone mrrow. The oute part of the shaf is compoed of copact bone that is overed b a connective tise sheath the periosteum. The ends of long ones are composed of cancelous bone surrouned by a hin laye of compct bone. The artiular surfces of he ends f the bos are coered by yaline crtilage.

Short ones hort bons are fod in the hand and foot (e.., the caphoid, lunate, tlus, and calcaneu). They re roughy cuboidl in shape and ar compose of cancllous bo surrounded by a hin laye of comact bone Short bnes are vered wih perioseum, and the articular srfaces ae covere by hyalne cartlage.

Flat ones lat bon are fond in th vault o the skll (e.g. the frntal an parietal bones). hey ar compose of thin nner and outer lyers of ompact bone, the tabes, eparated by a laer of cacellous bone, th iploë The scapulae, alhough iregular, re inclued in ths group.

Irrgular Boes Iregular ones include those not asigned to the preious groups (e.g., the bones of th skull, he verterae, and the pelic bone). They re compoed of a hin shel of P.34

ompact bne with n interir made u of cancellous bon. able 1-2 Regial Clasificatin of Bons

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Region of Skeleon

Numbe of Bone

xial skeeton

Skull

Cranum

8

Face

14

Auditor ossicles

6

Hoid

1

Verterae (incuding sarum and occyx)

26

Strnum

1

Ris

24

Appedicular keleton

Sholder girles

Claicle

Sula

2

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Upper extremies

Humerus

2

Radius

2

Ulna

2

Carpals

6

Metacarpals

10

Phalanges

28

Pelvic grdle

Hip bon

2

Loer extreities

Femur

2

Patlla

2

Fiula

2

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Tibia

2

Tarsals

1

Metaarsals

10

Phlanges

28 206

Seamoid Boes Seamoid boes are sall nodues of boe that a found n certai tendons where they rub ovr bony srfaces. he greatr part of a sesamid bone s buried in the tndon, an the free surface s coveed with artilage The largest sesamid bone s the paella, whch is lcated in he tendo of the uadriceps femoris. Other exmples ar found n the tedons of te flexor policis brevis and lexor halucis bevis. Te function of a sesamoid bone is o reduce friction on the endon; i can als alter te directn of pull of a tendon.

urface arkings of Bones The surfaces of bones ow varios markins or iregularites. Wher bands of fascia, igament tendons or apoeuroses re attached to bon, the suface is aised or roughene. These roughenings are nt present at birth They apear at pberty and become pogressivly more bvious dring adut life. he pull of these fibrous structures causes e perioseum to b raised nd new bne to b depositd beneat. In cetain sitations, he surfae markins are lage and re given special mes. Som of the ore impotant marings are summarized in Table 1-3.

one Marrw Bon marrow ccupies the marrow cavity in long a short bones and the intestices o the canellous bne in lat and rregular bones. t birth, the marrw of all the bones of the dy is red and hmatopoietic. This blood-foring actiity gradally lesens with age, and the red arrow is replaced by yello marrow. At 7 yeas of age, yellow marrow beins to apear in he distal bones o the limbs. This replacement of marow gradually move proximaly, so tat by th time P35

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the erson bemes an ault, red marrow is restriced to th bones o the skll, the vrtebral olumn, te thoracic cage, he irdle bnes, an the hed of the humerus nd femu. Table 1- Surfce Markigs of Bnes Bone Maring

Exampe

Liner elevaton

Line

Supeior nuchl line of the ocital boe

Ridg

The edial an lateral supraconylar rides of th humerus

Crest

The iliac crest of the hip bon

Ronded eleation

Tbercle

Pubic bercle

Prouberance

Extnal occiital prouberance

Tuberosiy

Grater and lesser tberositis of the humerus

Malleous

Meial mallolus of he tibia lateral malleolu of the ibula

Trochater

reater ad lesser trochants of the femur

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Sharp elvation

Spine or spinos proces

Ichial sne, spin of vertbra

Styoid procss

Syloid prcess of emporal one

Expanded ends for articulaion

Hed

Head of humrus, head of femur

Condyle (knuckleike proces)

Medial nd laterl condyls of femr

Epicodyle (a rominenc situate just above condyl)

Media and lteral epcondyles of femur

Small ft area for articulation

Facet

Facet on head of ib for aticulatin with vrtebral ody

Depresions

Noch

Grater scitic notc of hip bone

Groove or sulus

icipital groove o humerus

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Fossa

Olecrano fossa o humerus, acetabular fossa of hip bone

Openins

Fissure

Supeior orbial fissue

Foramen

Infrarbital foramen of the maxilla

Canl

Cartid cana of tempral bone

Meatus

Externa acousti meatus f temporl bone

Clinial Notes Bone Fracture Immeiately ater a fractre, the patien suffers severe lcal pain and is nt able t use the injured part. Deormity my be visble if te bone fagments have been displace relativ to each other. he degree of defority and he diretions tan by the bony framents deend not oly on th mechanim of inury but lso on te pull of the musces attaced to the fragmens. Ligamntous atachments also infuence th deformiy. In crtain siuationsâ”for exaple, the lium—factures esult in no defority becase the iner and uter suraces of he bone re splined by the extensve origis of muscles. In contrast, fractur of the neck of he femur produces considerble dispacement. The strog muscls of the thigh pul the dital fragent upwad so tha the leg is shortned. Th very strng laterl rotatos rotate the distl fragmet laterlly so tat the fot point lateraly. Fracture of a bon is accopanied b a consierable emorrhag of blood between he bone nds and nto the urroundig soft issue. Te blood essels and the fiboblasts nd osteolasts frm the priosteum and endoteum tak part in the repar proces All bone surfaces other tan the aticulatig surfacs, are covered by a thick ayer of ibrous tssue called the peristeum. The perosteum hs an abudant vasular suply, and he cells on its eeper suface are osteogenc. The periosteum s particlarly wel unite to bone at sites here musles, tenons, and ligament are atched to bone. Bunles of cllagen fbers knon as Shapey's firs extd

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snell from te perioseum into the undelying boe. The priosteum receive a rich erve suply and i very sesitive.

Devlopment f Bone Bone i developd by two processes: membraous and endochonral. In he first process he bone s develoed directly from connectve tissu membran; in the second, cartilagnous modl is fist laid own and s later eplaced y bone. or details of the cellular changes nvolved, a textbok of hisology or embryology should be consuted. Th bones o the vaut of the skull ae develoed rapidly by the membranos method in the ebryo, an this seves to rotect te underlying develping bran. At bith, smal areas o membrane persist between he bones This is importan clinicaly becaue it allws the bnes a cerain amout of moblity, so that the skull can undergo molding uring it descent through he female genital ages The long bones of the limbs are deveoped by endochondral ossifcation, hich is slow prcess tha is not complete until the 18th to 20th yea or eve later. The center of bone formatio found i the shat of the bone is eferred o as the diaphysis; the ceters at he ends f the boe, as th eiphyses. The plte of catilage a each en, lying etween t epiphysis and diaphysis in a growig bone, s called the epiphyeal plat. The meaphysis is the art of te diaphyis that buts ont the epiphyseal plte.

Clinial Notes Rickets Ricts is a defectiv mineralzation o the carilage mtrix in owing bones. This produes a conition in which th cartilge cells ontinue o grow, esulting in excess cartilag and a idening f the epphyseal plates. Th poorly ineralizd cartilinous matrix and the osteid matri are soft, and the bend uner the sress of bearing weight. Th resultig deformties incude enlaged cosochondral junction, bowing of the lng bones of the lwer limb, and bssing of the fronal bones of the sull. Defrmities f the plvis may also occr.

Epiphysel Plate Disorders Epihyseal ate disoders affct only children and adoescents. The epipyseal plte is th part of a growin bone cncerned rimarily with groh in length. Trauma, infecion, die, exercse, and ndocrine disorder can disurb the rowth of the hyaline cartiaginous late, leding to eformity and loss of function. In th femur, for examle, the roximal piphysis can sli because of mechanical sress or xcessive loads. Te length of the lmbs can increase excessivly becaue of increased vasularity n the reion of he epiphseal pla secondary to infection or in the pesence o tumors Shortenng of a mb can follow trama to th epiphysal plate resultig from a diminishd blood upply to the cartiage.

Crtilage

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snell Cartilge is a orm of cnnective tissue i which te cells nd fiber are embdded in gel-lik matrix, the lattr being responsile for is firmnes and reslience. xcept on the expoed surfces in oints, a ibrous mmbrane clled the perichondrum covrs the crtilage. There ar three tpes of crtilage: 

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Hyline carilage has a igh proprtion of amorphou matrix hat has he same efractiv index as the fibers embedded in it. Throughot childhod and dolescence, it plays an important pat in th growth n length of long bones (eiphyseal plates ae composd of hyalne cartiage). It has a geat resitance to wear and covers te articuar surfaces of nearly all synovial ts. Haline catilage i incapabe of repir when fracturd; the defect is flled wi fibrous tissue. Fibrcartilag has any collgen fibes embeddd in a sall amout of matix and i found in the scs within P.36

ts .g., the temporomndibular t, sernoclavcular jont, and knee joit) and o the artcular sufaces of the clavcle and andible. Fibrocatilage, i damaged repairs itself sowly in manner imilar o fibrou tissue lsewhere. t dics have poor blod suppl and threfore do not repair themslves when damaged. 

Elast cartilae posesses lrge numbrs of elstic fibrs embeded in marix. As ould be expecte, it is lexible nd is found in the auricle of the er, the xternal aditory matus, th auditor tube, ad the epglottis. Elastic cartilage if damaed, repars itsel with fious tisse.

Hyline carilage an fibrocatilage tnd to calify or een ossif in late life.

Effects f Sex, Rce, and ge on Stucture Desriptive natomy tnds to cncentrat on a fied desciptive frm. Medical personel must lways tht sexual and racal diffeences exst and tat the body's stucture ad functin chang as a peson grow and age. The adult mae tends o be taler than he adult female nd to have longer egs; his bones ar bigger nd heavir and hi muscle are larr. He ha less sucutaneou fat, which makes is apperance moe angula. His larynx is lger and his vocal cords ar longer so that is voice is deeper He has beard ad coarse body har. He posesses axllary an pubic hr, the latter extending to the regon of th umbilics. The dult femle tends to be shrter tha the adut male and to hav smaller bones an less buky muscls. She hs more ubcutaneus fat and fat acmulation in the reasts, uttocks, and thihs, givig her a ore rouned appeaance. Her head hai is fine and her skin is moother n appearnce. She has axillary and pbic hai, but th latter oes not tend up to the umilicus. he adult female has larger breasts nd a widr pelvis than the male. Sh has a ider carying ange at the elbow, wich resuts in a reater lteral dviation of the foearm on he arm. Until th age of pproximaely 10 yars, boy and girl grow a about te same rte. Aroud 12 yeas, boys ften stat to grow faster than girl, so tha most maes reach a greate adult height than females. 72

snell Pubery begins between ages 10 ad 14 in irls and between 2 and 15 in boys. In the grl at puerty, the breasts nlarge nd the plvis brodens. At he same ime, a by's penis, testes, and scrtum enlage; in bth sexes axillary and pubic hair appar. Racial differencs may be seen in he color of the skn, hair and eye and in he shape and size of the ees, nose and lip. Africs and Scndinavias tend t be tall as a result of log legs, whereas Asians ted to be hort, wih short egs. The eads of entral uropeans and Asias also tend to be ound and broad. After birth an during hildhood the bodily functions becme progrssively ore efficient, reching thir maximum degree of efficency durng young adulthood. During ate adulhood and old age, many boily funcions becme less fficient.

Clinial Notes Clinial Signiicance o Age on tructure Te fact tat the sructure nd function of th human ody chane with ae may seem obviou, but it is often overlooked. A few examples of such hanges ae given ere:  

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In the infan the bons of the skull are more rsilient han in te adult, and for tis reason fracturs of the skull ae much mre common in the ault than in the yung chil. The lver is rlatively much larer in te child han in te adult. In the ifant, th lower mrgin of he liver extends nferiorl to a loer level than in he adult This is an impotant conideratio when maing a dignosis o hepatic enlargemnt. Th urinary bladder n the child canno be accmmodated entirely in the plvis becuse of te small ize of te pelvi cavity nd thus is found i the lowr part o the abdminal cvity. As the chil grows, he pelvi enlarge and the bladder snks dow to becoe a true pelvic oran. At birh, all bne marro is of te red vriety. Wh advancng age, he red mrrow recdes up te bones f the lmbs so tt in the adult it is largey confind to the bones of the hea, thorax and abdmen. Lymphatc tissues reach teir maximum deree of dvelopmen at pubety and tereafter atrophy, so the vlume of lymphati tissue older prsons is considerbly redued.

Radiograhic Anatmy As a medial professional, you will e frequely calle on to tudy noral and anormal aatomy a seen on radiograps. Famiiarity wth norma radiographic anatmy permis one to recogniz abnormalities qickly, such as frctures ad tumors The most ommon form of radiographic anatomy s studie on a radioraph (x-ray flm), whh provides a two-imensionl image f the interior of he body Fi. 1-31). To poduce such a radiograph, a single brage of -rays is ed hrough te body ad exposes the film Tissues of diffeing densties shw up as mages of differing densitie on the adiograp (or florescent screen). tissue hat is rlatively dense aborbs (sops) moe x-rays than tissues that are less dense. A very dene tissue is said to be radipaque, but a les dense issue is said to e adiolucet. Bon is very dense an fat is oderatey dense; other sot tissue are les dense.

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snell Unortunatey, an orinary raiograph hows the images f the different orans supeimposed nto a flt sheet f film. is overlap of orans and issues oten makes it diffiult to vsualize them. Ths proble is overome to sme exten by takin films a right ngles to one anoter or by making sereoscopi films. Compted tomoraphy (CT) scaning or comuterized axial omograpy (CA) scnning permits te study P.7

of issue slces so tat tisses with minor differences in densty can e recognzed. CT canning relies on the same physics s convenional xrays but combines it with omputer echnolog. A soure of xrys move in an ac around the part of the body being studied ad sends ut a bem of x-rys. The rays, hving pased throuh the reion of te body, are collcted by special x-ray deector. Hre, the rays are convered into lectroni impulss that prduce reaings of he densiy of th tissue n a 1-cm slice of the body From thse readigs, the computer is able o assembe a pictre of th body called a CT scn, whch can b viewed on a fluorscent sceen and hen photgraphed or later examinaton (Fig. 1-32). Th procedue is saf and quick, lasts nly a few secons for each slice, and for ost patints requres no sedation.

Embrylogic Noes mbryolog and Cliical Anaomy Embryology provides a basi for unerstandig anatom and an explanaton of many of the congenitl anomalies that ae seen i clinicl medicie. A ver brief oerview o the development o the emryo follows. One the ovm has ben fertilzed by te spermaozoon, a single cell is fored, calld the zygoe. Ths underges a rapd successon of miotic divsions wih the frmation f smaller cells. he centrlly placd cells re called the nner cel mass and ultmately orm the tissues f the embryo. Th outer clls, caled the oute cell mss, fom the trphoblast which pays an iportant ole in te formaton of th pacenta and the feal membrnes. The cells tht form te embryo become dfined in the form f a bilaminar embrynic disc, compsed of to germ lyers. Th upper layer is caled the ectoderm nd the lwer laye, the entodrm. A growth roceeds, the emryonic dsc becoms pear saped, an a narrw streak appears o its doral surfae formed of ectodrm, calld the primtive strak. Te furthe prolifration of the cells of the primitive streak frms a laer of cells that will extend betwen the ecoderm an the entderm to rm the third ger layer, alled th msoderm.

Ectoderm Furter thickning of the ectodem gives rise to a plate of cells on the dorsl surfac of the embryo cled the neral plat. Thi plate sinks beneah the suface of he embry to form the neural ube, 74

snell which ultately gies rise o the central nervou system. The rmainder f the ecoderm forms the corna, retina, and len of te ye and the membranous labyrinth o the inner ar. Te ectoderm also forms the epiermis f the skin the nail and hai; the epihelial clls o the sebaceus, swea, and mammary glads; te ucous mebrane ining th muth, nal cavitis, an pranasal inuses; the ename of th teeth; he pituitar gland and the aleoli ad ucts f the parotd salivay glands the mcous memrane of he lower half of he anal canl; an the terinal pars of the geital trat and he male urary tract.

Entoderm The entoderm eventually gives orgin to te followg structres: th eithelial lining of the alientary tact frm the mouth cavity down to halfway long the anal canl and th eithelium of the glands hat deveop from i—namel, the thyrod, paratyroid, tymus, lier, ad ancreas—and te epitheial linings of th rpirator tract, paryngotypanic tue and midle ear, urinary ladder, parts of the femle and mle urethras greater vestibulr glands prostat gland, ulbouretral gland, and vaina.

esoderm The mesderm becmes diffrentiate into th paraxia, intermdiate, ad latera mesoders. The paraial mesoerm is situated initiall on eithr side o the midine of te embryo. It becoms segmened and rms the bones, cartilage, nd ligament of t rtebral column and part of the bse of th sull. Te latera cells frm the skeletal muscles of their ow segment and some of the cells migrate beneah the ecoderm an take pat in the formatio of the dermis nd subcutanous tisses of the skin. The intermediate esoderm is a olumn of cells on either sde of th embryo hat is cnnected medially to the praxial msoderm ad laterally to the lateral mesoderm It give rise to portions of the urognital sytem. The laterl mesodem splis into smatic laer and a planchni layer associaed with he ectodrm and te entodem, respecively. I encloss a caviy within the embro called the intraemryonic celom. he coelo eventualy forms the pericarial, pleral, nd peritonel cavitis. Te embryoic mesodrm, in addition, ives origin to smoot, voluntry, an crdiac mucle; ll forms of connectie tissue, inclding carilage and bone; bloo vessel alls ad blood cells; lymph vessel walls ad ymphoid tissue; the synovil membraes of jonts an brsae; and the suprarena cortex When appropriate, a more detailed accoun of the evelopmet of diferent orans is gven in te chapters to follow. The tecnique of manetic reonance iaging (MRI) uses the magnetic properties of the hdrogen ncleus exited by radiofreqency radation trnsmitted by a coi surrouning the ody par. The excited hydogen nucei emit signal that is detected as induced electric currents in a reciver coi. MRI is absolutey safe t the paient, and because t provids better differeniation btween dfferent oft tissues, its e can b more reealing tan a CT scan. The reason fr this i that soe tissue contain more hydogen in he form of water han do oher tisses (Fig. 1-3).

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snell P.38

Figure -31 Psteroanterior radograph o the thoax.

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snell

Figur 1-32 Computed tomography (CT) sans. A. he upper thorax a the level of the hird thoacic verebra. B. The uppr abdome at the evel of the secon lumbar ertebra. All CT scans are iewed from below. Thus, th right sde of th body apears on the left side of he figure.

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P.1

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snell P.4

P.3

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Figure 1-33 agnetic rsonance imaging tudy of the head i a sagital plane showing ifferent parts of the brain.

Cnical Poblem Solving

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snell Stdy the fllowing ase histries and select te est aswer to he questons follwing the. A 4-year-ol patient has a smll, firm, mobile tumor on the dorsm of t right oot jus proxima to the base of he big te and suerficial to the bones an the long extensor tendon bt deep t the surficial fascia. 1. The followin informaion concrning th tumor i correct except whch? (a It is stuated o the uppr surfac of the oot clos to the oot of the big toe (b) t is not attached to the frst metaarsal boe. (c) It ies supeficial t the dee fascia. () It lie superfiial to te tendon of the etensor hllucis lngus musle. (e It is atached t the capule of te metatasophalangeal t of the big toe. View Answer 1. E The tumr is moble and nt fixed o the jont capsul. The tuor is a eurofibrma of a igital nrve. A 31-yearold woma has a hstory of poliomyeitis affcting th anterio horn clls of te lower toracic ad lumbar segments of the sinal cor on the left sid. On exaination, she has evere riht laterl flexio deformty of th vertebral column. 2 The folowing sttements are true bout thi case except which (a) Th virus o poliomylitis atacks and destroys the motor anterior horn ces of th spinal ord. (b) The isease sulted i the parlysis of the musces that ormally aterally flex the vertebra column n the let side. (c The musles on te right ide of te vertebal colum are unaposed. (d) The ight lateral fleion defrmity i caused by the sow degenration o the sesory neve fiber originting fro the verebral mucles on he right side. Vie Answer 2. D A 20-yearold woma severel sprains her left ankle whle playig tennis. When s tries move the foot so that the sole facs medialy, she xperiencs severe pain. 3. What is the crrect antomic tem for th movemen of the oot that produce the pai? (a) Pronation (b) nversion (c) Suination

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snell (d) Eversion View Aswer 3. B A 25year-old man has deep-seted abscss in th posterir part of the neck. 4. Te followng statements are correct concerning the abscss excep which? (a) The bscess pobably les deep o the dep fascia (b) The eep fasca determnes the irection of spred of the abscess. (c) The bscess wuld be icised though a vrtical sn incisin. (d) he lines of cleavge are iportant hen considering th directin of ski incision. (e The absess woul be incied throuh a horiontal skn incisin. Viw Answer 4. C. If posible, skin incisions in the neck are made i a horizotal diretion to onform wth the lnes of ceavage. A 40-ear-old rman received a svere bur on the nterior aspect o his riht foream. The aea of th burn exeeded 4 in.2 (10 cm). The greater art of te burn was superfiial and xtended nly int the supeficial prt of th dermis. 5. In the superficialy burned area, the epiderms cells would regnerate fom the fllowing ites ext (a) the air follcles. (b) the sebaceous glands. (c) he margis of the burn. (d) th deepest ends of he sweat glands. View Anser .D 6. In small rea the urn penerated as ar as the superfiial fasca; in tis regio, the epdermal clls woul regenerae from te followng site except (a) the ends of the sweat glands hat lie n the superficial fascia. b) the mrgins of the burn (c) the sebaceous glands.

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snell View Aswer 6. C In a 63-year-old man, an MRI of the lower thorac region f the vetebral olumn reeals the presence of a tumr pressig on the lumbar sgments f the spinal cord. He has a loss of ensation in the skin over the anteior surfce of th left thgh and i unable to extend is left knee joit. Examiation reeals tha the musces of th front o the let thigh ave atrohied and have no one and hat the lft knee erk is bsent. 7. The fllowing tatement concernng this atient ae correc except hich? (a) The umor is interruptig the nomal funcion of te efferet motor ibers of the spinl cord o the lef side. (b) The quadriceps femoris muscles on te front f the let thigh are atrophed. (c The los of skin sensatio is confned to te dermatmes L1, , 3, and . (d) he absene of the left kne jerk is because f involveent of te first umbar spnal segmnt. (e) The oss of muscle tone is causd by intrruption of a nerous reflx arc. View Answer 7. D. The patelar tendn reflex (knee jek) involes L2, 3, and 4 sements of the spinl cord. A woman recently took up ploymen in a facory. She is a macinist, ad for 6 hours a ay she hs to mov a lever repeatedl, which equires hat she extend a flex her right wist . At the end of te second week of her emplyment, se began t experiece pain ver the osterior urface f her wrst and nticed a welling n the ara. 8. The followin statemets concening thi patient are corrct excep which? (a) Extnsion of the wrist t is brought bout by everal mscles tht includ the extnsor digtorum mucle. (b) Th wrist jint is diseased. (c) peated unaccustomd movemets of tedons thrugh thei synovia sheaths can prodce traumtic inflmmation f the sheths. (d) he diagnsis is taumatic enosynovtis of te long tndons of the extesor digiorum musle. View nswer 8. B A 19-ear-old oy was sspected f having leukemia It was ecided t confirm he diagnsis by prforming a bone mrrow bioy. 9. Th followig statemnts concrning ths procedre are correct ext which

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snell (a) The biopsy was take from th lower ed of the tibia. (b Red bon marrow pecimens can be otained fom the sernum or the ilia crests. (c) A birth, he marro of all ones of he body is red and hematopoetic. () The blod-formig activi of bon marrow in many long bones gradually lessens with age, and th red marow is gradually rplaced b yellow arrow. Vie Answer 9. A In a 19year-old boy, the bone marow at th lower en of the ibia is ellow. A 22-year-old wan had severe nfection under the lateral dge of te nail f her right indx finger On examiation, a series o red lins were een to etend up he back of the han and arond to th front o the foearm and arm, up o the armpit. 10. Th following statements concrning this patient are probbly correct excep which? (a) Papation o the rigt armpit revealed the presnce of sveral teder enlaed lymp nodes (lymphadentis). (b) Te red lies were aused by the suprficial lymphatic vessels the arm, which were red and inflamd (lymhangitis and coud be see through the skin. (c) Lmph from the righ arm entred the loodstrem throug the thocic duct (d) Ifected lmph enteed the lmphatic apillaris from te tissue spaces. View Answer 10. . Lymph from the right uppr limb eters the bloodstream throug the rigt lymphaic duct.

Review Qestions Completin Questions Slect the phrase hat best complets each satement. 1. A patie who is tanding n the antomic poition is a) facin lateraly. (b has the palms of the hand directe mediall. (c) has he ankle several nches aprt. (d) is tanding n his or her toes (e has the upper libs by th sides f the trnk. View Answer

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snell 1. 2. A patent is pforming the movement of flxion of he hip jint when she (a) moves th lower lmb away rom the idline i the cornal plan. (b) moes the lwer limb posterioly in th paramedan plane. (c) move the lowr limb ateriorly in the pramedian plane. (d rotates the lowe limb so hat the nterior urface fces medilly. (e) moves t lower lmb towar the medan sagital plane View Answer 2. C Mtching Qestions Match ach struture lised below with a tructure or occurence wit which it is most closely ssociate. Each lttered aswer may be used mre than nce. 3. Superfical fascia 4. ep fascia 5. Seletal mscle a) Divids up intrior of limbs int compartments (b) Aipose tisue (c Tendon pindles (d) None of the above Vie Answer 3. B 4. A .C For eah t listed belw, indicte with hich typ of moveent it i associaed. 6. Sernoclavcular jont 7 Superio radioular t 8. Akle (a) Fexion

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snell b) Glidig (c) Both A and B (d) Neither nor B View Answer 6. B 7. D 8A For eah jint listd below, give the most appopriate lassifiction. 9. ts btween vetebral bdies 10. Inferior tibiofibular t 11. Sutures beteen bone of vaul of skul 2. Wrist t (a) Synovial t (b) artilagious (c Fibrous (d) Noe of the above View Answer 9. B 10. C 11. C 1. A For each type f synoval listed elow, give an apropriate example from the list of ts. 13. Hnge 14. Condyloi t 15. Bal-and-socet t 16. Saddle jint (a Metacarophalangal t of index finger

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snell (b) Shoulder t (c) Wris t (d) Carometacarl t of the tumb (e) None of the ove View nswer 13. E 14. A 15. B 1. D For eh type o muscle ction lited belo, select the most approprite defintion. 17 Prime mver 1. Fixato 19. Synergist 20. Anagonist (a) A mscle tha contracs isometically t stabilie the orgin of aother mucle (b A muscl that oposes the action o a flexo muscle (c) A muscle that is chiefly esponsible for a articulr movement (d) A uscle that prevts unwanted movements in an intermdiate jont so tht anothe muscle can cross that jont and at primarly on a istal jont (e) A muscle that oppses the ction of a prime over Vew Answe 17 C 18. A 19. D 20. E Fr each tpe of blod vesse listed elow, seect an apropriat definition. 21. Ateriole 22. Poral vein

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snell 23. Antomic en artery 24. Venle ) A vesl that connects two capilary beds (b A vesse whose trminal banches d not anatomose wth brances or areries suplying ajacent aeas (c) A vessel that connects large veins to capillaries d) An arery <0.1 mm in diameter (e) A thinwalled vssel tha has an rregular cross dimeter View Anwer 21. D 22. A 23 B 24. C For ech of th lymphatc structres listd below, select a approprate struture or unction. 25. Lyph capilary 26. Thoracic duct 27. Riht lymphatic duct 28. ymph nod (a) Pesent in the cental nervos system (b Drains ymph dirctly fro the tisues (c) Cotains lyphatic tssue and has both afferent and effernt vesses (d) Dains lymh from te right ide of te head ad neck, te right pper lim, and th right sde of the thorax (e) Drains lymph from the right side of he abdomn View Answer 25. B 26. E 27. D

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snell 8. C Multple-Choice Questions Directions Read th case histories ad select the best nswer to the quetion folowing thm. The surgica notes of a patien state tat she hd a righ infraumbilical pramedian incision through he skin f the anerior abominal wal. 29. Where exctly was this incsion mad? a) In th midline below the umbilicus () In the midline bove the umbilicu (c To the ight of he midlie above he umbilcus (d) To the righ of the mdline below the bilicus (e) Just elow th xiphoid process in the mdline View Anwer 29. D Afte an attck of peicapsuliis of th left shulder jont, a paient fins that particuar movemnt of th t i restriced. 30. hich of the t movements is resticted an by how uch? (a) Abduction is limid to 30Â. () Latera rotatio is limied to 45°. (c) Medil rotatin is limted to 5°. (d) Fleion is lmited to 90°. (e) Extension is limited o 45°. View Anser 0. A Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

3. 2. The Thorax: Part I - The Thoracic Wall 20-year-old woman was th innocnt victim of a stret shoot-out involving drgs. On examination the patient showed signs of seere heorrhag and was in state of shock. He pulse was rapid and her blood ressure was dangerosly low. There was small ntranc wound about 1 cm across n the ourth eft inercostal space abou 3 cm from te lateral magin of the strnum. here was no exit 87

snell wond. Th left side o her cest was dull on pecussio, and breath sounds were bsent n that side o the chest. chest tube ws immeiately introduced hrough the chst wal. Becase of he massive aounts f blood pouring ou of th tube, it was decide to ener the chest (thoractomy). The phsician carefuly counted the ribs to fin the ourth intercstal sace and cut the layrs of tissue to enter the pleurl spac (cavity). She was articuarly careful to avod impotant natoic strcture. Te inision was mae in te forth left itercostal sace alng a lne tht exteded fom the laterl margn of the sternum t the anterio axillry line. The followng strctures were icised: skin subcuaneous tissue, pectral mucles ad serrtus anterior muscl, extenal inercostl musce and nterio intercostal membrae, internal intercstal muscle, innermst intercostal musce, endothoacic ascia, an prieal pleur. The internal thoracic artry, whch descends just ateral to the sternu and the intrcosta vessels and nerve must e avoied as he knife cut through the layers of tissue to enter he chet. The cause f the emorrhge was perfortion of the left atrium of the hart by the bulet. A physican mus have knowledge f chst wal anatmy to ake a reasond diagosis ad institute treatment.

Chapter Objectives  

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An understaning of the sructure of te chst wal and the diphragm is essential if on is to understand te normal moements of th chest wal in th procss of eratin of te luns. Contained wihin th protctive horacc cag are te important ife-sutaining orgas—lungs, hert, an major bloo vesses. In addition, the lower art of the cage ovelaps te upper abdminal rgans, such as the liver, stomah, and splee, and offers them consideable protecton. Alhough he chst wal is stong, blunt r penetratin wound can injure the sof organ beneah it. This is espeially so in n era in whih autoobile accidents, stb wouns, ad gunsot wouds are commoplace. Beause f the linicl impotance of the chest wall, examinrs ten to fous on his area. Questions concering te ribs and thir movments; the daphrag, its attachents, and its funcion; and the contents of n intrcosta spac have een ased may tims.

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Basi Anatomy he thrax (or ches) is te region of he bod betwen th neck and the abdomn. It s flatened n frot and ehind but rounded t the sides. The frmework of th walls of the thorax which is rferre to as the thoracic cag, s fored by he vertebral colum behin, the ribs and intecostal spaces on ethe side, and te sterum and costa cartiages in front. Supriorly the torax communiates wth the neck, and inerioly it s searated from te abdomen by the diaphagm. Te thracic cage potects the ungs ad hear and affords attachent fo the muscles of the thorax, uppr extrmity, bdome, and ack. The cavity of the thorax can be dividd into a medin parttion, alled he ediastnum, and he latrally laced leurae and lugs. Th lungs are coered b a thi membrne caled the viscral plura, which es from each ung at its rot (i.e, wher the main air aes and blood essels enter) to the inner urface of the chest wall, where t is alled he prietal pleura. I this anner, two

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snell mebranou sacs alled he pleural avitie ar forme, one on each side of the thorax, between the lngs an the toracic walls.

tructue of the Thoracic Wll The thoracc wall is coered on the utsid by sin and by mucles ttachig the shouldr girle to the trnk. It is lined wit parital peura. The thoracic wall is formed poteriory by te thorcic prt of he vertebral column; anterorly b the sernum nd cosal catilage (Fi. 2-1); lterall by th ribs and inercostl spacs; superiorl by th supraleural membrae; and inferorly b the daphrag, whic separtes th thoracic cavity fom th abdomnal caity.

Sternum The sernum ies in the midline f the anterir ches wall It is a fla bone hat can be dvided nto three parts: maubrium sterni, body of th sternm, and xiphoid procss. P.47

he mnubrim is the uppe part of th sternum. It articulates with th body f the strnum a the anubristerna t, and it also articulates wth the clavices and with he firt costl cartlage nd the upper art of the second costal cartilages on each sie (Fig. 2-1. It les oppsite te thir and furth thoracic vertebrae. The body of the sternu articulaes aboe with the maubrium at the manuriostenal jont and beow wit the xphoid rocess at the xiphsterna t. On each side it articuates wth the second to the seventh costal cartlages Fig. -1) The xiphod process Fig. 2-1 is a thin pate of cartilage tht becoes ossified at its roximal end durin adult life. No rib or cstal crtilags are attachd to i. The stenal angle (angle of Louis), ormed y the rticultion o the mnubriu with he body of the sternum, can be recognizd by te presnce of a tranverse idge o the nterio aspec of th sternum (Fg. 2-2). The trnsvers ridge lies a the lvel of the second cotal crtilag, th point from wich al costa cartiages ad ribs are counted. The sternal ngle les oppsite te intevertebal dis betwen the fourt and ifth thoraci verterae. The xiphistenal jont lies oposit the bdy of he ninh thorcic vetebra Fig. 2-2.

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Figue 2-1 A. Anterior view o the sernum. B Sternm, rib, and ostal artilages forming te thorcic skeleton.

linica Notes Strnum ad Marrw Biopsy Since he stenum posesses red hematopoetic mrrow troughot life it is a commn site for arrow iopsy. Uder a ocal aesthetc, a wde-bor needle is itroducd into the marrow cavity hrough the anerior urface of the bone. The sternum may also be split at peration to alow th surgeon to gin eas acces to te heart, great vesels, nd thyus.

Ribs There are 12 pairs f ribs all o which are atached osterirly to the thoracic vertebae (Fgs. 2-1, 2-3, 2-4, an 2-5). Te ribs are diided ito thre cateories:  

Tue ris: he uper sevn pair are atached anterirly to the strnum b their costal cartiages. False rib: he 8th, 9th, and 10t pairs of ris are attahed anteriory to ech other an to the 7th ib by means f thei costa cartilages nd smal synvial oints. 90

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Floating ribs: The 1th and 1th pars hav no anerior ttachment.

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Figure 2-2 Lateral view of the thoax shoing th relatonship of the surfac markings to the vetebral levels

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Figre 2-3 Thracic ertebr. A. Suprior srface. B Laterl surface.

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Figure 2-4 Fifth right rib as it articulaes wit the vrtebra colum postriorly and the stenum aneriorly. Not that the ri head articuates with the vertebral body of its ow numbe and tat of he vertebra mmediaely aove. Nte als the pesence of the costal groove along he infrior order f the rib.

Typcal Ri A typical ib is long, twiste, flat bone hving a rounded, smoth suprior brder ad a sharp, tin infrior brder (Figs 2-4 and 2-5. The nferio borde overhangs ad forms the ostal groove, wich accommodates the intercostal vessels and neve. Th anteror end of eah rib s attahed to the coresponing cotal catilage (Fig. 2-4).

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Figre 2-5 Fith rigt rib, as see from the posterior aspect.

rib has a ead, nck, tuercle, shaft, an ange (Figs. 2-4 and 2-5) The head has to facets for articulation ith th numerically corresponding vertebral body and tat of he verebra imediatly aboe (Fig. 2-4). Te nek i a contricte portin situted beween te head and the P.50

tuberle. Th tubercle is a prominence on the outer suface o the rb at te juncion of the nck wit the saft. I has a facet or articulation with the transverse prcess o the nmericaly corespondng verebra (Fig. 2-4) The haft i thin nd flatned and twisted on its long axis. Its iferior border has the costal groove. The angle s where the shaft o the ib bens sharly forard.

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igure 2-6 Thorcic oulet showing he cerical dme of pleura on the left sde of the body and its relationship to he innr bordr of te firs rib. Note aso the presene of bachial plexus and sbclavin vessls. (Anatomsts ofen refr to te thorcic oulet as the thracic nlet.)

Atypcal Ri The first ib is important clinically becaus of it clos relatonship to the lower erves of the brachil plexs and he man vessls to he arm namel, the ubclavan artry and vein (Fig. -6). Thi rib i small and flttened from aove donward. The sclenus anterior muscle is attached to its upper surfac and iner boder. nterio to th scaleus antrior, th subclvian vin croses th rib; posterior to the mucle attachment, the subclaian arery and the lower runk o the bachial plexus cross he rib and le in cntact ith th bone

linica Note Cervcal Ri A cervica rib (i.e., rib aising from te anterior ubercle of te tranverse proces of the seventh cevical ertebr) occurs in about 0.5% o humans (Fg. 2-7). t may have a free anterio end, may be conneced to he firt rib y a fbrous and, o may aticulae with the fist rib The iportane of a cervial 95

snell rib is that it can cause pressure on the lowr trun of th bracial plxus in some ptients produing pain down the edial side of the forearm and and an wastng of he small musles of the had. It can aso exert presure o the oerlyin subclvian atery and interfere with te circlation of the upper imb.

Rib xcisio Rib excisin is cmmonly perfored by thoracc surgons wshing to gain entrace to he thoacic cavity. A longitudinal inciion is made trough he perosteum on the outer urface of the rib and a sgment f the rib is remove. A seond logitudial incsion i then made trough he bed of the rib, wich is the iner covring o peristeum. After he opeation, the rib regenerates from the ostogenetc laye of th perioteum. P.51

Costa Cartiages Costal cartilages are bars of catilage connecing th uppe seven ribs t the lteral edge o the sernum nd the 8th, 9h, an 10th ibs to the catilage immeditely aove. Te cartlages f the 11th and 12th ribs nd in he abdminal usculaure (ig. 2-1). Th costa cartiages contribute sigificanly to he elsticit and mbility of the thoracic walls. In old age, the cstal artilaes ten to loe some of ther flexbility as the result of suerficial calcification.

Jints o the Cest Wal Jonts of the Sternum The manubriostenal jont is a artilainous oint btween he manbrium nd the body o the ternum. A small amount of angular movemet is pssible during respiation. The xiphistrnal jint is a cartilginous t etween the xihoid pocess (cartilage) and the body of the sternum. The xihoid pocess sually fuses ith th body f the sternu durin middl age.

Jints o the Rbs Jonts of the Heads of the Ris The fist rib ad the hree lowest ibs hae a sigle snovial t ith thir corespondng verebral ody. Fr the econd to the ninth ribs, the head articulates y means of a ynovia t with the corresponding vertebral body ad that of the verteba abov it (Fig. -4) There is a srong intrarticular ligament that connects the head to the inervertbral disc.

s of te Tubecles of the Ribs

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snell The tuberce of a rib ariculats by means of a synvial t wih the transverse prcess o the crrespoding vrtebra (Fig 2-4). (This t is absent on the 11th and 12t ribs.

s of te Ribs and Cotal Catilages These t are crtilagnous jints. o moveent is possibe.

Figre 2-7 Thoracic utlet s seen from above. Note the presece of he cerical rbs (black) on oth sies. On the right side of the thorax, the rib is almost complte and articuates ateriory wit the frst ri. On te left side f the horax, the ri s rudimentar but i contined forard a a firous band that is atached to th first costal cartilage. Nte tht the ervicl rib ay exet pressure o the lwer tunk f the brachal pleus and may kink the subclaian artery.

t of th Costa Cartiages wth the Sternu The first costal cartilages ariculat with he manbrium, by carilaginus joits tha permt no mvement (Fig. 2-1). Th 2nd t the 7h costl cartlages articulate with the lateral border of th sternum by ynovia t. In addition the 6h, 7th 8th, th, ad 10th costal cartilges ariculat with ne anoher alng ther borers by small ynovia t. The artilaes of he 11t and 1th ris are mbedde in th abdomnal muculatue.

Moveents o the Rbs and Costa Cartlages

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snell he 1st ribs and ther costl cartlages re fixd to he manbrium nd are immobie. The raising and lowering of the ribs during respirtion ae accopanied by movments n both the jonts of the head and the tbercle permiting te neck of eac rib t rotat aroud its wn axi.

penings of the Thorax Te ches caviy commnicate with the rot of te neck throug an opning clled te thracic utlet. It is called an outlet becaus imporant vesels ad nervs emere from the torax hre to nter the neck and upper limbs. Th openig is ounded posterorly b the first thoracic ertebr, lateally b the edial orders of the first ibs an their costal cartilges, ad antriorly by th superor borer of the manbrium terni. The opning is oblquely laced facing upward and frward. Through this small opening the esphagus and trachea nd man vesses and erves Becase of he obliquity of the openin, the apices of the lung ad plerae project pward nto th neck. Te thoracic cvity cmmunicates wth th abdomn thrugh a arge oening. The opening s bouned poseriorl by th 12th thoracic vertebra, aterally by te curving cosal margin, an anteiorly y the xiphisternal t. hrough this lrge opning, hich s closd by te diapragm, ass th esophgus an many arge vssels and neves, al of wich pirce th diaphagm.

linica Notes The horaci Outle Syndrme The bachial plexus of nerves (C, 6, 7 and 8 and T1 and he sublavian artery and vein are closel relatd to te uppe surfce of he firt rib nd the clavice as tey entr the pper lmb (see Fi. 2-6). I is hee that the neves or blood vessel may b comprssed btween he bons. Most of the symptms are aused y presure on the loer truk of te plexs prodcing pin down the medial side of the forearm nd han and wasting of the small muscle of th hand. Pressue on te blood vessels may comproise th circlation of the upper imb. P.52

ntercostal Saces The spaces betwee the rbs conain three muscles of respration the eternal intercotal, te intenal inercostal, and the innermost intercostal muscle The inermos interostal uscle s lined intenally y the endothoracic fascia, hich i lined internally by the parietal pleura. The interostal nerves and blod vesels ru betwen the ntermeiate ad deepst laers of muscle (Fig 2-8). Thy are rrange in te following rder fom aboe downard: itercosal vei, intercosta arter, and ntercotal neve (i.., VAN).

Intecostal Muscle

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snell Th exernal ntercotal mucle forms the most superficil laye. Its ibers re dircted dwnward and forward from the inferior boder of the ri above to the superir P.53

borer of he rib below (Fig. 2-8). The muscle extend forwad to te costl cartlage were it is repaced b an apneuross, the anteior (eternal interostal embran (Fig. -9)

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Figure 2-8 A. Secion though a intercostal space. B Strutures enetraed by a eedle when i e from skin srface to plural cvity. Dependng on he site of penetration, te pectoral muscles will e

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piered in addition to he seratus anterio muscl.

Figure 2-9 Cross section of the thoax shoing ditributon of typicl intrcosta nerve and a posteror and an antrior itercosal artry.

The intenal inercostl musce forms he intrmediate layer. Its fibers are directed ownwar and ackwar from he subostal roove f the ib aboe to te uppe borde of te rib elow (Fig. 2-8) The mscle etends backwad from the sternum in front to the angles of the ribs ehind, where the mucle is replacd by a aponerosis, the posterir (intrnal) ntercotal mebrane (ig. 2-). Te innermost intercstal mscle fors the eepest layer nd corespond to th transersus abdominis muscle in the anerior bdominl wall It is an incmplete muscle layer and crosses ore thn one ntercotal spce witin the ribs. t is elated internlly to fascia (endotoracic fascia) and parietal pleura and xternaly to the inercostl nervs and essels The inermos intecostal muscle can be divide into hree portion (Fig 2-9), whch are more o less eparat from ne anoher.

Action Wen the intercstal muscles contrat, the all tnd to pull te ribs nearer to one anothr. If he 1st rib is fixed y the contraction f the uscles in the root o the nck, naely, te scalni mucles, he intrcostal muscles raise the nd to the 12th ribs oward the fist rib as in inspirtion. f, conersely the 1th rib is fixd by he quaratus umboru muscl and te obliue musles of the adomen, the 1s to th 11th ribs will be owered by the contration f the intercstal mscles, as in xpiraton. In additin, the tone o the ntercotal mucles dring th diffeent phses o respiation erves to stengthe the tssues f the

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snell ntercotal spces, tus preenting the scking n or te blowng out of the tissue with change in itrathoacic pessure For frther etails concering the action of these muscles, see mechancs of espiraion on pae 100.

Nerve Supply The intercstal muscles are supplied y the orrespnding ntercotal neves. The intecostal nerves and blod vesels (te neuovascuar bunle), a in th abdomnal wall, run betwen the iddle and inermost layers of musles (igs 2-8 and 2-9). They are arrange in th folloing orer fro above downwad: inercostl vein interostal rtery, and inercostl nerv (i.e. VAN).

Intercstal Ateries and Vens Each intercstal sace cotains large single posteror intrcosta arter and to small anteior inercostl arteies. 



The posterior intrcosta arteres of the first two spces ar brances fro the sperior intercstal rtery, a branch of the costocervical truk of te subcavian rtery. The psterio interostal arteies of the loer nin space are ranche of th desceding toracic aorta Figs. 29 and -10. The anterior intercstal ateries of the fist six spaces are brnches f the nterna thoraic artry (Figs. 29 ad 2-1), which arises from te firs part f the ubclavan artry. Th anteror intercostal arteries of the lower spces ar brances of he muculophenic atery, one of he terinal banches of the internl thoacic atery.

Each inercostl artey give off banches to the muscles, skin, and parietal pleua. In he regon of he brest in he feale, te branhes to the suerficil strutures re particularly large. Th correpondin poserior ntercotal vens drain ackwar into he azyos or hemiazygos veins (Fgs. 2-0 ad 2-1), and the antrior itercosal veins rain frward nto th interal thoacic ad musclophreic veis. P.4

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igure -10 A. Intrnal vew of h posteior ed of to typial intercostl spaces; te postrior intercotal mebrane as been removed for clariy. B. Anterior view of he chet shoing th coures of the inernal horaci vessels. Tese vessels escen about one fingerbradth fom the latera margn of te sterum.

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Figue 2-11 Te commn arrangemet of te azygs vein, the uperio hemiaygos accessory heiazygo) vein and te infeior heiazygo (hemizygos) vein.

Itercosal Neres 104

snell The inercostl nervs are he antrior rami of the first 11 thoraci spina nerves (Fi. 2-12). he antrior ramus of the 12th thoracic nerve lis in te abdoen and runs frward n the bdominl wall as the subcostal nerve. Each inercostl nerv enter an intercostal space between the parietl pleua and he poserior ntercotal mebrane Figs 2-8 and -9. It hen rus forwrd infriorly to the intercstal vssels n the subcotal goove o the crrespoding rb, beteen th innerost itercosal and internl intecostal muscle The frst si nerve are istribted wihin thir intrcosta space. The eventh to ninth intercostal nerves leave the anterior ends f thei interostal paces by pasing dep to te costl cartlages, to entr the nterio abdoinal wll. Th 10th nd 11t nerve, sinc the crrespoding rbs ar floatng, pas directly nto te abdoinal wll.

Branches See Figure 2-9 and 2-12.       

Rai commnicants connect the inercostl nerv to a anglio of th sympahetic runk see Fg. 1-2). The gray ramus s the neve meial at the point at which the white ramu leave it. The collteral ranch runs forwad infeiorly o the ain neve on he uppr bordr of te rib elow. The laterl cutaeous banch reaces the skin o the sde of he chest. It divides into n anteior an a poserior ranch. he anterio cutanous brnch, which is the terminal portion f the ain trnk, reches te skin near he midine. I divides into a medial and a lateral branch. Mscular branches un to the intercostl musces. leura sensory branhes go to the paietal leura. Peritoneal ensory branches (7th to 11t interostal erves nly) rn to te parital peitoneu.

Clincal Noes Skin Innevation of the Chest all an Refered Pai Above the level f the ternal angle, the cutaneous innervation of the nterio chest wall i derivd from the upraclvicula nerve C3 and 4). Beow this leve, the nterior and lateral cutaneus brnches f the ntercotal neves suply obique bnds of skin i reguar seqence. he ski on th posteior suface o the cest wal is upplie by th posteior rai of te spinl nervs. The arrangment f the ermatoes is shown n Figres 1-3 nd 1-4. An itercosal neve not only supplie areas of ski, but also supplies the ribs, costal catilage, intecostal muscle, and parietal pleura lining the intercstal space. Frthermore, th 7th to 11th intercstal nerves leave the thoracic wall and enter te anteior adomina wall o that they, n addiion, spply drmatoms on te antrior abdomina wall, muscle of th anteror abdminal all, ad paretal pritonem. This latter fact is of great clinical importance becaue it mans tht disese in he thoacic wll may be revaled a pain in a drmatom that xtends across the costal margin into the anteror abdminal all. Fr examle, a pulmonay throboemboism or a pnemonia ith plurisy nvolvig the ostal arieta pleur could give ise to abdomial pai and tenderness and rigidity of the abdomial musculature. The abdomina pain in thee instnces i called refered pai.

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Herpes Zoster Herpe zoste, or singles is a relatiely comon cnditio cause by the reactvatio of th laten varicllazoter vrus in a patint who has prviousl had cickenpx. The lesion is sen as an infammatin and egenertion o the snsory euron n a canial r spinl nerv with he foration f vesiles wih infammatin of te skin In th thora the frst syptom i a ban of drmatoml pain in the distriution f the sensor neuro in a horaci spinl nerv, follwed in a few ays by a skin erupton. Th condiion ocurs mst frequently in patents oder thn 50 yars. The fist intrcosta nerve i e to th brachal pleus by large branch that is equivalent to the latera cutanous brnch of typica intercostal nerves The emainder of the first intercostal nerve s smal, and here i no aterior cutaneus brach. The second intercostal nerve is ed o the edial utaneos nerv of th arm b a brach caled the intecostobachial nerve, whih is equivalnt to the P.56

laterl cutaneous branch of other nerve. The econd ntercotal neve threfore supplis the kin of the arpit an the uper meial sie of he arm In oronar arter disese, pan is rferred along this nrve to the meial sie of te arm.

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Figue 2-12 Th distrbution of two intercostal nerves elativ to th rib cge.

Clinical Notes ntercostal Nerve Block Aea of nestheia The ski and te parital plura coer the outer and inner sufaces f each intercstal sace, rspectiely; te 7th o 11th interostal erves upply he ski and te parital peitoneu coverng the outer and inner sufaces f the bdominl wall respetively Therfore, n intecostal nerve lock wll als anestetize hese reas. n addiion, the perosteum of the adjacet ribs is anesthetized.

Indicaions

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snell Intercostal nerve block is indicaed for repair of laerations of the thoracic and abdoinal wlls, fr relif of pin in rib frctures and t allow pain-fee resirator movemnts.

rocedure To prodce anagesia of the anteror and laterl thoacic ad abdoinal alls, the intercostl nerve shoud be blocked befor the lteral utaneos branh ariss at the midaillary line. he ris may be identified by counting dwn fro the 2d (oppsite sernal angle) or up rom th 12th. The nedle is directed toward the rib ner the lower border (Fig 2-8), ad the ip coms to est ner the subcosal grove, whre the local anesthetic i infitrated around the neve. Reember hat th order of strctures lying in the neurovascular bundle from above downward is intrcosta vein arter, and erve ad that these tructures are situated between the posterior itercosal memrane o the iternal intercstal mscle nd the parietl pleua. Furhermor, lateally te nerv lies etween the iternal intercstal mscle ad the nnermst intrcosta muscl.

Anatmy of omplictions Comlication inclue pneuothora and emorrhge. Pneumthorax ca occur if the needle point isses he subostal roove nd penetrates too deply trough the paretal peura. Hemorhage is aused y the punctue of te intercostal blood vessels. This is a cmmon ompliction, o aspiation hould lways e perfrmed bfore ijectin the nestheic. A mall hmatoma may reult. P.57

With the exceptons nted, te firt six ntercotal nrves terefoe suppy the skin ad the parietl pleua covring te outer and inner urface of ech intrcostl spac, respectively, and the ntercotal muscles f eac interostal space nd the levatores costarum and serrats posterior muscles In additin, the 7th t the 11th inercosal neres suply the skin and the parietal peritneum coverin the oter and innr surfces of the abominal wall, respecively, and the anterior adomnal mscles, which includ the eternal obliqe, intrnal blique transversus adomini, and rectus abdominis mucles.

Surapleural Membrane Supriorl, the horax pens into th root of the neck b a narow aprture, the thoracic outet (see page 5). The otlet tansmit structures hat pas between th thora and te neck (esohagus, tracha, blod vessls, et.) an for te most part lie clse to he midine. n eithr side of these strctures the oulet s closd by a dense ascial layer called the suprpleura membrane (Fig 2-13). his tentshaped fibous sheet is attached latrally o the medial border of th firs rib ad costl cartlage. t is attached at it apex to the tip o the tansvere procss of the seenth crvical vertera and medially

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snell to the fasia invsting the stuctures ing frm the horax into te neck It prtects the unerlyin cervial peura ad resits the changs in intrathracic ressure occuring uring espiratory movement.

Edothoracic Fscia The ndothoacic fscia is thin layer f loos connctive tissue that sparate the arietl pleua from the thoracic wall. The suprapleral mebrane s a thickening of tis fasia.

Diaphragm The iaphragm is thin uscular and tendinus sepum tha separates te ches cavit abov from he abdominal cavity below (Fig. 2-16). It is pirced by the tructures that betwee the ches and he abdmen. The diaphagm is the most imprtant muscle of respiraton. It is dom shaped and consist of a peripheral muscular part, which arises from he marins of the toracic opening, and a centrally placed tendo (Fig. 2-1). The origi of th diaphragm can be dvided nto three parts:   

A sternal part arsing from th posterior surface f the iphoid proces (Fig. 2-2) A cotal pat arisin from the dep surfces of the lower si ribs nd thir cosal catilaes (Fig. 216) A vrtebral part arising b vertial columns o crura and from the arcuate ligamnts

The righ crus ariss from the sides of the boies of the fist thre lumbr vertbrae and the intervrtebra discs the ft crus aises fom the sides of the bodies of the first wo lumar vrtebrae and he intrverteral dic (Fig. 2-16). Lateral o the rura te diapragm aises fom the medial ad lateral acuate igamens (Fig. -16. The medial arcuate ligament extends from the side o the bdy of he seond lubar vertebra o the ip of the transverse process of the first lumbr vertbra. Te lateal arcate ligament xtends from te tip of the transverse proces of th first lumbar vertebra to the lower border of the 12th rib. he medal borers of the tw crura are cnnecte by a media arcuae ligaent, which crosss over the anerior urface of the aorta (Fig. 2-16).

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Figure 2-13 Lateral view of the uppr openng of he thoacic cge shoing ho the pex of the lung projects superiorly into the root of te neck The pex of the lug is cvered ith viceral nd paretal lyers o pleura and is protected y the uprapleural mmbrane, which is a tickenig of he endthoracc fasca.

Cliical Notes 110

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Toracic Cage Distortion The shpe of he thoax can be disorted by congenital anomalies of the vetebral column or by he rib. Destuctive diseas of the vertebral column that produces lateral flexio or scliosis resuls in mrked distorton of the thracic age.

Clincal Noes Tramatic njury o the Thorax Traumatic injur to th thora is comon, epecialy as a result of automobile accidents.

Fracture Sternm Th sternm is a resilient structure that i held n postion b relatively pliable costal cartilages and bendabe ribs For hese rasons, fractue of te sterum is ot comon; hoever, t does occur in hihspee motor vehicl accidnts. Rmember that te hear lies posteror to he stenum an may b severly conused by the sternum on impact.

Rib Contusion Bruising f a ri, secodary t traum, is te mot comon rib injury In ths painul condition a smal hemorhage ccurs beneat the priostem.

Rb Fracures Fractues of he rib are cmmon chest ijuries In children the rbs are highly elastic, and fractures in this ag group are terefor rare. Unfortnately the piable hest wll in he youg can be easily compressed so tht the nderlyng luns and heart may b injured. Wth inceasing age, the rib cage becomes more rigid, wing to the deposi of calcim in the costal carilages and te ribs becom britle. Th ribs hen end to break at ther weakst par, their anges. Th ribs prone t fractre are those that re expsed o relaively fixed. ibs 5 through 10 ae the most cmmonly fractured rbs. Th first four ribs are protcted b the clavicl and pctoral muscles aneriorl and by the capula and its assoiated uscles postriorly. The 1th an 12th ribs foat an move ith the forc of impact. Because th rib i sandwched between the skin exernall and te deliate plura internaly, it is not surpriing that the jagge ends f a frctured rib may penetrate the lung and resent as a pneumthorax Severe localized pain is usuall the mst imprtant symptom of a fractued rib The priostem of ech rib is innervated by te intercostal nerve above and beow the rib. o encorage te patent to breath adequately, it may be necssary o relive the pai by prformig an intercstal nrve blck.

Flil Chest 111

snell In sevre crush injuries, a numer of ibs ma break If limited to one side, the fractures ay occr near the rb angls and anterirly nea the cstochodral jnction. This causes flail hest, in whch a sction f the hest wll is isconncted t the rst of he thracic all. I the facture occur on either side of the sterum, te sterum may be flal. In ither ase, te stablity o the cest wll is ost, ad the flail egment is suced in uring nspiration ad drien out during expiraion, poducin paradxical nd inefectiv respratory movemets.

raumatc Injuy to te Back of the Chest The poterior wall o the cest in the mdline s formd by he verebral olumn. In sevre poserior chest injurie the ossibility of a vertbral facture with asociatd injuy to te spial cor should be considered. Remembe also the prsence f the scapul, whic overles the upper even rbs. Ths bone is covered with muscles ad is facture only n case of severe tauma.

Taumatc Injuy to te Abdoinal Viscera and the Ches Wen the anatom of the thorax is rviewed it is imporant to remembr that the upper abominal orgns—naely, te livr, stoach, and spleen—ma be ijured y trauma to the rb cage. In act, ay injry to he chest below the evel o the nipple ine may invlve abominal organ as wel as chest ogans. P.58

The diaphragm is inerted into a cetral tndon, hich i shapd like three leaves. The sperior surfae of te tendon is partialy fusd with the iferior surface of the fibrus peicardum. Soe of he musle fibrs of the riht cru p to the let and urround the esophageal rific in a slinglke loo. Thes fibrs appar to ct as sphinter an possily assst in he prventio of reurgitaion of the stomach ontents into the thracic part o the eophagu (Fig. 2-16).

Shape of th Diaphagm As sen from in frot, the diaphragm cuves up into right nd lef domes, or cupulae. Th right dome reaches as high as the upper order f the fifth ib, an the lft dom may rach th lower border of the fifth rib. (The right dom lies t a hiher leel, beause of the lrge sie of he rigt lobe of the liver. The cntral endon ies at the leel of the xihisteral joit. The domes suppor the right an left ungs, whereas the central tendon suppors the eart. he levls of he diphragm vary wth the phase of rspiraton, th postue, and the dgree o distetion o the adomina viscea. The diaphrgm is ower hen a erson s sittng or tandin; it i highe in th supin posiion an after a larg meal. When seen from the side, the diphragm has th apperance f an iverted J, the long limb extendin up from the vertebral column an the sort limb exteding frward o the iphoid proces (Fi. 2-2).

Neve Suply of he Diahragm

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Motor nerve upply: Th right and let phreic neres (C3 4, 5) Sensor nerve supply The parietal peura ad perioneum overin the central surfaes of the daphrag are fom the phreni nerve and th peripery of the diphragm is frm the ower sx intecostal nerves.

P.9

Figue 2-14 Tbe thoacostomy. A. Te site for inertion of the tube at the nterir axilary line. The skin incision is sually made oer the intercstal sace on below the sace to be pierced. B. The various layers f tisse penerated y the calpel and laer the tube a they ass trough he chet wall to entr the leural cavity (space). The incision through the interostal pace i kept lose t the uper brder o the rib to avoid injuring the inercostal vessels an nerve C. The tube avancing superiorly

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nd posteriorl in th pleural spac.

Ation f the Diaphram O contrction, the diaphragm pulls down is cental tenon and increaes the verticl diamter of the thorax.

Functions of the Daphragm 







Muscle of nspiration: On conraction, th diapragm plls its cental tenon dow and increaes the vertial diaeter o the thorax. The diphragm is th most importnt muscle usd in ispiration. Mscle of abdominal srainin: Th contrction f the diaphrgm asssts the ion of th muscls of the anterior abdomial wal in raising he inta-abdoinal pessure for micturiion, dfecation, and partuition. This mchanism is frther aided y the erson taking a deep breath and cosing the glttis of the lrynx. The diaphragm is unale to ise beause o the ar traped in the respiratry tract. Now and agin, ar is alowed to escape, producing a gruting sund. eight-lifting muscl: In a prson aking deep reath nd holing it (fixin the daphragm), the diaphragm asists he muscles o the aterior abdomial wal in raising he inta-abdoinal pessure to suc an exent tht it hlps the vertebral column and prevent fexion. This greatly assists the postvertebral muscles n the lifting of hevy weihts. Nedless to sa, it is impotant t have dequat sphinteric control of te bladder and anal canal nder tese circumstnces. Thoracoabominal pump: Th descet of te diapragm dcrease the itrathoacic pessure and at the same time increases te intr-abdomnal prssure. This pessure chane compesses he blod in te inferior vena cava and forces it upard ito th right atrium of the heart Lymph .60

witin the abdominal lmph vesels i also ompressed, and its age upward within the toracic duct i aided by the negatie intrthoracic prssur. The resenc of valves ithin he thoacic dct prevents backflow.

Clinical Ntes Nedle Toracosomy A needle thoracostomy is necessar in paients with tension pneumothorax air in th pleurl cavity under presure) o to dain flid (blod or us) awy from the plural cvity t allow the lng to e-expand. I may aso be ecessay to wthdraw a sampe of leural fluid or micobioloic exainatio.

Antrior Aproach

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snell For the anterior approah, the patien is in the supine osition. The ternal angle s idenified, and then the second costal cartiage, te secod rib, and th secon interostal pace ae foun in te midcaviculr line.

Lateral pproac For the lteral pproac, the atient is lying on the lateral sde. Th secon interostal pace is idenified s aboe, but the nterio axillry lin is usd. The skin is prepred in the usal wa, and local anesthetic s intrduced along he course of the nedle above the uper border of the tird ri. The thoracstomy eedle ill pierce te folowing structres as it pases though he chet wall (Fig 2-8): (a) skin, (b) superficial fascia (in the aterior approah the ectora musces are then pnetratd), (c serraus antrior mscle, d) external intercostal muscle, (e) internal itercosal musle, (f) innemost intercostal musce, (g) endothracic ascia, and (h) parietal leura. The needle hould e kept close o the pper border of the third rib to avoid injuring the inercostal vessels and nerve in the subcostal grove.

Tube Thoracostomy The prefered insrtion ite fo a tub thoraostomy is te fourh or ffth inercostl space at the anteior axllary ine (Fig. 2-14) The ube is introduced through a small incision. The neurovscular bundle changes its relationship to the ribs as it pases forard in the itercosal spae. In he mos posteior pat of te spac, the bundle lies i the mddle o the itercosal spae. As he bunle pases foward t the rb angl, it bcomes closely related to the lowe bordr of the rib above nd maitains hat poition s it curses forwar. The inroduction of a thoracostom tube r neede thrugh th lower intercstal saces i possile proided tat the presece of he doms of te diapragm i ed as they curve upward into te rib age as far as the fifth rib (higher on the right). Avoid dmaging the daphrag and etering the peitonea cavit and njurin the lver, sleen, r stomch.

Thracotoy In patiens with penetrting chest wunds with unontroled intrathoraic hemrrhage thoraotomy ay be life-aving procedre. Afer prearing he ski in th usual way, te physcian akes a incision over the fourth or fifh intecostal space, extending from the latera margi of the sternm to te anterior axllary line (ig. 2-15) Wheter to ake a ight o left ncisio depens on te site of the injury. For access to the heart and aorta, the chest should be entred fom the left sde. Th folloing tisues wll be ncised (Fig. 2-14): () skin (b) sbcutanous tisue, () serrtus anerior nd pecoral muscles, (d) external intercostal muscle and aterior intercstal embran, (e) nterna interostal uscle, (f) inermost intercstal uscle, (g) enothoracic fascia, and (h) parietal pleura. Avoi the internl thorcic arery, which runs verticlly donward ehind he costal cartilages abou a fingerbradth lateral to the margin of the sternum, and the itercostal vessels and nerve, which extnd forard in the sucostal groove in the upper part of the intercostal space Fig. -14).

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Hiccup iccup is the involutary sasmodi contrction f the diaphrgm accmpanie by te approximaton of he vocl fold and losure of the glotti of th laryn. It i a comon conition n noral indvidual and ocurs ater eaing or drinking as a result of gastric irritation of he vags nerv endings. It ay, hoever, e a smptom f disese suc as pleurisy, peritoitis, ericaritis, r ureia.

Paralsis of the Daphram single dome of the diaphrgm may be parlyzed y cruhing o sectining o the phrenic nerve in the neck. This may be necessry in he tretment f certin fors of lng tubrculoss, whe the hysicin wishs to rst the lower lobe of the lung on ne side. Occsionally, the contriution rom th fifth cervicl spinl nerv the prenic erve lte as branc from he nere to te sublavius muscle. This i known as th accssory hrenic nerve. To obtain complete paralysis under these circumstaces, te nerv to th subclvius mscle must also be setioned

Pnetratng Injries o the Diaphram Penetratin injures can result from tab or bullet wound to th chest or abdmen. Ay penerating wound to the chest below he levl of te nippes shold be uspectd of cusing amage o the diaphrgm untl provd otherwise. The arching domes of the daphrag can rach th level of the fifth ib (th right dome cn reach a higher level).

Openings in the Daphrag The diapragm hs thre main penings:  



Th aortic opening lies anterio to th body f the 2th thracic ertebr between the crura Fig. 2-16). It ransmis the orta, he thoacic dct, an the aygos vin. The esophaeal opning lies at th level of the 10th thoraci vertera in sling of musle fibrs derved frm the ight cus (Fg. 2-6). It trnsmits the esphagus, the right ad left vagus erves, the esophageal branches o the lft gasric vesels, nd the lymphaics from the lower hird o the eophagu. The aval opening lie at th level of the eighth thoracic vertebra n the entral tendon (Fig. 2-16). It transmts the inferior vena cava and terinal banches of the right hrenic nerve.

In addition o thes openigs, th sympahetic splancnic neves pirce th crura the sympathtic trunks pas posterior o the edial arcuate ligamet on ech sid; and he suprior pigastic vesels pas betwen the sternal and costal rigins of th diapragm o each ide (ig. 2-6) P.61

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Fgure 215 Left toracotmy. . Site of skin icision over furth o fifth intercstal sace. B. The exposed ibs an assocated mscles. The lne of ncisio through th interostal space sould b place close to the upper order f the rib to avoid njurin the itercosal vesels an nerve C. The pleura space opened and the left side o the mdiastium expsed. he lef phrenc nerv desceds ove the pricardum beneath te medastina pleur. The ollapsd left lung must be pushed out of the way to vsualiz the mdiastium.

P.62

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Figure 216 Diaphagm as seen fom belw. The anterir porton of he rigt side has een reoved. ote th sternl, cosal, an verteral orgins o the muscle nd the importnt strcture that ass through t.

Ebryolgic Notes Deelopmet of te Diapragm The diaphragm is frmed fom the following structure: (a) he septum tansverum, which forms he musle and centra tendo; (b) he two pleuoperitneal mmbrane, which are larely responsible for te peripheral areas f the diaphagmati pleur and pritoneum tha cover its uper and lower surfacs, respetively and () the orsal esentey of te esopagus, in whih the rura dvelop. The septu transersum s a mas of msoderm that is formed in the neck by the fusin of he myoomes o the tird, furth, and fith cerical sgments With he desent of the hert fro the eck to the thorax, he sepum is ushed audall, pullng its nerve supply with i; thus its mtor neve suply is erived from te thir, fouth, an fifth cervicl nervs, whih are ontaind withn the phreni nerve The leuropritonel membranes grow medially from the ody wall on ach sie untl they fuse ith th septu transersum anterir to te esopagus ad with the dosal meentery posterior to the esophagus. During the proces of fuion, te mesoerm of the setum tansverum extnds ino the ther prts, frming ll the muscle of te diapragm.

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snell Th motor nerve upply to the entire muscl of th diapragm i the prenic erve. he central pleura on the uper suface f the iaphram and he pertoneum on the lower urface are alo fored from the septum transvesum, wich exlains heir snsory innervtion fom the phreni nerve The snsory nnervaion of the pripherl part of th pleur and pritonem coveing th periperal reas o the uper an lower surfaces of he diahragm s from the lwer si thoraic neves. Tis is nderstndable since the peiphera pleua and eritonum fro the peuropeitonea membrnes ar derivd fro the bdy wall.

Diaphragmatc Hernae Congnital erniae ocur as the rsult o incomlete fsion o the sptum tansverum, th dorsa mesetery, and th pleurperitoneal membranes from he bod wall. The hrniae ccur at the fllowin sites (a) te pleuoperitneal cnal (ore comon on the let side cause by falure o fusio of the septum transversum with he pleroperitoneal embran), (b) the opning etween the xihoid ad costl origns of he diahragm, and (c) the esophaeal hitus. Acqired hrniae may occur in midle-age peopl with eak muculatue aroud the sophagal oening n the iaphram. Thee hernae may be eiter sliing or paraeophagel (Fi. 2-17). P.63

Fgure 2-17 A. Sliding esophageal herna. B. Paaesophgeal hrnia.

Iternal Thoracc Artery 119

snell The inernal horaci arter supplies the anterior wall of te body from te clavcle to the umbilicus. It is a brach of he first art of the suclavia arter in th neck. It descends vertically on the peura bhind te costl cartlages, a fingrbreadh lateal to the strnum, nd end in th sixth intercstal sace by dividig into the sperior epigasric an muscuophrenc arteries (Figs. 2-9 and 2-10.

Brances      

Two aterior interostal rterie for the upper six intecostal spaces Perforating arteries, which accompay the ermina brances of he coresponding intrcosta nerve Th percardiaophrenc artey, which accompanies the phrenic nere and upplies the pricardum Mediasinal ateris o the ontens of the anteior meiastinm (e.g, the hymus) The sperior epigasric arery, whic enters the rectus sheath of the anerior bdominl wall and supplies the rectus mucle as far as the umilicus he msculoprenic rtery, whch runs around the costal margin f the iaphram and upplie the lwer intercotal spces an the daphrag

Interna Thoraic Vei The intenal thracic ein acompanis the nterna thoraic artry and drains into the brahiocepalic vin on ach sie.

Levatores Cotarum There are 1 pairs of musles. Ech levtor cota is trianglar in shape and arises b its apex from the tip of he trnsvers proces and s inseted ino the ib belw.  

Action Ech raies the rib beow and is therefore an insiratory muscl. Nerve supply: Psterior rami of thoacic sinal nrves

erratus Postrior Sperior Muscle The seratus posteror suprior i a thi, flat muscle that arises from the lower cervial and upper horaci spine. Its fibers downward and laterally and ae inseted ino the pper ribs.  

Acton: It elvates the ris and s therefore an inspratory muscl. Nerve suppy: Interostal nerves

Seratus Posterir Infeior Muscle The serrtus poterior inferor is a thin, flat uscle that arises rom th upper lumba and lwer thracic pines. Its fiers upward and laterally and are inserted into te lowe ribs.  

Action: It depesses the ribs and s therfore a expirator muscl. Nerve suply: Intercostal nerves

A sumary of the mucles o the thorax, their erve spply, nd ther actins is iven i Table 2-1.

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Raiograpic Anaomy This is fuly descibed o page 31.

Clinical Ntes Inernal horaci Artery in the Treament o Coronry Artry Disase In ptients with occlusive coronary diease cused b atheosclersis, te disesed arerial egment can be byed by insertng a gaft. he grat most commony used is the great aphenos vei of te leg see pge 572). In some patints, the myocrdium an be evascularized by surically mobiliing one of the inernal horaci arteres and in its dstal ct end o a cronary artery

Lmph Drinage f the horaci Wall he lymph drainage of the sin of he antrior cest wal s to te anteior axllary ymph odes; that from the posterior chet wall es to the posteror axllary odes (Fig. 2-18. The ymph drainage of the intecostal spaces es forwar to th interal thoacic odes, ituate along the inenal thracic rtery, and poteriory to he poserior ntercotal noes and the para-aortic nodes in the posterior ediasinum. he lymhatic rainag of th breas is dscribe on pae 427. P.64

Surface Aatomy nterior Ches Wall The suprasternal notch is the suerior argin of th manurium terni nd is asily felt btween the prminent medial ends of the clavicles in the midline (Figs. 2-19 and 2-20). It lies opposite the lwer boder of the boy of te secod thorcic vetebra Fig. 2-2. The sternal angle (angle of Louis) is th angle made between the manubrium and body of the ternum (Fig. 2-19 an 2-20). t lies opposie the ntervetebral disc btween he fouth and fifth horaci verterae (Fig. 22). The psition of the sterna angle can easily be felt and is often seen as a tranverse idge. he finer movd to te right or to the left will directly onto the second costal catilage and thn the econd rib. All rib may b countd from this point. Occasionally n a vey musular mle, th ribs nd intrcosta space are oten obcured by large pectoral muscles. In these case, it my be esier t count up frm the 2th ri.

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igure -18 Lymp drainge of he skn of he thoax and abdome. Note that lvels f the umbilicus anteriorly and iliac crets poseriorl may b regaded as waterseds fo lymph flow.

The xipisternl i the jint between the xiphoid process of the sernum nd the body o the sernum Fig. -21). It ies oposite he bod of th ninth thoracc vertbra (ig. 2-2). Te subcostal angle is ituate at th inferor end of the sternu, betwen the sternal attahments of the sevent costa cartiages (Fig. 2-21. he cstal argin is the lwer bondary f the thorax and is formed by th cartiages of the 7th, th, 9t, and 0th ris and the ens of the 11h and 12th cartilaes (Figs. -19 and -20). The lowest part of the costa margi is fomed by the 10th rib and lis at the levl of te third lumbr vertbra. P.65

Table 2-1 Muscles of te Thorx

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Nae of uscle

Orign

Insrtion

Nerve Suppl

Acton

xternal intecostal muscl (11) (fiber ownwar and forward

Infeior boder of rib

Suerior order f rib elow

Itercostal neves

With firs rib fixed, they rase ris durig inspration and thus incease ateropoterior and tansverse diameters of thorx

Internal intercosta muscl (11) (fiber ownward and bakward)

Inferor borer of ib

Supeior boder of rib blow

Intrcostal nerves

With lst rib fixed y abdominal muscle, the lower ribs dring expiration

nnermot intecostal muscl (incoplete ayer)

Adjcent ibs

Adjacent ris

ntercotal nerves

Asssts eternal and inernal intercstal mscles

Diphragm (most importnt muscle of respiration)

Xiphoid rocess lower six costal cartilaes, fist three lumar vertebrae

Central tenon

Phrenc nerv

Vry imprtant muscle of ispiraion; icreass vrtical diameter of horax y puling central tendon downwrd; asists in raisng lower rib Also used i abdomnal staining and

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weight lifting

Levatores ostaru (12)

Tip of tansvere procss of 7 and T1–11 vertebre

Rib below

Poserior ami of thoracc spinal nerves

Rases ribs and therefore inspirator muscls

Serraus poserior uperio

Lower cervicl and pper toracic spines

Uppe ribs

Intercostal nervs

Raises ribs ad therfore ispiratry muscles

Serrtus poterior inferor

Uppe lumba and lwer thracic spines

Lower ribs

Interostal erves

Deresses ribs ad therfore epiratory muscles

Clinica Notes Anatmic an Physilogic hanges in the Thorax with Aing Certan anatmic an physilogic hanges take pace in the thrax wih advacing yars:    

The rib cage become more igid and loses its elasticty as he reslt o calcfication and even osificaion of the costal cartilages; this also alters their sual rdiograhic apearanc. The stooped osture (kyposis), so often seen in the ol becaue of dgeneraion of the intervertebral discs, decreases the hest acity. Disuse arophy of he thoacic and abdminal uscles can result i poor respiratory mvements. Degeneation f the lastic tissue in the lugs and bronch resuls in ipairmet of te movement of expiration.

Tese chnges, hen seere, dminish the efficiency of respiratory movements and imair th abiliy of te indiidual o witstand espiraory diease.

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snell The clavcle is subcutaneous thrughout its enire legth an can b easil palpaed (Fgs. 219 nd 2-0). It ariculats at it laterl extremity with the acroion prcess of the capula

Ribs The firs rib lies dep to te clavicle and cannot be palpated. he lateral srfaces of the remaiing rbs ca be fet by pressing the ingers upwar into he axila and drawing them downard over the laeral surface of the chest wall. The 12h rib an be used to idenify a articular ri by conting rom below. Hwever, in some indvidual, the 2th rb is vry shot and ifficult to feel. For thi reasn, an alterntive ethod ay be used t identfy rib by first plpatin the sernal ngle and the second costa cartiage.

Diphragm The centra tendon f the iaphragm lis diretly ehind the xiphistenal jont. In the mdrespiratory positon the summit of te righ dome of the diaphragm arches upard as far as the upper brder f the fifth ib in the miclaviular line, but the left dome ony reaces as ar as he lowr border of the fifth rib. P.6

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Figure 2-1 Aterior view of the horax of a 2-year-old ma.

Nipple In th male, the niple usually ies in the furth ntercotal spce about 4 i. (10 cm) fom the midline. In he femle, is posiion is not cnstant

Apex Beat of the Heart The apex of the hert is formed by the lower portio of te left ventricle. Te apex beat is causd by te apex of th heart being thust foward aainst he thoracic wall as the hart cotracts (Th heart is thrust foward wth each venticular contration because of the ejecion of blood rom the left ventrile int the orta; he foce of he blood in he aora tend to cuse th curve aort to sraightn sligtly, hus pshing he heart forward.) he ape beat can usually be felt by placing he fla of the hand on the chest wall over th hear. Afte the aea of cardia pulsaion has been detemined, the apex bet is accurately lcalize by placing wo fingers over the interostal spaces and moing them untl the oint o maximm pulation is found. Th apex eat i normaly foud in the fifh left intercostal space .5 in. (9 cm from the miline. hould you hae dificulty in indin the aex beat, hav the ptient ean forwar in the sittng psition. In a femle wit pendulous beasts, the examinin fingrs shold gently rase the left reast rom below as the itercotal spces ar palpated.

Axillar Fold The antrior old is fomed by the lower boder of the petoralis majo muscl (Figs. 2-1 ad 2-2). This cn be made to stand ou by asking te patint to ress a hand hard aginst te hip. The postrior old is fomed by the tndon o the ltissims dorsi musce as i e aroun the lower brder o the teres ajor mscle.

Postrior Cest Wal he spinous processes of th thoacic vertebre can be palpate in th midline poseriorly (Fi. 2-22). The inex finger shuld be place on th skin n the midlin on th posterior urface of the neck nd dran dowward in the nuchal roove The irst sinous process to be felt i that of the sevent cervial vetebrae (vertebra romines) Below this level re the overlapping spines f the horaci vertbrae. he spines f C1 to 6 vetebrae are covered y a large liament, the liamentum nucae. It should be noed tha the ip of spinos process o a thracic verteba lies posteror to the boy of the nex vertera belw. he sapula (shoulder blade) is flt and riangular in shape nd is locate on th uppe part f the osterior surace of the thrax. The superior angle lie opposite th spine of the secon thorcic vertebra (Figs. 2-20 and 2-22). The sine of the scapula is ubcutneous, and te root of the spine

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snell lies o a levl with the sine of the third thracic ertebr (Fis. 2-2 ad 2-2) The inferir ange lies on a level with the spine of the sventh horacic vertebra (Figs. -20 and 2-22). P.6

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Fgure -20 A. Anterior vew of he thorax an abdomn of 29-year-old woman. B Postrior iew of the thorax o a 29-year-ol woman.

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Clinial Nots Clnical xamination o the Cest As medical persnnel, ou wil be eaminin the chest t detect evience o diseae. Yor examnatio consits of inspecion, alpation, pecussio, and usculation. Inspecton shows the configuation of th chest, the ange o respiratory movemet, an any inequaities on the two sies. The type and rte of espiraion ar als noted Palpaton enabls the physican to confir the ipressins gained by inspecion, especially of the rspiratry movements of the chest wall. bnorma protuerances or ecessin of prt of the chst wall is nted. Abnormal pulsations are felt and tender areas etected. ercusion is a harp tappin of the ches wall ith te fingrs. Ths produces vbratins that extnd thrugh th tissues of he thorax. Ar-containing organs such as th lungs produe a resonan note convrsely, a more solid viscs such as th heart produces a dull not. With practce, it is pssible to disinguish the lungs fom the heart or livr by pecussion. Ascultation enabes the physcian o listn to te breah souns as the air enters and eaves the respiratory pasages. hould the aleoli o bronchi be disease and filled with fuid, he natre of the breath sunds wll be altered. The rate nd rhythm of the hart can be cnfirme by aucultaton, and the variou souns prodced by the heart and its vlves dring te different phases of the cardiac cycl can b heard. It may be ossibl to dtect frictio sound produed by he rubing together of diseased layers of plura or pericrdium. To make thee examinatios, the physcian mst be familiar wit the normal tructue of the thoax and must ave a mental image of the norma positon of the lugs and heart in reltion to identifiable surace lndmark. Furtermore, it is essenial tht the physician be able t relat any bnorma findigs to easily identfiable bony lndmarks so tat he r she can acuratel recor and ommunicate tem to olleagues. Since the thoracic wal activly participaes in he movements of repiratin, man bony landmaks change thir levels wih eac phase of repiratin. In practie, to simpliy mattrs, the leves given are those sually found at abot midway beteen ful inspiratio and ull exiration. P.68

Lines of Orintatio Sveral imaginary lines are sometmes usd to describ surface locations n the anterior and posteror chet walls. 

Midstrnal lne: Lies n the median plane ver the sterum (Fig. 2-1)

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snell     

Midclavicular line: Rus vertcally downward fro the mdpoint of th clavile (Fig. 2-1 nterior axilary lie: Runs verticaly downward from th anterior axllary old (Fig. 2-21) Posteror axilary ine: Runs verticlly dwnward from te posterior xillar fold Midxillary line Runs vetically downard fom a point situated midway between the nterir and posterior axilary flds Scapular lne: Runs verically downwrd on he poserior all of the torax (Fig. -22), ing trough he infrior agle of the sula (arms at the sdes)

Cinical Notes Rib and ostal artilae Identification Wen one is exmining the chest frm in ront, he sernal angle is an important landmark. It position ca easil be fet and often e seen by the presnce of a transverse ridge. The fnger mved t the right r to te left e direcly ont the second cotal cartilag and hen th secon rib. All oter rib can b countd from this oint. The 12th rib can usally b felt rom behind, but in ome obse persons this may prove diffcult.

rachea The trachea extend from he loer boder o the cicoid cartilage (oposite the bdy of the sith cervical vertebr) in te neck to te leve of the sternal ange in te thorx (ig. 2-23) It ommences in he midine and ends just t the rght of the mdline by diiding nto th right and left pricipal ronchi At the root of the neck it may be palpated n the midline in the supraternal notch.

Lung The apex f the lung proects into th neck. It ca be maped ot on he antrior srface of te body by drwing a curved line, convex upward from he sternoclvicula t to a oint 1 in. (2.5 cm) above the juction f the medial and itermedate thirds f the lavicle (Fig. -23). The anterior borde of th right lung beins beind the steroclaviular oint ad runs downwrd, alost rachin the mdline ehind the strnal agle. I then contines downward until t reaces th xiphiternal t (Fig. 2-23). Te anerior border of the left ung has a similar couse, bu at th level of th fourt costal cartlage t deviates lterall and etends or a ariabe distnce beyond te latral magin of the sernum to for the cardic noth (Fig. -23). This notch is poduced by the heart displcing te lung to th left. The anterior borde then turns sharply downward to the levl of te xiphisteral t. The lower order of the lung in idinsiratio follos a curving ine, wich crsses the 6th rib in the idclavicular line ad the th rib in th midaxllary line, and reches te 10th rib ajacen to the vertebral clumn psterioly (igs. 2-23 2-24, and 2-5) It is important to undersand tht the level of the inferior border of he lung changes durng insiratin and xpiraton. The posteior boder of the lung extens downward from the spinous procss of the 7t cervcal vetebra to th level of the 10th horacic vertbra and lies about .5 in. (4 c) from the midline Fig. 224).

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snell The oblique fissre of the lung can be indicaed on the suface b a lin drawn from he root of the spie of te scapla obiquely downward, laterally and aneriorly, following the curse o the ixth rb to the sixth costchondrl junction. In the left lng the upper lobe les aboe and anterir to this lne; th lower lobe ies beow and posterior to it (Figs. 2-2 nd 224. In th right lung i an aditional fisure, the hrizontl fissure, whic may be reprsented by a ine drwn P69

horizontally alng the fourth costal cartilage t meet the obique fssure n the midaxillary line (Figs. 2-23 and 2-25). Aove th horizontal issure lies te upper lobe and below it lies te middle loe; below and posteror to the obique fssure ies th lower lobe

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Fiure 2-21 urfac landmarks o anteror () and poserior (B) thoacic wlls.

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igure 2-22 Surfce landmarks of the posterior thracic all.

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Fiure 2-23 Surfac markigs of lungs nd paretal peura on the nterio thoraic wal.

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Fiure 224 Surfac markings o the lungs ad parital plura on the psterio thoraic wall.

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Figue 2-2 Srface markins of te lungs and parieta pleur on the lateal thoacic walls.

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Plura Te boudaries of th pleurl sac can be marked ou as lnes on the surface f the body. The lies, which inicate the liits o the parietal pleur where it lies clos to th body urface, are refered to s the lins of peural reflecion. The cervical leura bules upard into the neck and has a srface markin idenical t that of the apex of the lung. A curved line may be drawn, conve upwar, from the sternocavicuar joit to a point 1 in. (2.5 c) above the unctio of the medial and intermdiate thirds of the clavicle (Fig. 2-23). Th antrior border f the ight peura rus down behin the ternocavicular joit, almst reaching he miline bhind te stenal anle. It then continus downard unil it reachs the iphisternal oint. he aterior borde of th left pleura has a siilar course, but at the level of the forth cotal crtilag it eviate laterlly and exteds to he latral mrgin o the sernum to fom the ardiac notch. (Note that he pleral cardiac otch i not as lare as he ardiac notch of the lung) It ten turs sharly dwnward to the xiphiternal t (Fig. 2-23). Th lowr bordr of the plera on bth sids follws a curved line, hich cosses he 8t rib i the idclavicular line ad the 10th rb in te midaillary line, and raches he 12t rib adjacent to th vertbral clumn—that is at th lateal border of the erctor sinae uscle Figs 2-23, 224 and 2-25). Noe tha the lwer magins of the ungs coss th 6th, th, an 10th ribs at the midclaicular lines, the mdaxillary lies, and the ides f the vertebral colmn, respectiely; te lower margins of he plera crss, at the sme points, the 8th, 10th, nd 12th ribs respetively The istance betwen the two brders orresponds t the costodiaphragmatic recess. (See pge 84.)

Clinicl Note Pleral Reflections t is ardly ecessay to emphasie the importnce of knowing the surfac markigs of the plural reflectons an the lbes of the lungs. hen litening to th breat sound of th respiratory trac, it sould b possible to have a mental image of the structures hat li beneath the stethocope. The cervical ome of the pleura and he aex of he lungs xtend up int the nck so that a thei highet poin they ie abot 1 in. (2.5 cm) abve the clavicle (Fgs. 2-6, 2-13, an 2-23). Consequently, the are vlnerable to tab wunds in the root of the eck or to damage by an anesthetit's nedle when a nrve block of the lower tunk of the brachial plexus is being performed.

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snell Rememer als that he lower lmit of the peural reflecion, as seen from the back, ay be damage during a nehrectomy. The pleur croses th 12th ib an may b damagd durig remval of the kidney hrough an inision n the loin.

Figre 2-26 Surface markins of the hart.

Hert For practcal prposes the heart my be cnsidered to ave boh an aex and four order. Th apex, formed by the left ventricle, crresponds to the apex bea and is foun in the fift left intercostal pace 35 in. 9 cm) rom the midlne (Fig. 2-6). The supeior boder, formd by the roots f the great blood vessels extens from a poit on te secnd left costl cartlage (emember steral ange) 0.5 in. (.3 cm) from the ede of he stenum t a poit on te third righ costa cartilage 0.5 in. (1.3 cm) fro the ege of the sternum (Fig. 2-26). The right bordr, formed by te right atrium, extnds frm a point on the third right costal cartilage 05 in. 1.3 cm) from the ede of te sternum donward o a pint o the sxth right cotal cartilag 0.5 i. (1.3 cm) from the edge f the sternum (Fig. -26). The left border, formed y the left ventrice, extnds frm a point on the scond lft costal cartilag 0.5 i. (1.3 cm) rom th edge of the sternu to th apex beat f the heart Fig. 2-26). The infeior boder, formed by he right venricle nd the apical part f the eft ventricl, exteds from the sixth .73

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rght cstal crtilag 0.5 i. (1.3 cm) fom the sternm to te apex beat Fig. 2-26).

Clinical Notes Poition and Enargemet of the Heat The surfac markings of the hert and the psition of the apex beat my enabe a pysicia to dtermin wheter the heart has shifted ts position n relaion to the chest wal or wether the hert i enlared by diseas. The apex bat can often e seen and almost alwas can e felt The positio of th margins of he heat can e deermine by pecussio.

Thoracic Blod Vesels The arch f the aorta and the roots of the rachiocephalc nd lft comon carotid ateries li behin the manubrium steri (Fig. 2-2). Th suprior vena caa nd the termial parts of he right and left brachioephali veins alo lie behind the maubrium stern. Te inernal horacic vessls run verticaly downard, psterio to the costl cartlages 0.5 i. (1.3 cm) lateral o the edge o the sernum (Figs. 2- and 2-10), as ar as the sith intrcostl spae. The itercosal vessels ad nerv (“vein, artry, nrve―—VAN—is the oder frm above downward) ae situted immediately beow ther correspondng rib (Fi. 2-8).

Mmmary land The mammary gland lies i the superfiial fascia cvering the anterior chest all (Fig. -20). I the cild an in me, it s rudientary In the femae afte pubety, it enlarges and assumes its emisphrical shape. In the young adult female, it overlies the seond to the ixth rbs and their costal cartilages and extends rom the lateral marin of the strnum to the midaxilary ine. Is upper lateal edg exteds arond te lower border of he pecoralis major and eners the axilla. In iddle-ged multipaous woen, the breats may be lare and pendulous. In older women past mnopaus, the adipos tissu of th breast may ecome reducd in aount ad the hemisperical shape lost; the brests then become smller, nd the overlying skn is winkled. The structur of the mammary glad is deidoub full on pae 427.

Cliical Poblem Solving Study the followin case istories and select the bst anser to he quetions following thm. On percussng the anterir chet wall of a patient you find th right margi of the hear to li 2 in. (5 cm to th right of the edge f the sternu. 1. Which chmber of the eart i likely to b enlared?

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snell (a) The left entrice (b The left atium (c) The rght ventricl (d) The riht atrum View Answr 1. D A 31-year-old soldier receved a shrapnl wound in te neck durin the ersian Gulf War. Recently during a phsical examintion, t was noticed tha when e blew his nse or neezed the sin abve the right clavcle buged upard. 2. The upward bulging of the skin could be explined b (a) injur to th cervial pleura. (b) damage to th suprapleural membrne. (c) damage to the deep fascia in the root of the eck. (d) unnited fractue of te first rib. View Answr 2. B The sprapleral membrane prevens the cervicl dome of the pleura from ulging up ino the eck. A 5-year-ld woan was itted to he hosital wth a diagnoss of ight-sided peuris with pneumoia. It was dcided to remve a smple of pleral flid from her pleural cavity The residen inserted th neede cloe to te lowr border of he eigth rib in the anteror axllary line. he nex morning he was surrised o hear that he patient had comlained of alered sin senation extendng fro the point here te neele was insertd downward ad forwrd to the miline of the abdomial wal above th umbiicus. 3. The altered skin senstion in this patiet afte the nedle toracostomy culd be explained by which f the followng? (a) The eedle as insrted oo low down in the ntercotal space. (b) Te needle was nserte too close t the lwer boder o the eghth rb and damage the ighth intercstal nrve. (c) The eedle had imaled te eighh rib. (d) The needle had penetratd too eeply and pirced te lung. View Answr

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snell 3. B A 68year-old man complaned of a swelling n the kin o the bck of he chest. He had noticed it for the lst 3 yars an was concernd becase it was rpidly enlarging. On examination, a hard lump as fond in the sin in the right scaula line opposite te seveth thoacic vrtebr. A bopsy rvealed that he lum was mlignan. 4 Because of the rapid icreas in sze of the tuor, which of the folowing lymph nodes ere eamined for metastass? (a) Sperficial inuinal odes (b) nterio axillary noes () Poserior xillar nodes (d) Exteral ilic node (e) Deep cervica nodes View Answer 4. C A 65-yer-old an and a 10-year-ol boy ere inolved n a severe utomoble accdent. In bot patints th thorax had een baly crshed. Radiogaphic xamination rvealed that te man had fie fractured ribs bt the boy ha no frctures 5. Wat is he most likey explnatin for his difference in mdical findins? (a) The paients ere i diffeent sets in the veicle. (b) Te boy as weaing his seat belt nd the man was not. (c) The ches wall of a cild is very lastic and fractures of rbs in hildren are rare. (d) The man anticipaed the impact an tense his uscles incluing those of the shulder girdle and abdomen. View nswer .C On examinaton of posteroanteior chest raiograp of an 18-yer-old woman, it wa seen that te left dome f the iaphragm was higher than he right dom and rached o the upper order f the fourt rib. 6. Te posiion of the left dom of te diapragm could b explained by one o the fllowig condtions xcept which? (a) The left lng could be ollapsd.

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snell (b) here is a colectio of blood uner the diaphrgm on the let side. c) There is n ameic abscess in th left lobe of the lver. d) The left ome of the daphram is nrmally higher than he rigt dome. () Ther is a peritoeal abcess beneath the diphragm on th left ide. View Answer 6. D A 43-year-ld man was inolved in a volent uarrel with is wife over anothr woman. In fit of rage the wfe piced up carving knife and lunged forwad at her husband, sriking his anerior neck over th left clavile. Th husband collapsed n the itchen floor, bleedng prfusely from the woud. The distraught wfe caled an mbulane. 7. O examnation in the emergncy departmet of te hosptal, the folowing conditons were foud excet which? (a) A wound was sen abot 1 in. (2.5 cm) wie over the lf clavicle. () Auscltation reveled diinished breath souns ove the lft hemthorax. (c) The trachea was deflectd to te left. (d) Th left upper imb wa lying stationary o the table, and actve movment of the small muscles of th left and wa absent. (e) The paient ws insesitive to pin pric along the lateral side of the lft arm foream, and hand. Viw Answer 7. E. The lower trunk f the rachil plexus was cut by the knife. Tis wold explain te loss of movement f the small uscles of the left hand. t woul also explai the lss of skin sensatio that occurred in the C8 and T dermatomes on the edial, not on the lteral, side o the left frearm nd han. The knife ad als pierced the left dme of the cervical pleur, causng a left pnumothoax wit left-sided iminised breath sounds and a dflection of the trchea t the lft. A 72-year-od man omplaiing o burnig pain on th right side o his chest was see by hi physician. n examnation the patient ndicatd that the pain ed forward ver th righ sixth interostal space from te posterior xillar line orward as fa as th midlie over the ternum The pysician note that here wre seeral wtery bebs on the skin in the panful aea. 8. The following tatements ar correct ext whih? () This patiet has erpes zoster (b) A viru desceds along the cutaneus nerves, causing ermatomal pan and the erption of vesicles. (c) Te sixh righ interostal nerve as invlved. 141

snell d) The condiion wa confined to the anerior cutaneus brach of he sixth intrcosta nerve. View Answer 8. D. Te skin over the sixth intrcosta space is innervate by th lateral cutaneous branc as wll as he antrior ctaneous branh of he sixh intercosta nerve An 18-year-old wman was thrown from a horse whil attemting t jump a fence. She landed heaviy on the grund, sriking the lower pat of er chst on the left side On exminatin in te emegency departent she was conscious bu breathless. The lwer let side of her chest was bdly brised, and the 9th ad 10th ribs were extremely tender to tuch. Se had evere tachycrdia, nd her systoic blod presure wa low. 9. The following sttements are ossibly corrct ext whih? a) Thee was evidene of tndernes and muscle spasm n the left upper qudrant f the anterir abdominal all. (b) A postroanterior rdiograh of he chest revaled fractures of te left 9th ad 10t ribs ear thir angles. (c) The blut traua to the ribs had esulte in a ear of the underlyig spleen. (d) he preence of bloo in the pertoneal cavity had iritate the prietal peritoneum, roducing relex spsm of the uper abdminal muscles. e) The muscls of te anterior adominal wall are no suppled by thoracc spinl nervs. View Answer 9. . The th to he 11th intecostal nerve suppl the muscles of the anterior abdminal wall.

Review Questons Muliple-Coice Questios Slect he best answr for each qestion. 1. The fllowin stateents cncernng strctures in the interostal pace ae correct except wich? (a) The antrior intercostal areries f the pper six intrcosta spacs are ranches of te internal toracic artery (b) he intrcostal nervs travl forward i an inercostl spac betwen the internal intrcosta and inermost intrcostl musces. (c) The intercostal lood vssels and nrves ae posiioned in the order f vein, nerv, and rtery from uperior to inferior in a subcostl grooe. (d) The lower five ntercotal neves upply ensory innervation to the kin of the lateral horacc and anterir abdominal alls.

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snell (e) The poserior ntercotal veins drin bacward into the azygo and hmiazygos veins. View Answer 1. C. The orer from superior to inferor is ntercostal vin, artery, and nere. 2. Th follwing satemens concerning the daphrag are crrect xcept hich? (a) The right rus prvides musclar sing around te esopagus nd posibly prevent regugitatin of tomach contets int the eophagu. b) On contraction, he diaphragm raise the ntra- abdominal presure and asssts in the return o the vnous lood to the ight arium o the heart. (c The lvel of the daphrag is higher i the rcumbent position thn in the stnding positin. (d On contracton, th centrl tenon desends, reducing the ntrathracic ressure. (e The eophagu es through the diaphagm at the level of the eihth thoracic vertebra. Vie Answer 2. E. The esophags s throgh th diaphagm at the level of the 10h thorcic vetebra 3. The fllowin stateents cncernng the intercostal erves re corect exept which? (a They provid motor innervation o the eripheal pars of he diahragm. b) The provde motor innrvatio to the intecostal muscle. (c They rovide sensoy innevation to th costa parieal plera. (d) Thy contain sypathetc fibers to nnervae the vasculr smooth musle. (e) Te 7th to the 11th itercosal neres provide snsory nnervation to the prietal peritneum. Vew Answer 3. . The provie sensry innervatin to the plera and peritoneum cvering the peipherl part of th diaphragm. 4. To pss a nedle ito the pleural spae (cavity) in the mdaxillry lin, the folloing stucturs will have to be pierced except which? (a) Internal intercosta muscl () Levatores costaru (c) Exteral intrcostal musce () Parietal peura e) Innermost intercstal muscle

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snell View Answer 4. B. The levator cstarum is ocated on th back way frm the area ivolved 5. The following statemnts cncerning the thoracc outlet (antomic inlet) are tre except whih? () The manubrium steni for the anterio borde. (b) n each side, the loer truk of the brachial lexus and the subclavian artery emerg throuh the outlet and pss laterally over te surfce of the fist rib. (c) The boy of te seventh cervical verteba form the posterir bounary. (d) The first ribs form the laeral oundaries. (e The esophags and rachea hrough the oulet. View Aswer 5. C. Th body of the first horacc vertbra forms th posterior bundary 6. he following statemnts cncernng the thoracc wall are crrect xcept hich? (a) The tracha bifucates pposite the manubristerna (angl of Lois) in the mdrespratory positon. (b) The arh of te aort lies behind the body of he stenum. (c) The ape beat of the heart can nomally be fel in te left intercstal sace about 3. in. ( cm) from th midlie. (d) Te lowe margin of the righ lung on ful inspration could extend down i the midclavcular line t the eighth costal cartilge. (e) Al intercosta nerve are derived from te anterior rmi of horacic spinal nervs. View Answer 6. B. The arh of he aora lies behind the anubrim steri. Completin Quesions Selec the prase tat bet competes each sttement. 7. Clincians define the thracic outlet as (a) the lower openng in he thoracic age. () the gap between the crua of te diapragm. c) th esophgeal opening in the diaphagm. (d) the upper oening n the horacic cage

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snell (e) te gap etween the sernal nd cosal origins o the daphrag. Vew Anwer 7. D 8. The costal mrgin i formed by (a) the 6th, 8th, nd 10t ribs. (b) the nner mrgins of the 1st rbs. (c) the ede of te xiphid process. (d) the cstal crtilages of the 7th 8th, 9th, ad 10th ribs. (e) te costl cartlages of the 7th to the 1th rib and te ends of the cartiages o the 1th and 12th ribs. Vie Answe 8. E 9. Th lower margin of th left ung in midrepiration crosse (a) the 6th, 8th, nd 10t ribs (b) the th, 8t, and 9th ris. () the 10th, 1th, ad 12th ribs. (d) the th rib only. (e) te 6th, 11th, and 12h ribs Viw Answer 9. 1. The suprapleural membrae is ttache laterally t the margins of (a) the 1st rib. (b) the 6th, 8th, nd 10t ribs. (c the mnubristerna juncton. (d) he 2nd rib. (e) the xiphoid cartlage. View nswe 10. A

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snell 11. he mammary gand in the yong adlt femle overlies (a) te 1st o the 5th ris. b) th 2nd t the 6h ribs (c) the 1t and nd rib. () the nd and 3rd ribs. (e) the 4th to the 6h rib. View Answer 11. B 12. The parietl pleua (a is sensitiv only o the sensaton of tretch. (b) i sepaated fom the pleurl spac by endothorcic facia. (c) i sensiive to the snsations of ain and touc. (d) eceives its ensory innervation rom the autoomic nrvous ystem. () is ormed rom slanchnpleuric mesoerm. View Answe 12. C Fill-in-the-Blank Qestion Fil in te blak with the bet anser. 13. Th thoracic dut es thrugh the _______ opning n the diaphragm. 14 The sperior epigastric atery psses through the _______ pening in th diaphagm. 15. The rigt phreic nere es thrugh th ________ opening i the daphrag. 16. The lft vags nerv es throgh the ________ opening in the diphragm (a) artic () esopageal c) caval (d) none of the abve Vie Answer

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snell 13. 14. D. The uperio epigastric rtery nters the anterior abdomnal wall beteen th steral and the costal oigins f the diaphragm. 15. 16. B 17. The artic oening n the diaphrgm lies at te leve of th _______ thoracic ertebra. 1. The xiphisernal oint les at the leel of he _______ thoraci vertera. 1. The caval pening in the diaphagm les at he leel of he _______ toraci vertera. (a) 10h (b) 2th (c) 8th (d) 9th (e) 7h iew Answer 17 B 18 D 19. C Muliple-Coice Qestion Rad the case istory and seect te best answe to the questin follwing it. A 5-yearold man complaning o severe pain n the lower prt of his left chest was sen by is phyician. he patent ha been oughin for he last 4 days and wa produing blod-staied spuum. He had an incresed respiratoy rate and had a pyreia of 04°F. On exaination, the patent wa found to hae flui in the left pleura space 0. With the patient in the standng poition, the pleural luid wuld mot likely graitat down o the () obliue fisure. (b) crdiac otch. (c) costomeiastinl recess. () horiontal issure.

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snell (e) costodiaphragatic rcess. View nswer 20. E. This patient tarted his ilness wth an upper rspiratry inection which he igored. ow he as lef-sided pneumnia complicatd by peurisy With pleurisy, the nflammaory exdate my reain at the sie of te pneuonia. If the pleural luid i excessive ad the ptient assumes the upight poition, the flud may ravitae downard to he lowst par of th pleurl spac—namel, the costodaphramatic ecess. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

4. 3. The Thorax: Part II - The Thoracic Cavity A 54-yar-old woman complining f a sudden ecruciaing kifelik pain in the front of the chest was seen by a physcian. During the curse f the xamination, he sai that she could aso feel the pain in her back btween the shulder blades. On clse quetionin she said se felt no pain down the ars or i the neck. Hr bloo pressure ws 200/110 mm Hg in he riht arm and 120/80 m Hg in the eft ar. The ealuation of chest ain is one o the ost comon poblems facin an emrgency physcian. he caue can vary from the simpe to one of life-theatenig proprtion. The evere ature of the pain and it radiaion though to the back mae a prliminay diagosis of aoric disection a strng posibilit. Myocardial infarcion commonly resuls in rferred pain own th inner side of the arm or p int the neck. Pin impulses riginaing in a disased descending thracic aorta to the central ervous syste along sympahetic nerves and are then referrd along the somati spina nerve to the ski of the anteior an posterior cest walls. I this atient the aortic issecton had partially blcked te orign of the lef subcavian rtery, which would xplai the lower bood pressure recorded in the let arm.

Chater Ojectives  

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To nderstand th general arrngement of te thoracic vscera nd ther relationshp to one anoher an to the ches wall. To be able to define wht is eant by the erm mediasinum and to learn the arrangment of the leura elativ to th lungs. This inforation s fundamenta to th comprhension of te function ad diease o the lungs. Apreciting tat the heart and the lung are enveloed in erous membraes tha provide a lbricaing mehanism for these mbile vscera nd being abl to ditingush beteen suh tems as thorcic cavity, leural cavity (pleural space), pericardil cavity, and ostodaphragatic recess. To larn th structure o the hart, includng its conduting system nd the arrangment of the differnt chambers and vaves, which i basic to understaning th physiologic and ptholoic features f the heart. The citical nature of the blood suppy to te heart and the end arteris and myoardil inarction is emhasize. T undestand hat the largst blod vessels n the body ae located wihin th thoraic cavity, amely, the arta, the pulmonary rteries, the venae cavae, and th pulmonary veins. rauma to the chest wall cn resut in disrupton of hese vessel, with consequent rpid 148

snell heorrhae and eath. ecause these vesses are idden from vew within th thora, the diagnois of major blood essel injury is oftn delaed, wih disstrous conseuences to te patint. .78

Basic Anatmy Cest Caity The chst caity is bounded by the chet wall and below b the daphragm. It xtends upwar into the root of the nec about one ingerbeadth bove the claicle o each ide (see Fig. 3-5). The diaphrag, whih is a very hin mucle, i the only stucture (apar from the plura nd pertoneum) that separaes the chest from he abdminal viscer. The hest cvity can be ivided into a media partition, called the mdiastium, nd the laterlly placed peurae nd lngs (Fgs. 3-1, 3-2, and 3-3). P.9

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Fgure -1 Cros section of he thorax at the leel of he eighth thoracic vertebra. Nte the arrangement f the leura nd plural cvity (pace) and te fibrous an serous periardia.

Figure 3-2 Subdvision of th mediastinum

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Figre 3-3 Plurae fom aboe and in frnt. Noe the ositin of te medistinum and hilum of each lung.

Medastinum The medistinum thoug thick, is a movabe parttion that etends superirly to the thoracic outlet and te root of the neck and ineriorly to the diapragm. It extnds aneriory to te sterum ad postriorl to the vertebral clumn. t contains the remans of he tymus, he heat and large lood vssels, the tachea nd esohagus, the horaci duct nd lymph nods, the vagus nd phrenic nerves, nd th sympathetic trunk. The mediasinum i dividd into superior and infeior meiastina by an imaginry plae pasing from the sterna angle anterorly t the ower border f the body o the fourth thoraci vertera posteriorly (Fg. 3-2). he inferior ediastnum is further subdvided nto th midle meiastinm, which onsist of te periardiu and hart; te anerior ediastinum, whih is a space betwee the pricardium an the sernum; and the psterir medistinum, wich lies beteen th pericrdium and th verteral column.

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snell For urposes of oientaton, it is covenien to emembe that he major medastina strutures re arranged in the followng ordr from anteror to osterior.

Sperio Medistinum (a) Thymus, (b large veins (c) large ateries (d) tachea, (e) esophagu and toracic duct, and (f sympathetic trunks The sperior mediatinum s bouned in front y the anubrium steni and behind by the first four horacic vertbrae (Fig. 3-2).

Inerior ediastnum (a) hymus, (b) hert within th pericardium with the phrenic nrves o each side, c) esophagus and thoracic duct, d) decendig aort, and e) sympathetc trunks The infeior meiastinum is ounded in front by he bod of th sternm and behind by the lower eight thoracc vertebrae Fig. 3-2).

Pleurae The plerae an lung lie o either side of th mediatinum ithin the chst cavty (ig. 33) Befor discusing te pleurae, i might be helpful t look t the llustrtions of the develpment f the lungs n Fiure 34. P.1

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Figure 3-4 Formatio of the lung. Note that each lug bud nvagintes th wall of te coeomic cvity and the grows to fil a greater part o the cavity. ote alo that the lung is covered with isceral pleua and he toracic wall s line with arietal pleua. The originl coelomic cavity s redued to a

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slilike sace caled th pleual cavty as result of he groth of he lung.

Clinical Noes Delectio of Mediastium In th cadaver, the mediatinum as the resut of te hardening effect of the preseving fluids, is an inflexible, ixed tructue. In the liing, i is vey mobile; th lungs heart and large rteries are n rhytmic plsatio, and the esphagus distends as each blus of food asses through it. If air eners the pleual cavty (a conditon called neumothorax), he lun on tht sid immedately collapes and the meiastinum is displaed to he oposite ide. This condition reveals itsef by te patient's being reathless an in a state f shock; on xaminaion, te trachea ad the eart ae found to b displced to the opposite side.

Meiastinitis The sructurs that make p the ediasinum ae embeded in loose connetive tssue tat is continuous with that of te root of the neck Thus, it is ossibl for a deep infectin of te neck to sread radily into te thorx, proucing a medistinits. Pentratin wounds of he chet involving he esohagus ay prouce a mediatinits. In sophagal perorations, air escaps into the connectve tisue spaces and ascens benath the fasca to te root of the neck, produing subcutaneous emphysma.

Mediastina Tumor or Cysts Because man vital strucures ae crowded toether within the mdiastium, thir funtions can b interered wth by an enarging tumor or orgn. A tmor of the left lun can rpidly pread to inolve the medastina lymph nodes, which on enlargemet may compres the left rcurrent larygeal nrve, poducing paralysis o the eft voal fod. An xpandig cyst or tuor can partially occlude te suprior vena cava, cauing svere congeston of he veis of the uppr part of te body. Othe pressre effects can be sen on he sympathetic truks, phenic erves, and soetimes the tachea, main bronchi and sophagus.

Meiastinoscopy Medastinoscopy s a diagnostc procedure hereby specimens o tracheobronchial lmph ndes are obtaned wihout oening the pleural cavitie. A small inision s made in the midlie in te nec just above the surasternal noch, an the sperior mediatinum s expored own to the reion of the bfurcaton of the trachea. he procedur can be used to detrmine the diagnosis and deree of sprea of crcinom of the bronchus.

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igure -5 Different aras of he parietal leura. Note the cuff of plura (dotted lines) hat suround structures enterin and laving he hilum of he lef lung It is here that th parietal an visceral layers o pleura becoe coninuous Arrow indicate th positon of he cotodiapragmatic recess.

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Each pleur has to parts: a arietl laye, which lines he thoacic all, cvers te thoracic surface of the diaphagm and the lateral aspect of th mediatinum, and extends nto te roo of th neck to lin the udersuface o the sprapleral mmbrane at th thoraic oulet; ad a iscerl laye, hich completey coves the outer surface of th lung and etends nto the depths of te intelobar fissurs (igs. 3-1, 33, 34, 3-5, and 3-6). The to layes become continuous with one anoher by mean of a uff of pleura that urrouds the structures etering and leaving the lug at te hilum of ech lun (Fis. 3-, 3-4, and 3-5). To allow for

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snell mvement of the pulmoary vesels ad large bronhi durng respiraton, th pleural cuff hangs down a a loose fol calle the pulmonry liament (Fig. 3-).

Figue 3-6 Cros section of the thorax. A. At he inlet, as seen from bove. B. At the fourth thoracic ertebr, as seen frm below.

Te paretal ad visceral layers o pleur are separate from ne another by a slilike space, he peural avity (igs. 33 and 34). (Clincians are inreasinly using the term pleural spae instead of th anatoic term pleural cvity. Thi is probably to avoi the cnfusion betwen

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the leural cavit [slitike] sace and the larger hest cvity.) The peural cavity normaly contins a small amount of tisue flud, the pleral flid, whic cover the srfaces of th pleur as a thin flm and permits the two laers to move on each other ith the minium of friction.

Figue 3-7 Lteral iew o the uper opning of the horaci cage howing how te apx of te lung projets

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superiorly into te root of the neck. ote tat the lung apex is covere with isceral and parietl layes of leura and is proteced by the surapleral mebrane.

For urposes of descripton, it is customary to divde th parieal plura accordng to the reion in which it lies or te surace tat it covers. The crvical pleura extens up ito the neck, lining the ndersuface of the supraplural membran (Fg. 3-7). t reaces a lvel 1 to 1.5 in. (25 to 4 cm) above th media third of the clavile. The costl pleura ines te inner suraces o the ibs, te costl cartilages the itercostal saces, he sids of he vetebral bodies and te bac of th sternm (Fg. 3-3). The diaphragmatc pleura covers the thracic surfac of te diapragm (Figs. 3-3 and -5. In uiet respiraion, te costl and iaphragmatic pleura are i apposition to eac other below the lower borer of the lung. In eep ispiraion, te margins of the bae of te lung desced, and the cstal and diahragmaic plerae separate This ower area of the peural cavity into wich the lung expans on ispiration is referrd to as the costodiapragmatic recss (Fig. 3-4 and 3-5). The medistinal pleur cvers ad fors the ateral bounday of the medastinu (Fig. 3-3 an 3-5). At the ilum o the lng, it is refected as a cuff arond the vessel and bronch and hre becmes continuos with the visceral pleura. It is thus een tht each lung les fre excep at it hilum where it is attaced to he blod vessls and bronchi that constitute th lun root. Dring fll insiratio the ungs epand and fill the peural avitie. Howver, dring qiet inpiratin the ungs d not fully occupy te pleral caities t four sites: the riht and left ostodiphragmtic rcesses and th right and left cosomediatinal recesss. he cstodiaphragmtic reesses ae slitike spces btween he cotal an diaphragmatc parietal pleurae that are seprated only by a capllary ayer o pleural flud. Duing inpiration, th lower margins of te lung descend into the ecesse. Durig expration the lwer margins of the ungs acend so tha the cstal ad diaphragmatic plerae coe together aain. The costomediatinal ecesss are situated along he antrior mrgins of the pleur. They are slitlik space between the costal and th mediastinal parietl plurae, hich ae sepaated b a capillary layer of pleural flid. Dring nspiraion an expirtion, the anterior border of th lungs slid in an out of the ecesse. The surace markings of the lungs and pleurae were descried on ages 8 and 2.

erve Supply f the Pleura The parital plura (Fig. 3-8) is sesitive to pain, temeratur, touch, and pressue and is suplied a follos:   

The costal peura is segmentally suppled by he intrcostal nervs. he mediastial pleura is suppled by the prenic erve. The daphragmatic leura s supplied over the does by the phrenic nrve an aroun the eriphey by he lowr six intercostal erves.

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snell The viceral pleura covering the lungs is sensitive to stetch bt is insensiive to commo sensaions uch as pain and touh. It receies an utonomic nere suppy from the plmonar plexu (Fig. 3-8). P.85

Figre 3-8 Diagram howin the innervaion of the prietal and vsceral layer of pleura.

linical Note Pleural Flid Te pleural spce norally cntains 5 to 0 mL o clear flui, whic lubriates the appsing srface of th visceal and parietal plurae dring respiraory moements The frmation of the fluid reslts from hydostatic and osmotic pressues. Sice the hydrstatic pressures are greatr in te capilaries of th parieal pleura than in he capllarie of the viscral plura (plmonary cirulatio), the pleurl flui is normally absorbed int the apillaries o the viscera pleura. Any conditon tha incrases te prouction of th fluid (e.g., inflamation malignancy, congestive heart dsease) or imairs the drainage of he fluid (e.., colapsed lung) results in te abnomal accumulaion of fluid, called a pleural efusion. Te presence of 300 m of flid in the cotodiaphragmatic recess in an ault is sufficient t enabl its clinical detecion. Te clinical igns iclud decresed lug expnsion n the side o the effusion, wih decrased breath ounds and dullness n percssion over he effusin.

Pleurisy Inlammaton of te pleur (pleuitis or pleuisy), seconary to inflammtion of the lung (e.g. pneumonia), results in th pleura surfacs becoming coated with inflammtory eudate, ausing the suraces to be roughened. This roghening produce fricton, and a pleual rub can be heard

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snell with te stethscope on inspiration ad expirtion. ften th exudat becoes invaed by ibroblats, whih lay dwn colagen an bind te viseral plura to he parital plura, foming plural adesions.

Pneumthorax, Empyema, and Peural Efusion As the resut of disease o injury (stab r gunsht wouns), air can enter the leural cavity rom th lungs r throuh the hest wal (pneuothora). In te old teatment of tubrculosi, air was purosely njected into te pleurl cavit to colapse an rest te lung. This was know as artificia pneumohorax. A spotaneous pneumothorax is a conditin in whch air nters the pleural caviy suddely witout it cause being imediately appaent. Afer invtigatin, it i usualy found that ir has ntered rom a dseased lung an a bull (bleb has ruptured. Sta wounds of the thoraci wall may piere the prietal pleura so that the pleral caity is open to the outide air This ondition is caled ope pneumothorax. Eac time he patint insires, it is posible to hear air unde atmosheric pessure eing scked ino the pleural cavity. ometime the clohing ad the lyers of the thracic wll combne to form a alve so that ai enter on insiration but canot exi through the wound. In thee circustances, the air pressre buils up on the wunded sde and ushes the mediastinum oward te oppote sid. In tis sitution, a collapsd lung s on t injurd side and the opposie lung is compessed by the dflecte mediastinum. his dagerous conditin is caled a tesion pneumothorax. Air n the pleural avity asociatd with erous luid is known a hydropneumothorax associted wih pus a pyopnemothora, an associted wit blood as hemoneumothrax. A collection o pus (wthout ir) in the pleral cavty is clled an empyem. Th presece of srous flid in te pleurl cavit is reerred t as a pleural efusion (Fig. 3-9) Fluid (serous blood, or pus) can be drained from th pleura cavity throug a wid-bore nedle, a described on age 60. In hemopneumothorax, lood enters the pleurl cavit. It cn be cased by stab or bullet wounds to the chest wll, reslting i bleedng from blood essels n the cest wal, from essels n the hest cvity, o from laceraed lung P.6

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Figure 3-9 Case of rigt-sided pleura effusin. The ediastium is isplace to the left, the riht lun is comressed, and the bronch are narowed. Ausculation wuld reval onl faint reath sounds oer the compresed lung and asent brath souds over fluid n the peural cvity.

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igure 3-10 Thoraci part of the tachea. ote tha the right pricipal bonchus s widr and hs a mor direct continuation o the trchea tan the eft. ifurcaton of the trachea viewd from bove i also sown.

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Tachea The trachea is a moile catilaginous and membraous tub (Fig. -10) It bgins in the nek as a continution of the laynx at he lowe border of th cricoi cartilge at he leve of the sixth ervica vertera. It escends in the midline of the neck. I the thorax th tracha ends elow at the caina y divding ino right and lef prinal (main) brochi at the level of the sternal angle (opposite the isc beteen te fourt and fifth thracic vrtebrae. Durin expiration th bifurction rises by about oe verteral levl, and during eep insiration may be owered a far a the sixth thoacic vetebra. In adults he tracea is about 4Â in. (1.25 cm) long and 1 in. (2.5 cm in diaeter (Fig. 3-10). The firoelastc tube s kept patent by the pesence f U-shaed bars (rings of hyaine catilage embedded in it wall. he postrior fee end of the cartilae are cnnected by smooth muscle, the tracheals muscl. The relaions of the trachea in the neck are dscribed on page 810.

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Figue 3-11 A. How te interostal mscles raise th ribs during ispiration. Note that he scaleni musles fix the first rib r, in frced inpiratio, raise the frst rib B. How the intercstal mscles cn be usd in forced exiration providd that the 1th rib s fixed or is made to escend y the adominal muscle. C. How the liver rovides the plaform that enabes the iaphrag to raise the ower ris.

The relations f the tachea i the sperior ediastinum of he thorx are a follos: 

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Anteiorly: The sternu, the thymus, he left brachioephalic vein, he origns of the rachiohalic nd left common carotid arteris, and he arch of the aorta Figs 3-6A, 3-10, and 331) Posteiorly: The sophagu and the left recurren laryngal nerv (Fig. -6A) Rght sie: Te azygo vein, he rigt vagus nerve, nd the pleura igs. 36, 3-6A, and 3-17)

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Lft side: Te arch of the orta, the left common arotid and lef subclvian ateries the let vagu and let phrenc nerve, and he pleua (Figs. 3-6 3-16B, and 3-18)

Blood Supply o the Trchea Te upper two thirds are supplie by the inferir thyrod arteres and the lower third is suplied by the bronchial rteries P.88

ymph Drinage f the Tachea The lymp drains into te pretracheal nd pararacheal lymph ndes and the dep cervial nods.

Nerve Supply f the Tachea The sensry nerve suppl is fro the vai and he recurent layngeal nerves. Sympathtic neves suply the racheals musce.

The Brnchi The trachea bifurctes beind the arch of the aota into the right and eft pricipal (rimary or mai) bronchi (Fgs. 3-0, 3-9, and 3-20). Th bronchi divid dichotomously giving rise to several millio termial brochioles that terminate in one r more espiratory brnchiole. Each espiratry bronhiole divides nto 2 t 11 alvolar ducts tht ente the aleolar sacs. Th alveol arise from the walls f the sacs as divertcula (se page 94).

Pincipa Bronch The riht prinipal (min) brnchus (ig. 3-12) i wider, shorter and mre vertcal than the lft (Figs. 3-10, 3-19, and -20) and is bout 1 in. (2. cm) log. Befoe enterng the hilum o the riht lung, the pincipal bronchs gives off the superir lobar bronchus. O enterig the hlum, it divide into middle and an inferor lobar bronchus.

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Fgure 3-12 Rlationsip of he pulmonary ateries o the bronchial tree.

The left principal (main) bronchu is narrower, onger, and moe horizntal thn the right ad is aout 2 i. (5 cm) long. It pases to the left below te arch of the orta an in frnt of te esophagus. On enering te hilum of the left lug, the rincipa bronchus divides into a superr ad an inferior lbar brochus.

linica Notes Compression o the Trachea Te tracha is a membranous tub kept patent under normal onditins by Ushaped ars of cartilage. In the neck a unlateral or bilteral enlargement of th thyroid gland cn cause gross displcement or comession f the tachea. A dilatation of te aortc arch (aneurym) can compres the trahea. Wit each crdiac ystole he pulsating anerysm ma tug at the trachea and eft brnchus, clinicl sign that can be fel by plpating the trahea in the supasternal notch.

Trachetis or ronchitis The ucosa lning th trache is innrvated y the ecurrent laryngel nerve and, in the regin of is bifuration, y the ulmonary plexus. A trachitis or ronchitis gives rise t a raw, burnin sensaion felt deep to the sterum insted of actal pain Many horaci and abominal viscera, wn disesed, gie rise o discofort tat is felt in he midine (se page 280). It eems tht orga possesing a ensory nnervaion

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snell tht is no under normal conditions dirctly reayed to consciousness isplay his phnomenon. The aferent fibers rom thee organs traveing to the cetral nevous sytem acompany utonomi nerves

Inhaed Foregn Bodis Inhalation f forein bodie into he lowe respirtory tact is common, especialy in hildren Pins, screws, nuts, blts, peanuts, and pars of chicken bnes and toys hae all ound thir way into the bronhi. Pars of teeth may be inhaed whil a patient is under aesthesi during a difficult detal extaction Becaus the rght brochus is the widr and re dirct contnuation of the trachea (igs. 3-19 nd 3-20), foreign bodies tend to nte the riht instad of the left bronchu. From there, hey usally pas into he middle or lwer lobe bronci.

Bonchosopy Bronchoscopy enables a physiian to examine the intrior o the trchea; is bifuration, called he carna; nd the ain brnchi (Fgs. 3-1 and 3-14. With experiece, it is possble to xamine he intrior of the loar brochi and the beinning of the irst semental ronchi By meas of tis procdure, t is alo possile to otain biopsy spcimens f mucos membrane and to remoe inhaed foregn bodis (eve an ope safety pin). Lodgmen of a freign dy in the laryx or edma of the mucus membane of he laryx secondary t infecton or tauma ma requie immedate reief to revent sphyxiation. A method ommonl used o reliee complte obstruction is traceostomy (see page 813). P.9

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Figur 3-13 The ifurcaton of the trachea as sen throgh an oerating bronchoscope Note te rdge of he caria in th center and the openig into he righ main bonchus on the right, wich is a more direct contination of the tachea. Courtes of E.D Andersen.)

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Figure 3-14 The iterior f the eft mai bronchs as sen throuh an operating bronchoscope. The opeings ino the lft uppe lobe ronchus and it divison and he left lower obe bronchus are indiated. (ourtesy of E.. Anderen.)

Lung Dring lie, the right ad left lungs ae soft and spngy and very elstic. If the toracic cavity ere opned, th lungs would imediatly shrik to on third r less n volume. In the child they re pin, but wth age, they bcome dark and mottled becaus of th inhalaion of dust particles hat becme traped in the phagcytes f the lng. Thi is especially well sen in city dwelers and coal miners. he lung are situated so that one lies on each side f the ediastium. Th are terefore separated from each oter by te heart and great vessels and other sructures in the mediasinum. Each lun is coical, covered with viseral plura, an suspeded fre in its own pleural cvity, bing attched to the meiastinum only y its rot (Fig. 3-4).

Fgure 315 ositio of the heart alves. , pulmoary vale; A, artic vve; M, mitra valve; T, tricuspid

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valve. Arows indcate poition here vaves ma be heard with least iterferece.

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Figre 3-16 A Right ide of the medastinum B. eft sid of the mediasinum.

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igure -17 Dissecion of he righ side f the mdiastinm; the ight lug and the percardiu have ben remoed. The costal arietal pleura as also been emoved.

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igure 318 Dissecton of the left side of the meiastinu; the lft lung and the pericardium ave bee removed. The ostal prietal pleura as also been emoved.

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Figure 3-1 Tachea, ronchi, broncholes, aveolar ucts, aveolar acs, ad alveli. Noe the pth take by insired ai from the trachea to te alveli.

Eah lung as a blnt apex, whch projcts upard int the nek for bout 1 n. (2.5 cm) abve the clavicl; a conave bas tha sits on the daphragm a convx costa surfac, whch corrsponds o the oncave hest wll; and a concve mediastinal urface, whic is moded to he periardium and other mediatinal structurs (Figs. 3-21 and 3-22). t about the middle of this surace is he hilu, a epression in which the bronchi, vesses, and nerves hat form the root eter and leave the lung.

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snell Te anteior borer is thin and ovrlaps te heart it is here on the let lung hat th cardia notch is fund. Th posteror bordr is tick and lies beide the vertebal colun.

Lobes and Fisures Right ung The rght lun is slihtly lager than the lft and s dividd by te obliqe and hrizontal fissues into three lbes: th upper, middle, and lower lobes (Fig. 3-21). The oblque fisure runs from the inferir borde upward and bakward aross th medial and costal sufaces util it uts the posteror bordr about 2.5 in. (6.25 cm) belw the ex. Th horizontal fisure runs hrizontaly acrs the ostal surface t the lvel of the fouth cosal cartilage t meet te oblique fissre in te midaillary ine. The midde lobe s thus small riangulr lobe bounded by the horizontal and oblique fissure. P93

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Figure 3-20 A pastinizd specimen of an adult trachea prinal brochi, an lung some o the lung tisse has been disected t reveal the larger ronchi. Note tat the ight main bronchus is ider ad a mor direc continuation of the trachea than th left min brochus.

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Fgure 3-1 Lteral and medil surfaes of te right lung.

Lef Lung Th left lng is dvided b a similar oblque fisure into two lbes: th upper and lwer loes (Fig. 3-2). Tere is o horizntal fissure i the let lung.

ronchoulmonar Segmets The bronchoulmonar segmens are he anatmic, fnctiona, and surgical units o the lungs. Eah lobar (seconary) bonchus, which es to a lobe of the ung, gies off branche calle segmntal (ertiary bronchi (Fig. 3-19). Eah segmtal brnchus psses to a structurally and funtionally indepndent uit of a lung lobe calld a brochopulonary sgment, whic is surrounded by connctive tssue (Fg. 3-23). Te segmental brnchus is accomanied b a branch of te pulmoary arery, bu the

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snell tributaris of th pulmonry vein run in the conective tissue between djacent bronchoulmonary segments. Each segmen has it own lmphatic vessels and autnomic nrve suply. On entering bronchopulmonary segmet, each segmenta bronchs divids repeaedly (Fg. 3-23). As the brnchi beome smaler, th U-shapd bars f cartilage found in th trache are grdually replace by irregular plates of cartilage, whch becoe smaller and feer in nmber. Te smallst bronhi divie and give rise to brnchiole, whch are ess tha 1 mm i diametr (Fig. -23). Broncioles pssess n cartilge in teir wals and ae lined with clumnar iliated epithelum. The submucoa possesses a complete yer of circulrly arrnged smoth musle fibes. The bronhioles hen divde and ive rie to terminal bonchiols (Fi. 3-23), whch show delicat outpouhings fom thei walls. Gaseous exchang betwen blood and air takes pace in he wall of thee outpochings, which xplains the nam respiraory bronchiole. The diamete of a respiratoy bronchiole is about 0. mm. Th respirtory brnchioles end by branchig into aveolar ucts which ead in tubulr aes with numerou thin-wlled oupouchins calle alveolar sacs. The aveolar acs conist of everal lveoli pening nto a sngle chmber (Fis. 3-23 and 324). Each aveolus s surronded by a rich twork of blood apillares. Gaeous exhange tkes pla between the ai in the alveola lumen through the alvolar wal into he bloo within the surounding capillries. P.95

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Fiure 3-2 Lateral an medial surface of the let lung.

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Figre 3-23 A ronchopulmonary segmen and a ung loble. Not that te pulmonary vens lie within he connective tssue seta that separate adjacent segments.

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Fiure 3-2 Scanning electron microgrph of the lung showing nmerous lveolar sacs. The alveoli are he deprssions, or alcoes, alng the alls of the aleolar sc. (Coutesy of Dr. M. ering.)

The main charactristics of a bronchopulonary sgment may be summarized s follos:    

It is a subdivision of a lung obe. It is pyraid shapd, with its apex towar the lug root. It is surrouned by cnnectiv tissue It has a segmntal brnchus, segmetal artry, lymh vesses, and utonomi nerves

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he segmntal ven lies n the cnnectiv tissue between adjacent bronchopulmonary sements. Becuse it is a structural unit, a disease segmen can be removed surgically.

The main brnchopulonary sgments igs. 325 ad 3-26) are a follows: 

Right lun Superir lobe: Apicl, postrior, anterior Middl lobe: Lateral, medil Inferior lbe: uperio (apica), medil basal anterir basal latera basal, posterir basal



Left lung Superor lobe Apial, poserior, anterior, superor linglar, inerior lngular Iferior obe: Superior (apicl), medal basa, anteror basa, laterl basal posteror basa

Altough th genera arrangment of the brochopulmnary sgments s of clnical iportanc, it is unnecesary to memorize the deils unlss one ntends o specilize in pulmonay medicine or rgery. The rot of te lung is frmed of structues that are entring or leaving the lung. It is made up of the bronchi pulmonry artey and vins, lyph vessels, bronchial vssels, nd nerves. The oot is urroundd by a ubular heath o pleur, which s te mediatinal prietal leura t the viceral leura covering the lungs (Figs. -5, 316, 317, and 3-18).

Blood Supply of the Lngs The bronchi the conective tissue of the lung, and the viceral peura reeive thir bloo supply from te broncial artries, hich ar branchs of th descening aora. The ronchia veins which ommunicte with the pulonry vein) drain into he azygos and hmiazygos veins. P.9

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igure 325 Lngs vieed from the riht. A. Lobes. B. Bonchopumonary egments.

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Figre 3-26 Lung viewed from th left. A. Lobs. B. Bronchoulmonar segmens.

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The alveli receive deoxgenated blood fom the erminal branchs of the pulmony artees. The oxygenated bloo leavin the aveolar apillares drais into he tributaries of the pumonary veins, hich folow the intersemental onnectie tissu septa o the ung roo. Two plmonary veins leave each lung root (Fig. 3-16 to empy into he left atrium of the heart.

ymph Drinage o the Lungs

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snell The ymph vesels orginate in supericial and deep lexuses (Fig. 3-7); hey are not preent in he alveolar wall. The superficial (subpural) plexus lies bneath the viscerl pleur and drins ove the surface of the lung towar the hium, whee the lmph vesels entr the brnchopulonary ndes. The dee plexus travels alon the brnchi an pulmonry vessls towad the hlum of the lung, ing through pulmonay nodes locted witin the ung subtance; he lymph then enters the bronchpulmonay nodes in the ilum of the lun. All te lymph from th lung eaves the hilum and drans into the traceobroncial nods an then ito the bonchomeiastina lymph runks.

Figure -27 ymph drainage the lng and ower en of the esophags.

Nerve Suply of he Lung At the oot of ach lun is a pumonary plexus compsed of fferent and affrent auonomic erve fiers. The plexus is fored from branche of the sympathtic trunk and receives arasympthetic ibers fom the agus neve.

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snell The smpathetc effernt fibers produe bronhodilattion an vasocostriction. The parasympathetic fferent fibers produce ronchoonstricion, vasodilatation, and increasd glanular secretion Affeent impulses derived frm the bonchial mucous membran and frm streth receptors in he alveolar wal pas to th centrl nervos syste in bot sympatetic an parasympathetic nerves.

Embryolgic Nots Devlopment of the ungs an Pleura A lonitudina groove develop in the entoderal lining of the floor o the phrynx. Tis grooe is knwn as te larynotracheal groove. The linig of th larynx trache, and bonchi ad the eitheliu of th alveol develo from tis grooe. The margins of the grove fus and frm the lryngotracheal tube (Fi. 3-28). Te fusion process starts distally so that the lumn becomes sepaated from the developing esophaus. Jut behin the developing tongue, a small opening persist that wll becoe the prmanent opening into the laryn. The lryngotrheal tue grows caudall into te splanhnic msoderm and will eventually lie anteror to te esophgus. Th tube ivides distally into the right ad left lung bus. artilag develops in the mesenchyme surrunding he tube and th upper art of he tube becomes the laryx, hereas he lower part becomes the trache. Eah lung ud consists of n entodrmal tue surrounded by splancnic mesderm; fom this all th tissue of the correspnding ung are derived. Each bd grows lateraly and pojects nto the pleura part o the embryonic oelom (Fg. 3-28). Th lung bd divid into three lobs and ten into two, coresponding to te number of main bronchi and lbes ound in the fuly develped lun. Each ain brochus then divids repeaedly in a dichoomous mnner, util eventually he termial bronhioles and aleoli are fomed. The diision of the teminal bonchioles, with the foration of additonal bronchiole and aleoli, cntinues for some time after birh. Each lung wll receve a covering o visceral pleura derived from the splnchnic esoderm The paietal pleura will be formed rom somtic mesderm. B the seenth moth, the capillry loop conneced with the pulonary crculatin have ecome ufficietly wel developed to lfe, shold premture bith tak place. With the onset of respiration at birth, he lung expand and th alveol become dilated Howeve, it is only afer 3 or 4 days of postatal lie that he alveoli in te peripery of ach lun become fully expanded.

Congental Anoalies Esophagal Atreia and racheoeophagea Fistul If the mrgins of he laryngtracheal grove fail to fus adequaely, an abnorma openin may be left beween the larygotrachal tube and the esophags. If te trachoesophageal septum formd by the fusion of the margins of the laryngoracheal groove should e deviaed poseriorly the luen of te esophgus woud be mch redued in dameter. The diferent tpes of tresia, with an without fistu, are shown in Figure 3-29. Obstruction of the sophagu prevents the child from swallowng salia

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snell and ilk, ad this eads to aspiraton into the larnx and rachea, which sually esults n pneumonia. With early diagnoss, it i often possible to correct this serious anomaly surgicaly. P99

Figure -28 he deveopment f the lngs. A. The laryngotacheal roove and tube have bee formed B. Th margin of the laryngoracheal groove fuse to frm the laryngoracheal tube. C. The ung buds invagate the wall of the intaembryoic coelm. D. The lun buds dvide to form th main bonchi.

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Figre 3-29 Diffrent tyes of eophagea atresi and trcheoesophageal fistula. A. Cmplete lockage of the sophagu with a tracheoesophageal fistul. B. Similar to type A, but he two arts of the esohagus ae ed together by fibrous tisue. C. Compete blockage of the esohagus; he distl end i rudimetary. D. A tacheoesphageal fistula with narowing f the eophagus E. An esopagotraceal fisla; the esophags is nt connected with the disal end, which i rudimetary. F. Sepaate esohagotraheal an tracheesophagal fistulas. G. Narrwing of the esohagus wthout a fistula In mos cases, the lower esopageal sgment cmmunicaes with the tracea, and types A and B ccur moe commoly.

Th Mechancs of Rspiratin Respration consists of two phasesâ€inspiration and expiraton—whch are ccomplihed by he altenate inrease ad decrase of he capaity of he thorcic cavty. The rate vaies beween 16 and 20 er minue in nomal resting patients an is faser in hildren and sloer in te elderly.

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Ispiration Quiet Inspirtion Comare the thoracic cavity to a bx with single entranc at the top, which is a ube called the trachea (Fig. 330). The caacity o the bo can be increase by elongating ll its diametes, and his reslts in ir unde atmosperic prssure entering the box hrough he tube onsider now the three dameters of the horacic cavity nd how hey may be incrased (Fi. 3-30).

Vertial Diamter Theoeticall, the rof could be raied and he floor lowered. The oof is ormed by the surapleural membrane and is fixed. Converely, th floor s forme by the mobile iaphrag. When he diaphragm cntracts the does becoe flattned and the levl of the diaphragm is lowered (Fig. 330).

nteroposterior iameter If the downwar-slopin ribs wre raisd at thir stenal end, the aneroposterior diameter f the toracic avity wuld be increasd and the lower nd of te sternm would be thrut forwad (Fig. -30) This an be bought aout by ixing te first rib by he ion f the caleni muscles o the nek and cntractig the itercostl muscles (Fig. 3-11. By ths means, all the ribs ar drawn ogether and raied towad the first rib.

Transverse Diamter The ibs artculate n front with the sternu via thir cosal cartlages ad behin with te verteral colmn. Becuse the ribs crve dowward as well as forward around he ches wall, hey reemble bcket hadles (Fi. 3-30). It therefoe follos that f the rbs are raised (lke buckt handls), th transvrse diaeter of the thoacic caity wil be inceased. s descibed previously, this can be accomplished by fixng the first rb and aising he other ribs to it by cntractig the itercostl muscles (Fig. 3-11. An additioal factr that ust not be overlooked i the efect of the desent of he diapragm on the abdminal vscera ad the tone of e muscls of th anterir abdomnal wal. As the diaphram desends on inspiraion, inraabdomnal pressure rises. This rise in pressre is acommodated by th reciprcal relxation f the adominal wall msculature. However, a point is rached hen no urther abdominal relaxaion is ossible, and th liver nd othe upper bdominal viscea act as a platform tht resiss furthr diaphragmatic descent. On furher conraction the diphragm ill now have it centra tendon suppord from below, ad its sortenin muscle fibers ill assst the ntercostal muscles in aising the lower ribs (Fg. 3-11). P.101

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Figure -30 he different was in which the capacity of the horacic cavity s increased duing insiration.

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Apar from te diaphagm and the intrcostal, other less iportant muscles also contract o inspirtion an assist n elevating th ribs, amely, he levatores cotarum mscles and the serrats posteior suprior mucles.

Foced Insiration n deep orced ispiratin, a maimum increase in the acity f the toracic avity ocurs. Eery musle that can raie the ribs is brought into acion, including the scaleus anteior and medius and the sternocleidomasoid. In respiratory ditress the action of all the musles alrady engged becmes mor violen, and te scapulae ar fixed by the rapezis, levaor scaulae, ad rhomboid musces, eabling he serrtus anerior ad pectoralis mnor to ull up te ribs If the upper libs can be ed b grasping a chair back or table, the stenal orign of the pectorlis majo muscle can alo assit the process.

Lung Canges on Inspirtion In inspirtion, he root of the lung descends nd the evel of the bifucation o the trachea ma be loweed by a much as two veebrae. he bronhi elongte and ilate and the alvolar caillarie dilate, thus asisting the pulonary crculation. Air is drawn into the bronhial tre as th result of the ositive atmosphric pressure exerted through the uper part of the spiratoy tract nd the egative pressure n the uter surace of te lungs brought aout by the incrased caacity of the thoracic cvity. Wih expanson of th lungs, the elasic tissu in the bronchil walls and connective tissue re streched. As the diahragm decends, te costoiaphragmatic recess o the plural cavty opens and the expandig sharp ower edgs of the lungs scend t a lower level.

Expiraton Quit Expirtion Quet expiation i largel a ve phenoenon and is broght abou by the lastic rcoil of he lung, the relaxation the itercosta muscles and diapragm, and an incrase in one of te muscles of th anterio abdominl wall, which foces the relaxing diaphrgm upwad. The serratu posterir inferor musces play a minor role i pulling down the lower ris.

Fored Expiration

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snell Forcd expiraion is an active proces brough about by the forcible contracton of te muscuature of the anteior abdminal all. Th quadraus lumboum also ontracts nd pulls down th 12th ribs. It is conceiable tha under tese cirumstance some o the inercostal muscles ay contract, pull the rib togeth, and deress them to the lowered 2th rib ig. 3-1). Th serratu posteror inferor and he latisimus dorsi musles may also pla a minor role.

Lung Changes on Expiration In xpiration, the roots of te lungs scend alng with the bifucation o the trchea. Th bronch shorten and . The elastic tissue f the luns recois, and th lungs ecome reuced in size. Wih the uward movment of he diapragm, inreasing areas of the diahragmati and cosal parieal pleua come into appoition, and the costodiphragmaic reces becoms reduce in size The lowr margis of the lungs shink and rise to higher level.

Tpes of Respiration In babes and yung children, the ribs ae nearly horizonal. Thus babies have to ely maily on th descent of the diaphragm to increase thir thorcic capcity on inspiraion. Beause this is acompani by a marked inward and outward excursin of th anteror abdoinal wal, which is easily seen, respiraion at his age is refrred to as the abdomina type o respirtion. fter th second year of life, the ribs come moe obliqe, and the adult frm of repiratio is estalished. In the adut a sexal diffrence eists in the typ of repiratory ovement. The feale tend to rely mainly n the moements f the rs rathe than on the desent of th diaphrgm on inpiration. This s referrd to as the thorcic type of respration. The ale uses both he thoraic and bdominal forms of respirion, bu mainly te abdomial form.

Clinical otes Physical Emination of the ungs Fr physial examnation f the ptient, t is helful to hat the upper loes of he lungs re most easily eamined from the front o the chest and te lower obes fr the bak. In te axille, areas of all lobes can be examned.

Trauma to te Lungs A physicin must always rmember hat the pex of he lun projecs up into the neck (1 in. [2.5 cm] aboe the clavicle) and ca be damaged by stab or bullet wunds in this are. Althugh the lungs are well prtected y the boy thoraic cage, a spliner from fractured rib cn nevertheless enetrate the lung and ai can ese into he pleurl cavity causin a pnemothorax and colapse of he lung. It can also fin its way int the lng connctive tissue. Frm there, the air oves under the isceral leura until it raches th lung rot. It thn es into the mediastnum and

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snell up to the neck. ere, it ay distnd the sbcutaneos tissu, a conition knwn as sucutaneous emphysma. he chanes in the positon of te thoraic and pper adominal viscera and the evel of the diapragm durng diffeent phaes of rpiratio relativ to the chest wll are f considerable clinical impotance. A penetraing woud in the lower prt of th chest may or ay not dmage abdminal vscera, dpending n the pase of espiratin at the time of injury.

Pai and Lun Diseas Lung tisue and the viceral peura are devoid f pain-sensitive nerve enings, so that pan in th chest is alway the result of onditions affectin the surounding structurs. In tberculois or pnumonia, for exaple, pai may nevr be exerienced Once lung disese crosss the viscera pleura and the pleural cavity o invole the paietal pleura, pain become a prominent feture. Lbar pneuonia wit pleuris, for exmple, produces a evere earing pin, accentuated y inspiring deepl or couging. Becuse the lower pat of the costal parietal peura receives it sensory innervaion from the lowe five inercostal nerves, which aso innrvate te skin of the nterior abdominl wall, pleurisy in this area comonly poduces pain that is refered to te abomen. This has someties resulted in mistakn diagnois of an acute adominal esion. In a similr manner pleuriy of the central art of te diapragmatic pleura, hich recives sesory innrvation from the phrenic nerve (C, 4, an 5), ca lead to referrd pain ver the shoulder because the skn of ths region is suplied by he supaclavicuar nerve (C3 and 4).

Surical to te Lungs urgical access t the lun or medastinum s commony undertkn throu an intecostal space (see page 0). Special rib retactors hat allw the ribs to be widely sparated re used The costal cartlages ar sufficiently elstic to ermit cnsiderabe bendin. Good eposure f the lugs is obained by this mehod.

Segental Reection o the Lun A locaized chonic leion such as tht of tuerculosis or a benign neplasm ma require surgical removal If it i restrited to a bronchopulmoary segent, it is possile careflly to dssect out a paricular egment nd remoe it, laving th surrouning lung intact. Segmental resecton reques that he radilogist ad thoracc surgon have sound kowledge f the bronchopulmonary sements and that they cooperate fly to lcalize te lesion accuratly befor operaton.

Broncogenic Ccinoma Bonchogenc carcinma accouts for aout one hird of all caner death in men nd is bcoming icreasingy common in wome. It comences in most ptients in the mucos membrne lining the lager brochi and s therefre situaed clos to the hilum of the lung The neoplasm rpidly spreads to te trachobronchil and brnchomedistinal nodes an may involve the ecurren laryngel nerve, 193

snell leadig to harseness of the voice. Lymphatc sprea via the bronchoediastinl trunk may reslt in ealy involvment in the lower deep cevical noes just above te level of the cavicle. ematogenus spred to bones and te brain ommonly ccurs.

Conditons Tha Decreae Respiratory Eficienc onstricion of he Brchi (Bonchial Asthma) One of the probles assocated wih broncial astma is he spasm of the mooth mscle in the wal of the bronchiles. Ths partcularly reduces the diamter of he bronhioles uring epiration, usualy causng the sthmati patient to exprience great dificulty n expirng, although insiration is accmplished normall. The lngs cosequenty become greatly distende and th thoracic cage beomes permanentl enlarge, formig the s-called barrel hest In adition, the air flw throug the brochioles s furthr impede by the presence of exces mucus whic the paient is nable to clear ecause an effectie cough annot be produced

Loss o Lung Easticity Many disases of the lungs, such s emphysema a pulmonay fibross, estroy th elasticity of te lungs, and ths the lugs are nable to recoil dequatel, causig incompete expration. The resiratory muscles in thes patients have to assist i expiraton, whic no longr is a assive henomeno.

Los of Lung Distensbility Dseases sch as silicosis, sbestosis, cancer, and pneumonia interfere with th proces of expding th lung in inspiration. A dcrease in the comliance f the lugs and te chest wall then occurs and a reater ffort ha to be ndertaken by the inspiratry muscls to inlate th lungs.

Potural Dainage Ecessive accumulation of bonchial secretis in a lbe or egment o a lung can seriusly inerfere wth the nrmal flw of ai into te alveol. Furthemore, th stagnaton of such secreions is often uickly followe by infction. o aid i the nomal dranage of bronchal segmnt, a phsiotherist often alter the position of he patint so tht gravit assists in the pocess of drainag. Sound knowledg of the ronchial tree i necessay to detrmine the optimu positin of the atient for good postural drainage. P.103

Pericrdium The pericarium is fibroseous sa that enloses te heart and the roots of the gret vesses. Its unction is to rstrict excessiv movemens of the heart a a whole and to erve as lubricted

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snell continer in hich th differet parts of the hert can contract The percardium lies witin the iddle medastinum Figs 3-2 3-31, 3-32, and 3-3), osterio to the body of he sterm and te second o the sith costa cartiages an anterir to the fifth to the eighh thoracc verterae.

Fibrous Peicardiu he fibrus pericrdium is the strng fibrs part o the sc. It is firmly ttached elow to the cental tendn of the diaphrgm. It fses with the oute coats o the grat blood vessels ing through t (Fig. 332)â”namely the aora, the plmonary runk, the superior and iferior venae cavae, nd the pulmonary veins (Fig. 3-33). The fibros pericardium s attachd in frnt to th sternum by the strnoperiardial lgaments.

Serous Pericardium The srous pericardim lines the fibous percardium and coat the heat. It is divided into paretal and visceral layers (Fg. 3-32). The arietal layer lines te fibrou pericarium and is reflected aroud the rots of the great vessels to becom P.104

coninuous ith the viscera layer f serou pericadium that close covers the heart (Fig. 3-33).

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Fiure 3-3 The pericardum and te lungs xposed fom in frnt.

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Figre 3-3 Diferent lyers of the percardium

The visceral layr is closely applie to the heart an is oftn calle the epicardium. The slitlik space between te parieal and isceral layers s refered to a the percardial cavity (Fig. -32) Normaly, the avity contains a small aount of tissue luid (aout 50 L), the ericardal flui, whch acts as a luricant o faciltate movements o the hert.

Pricardil Sinuss On the posterir surface of the heart, the refection f the serous pericardiu around the lare veins forms a recess alled te oblique sinus (Fig 3-33). Also on the posterior surface of the eart i the trasverse inus which is a shrt ge that lies beween the reflection of srous pricardim aroun the aota and ulmonary trunk ad the rflectio arond the large vins (Fig 3-33). The ericardial sinues form s a cosequenc of the way the heart beds durig develpment (ee page 18). They hae no clinical sinificane.

Nerve Supply f the Pericardium The fibrous ericardm and te parietal layer of the serous pericarium are supplie by the phrenic nerves. The viseral lyer of he sero pericadium is inervated by branhes of he sympathetic trunks and the agus nerves. 197

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Fiure 3-3 The great bood vesels and the intrior of the pericardium.

Cinical otes Peicardits In inflmmation of the serous pricardim, called pericarditis, pericarial flud may acumulat excessvely, wich can compress the thn-walle atria nd intefere wih the filling of the hert durg diastle. Thi compresion of the heat is caled cariac tamonade. ardiac amponade can also occur secondary to st or gushot wonds whe the chmbers o the hert have been penetrated. The blod escaes into the percardial cavity nd can restrict he filing of the heat.

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snell Roughening of the viscera and paietal layers of serous ericardum by iflammatry exudte in aute percarditis produce pericardial frition ru, whch can e felt n palpaion and heard through a stethosope. Pericadial flid can e aspirted fro the peicardial cavity should xcessiv amount accumuate in ericardtis. Ths procs is called parcentesis. The needle can be ntrodued to the left of the xphoid pocess in an upward and ackward directin at an angle o 45° t the skn. When paracentsis is performd at ths site, the plera and lung are not damaed because of he presnce of he cardac notch in thi area.

Heart The eart is a hollow muscular organ that is somewhat pyramid shaped nd lies within he periardium in the ediastinum (Figs 3-34 and 3-35). It is conncted at its bas to the great bood vesels but otherwie lies ree within the ericardum.

urfaces of the eart The heart hs three surface: sterncostal anterior), diapragmati (inferor), an a base (posteror). It also ha an apex, which is directed dowward, frward, nd to te left. Te sternoostal srface is formed mainly by the right atrum and he rigt ventrcle, wich are separted from each other by the verical atrioventricular roove (Fg. 3-35). he righ border is fored by te right atrium; the lef borde, by the left ventrice and part of he left auricle. Te right ventrice is sparated from te left entricle by th anterior interentricuar grove. The diphragmtic surace f the eart is formed ainly b the riht and left ventricles eparate by the posterior interentricuar grooe. The nferior surface of the right atrium, ino which the infrior vea cava pens, aso form part f this surface. The bae of th heart, or te posteior surace, is formed ainly b the let atrium, into hich open the for pulmoary veis (Fig. -36) The bae of the heart lies opposite the apex. P106

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Figure -34 The antrior suface of the heat; the ibrous ericardum and he paretal seous percardium have been remove. Note he presnce of at benath the visceral serous ericardum in te atrioentricuar and intervetricula groove. The cronary rteries are embeded in his fa.

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Figure 3-35 The antrior suface of the heat and the great blood vesels. Nte the course f the coronary ateries nd the ardiac eins.

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Fgure 3-6 Th posteror surface, or the base of the eart.

Th apex of the heat, frmed by the lef ventrile, is irected downward, forward, and o the left (Fig. 3-35. It les at te level of the ffth lef intercstal spce, 3.5 in. (9 cm) fro the miline. In the region of te apex, the apex beat can usualy be sen and alpated in the iving ptient. Note that the base of th heart is calle the bae becase the eart is pyramid shaped; the bae lies pposite the ape. The heart des not est on ts base it ress on it diaphrgmatic (inferior) surfce.

Border of the Heart Th right order i formed by the ight atium; th left brder, by the left auricl; and blow, by the left ventrile (Fig. 3-35. The ower boder is ormed minly by the rigt ventricle but also by the riht atrim; the pex is formed by the left ventrile. Thee bordrs are importnt to rcognize when examining a radiogrph of te hear.

Chambers of th Heart Te heart is divied by vrtical epta ino four chamber: the right and left atra and te right and lef ventriles. Te right atrium ies anterior to he left atrium, and the right entricl lies aterior o the lft ventricle.

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snell The walls o the heart are composed of cardiac muscl, the myocarium; covered externlly wit serous pericardium, the epicardum; nd lined internally with a layer of endohelium, the endcardium.

Right Arium The ight atium consists of main cavity an a smal outpouhing, te aurice (Figs. 3-35 and 3-37). On the outide of he heart at the junction between the rigt atriu and th right uricle s a verical grove, the sulcus erminals, wich on he insie forms a ridge the crita termnalis. The ain par of the atrium hat lies posterior to th ridge is smoot walle and is derived embryolgically from th sinus venosus. The par of th atrium in fron of the ridge is roughened or trbeculatd by bndles o muscle fibers, the muscli pectnati which un from the crita terminalis to the aurcle. Ths anteror part is deried embrologically from he primtive atium.

Openings into te Right Atrium he supeior ven cava (Fig. 337) opens ito the pper pat of the right trium; it has no valve. It retuns the lood to the heat from he uppe half o the body. The iferior ena cav (lrger thn the superior na cav opens into the lower prt of te righ atrium it is uarded y a rudimentary, nonfuncioning alve. I returs the bood to the hear from te lower half of the bod. he coronry sinu, whch drais most f the bood from the heart wall (Fig. 337), opens nto the right arium beween the inferior vena cva and he atroventriular orfice. I is guarded by a rudimentary, nnfunctining vlve. The ight atioventricular orfice lies anerior t the inerior vna cava openin and is guarded by the ticuspid valve (g. 3-37). May small orifice of smal veins also drin the all of he hear and ope directy into he righ atrium

etal Renants In ddition to the rudimentary valv of the inferior vena caa are te fossa ovalis and anlus ovais. hese later strctures ie on he atria septum, whih separtes the right arium from the left atrium (Fig. -37). The fossa ovalis is a sallow dpressio, which is the ite of he foramn P108

vale in the fets (Fig. -38). The anulus ovlis fors the uper marin of te fossa The floor of the fossa represets the ersistet septu primum of the eart of the embyo, and the anuus is formed from th lower edge of the sepum secundum (Fig. 338).

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Figure 3-3 Inerior o the riht atrim and te right ventrice. Note the poitions f the snuatria node ad the atrioventricular nde and bundle.

ight Ventricle The right ventricle comunicate with te right atrium through the atroventricular orfice and with te pulmoary truk throgh the pulmonary orifice (Fig. 337). s the cvity appoaches the pulmonary orice it becomes funnel shaed, at which poit it is referre to as he infudibulum The walls of the rigt ventrile are uch thicer than those of the righ atrium nd show several nternal rojecting ridges formed of musle bundes. Th projecing ridges give the vetricula wall a sponglike apearanc and ar known s trabeulae carneae The trbeculae carneae are comosed of three tyes. The first tye compries the ppillary muscles, whic project inward, eing attched by their baes to the ventriular wll; thei apices re conneted by fbrous chords (the chordae tendineae) to the cusps of the tricuspi valve (Fg. 3-37). The second ype is atached t the eds to te ventricular wal, bein free i the midle. One of these the modrator bad, cosses te ventriular cavty from he septal to the nterior all. It conveys the rigt branch f the arioventriular budle, which is pat of th conductng syste of the eart. Th third tpe is smply cmposed o prominnt ridge. The tricuid valve guars the atioventriular orifice (Fi. 3-37 and 3-9) an consiss of three cusps formed by a old of ndocardum with some connectiv tissue enclose: anteior, septal, and infeior (posteror) cuss. The anterior cusp lie anterirly, th septal cusp les agaist the ventriculr septu, and te inferor or psterior cusp les infeiorly. The bases of the usps ar attachd to th fibrous ring 204

snell of the keleton of the eart (se below, whereas their ree edgs and entricuar surfces are attached to the hordae endinea. The chordae tendinee connet the csps to he papilary musles. When te ventricle contracts, te papilary musles conract an prevent the cusps from being frced ino the arium an turnin inside out as the intaventriular prssure rses. To assist n this process, the chodae tenineae o one paillary uscle ae connected to he adjcent pats of two cusps. Th pulmoary vale gards th pulmoary oriice (Fig 3-39A) an consiss of three semlunar csps fored by folds of endocarium wih some onnectie tisse encloed. The curved lower mrgins ad sids of ech cusp are attched to the arterial wll. The open moths of the cuss are drected upward into the pulmonay trunk No chodae or papillary muscle are asociated with thse valv cusps; the attachments of the ides of the cuss to th arteril wall revent he cusps from prolapsin into te ventrcle. At the roo of the pulmonay trunk are thre dilattions clled th sinses, and one is ituated externa to each cusp (see aorti valve). The hree seilunar usps ar arranged with one poserior (eft cus) and to anterir (antrior an right usps). P.109

(The cusps of the ulmonary and aotic valves are nmed accrding t their positio in the fetus bfore th heart has rotated to th left. This, ufortunaely, cases a geat deal of unnecessary onfusio.) During venticular ystole, the cuss of th valve are presed against the wall of he pulmnary trnk by te out-rshing bood. During diastole, bood flos back toward he hear and enters the sinuses; te valv cusps ill, coe into ppositin in th center of the lmen, an close the pulonary oifice.

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Figur 3-38 A. Nrmal feal hear. B. Atrial eptal defect. C. Tetraogy of allot. D. Patent ducts arteiosus (note the lose reationshp to te left ecurrent laryngel nerve. E. Corctation of the aorta.

Lef Atrium Smilar t the riht atrim, the eft atrum consists of a main cvity an a left auricle The let atriu is sitated behind the right arium an forms he greaer part of the bas or the posterior surfce of the

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snell heart (Fig. 3-6). ehind i lies the oblique sinus of the srous peicardum, and the fious pericardium separats it frm the eophagus (Figs. 333 ad 3-40). The interor of the left arium is smooth, but the left auicle posesses uscular ridges s in th right uricle. P.10

Figure 3-9 A. Position of the tricupid and ulmonry valvs. B. Mitral usps with valv open. . Mtral

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cups with valve closed. D. Semlunar csps of the aorti valve. E. Crss secton of te ventrcles of the heat. F. Path taen by te blood through the heat. G. Path taen by te cardic impulse from te sinuarial noe to th Purkine netwok. H. Fibrous skeleto of the heart.

Opeings ino the Lft Atrim The fur pulmnary veins, two rom eac lng, ope throug the poterior all (Fig. 3-36) and ave no alves. The left triovenricular orifice is guared by te mitra valve.

Left Ventrcle The left ventrcle comunicate with te left trium hrough he atrioventricular orifice and with th aorta through the aortc orifie. The alls of the left ventrile (Fig 3-39) are hree ties thicer than those o the riht venticle. (Te left ntraventicular bood presure is ix time higher than tht insid the rght venricle. In cross sectin, the eft venricle i circular; the right is crescentic becase of he bulgig of the ventriclar sepum into the cavity of the right entricl (Fig. 3-39). Thre are elldeveloped trabeculae carneae two lage papilary mscles, bt no modrator bad. The prt of the ventrile below the aoric orifce is called the ortic vetibule. P111

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Fgure 3-0 Crss section of th thorax t the eighth thorcic vertebra, as een frm below. (Note tat all omputed tomography scans and magneti resoance imging sudies ae viewe from blow.)

The mitrl valve guards the arioventicular rifice ig. 3-3). t consits of two cusps, one anrior and one poterior, which hve a sructure similar to that of the usps of the tricuspid vave. Th anteror cusp is the arger and intervenes beteen the atriovetricula and te aorti orifices. The attachmen of the chordae tendinee to th cusps and the papillay muscles is simlar to hat of he tricspid vlve. The aoric valv guads the ortic oifice and is precisely smilar i structre to te pulmoary vale (Fig. 39) One csp is stuated on the anterior wll (rigt cusp) and two are loated on the poserior wll (lef and posterior usps). ehind ech cusp the aoric wall bulges o form n aortic sinus. The nterior aortic inus gies origin to th right coronary rtery, and the left poterior inus gies orign to the left coronary artery.

Struture of the Heat The wlls of he heart are comosed of a thick layer o cardic muscl, the mocardiu, coverd exterally by the epiardium and lined internlly by he endoardium. The atral porton of the heart has relatively thin walls and divided by the atrial interatrial) septum into the right and left tria. Te septu runs fom the anterior wall o the hert backard and to the ight. The ventriular potion of the hert has hick wals and s dividd by th ventriclar (inerventrcular) eptum into the righ and left ventricles. Th septum is placd obliqely, wth one rface facing forward an to the right ad the oher facng bacward and to the eft. It positin is inicated n the sface of the hert by te anteror and osterior intervtricular groove. The ower pat of th septum is thick and fored of mscle. Te smaller uppr part of the eptum s thin nd membranous nd attached to he fibous skeeton. The s-called keleton of the eart (Fig. 3-39) onsists of fibrus ring that srround he atriventricular, pulmonary, and aoric orifces and are continuou with te membranous upper part of the ventricular septum. The ibrous ings arund the atrioventricular orifices sepaate the muscula walls f the aria fro those of the ventricle but prvide atachment for the muscle ibers. The fibrous rings suppor the baes of te valve cusps ad prevet the alves fom stretching an becomig incometent. he skelton of the heart forms he basi of eletrical iscontiuity between the atria and the entricls.

onductig Syste of the Heart Te norm heart contracts rhythically at about 70 to 9 beats er minue n the rsting ault. Th rhythmic contratile pocess oiginate spontaeously in the conducting system nd the impulse travels to diffrent reions of the heat, so te atria contrat first and together, to be follwed latr by th contrations f both entricles together. The light dlay in he ge of te impulse from the atri to the ventrices allows time or the tria to empty heir blod into the vetricles before he ventricles contract. The cnducting system of the hart coists of specialzed cariac musle presnt in the sinuatial nod, th atrioventricular node, the arioventicular undle and its right ad left erminal branches, and

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snell te subenocardia plexus of Purkije fibes (secializd cardiac musce fibers that orm the conductng systm of the heart). .112

Figure -41 he condcting sstem of the hear. Note he internodal pahways.

Siuatrial Node The inuatril node s locatd in th wall o the riht atrium in th upper art of he sulcs termialis jut to th right f the opening o the suprior vea cava igs. 3-7 an 3-39. The ode spotaneousy gives origin o rhythic electrical impulses hat sprad in al direcions though the cardiac muscle f the aria an cause he musce to contract.

trioventricular Node

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snell The atriovetricula node i strateically laced o the lwer par of the atrial eptum jst abov the attachment of the sptal csp of te tricupid vale (Figs. 3-37 and 3-39). rom it, the cariac implse is onducted to the ventricls by th atrioentricuar bunde. The atrioventricular ode is timulatd by th excittion wave as it es trough te atria myocarium. The sped of coduction of the ardiac mpulse through the atriventriclar nod (about 0.11 seonds) llows sufficient time fr the aria to mpty thir bloo into the ventricles befre the ventrices star to conract.

Atrioventricular Bundle The atriovetricula bundle (bundle of His) is the only pathway of ardiac muscle tat connects the myocardum of te atria and th myocarium of he ventricles an is thu the ony route along wich th cardia impuls can travel from the atia to t ventricles (Fig. 3-41). The bundle descend through the fibrous skeeton of the heat. The atroventriular budle the descens behin the sptal cusp of the tricuspd valve to reach the inerior brder of the mebranous part of the venricular septum. At the uper borer of te musclar par of the septum t divids into two brances, one for eac ventrcle. Th right undle branch (RBB) e down o the riht side of the ventriclar septum to reach the oderato band, where it crosses to the anterio wall of the riht venticle. Hre it bcomes cntinuou with he fibers of the Purkinje plexus (Fig. 3-41). The lft bunde branch (LBB) pierces he sept and psses don on it left sde beneath the ndocardum. It sually divides into two branche (anteror and osterio), whic eventually become continuous wth the ibers o the Pukinje pexus of the lef ventrcle. It is thus sen tha the conductng system of te heart is resonsibe not oly for generatng rhytmic cariac implses, bt also for conucting these impulses raidly thoughout the myoardium f the eart so tat the ifferen chambes contract in a coordinted and efficent maner. The acivities of the onductig syste can be influenced by the autonmic nere suppl to the heart. he parsympathtic neres slow the rhytm and diminish he rate of conuction f the impulse; he sympthetic nerves have the opposite effect.

Iternoda Conducion Paths* Imulses fom the inuatril node ave bee shown o travl to the atriontricular node more rapidly tha they cn trave by pasing alng the ordinary myocardim. This phenomenon as been explaied by te descrption o specia pathwas in th atrial all (Fig. 3-41), whic have a structue consiting of a mixtue of Pukinje fibers and ordinar cardia P113

muscle cells. he anteor internodal pathway leave the anerior ed of th sinuatial nod and psses anterior to the suerior vna cava openin. It decends on the atral septm and nds in he atriventriclar nod. The midle intrnodal pathway leavs the posterior nd of te sinuarial noe and

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snell psses poerior to the sperior ena cavl openig. It descends the atrial sepum to he atriventriclar node. The poterior nternodl pathwy laves th posteror part of the sinuatria node ad desceds throgh the crista erminals and te valve of the inferior vena cava to the atrioentricular nod.

Cinical otes Filure o the Conduction System f the Hart he sinutrial nde is te spontneous surce of the cadiac impulse. The atriovntricular node is respnsible or picking up te cardic impule from he atri. The atioventricular bndle i the oly rout by whih the crdiac impulse can spread from th atria to the entricls. Failre of te bundle to condct the ormal ipulses results in alteation in the rhythmic contractio of the ventrices (arhythmia) or, i complee bundl block occurs, cmplete dissocition beween th atria nd venticular rates of ontracton. Th common cause o defectve conduction through th bundle or its branche is athrosclersis of he coronary arteies, whch resuts in diminihed blood supply to the conductng systm.

Arterial Supply of the Heat The rterial supply of the hert is provided y the ight an left cronary rteries, which rise frm the ascending aorta immediately above the aoric valv (Fig. 342). The coronary arteries nd thei major ranches are disributed over th surface of th heart, lying wthin suepicardal connective tissue. The righ coronay arter arses fro the anerior artic sinus of the ascendng aort and runs forwrd betwen the ulmonar trunk and the ght aurcle (Fig 3-35). It escends almost erticaly in th right triovenricular groove, and at the infeior borer of te heart it contnues poteriorly along te atriventriclar grove to aastomos with the left cronary rtery n the posterior intervetricula groove The folowing ranches from th right coronar artery supply the right atrium nd righ ventrile and parts o the let atrium and le ventrile and he atriventriclar setum.

Branches  

 

he righ conus artery supples the nterior surface of the ulmonary conus (infundiblum of the rigt venticle) and the uper part of the anterio wall of the riht ventricle. The aterior entricuar branhes re two r three in numbr and spply th anterior surface of the right vntricle The marginal branch is the largest ad runs long th lower argin o the cotal surace to reach th apex. The poterior entricuar branhes re usualy two n numbe and supply the diaphragmatic surface of the rigt ventrcle. The sterio interventricula (desceding) atery runs tward th apex i the poterior ntervenricular groove. It give off branches to the riht and eft venricles, includig its ierior wall. I supplies branches to th posteror part of the entricuar sepum but not to the apical part, wich recives it supply from th anterior interentricuar branh of th left cronary rtery. A large septal banch suplies the atrioventricular noe. In 10% of individals the posterir interentricuar artey is replaced by a branc from te left oronary artery.

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The atrial branche suply the anterio and laeral sufaces of the riht atrium. One branch upplies the posterior suface of both th right nd left atria. The artey of th sinuatial node suplies th node ad the right and left atra; in 3% of inividual it aries from the let coronry artery.

The eft cornary arery, whch is uually lrger thn the rght cornary arery, supplies te major part of the heat, inclding th greate part o the left atrium, left entricl, and vntriculr septu. It arses fro the let postrior aotic sins of the ascendig aorta and pases forwrd beteen the pulmonary trunk and the eft aurcle (Fig 3-35). It ten entes the arioventicular roove ad divids into n anteror inteventriclar brach and a circumflex brach.

Branchs 



Th anterior interventriculr (descnding) branch runs ownward in the anterior ntervenricular groove o the aex of te heart (Fig. 3-2). In most individals it hen es around the apx of th heart to ente the poterior ntervenricular groove nd anasomoses with the termnal branches of the righ coronay arter. In on third f individuals it ends at the apex of th heart. The antrior iterventicular ranch spplies he righ and let ventrcles with numerus branhes tha also spply th anterir part of the vetricula septu. One o these entricuar branches (lef diagonl artery) ma arise directly from the trunk o the let coronry artey. A smll left onus arery upplies the pulmonary cnus. The cicumflex artery is th same sze as te anterorinterentricular artery (Fig. 3-42) It wins around the left margin of the eart in the atroventriular grove. A lft margnal artry is a larg branch that suplies te left margin of the left ventrile down to the pex. Anterior ventricula and osterio ventricular brnches supply the left ventricle. Atrial branches supply the left atrium.

Varitions i the Coonary Ateries Variatons in the blood supply to the eart do occur, and the ost comon varitions afect th blood upply t the diaphragmatic surfce of bth venticles. ere the origin, size, ad distribution of the posterior intervetricula artery are varable (Fi. 3-43). In rght domnance, the osterio intervntriculr arter is a lrge branch of the right coronar artery Right ominanc is preent in most indviduals 90%). I left doinance, the osterior intervenricular P.14

atery is a branc of the ircumflx branc of the eft coroary artery (10%)

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Figure 3-42 Coronry arteries and veins.

Coronary Atery Anatomoses nastomoes between the teminal banches of the right and left cronary rteries (collatral circlation) exist, but the are uually not larg enough to provide an adequae blood supply o the ardiac muscle hould oe of th large ranches ecome bocked by disease. A sudden block f on of 214

snell the larger branchs of eiher cornary arery usully leds to mocardial death myocardil infarcion), alhough soetimes te collaeral cirulation is enouh to sutain the muscle.

Summry of the Overall Arteria Supply o the Hert in Mot Indiviuals The right cronary rtery supples all f the rht ventrcle (except for he small area to he righ of the anterior nterventricular roove), he variable part of the diapragmati surfac of the left venricle, the poseroinfeior thrd of the venticular eptum, he rigt atriu and pat of te left atrium, and the inuatria node an the atroventriular nod and budle. The LBB als receive small banches. The left coroary artey spplies ost of te left entricle, a small area of the right entricle to the right of the inteventricuar grooe, the anterio two hirds of the venricular eptum, most of the lef atrium, the RBB and te LBB.

Arterial Supply to the nductin System The snuatrial node is usually upplied by the rght but sometimes by the left cornary arery. Te atrioventricular node and th atriovntriculr bundle are suplied by he righ coronar artery. The RB of the triovenricular bundle i supplie by the left cornary atery; t LBB is supplied y the rght and eft coronary artries (Fi. 3-43). P.11

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Fiure 3-4 A Posteror view f the heart showng the oigin an distribtion of he posterior inerventriular artry in te right ominance B. Psterior iew of te heart howing te origin and disribution of the osterior intervetricula artery in the eft domnance. C. Aterior view of the heat showig the relationship of th blood upply t the coducting system.

Clinical Noes Cornary Arery Disase The myocardim receives its lood suply thrugh the right nd left coronar arteris. Althugh the coronar arteries have umerous anastomses at he arteiolar lvel, they are essentiall functioal end rteries. A udden blck of oe of the large brnches of either coronary rtery will usualy lead o necrosi of the ardiac muscle myocardil infartion) in that vacular aea, and ften the patient ies. Most cases of coroary artry blockge are cused by an acute thromboss on tp of a ronic atherosclrotic nrrowing of the umen.

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snell Arteiosclertic disase of he coroary artries may preset in tree way, depening on the rate of narowing f the lmina o the ateries: (1) Genral degeneratio and firosis o the mocardiu occur ver man years nd are caused by a gradual narroing of the cornary areries. 2) Angina pectoris is cardia pain tat occus on exrtion ad is relieved by rest. I this onditio, the cronary rteries are so narrowed that mycardial ischema occur on exertion but not at est. (3 Myocardial infarction occurs when coronary low is uddenly reduced or stoped and the cardiac musle undegoes nerosis. yocardil infartion is the majo cuse of eath in industrialized nations. Tabe 3-1 shows he diffrent cronary rteries that suply the different areas of the yocardim. Thi information can be helpful when attemptng to crrelate the sit of mycardial infarction, the artery nvolved and th electocardiographic signatur. Beause coonary by sugery, cronary ngioplaty, an coronay arter stentig are nw commonly accepted methds of reating coronar artery disease it is ncumben on the student to be repared to intepret stll- and motion-icture ngiogras that have been carrie out beore tretment. or this reason, a workig knowledge of he orign, coure, and istribuion of he coronary arteies shold be emorize. P.11

Tabl 3-1 Coronar Artery Lesions Infarc Locatin, and ECG Signure Coronary rtery

Infart Locaton

CG Signture

Proxial LAD

Lrge antrior wal

ST elvation: I, L, V–V6

More distal LAD

Aneroapicl

ST elevation: 2–V4

Iferior all if raparoud LAD

ST elevtion: I, III,

Dista LAD

Anteroseptl

ST elvation: V1–V3

arly otuse, mrginal

High ateral all

ST levation: I, L, V4–V6

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More istal mrginal branch, circumlex

Small ateral all

ST elevatin: I, L or V4â“V6, o no abnrmalit

Crcumfle

Posterlateral

ST elevation: V4–V6 ST depession V1–V

Distal RCA

Sall inrior wll

ST eevation II, III, F; S depresion: IL

Proximal RA

Large nferior wll and posterir wall Sme lateral wall

ST levati: II, II, F; T depresion: I L, V1â“V3 ST elevtion: V5–V6

RCA

Rght venricular

ST elevtion: VR–V4R some S elevaton: V1; or ST depression: V2, V3

Usally inerior

ST elevation: I, III, F

ECG, elctrocariographc; LAD, left anerior dscending (interventriculr); RCA right coronar artery.

Venos Drainge of the Heart Most blod from the hea wall drains into the right atrum throgh the oronary sinus (Fg. 3-42), whch lies in the osterio part o the atioventricular grove and is a cotinuatin of th great cardiac vein. It opens into the rigt atriu to the eft of he inferior vena cava. Te small and mddle cadiac vens ae tributaries of the coronary snus. The remaindr of th blood s retured to te right atrium by the anerior crdiac vein (Fg. 3-42) and by small veins that open directl into te heart chamber.

Neve Suppy of th Heart The heat is innervated by sympathetic and parasmpathetc fiber of the autonomc nervos syste via th cardiac plexuses situated blow the arch of the aora. The ympatheic supply arises from

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snell the cerical and upper toracic ortions of the ympatheic truks, and the parasympatheic suppy comes from th vagus erves. The ostgangionic smpathet fibers terminate on the sinuarial an atriovntriculr nodes on cardiac musce fiber, and on the conary ateries. Activaton of tese neres results in cardiac cceleration, increased force of ontracton of te cardic muscl, and ilatation of the coronar arteris. Th postgaglionic parasymathetic fibers erminate on the sinuatral and triovenricular nodes ad on th coronay arteries. Activtion of the parsympathtic neres resuts in a reductin in th rate nd forc of contraction of the heart ad a contrictio of the coronay arteries. Afferent fibers runnng with the sympathetic nerves carry nrvous ipulses hat norally do not reah conscousness. Howeve, shoul the blod suppy to th myocardium become impaied, pan impules reac consciusness ia this pathway Afferent fibers runnig with he vagus nerves ake par in cariovascuar reflxes.

Cinical Notes Crdiac Pin Pain oiginatig in th heart s the result of acute yocardil ischeia is asumed t be caued by oygen deiciency and th accumuation of metabolites, whch stimlate th sensor nerve endings in the yocardim. The afferent nerve fiers ascnd to te cental nervus system through the cadiac brnches o the sypatheti trunk and enter the spnal cor throug the poterior oots of the upper four thoracic nerves. The naure of the pai varies considerably, from a severe cruhing pan to nohing moe than mild discomfort. The pain is not fel in the heart, ut is referred the sin area supplid by th corresonding pinal nerves. T skin areas suplied b the uper four intercostal neres and b the itercostbrachia nerve T2) are therefoe affeced. The intercostobrachal nerv communcates wth the edial cuaneous nerve f the am and i distriuted to skin on the medal side of the upper part of th arm. A certain amount f sprea of nerous infrmation must ocur witin the entral nervous system, fr the pin is smetimes felt i the ne and the jaw. Myocardial ifarctio involving the nferior wall or diaphramatic srface o the hert ofte gives ise to iscomfot in the epigasrium. Oe must ssume tat the fferent pain fibers fro the hart ascnd in te sympahetic nrves an enter the spina cord i the psterior roots o the seenth, eighth, a ninth horacic spinal nerves nd give rise to referred pain i the T7, T8, and T9 thorcic dematomes in the pigastrum. Because the heat and te thoraic part of the sophagu probaly have similar fferent pain pahways, t is no surpriing tha painfl acute esophagiis can imic th pain o myocarial infarctio. P.117

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Action of the Heart The heart is a mscular ump. The series of chages tha take lace wihin it s it fills wit blood and empies is eferred to as the cariac cyle. he norml heart beats 0 to 90 times er minue in he resting adut and 130 to 10 times per miute in he newbrn child. Blood i contiuously eturning to the heart; uring entricuar systole (ion) when te atrioentricuar valvs are losed, he blood is temprarily ccommodted in he larg veins nd atra. Once ventricular diastole (reaxation occurs the arioventicular alves open, and lood pasively lows frm the aria to the ventricles (ig. 3-3). Wen the ventrices are nearly full, atril systoe occur and foces the remainder of the blood in the atria ito the entricls. The inuatril node initiates the wae of cotractio in the atria, hich comences around the openigs of te large veins ad milks the blod toward the ventricle By this means, blood des not eflux ito the eins. The crdiac ipulse, having rached the atrioentricuar nod, is coducted o the papillary muscles by the atrioventricular bundle nd its branches Fig. 3-39) The apillar muscles then egin to contrac and tae up th slack f the hordae endineae. Meanwhle, the ventrices star contrating an the atrioventricular vlves clse. The spread f the crdiac impulse along the atriovetricular bunde (Fig. -39) and its terminal branches, incuding te Purkije fibes, ensues that myocardial ion ccurs a almost the sam time troughout the ventricles Oce the intravericular blood pressure exceeds that present in the lare arteres (aorta and pulmonary trunk), the seilunar alve cups are ushed aide, and the blod is ejcted frm the eart. A the coclusion of venticular systole, lood beins to move bak towar the vetricles and immediately ills th pocket of th semiluar valves. The cusps flot into ppositin and cmpletel close the aortic and pulmonary orifices.

Surfae Anatomy of th Heart alves The surace proection f the hart was deidoub on pae 72. The surfac markins of th heart alves ae as folows (Fig. -15)    

Te tricuspid valv lis behin the right half of the sernum oposite he fourh interostal sace. he mitr valve lies behind the left half of the stenum oppsite th fourth costal artilag. The pumonary alve lies beind the medial nd of te third left cotal cartilage and the ading part of he sterum. The aortc valve lies behind he left half of the stenum oppsite th third ntercosal spac.

Clinial Note Auscultation of the Heart Valvs On listening to the heart wth a stthoscop, one cn hear wo souns: lūb-ūp. The fist soun is prouced by the conraction of the ventricls and the cloure of the tricuspid ad mitra valves. The seond soud is produced by the shrp closre of te aorti and pumonary lves. I is imortant or a phsician to know were to lace th stethocope on the chst wall so that he or sh will b able t hear sunds prduced a each alve wih the mnimum o distraction or nterfernce.

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Th tricusid valve is est head over he right half of the lowr end o the boy of th sternu (Fig. 315). The miral vale is best herd over the ape beat, hat is, at the evel of the fifth left ntercostal spac 3.5 in. (9 cm) from th midlin (Fig. 315). The pulmnary vave s heard with last intrferenc over te media end of the second left intercotal space (Fig. 3-15. Te aortic valve is bet heard over th medial end of he secod right intercostal space (Fig. -15)

Vavular Dsease o the Hert Inflmmation of a vave can ause th edges f the vlve cusps to stick togeher. Laer, fibous thikening ccurs, ollowed by loss of fexibiliy and srinkage Narrowing (stenosis) an valvulr incopetence (regurgtation) result, and the heart cases to functio as an efficient pump. n rheumtic disase of he mitrl valve, for example, nt only o the csps undrgo fibrosis an shrink, but also the cordae tndineae shorten prevening cloure of he cusp during ventriular systole.

Valvular Heart Murmurs Apart from te sound of the valves losing, ūb-dū, te blood es hrough the normal heart silently Should the vale orifces becme narrwed or the valv cusps distorted and shrunken by disease, howevr, a ripling efect wold be st up, lading to turbulnce and vibratins that are head as hert murmrs.

raumati Asphyxa The sudden caving in of the antrior chst wall associted wit fractues of te sternm and bs causes a dramatic rse in itrathorcic presure. Aart from the immediate eidence f respratory istress the antomy of the venus system plays a signiicant rle in te prodution of the chaacteristic vascular sign of trumatic sphyxia The thnness of the walls of th thoracc veins and th right trium cuses their collpse undr the raised inrathoraic pressure, an venous blood i dammed back in the veis of the neck and head. This prduces vnous cogestion bulgin of the eyes, hich become injected; ad swellng of te lips nd tonge, which become cyanoti. The sin of te face, neck, ad shoulers becomes purple.

he Anatomy of Cardiopulmonary Resuscitation ardioplmonary resuscitation (R), acieved by compresion of the chet, was riginaly belieed to scceed bcause o the compression of the heart btween te sternum and he vertbral clumn. Nw it is recognized that the blood flows n R bcause te whol thoracc cage is the pump; the eart fuctions erely a a conuit for blood. An extratoracic ressure gradien is creted by externa chest compressins. The pressue in all chamber and loations within he ches cavity is the ame. With compression, bood is orced ut of te thoraic cage The blood prefeentiall flows ut the arteria side o the circulation and bac down te venou side bcause he venous valve in the interna jugular system prevent useles oscilatory mvement. With th releas of comession, blood eters th thoraic cage preferentially down th venous side of the systmic ciculation.

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Ebryologc Notes Develoment of the Heart Formation f the eart Tue Clustes of cels arise in the mesenchme at te cephalic end f the ebryonic disc, halic o the ste of te deveoping mouth and the nervus systm. Thes clustes of cels form a plexus of endothelial blood essels that fuse to form the right and left enocardia heart tube. Thse, too soon fuse to fm a single medin endocardial tue. s the had fold of the mbryo dvelops, the endcardial tube and the peicardial cavit rotat on a tansvers axis trough amost 10°, so that tey come to lie entral to (in frnt of) he esopagus an caudal to the developing mouth. The eart tue start to bulge into he periardial cavity (Fig. 3-44). Meanwhile, he endardial ube becmes surounded y a thick layer of mesenhyme, wich wil differntiate nto the yocardim an the viseral laer of te serou pericadium The rimitiv heart as been established, and the cepalic en is the arteril end ad the caudal end is the enous ed. The rterial end of the priitive heart is continuus beyod the pericardim with large vessel, the aortc sac (Fig. 345). The heat begins to beat during he thir week.

Furher Devlopment of the eart Tue The heart tbe then undergos diferentil expasion so that sveral dlatatins, seprated y groovs, reslt. Fro the aterial to the enous end, thee dilattions ae calle the bulbus cordis, th ventrile, he atrim, ad the rght and lef horns of the sinu venosu. The bulus cords and vntriculr parts of the tube no elongate more rapidl than te remainder of the tube, and sice the arteria and vnous eds are fixed b the peicardiu, the tbe begns to bnd (Fig. 346). The bed soon ecomes -shaped and the forms compound S-shape, with the atrum lyin posteror to te ventrcle; ths, the venous and arteral ends are broght cloe togeter as tey are in the adult. Th ag betwee the atium and the venricle narrows to form th atriovntriculr canal. As these canges ae takin place, a gradul migraion of the heart tue occur so tha the heart es from the neck region to what ill beome the thoraci region

Develoment of the Atra The primitive atrium ecomes ivided nto two€”the rght and left atia—in the following mnner (Fi. 3-47). Fist, the atriovetricular canal wdens trnsversey. The anal thn becoes divied into right ad left alves b the apearance of vental and dorsal trioventricular cushions which fuse to orm the septum intermedim. Manwhile anothe septum the sepum primm, evelops from th roof o the prmitive atrium ad grows down to fuse wih the sptum inermediu. Befor fusion occurs, the openg betwen the lower ege of te septu primum and sepm interedium i referrd to a the formen prium. he atrim now s divided into right an left prts. Beore comete obliteration of th forame primum has takn place degeneative changes ocur in te cental porton of te septu primum; a foramn appeas, the framen scundum, so hat the right and left arial cambers gain

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snell communicat Another, thicker, septm (the septum secundum) gros down rom the atrial oof on he righ side of the setum prium. The lower edge of te septu secundm overlps the oramen secundum in the septum rimum bt does ot reac the floor of the atriu and dos not use wit the setum intrmedium The space between the free margn of te septu secundm and te septu primum is now nown as the foraen oval (Fig 3-47). Bfore bith, the foramen ovale alows oxgenated blood hat has entered the rigt atriu fro the iferior ena cava to into te left trium. owever, the lowr part f the septum prum seres as a flaplik valve o prevet blood from moing fro the let atrim into the right atrium. At birt, owing to raisd blood pressur in th left atrium, th septum primum s pressd againt the sptum secundum ad fuses with i, and he foramen ovale is clsed. Th two tria ths are eparated from ach othr. The ower ede of t septum secundum seen n the rght atrum becoes the anulus ovalis, and the depression belw this s calle the fossa ovalis. Th right and let auriclar appendages later evelop s small divertiula fro the right and left atri, respetively.

Deveopment of the Ventricle A muscular patition projects upward rom the floor o the priitive vntricle to form the venricular septum (Fig. -47). The space boundd by th cresceti upper edge of the septm and te endocrdial cshions orms th interventricular foramen. Meanwhile, spiral ubendocrdial tickenins, the blbar riges, appear n the distal part of the bulbus cordis. The bulbar ridgs then grow and fuse to orm a spral aoricopulmnary setum (Fi. 3-48). The intrventriular foamen clses as he result of proliferatn of te bulba ridges and the fused edocardil cushions (septm intermedium) This newly formed tisse grows down an fuses ith the upper dge of the muscular venticular eptum t form te membrnous pat of th septum (Fig. 3-47. The losure f the iterventricular forame not ony shuts off the path of communication btween te right and lef ventriles, bu also ensures that the right entricuar caviy commuicates ith the pulmonry trun and the left ventricula cavity communiates wih the orta. I additin, the right atrioventricular opening nw connets exclusively with the right vntriculr cavit and th left triovenricular opening with te left ventricuar cavity.

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Fgure 3-4 The develpment of the endocardial tube in relatio to the pericarial cavty.

Developmen of the Roos and Poximal Portions of the orta and Pulmonay Trunk The distal art of he bulbs cordi is knon as th truncus arteriosus ig. 3-4). t is diided by the spiral aoticopulonary sptum to form the roots nd proxmal porions of the aora and plmonary trunk (Fg. 3-48). Wth the stablisment of right ad left entricls, the proximal portion of the bulbus cordis beomes inorporatd into he righ ventricle as the defintive conus arteiosus or infundibulum, and into the left ventricle as the ortic vstibule. Jus distal to the aortic vves, th two coronary ateries arise as outgrwths frm the dvelopin aorta. 224

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evelopment of the Cardiac Valves Smilunar Valves f the Arta and Pulmonay Arteres After te formaion of he aortcopulmoary sepum, thee swellings appear at te orifies of both the aorta an the plmonary artery. Each swlling cnsists f a covering of ndothelum ove loose onnectie tissu. Gradully, th swelligs become excaated o their pper sufaces t form the semilunar valvs.

Fiure 3-4 The parts o the enocardia heart ube witin the ericardum.

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Figure 3-46 The bending of the eart tue within the pericardial cavity. The ierior f the dvelopin ventriles is hown at the botom righ.

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Figue 3-47 The ivision of the rimitiv atrium into th right nd left atria by the apearanc of the septa. Te sinuarial orfice an the fae of th venous valves are show, as is the apparance f the vntriculr septu.

Atroventriular Vlves Afer the ormation of the septum ntermedum, the atrioventricula canal ecomes ivided nto rigt and lft atroventricular orifices. Rised fods of edocardim appea at the margins of these orifices. These folds are invaed by mesenchyml tisse that ater beomes hollowed ot from the ventrcular sde. Thre valvlar cuss are fmed abot the rght atroventriular orfice and constiute the tricuspd valve two cusps ae forme about he left atriovetricula orifice to become the itral vlve. The nely

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snell formd cusps enlarge and thir mesechymal ore becmes differentiaed into fibrous tissue. The cuss remai attachd at itervals to the entricuar wall by musclar strnds. Laer, the musculr strands become differntiated into papllary mscles and chodae tenineae.

igure 348 Te divison of te bulbu cordis by the piral aorticopumonary sptum into the aorta and pulmonay trunk A. Te spiral septum in the runcus rterioss (uppe part o the bubus coris). B. The lwer par of the bulbus rdis shwing th formaton of te spiral septum by fusio of the bulbar idges (rd), hich thn grow own and th septum intermedium (blu) and the musular pat of th ventriular setum. C. The rea of he venticular eptum tat is formed fro the fued bulbr ridge (red and th septum intermedium (blu) is called the membranous pat of th ventriular setum.

Conenital nomalie of the Heart Atria Septal Defects 228

snell After bith, the foramen ovale bcomes mpletey closed as the esult o the fuion of the sepum primum with te septu secunum. In 5% of harts, a small opening persists, ut this is usully of uch a mnor natre that it has o clinical significance Occasionally, he openng is mch largr and results i oxygenaed blod from he left atrium assing ver into the rigt atrium (Fig. 3-38.

Ventriular Setal Defects The ventrcular sptum is formed n a comlicated manner and is complete nly whe the membranous part fuses with the musular prt. Venricular septal efects are less frequent than atial sepal defcts. Thy are fund in he membanous part of the septu and can measure 1 to 2 cm in dameter. Blood uder hig pressue es through the defect fro left t right, causing enlargeent of he right ventricle. Lare defecs are erious ad can shorten life if srgery i not prformed

Ttralogy of Fallt Normaly, the ulbus crdis beomes diided ino the orta an pulmonary trunk by the formation of the spiral aorticoulmonar septum This sptum is formed y the fusion of he bular ridgs. If te bulba ridges fail o fuse orrectly, uneqal division of he bulbs cordi may ocur, wit conseqent narowing of the pumonary runk reulting n intererence ith the right ventricular outfow. This congenial anomly is rsponsibe for aout 9% all congenital heart dsease (Fg. 3-38). The anatoic abnomalities inclue large ventriclar sepal defet; stnosis o the pumonary runk, which can occur at the ifundibulum of the right ventrice or at the pulonary vlve; ext of th aorta immediatly abov the vetricula septal defect instead of from the lef ventriular caity onl); and evere hpertropy of te right ventrile, becuse of he high blood pressure in the right venticle. he defets caus congental cyaosis and consideably liit actiity; ptients ith sevre untreated abnrmalitis die. nce the diagnoss has een made, most children an be sccessfuly treaed surgcally. Most chilren fin that asuming he squating poition after physical acivity rlieves their beathlesness. Tis happns becuse squatting reduces th venous return y comprssing te abdoinal vens and increasing the sstemic aterial esistane by knking te femoral and popliteal rteries in the egs; boh these mechansms ten to decase the right t left sunt thrugh the ventriular septal deft and improve te pulmonary cirulation P.118

P.119

P.12

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P.11

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Large Veins of the Thorx rachioephalic Veins Te right brachiocephalic vein is formd at th root of the neck by the union of he right subclavan and the right internal jugular eins (Fis. 3-16 and 3-9). Te left bachiocepalic ve has a similr origin (Figs. 331 an 3-33. It psses obliquely downward ad to the right bhind th manubrum sterni and in front f the lrge braches of the aoric arch. It s the right brachocephali vein t form th superio vena cava (Fig. -49)

Suprior Vea Cava Te superior vena cava cotains al the veous blod from the head and neck and both upper limbs ad is frmed y the uion of the two rachiocephalic vins (Fgs. 3-3 an 3-49. It pases downard t end in the rigt atrium of th heart (Fg. 3-30). The vena azos the poterior apect of he superor vena ava just before enters the periardium (Fgs. 3-1 and -49)

Azygos Vins The azgos vein consist of the ain azygs vein, he infeior hemizygos vin, and te superor hemizygos ven. They drain bood fro the posterior prts of te interostal spces, the posterio abdomnal wall, the pricardim, the iaphram, the ronchi, and the esophags (Fig. 3-49.

Azyos Vei The origin of the aygos vei is varable. I is ofte formed by the nion of the right ascening lumbar vei and the rigt subcotal vei. t ascends throgh the ortic opning in the diahragm n the rght sie of th aorta to the leel of te fifth thoraci verteba (Fig. -49) Here t arche forwar above he root of the right lung to empy into he postrior suface of the suprior vea cava (ig. 3-1).

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snell he azygs vein as numerous tributaries includig the eght lowr right intercostal veins, te right superior intercotal vei, th superio and inferior hemiazygos vein, an numeros mediastinal veins.

Inferior Hemiazygos Vein Te inferor hemizygos vin is oten fored by te union of the left ascnding lmbar ven and te left ubcosta vein. t ascends through the lft crus of the iaphrag and, a about he level of the eighth thoracic verteba, turn to the right ad s the azygos vei (see Fi. 2-11). It receives as tribtaries ome lowe left itercostl veins and mdiastinl veins

Superior Hemiazygos Ven The sperior emiazygos vein is formed by the union of the forth to he eighh interostal vins. It s te azygo vein a the level of the sevenh thoraic vertbra (se Fig. 2-1).

Inferior Vena Cava The iferior vena cav pierce the cetral tedon of he iaphragm opposte the eighth thoraci verteba and amost immediately enter the loest part o the riht atrim (igs. 3-16, 337, and 3-49).

Cinical otes Aygos Vens and aval Obtructio In obtructio of the superio or infrior veae cavae, the ygos veins provde an aternatie pathwy for te retur of veous blod to the right atrium of the heat. This is pssible ecause these vins and their tibutaris connet the serior and inferor vene cavae

Pulmnary Veins Two pulmonary veins leae each lung carrying oxygenated blood t the let atriu of the heart (Fgs. 3-1, 3-3, an 3-40.

Large Ateries of the Thorax Aorta The aorta i the man arteral trunk that delivers xygenatd blood from th left vntricle of the eart to the tisues of he .124

body. It is dvided fr purpoes of dscription into the folloing parts: asending orta, ach of te aorta descening thoracic aorta, and abdominal aorta

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Fiure 3-4 A. Major veins etering he hear. B. ajor vens draiing int the suerior ad inferior venae cavae.

Asceding Aota The asending orta beins at he base of the eft vetricle nd runs upward and forwrd to come to lie behin the riht hal of the sternum at the evel of the stenal angl, where it becoes coninuous ith the arch of the aora (Fig. 3-35) The asending orta lis withi the firous pericardium (Fig. 3-33) ad is enlosed wth the ulmonar trunk n a sheath of serous percardium At its root it possesss three bulges, the sinuses of e aorta, one behind ach aoric valv cusp.

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ranches Th right cronary artery arises from the anterir aorti sinus, and the left coronary artery arises from the eft P125

posterr aortic sinus (Figs. 3-35 ad 3-42). The urther course of these important arterie is desribed o pages 13 to 14.

Arch f the Arta The ach of te aorta is a coninuatio of the ascendig aorta (Fig. 335). It lies behind the manubrium serni an arches upward, backwar, and t the lft in front of e tracha (its ain dirction i backwad). It then pases dowward to the lef of the trachea and, at the leve of th sterna angle, becomes continuus with the descending arta.

Brnches The bachiocehalic atery arises rom the convex urface f the artic arh (Figs. 3-35 and 3-50). It es upward ad to the right of the trachea ad divids into he rigt subclvian and right ommon carotid areries bhind th right sternocavicula t.

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Figure -50 ajor brnches o the aota.

The left common arotid rtery arises from th convex surface of the ortic arch on the left ide of the brachiocephalc arter (Figs. -35 nd 3-50). It uns upwrd and o the left of th trache and enters the neck beind the left strnoclavcular jint. The left ubclavin arter aries from the aortic arch behind e left common crotid atery (Fis. 3-35, 3-3, an 3-50. It rus upward along e left ide of he tracea and he esopagus to enter te root f the neck (Fig. 3-16). It arces over the ape of the left lug.

Descening Thoracic Aorta The dscendin thoracc aorta lies in the poserior ediastium and begins as a contiuation f the ach of te aorta on the left sie of th lower border of the bdy of te fourt thoracic vertebra (i.., oppoite the sternal angle). It runs downwar in the posterior mediatinum, nclinin forwar and

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thoacic vetebra, it es behind the diapragm (trough te aorti openig) in the midline and becomes cotinuous with th abdomial aora.

Branche Poterior ntercosal arteies re give off to the lowr nine ntercosal spaces on eah side ig. 3-5). Sucostal rteries are iven of on each side and run alng the ower boder of he 12th rib to nter th abdominal wall. Pricardil, esopageal, and bronchial arterie ar small ranches that ar distriuted to these ogans.

linical Notes Aneurysm and Coactation of the Aorta The arch of the arta lie behind the manbrium serni. gross ilatatin of the aorta aneurysm) may sw itsel as a ulsatil swellig in th suprasternal notch. Coarcttion of the aora is a ongenitl narrowing of the aort just poximal, opposit, or dital to he site of attahment of the ligamentu arterioum. Thi condiion is elieved to resut from an unusal quanity of uctus arteriosus muscle issue i the wal of te aorta When te ductus arterious s, te ducta muscle in the aortic wall also contracs, and he aortc lumen becomes narrowe. Late, when fibrosis takes pace, th aortic wall also is inolved, and permanent narowing ccurs. Clnically the carinal sig of aoric coarcation is absent r diminshed pulss in te femora arteri of bot lower imbs. To compenste for te diminihed volue of blod reachng the ower part of the body, an enormous collateal circulation develops, with dilattion of the intrnal thoracic, subclavia, and poterior ntercostl arteris. The dilated intercostal arteries erode the lowe bordes of the ribs, prducing caracterstic nothing, whch is seen on diograpic examiation. Te condition shoud be treted surcally.

Pulmonary Trunk The ulmonar trunk conveys doxygenated bloo from te righ ventrile of te heart to the ungs. I leaves the upper part o the rght venricle ad runs pward, backward, and to the left (Fig. 335). It is bout 2 n. (5 cm) long d terminates in the conavity o the artic arh by dividing ino right and lef pulmonry arteies (Fig 3-12). Togeher with the ascending arta, it is enclsed in th fibrou pericadium an a sheah of seous pericardium (Fig. 3-33).

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snell The rigt pulmoary artery rns to te right behind the ascening aorta and sperior ena cav to entr the rot of te right lung (Figs. 3-12, 3-16, and 335). Th left pumonary artery runs to the left in frnt of te desceding aota to eter the root of the lef lung (Figs. 3-1, 3-1, and -35) The liamentum arteriosum is a fibrus band that connects the bifurction of the pulonary tunk to he lowe concav surface of the aortic ach (Figs 3-16 and 3-3). he ligaentum ateriosu is the remains of the uctus arteriosus which in the etus cnducts bood fro the pulonary truk to the aota, thu bying the ungs. Te left ecurren laryngel nerve hooks round the lower border of this tructur (Fis. 3-16 and -36) After birth, the ductus close Should it reman paten, aorti blood will ener the ulmonar circulation, producing pulmonar hypertnsion nd hypetrophy f the right ventricle (Fi. 3-38). Surical liation o the dutus is hen neessary.

Clinica Notes Patent uctus Ateriosus The ductus arteiosus rpresent the dstal portion of the sixh left ortic ach and onnects the lef pulmonary artery to the bginning of the escendig aorta (Fig. 3-8D). During fetal lfe, blod e throug it fro the pulmonary artery t the rta, thus bypasing the lungs. fter bith, it ormally constrcts, later close, and bcomes te ligamtum artriosum. Filure o the dutus artriosus o close may occr as a isolated congenital abnrmality or may e associated wih congeital hart disase. A persisten patent ductus rterioss resuls in hgh-presure aortic bloo in into te pulmoary artery, which raise the prssure i the pumonary irculaton. A ptent dutus areriosus is life threateing and should be ligate and diided srgicall.

Lymph Nodes ad Vesses of th Thorax Thoacic Wal The lymh vesses of th skin o the anerior toracic ll drai to the anterio axillary nodes. The lymph vssels o the skin of th posterior thoracic wal drain to the posterior axillry node. Te deep ymph vesels of the anterior parts of th intercstal spces dran forwad to the interna thoracc nodes alog the iternal thoracic blood vesels. Fom here the lyph s to te thoraic duct on the eft side and te broncomediasinal trunk on te right side. Te deep ymph vesels of the poserior parts of te intecostal paces dain bacward to the postrior inercosta nodes lying near th heads of the ribs. Fro here, he lymp enters the thoacic dut.

Mediastinum In additio to the nodes daining he lung, other nodes re found scatteed through the ediastinum. They drain lmph fro mediatinal sructures and empty into he bronhomediatinal tunks an thoraic duct Diseas and enlargement of thes nodes ay exer pressre on iportant neighboring medistinal tructurs, such as th tracha and sperior ena cav.

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Thracic Dct The thoacic dut begin below n the adomen a a dilated sac, the cistrna chyi. I ascend throug the aotic opening in the diaphagm, on the rigt side f the dscendin P.127

arta. It gradualy crosss the mdian plne behid the esophagus nd reaces the eft borer of te esophgus (Fig 3-6B) at te level of the ower boder of he body of the ourth tracic vertebra (sterna angle) It the runs upard alog the lft edge f the sophagu to enter the rot of th neck (Fg. 3-B). Here, t bends lateraly behin the caotid shath and in front of the vertebrl vessels. It trns dowward in front o the let phrenc nerve and crsses the subclavan artey to ener the eginnin of the left bachiocephalic ven. At the oot of he neck, the thoracic dct receives the eft juglar, suclavian, and ronchomdiastinl lymph trunks, althugh the may drin directly into the adjcent lage vein. The toracic duct thus conveys to the blood all lymph from th lower imbs, plvic caity, abominal avity, eft sid of the thorax and let side f the had, neck, and let arm (ee Fig 1-21).

Rigt Lymphtic Duct The rigt jugulr, subclavian, and bronchomediastinal tunks, wich dran the rght sid of the head an neck, the right upper imb, and the riht side of the horax, espectiely, ma to form he right lymphatic duct. This comon duc, if prsent, i about 0.5 in. (1.3 cm long and opens into the begining of the right bachiocehalic vin. Altrnativey, the runks open indepndently into te great veins a the rot of th neck.

Neves of he Thorx Vagus Nerves Te right vagus nrve escends in the horax, irst lyng posteolatera to the brachioephalic artery ig. 3-6), thn laterl to th trache and medial to the terminl part f the aygos vein (Fig. 3-16. It pases behid the root o the riht lung and asssts in he formtion of the pulmnary plxus. On leavng the lexus, the vagus es nto the posterir surfae of th esophaus and takes part in the formatin of th esophageal plexus. It then es trough te esophgeal opning of the diahragm bhid the esophagus to reac the poterior urface f the somach. The left vagus nerve descend in th thorax between the left common arotid nd the eft sublavian rteries (Figs. 36 and 3-16) It ten crosses the left side of the ortic ach and s itsel crosse by th left phrenic nerve. The vagus ten turn backwad behind the oot of he left lung an assists in the ormatio of the ulmonar plexus. On eaving he plexs, the agus pases onto the anterior srface o the esphagus nd take part in the formation of the esphagea plexus. I then psses though th esophaeal opeing in he diaphragm in ront o the esphagus o reach the antrior surface of the stomch. 237

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ranches Both vagi upply te lungs and esohagus. he right vagus ives of cardia branchs, and he left vagus gves oriin to the left recurret laryngeal nere. (The right recurrent laryngea nerve arises from the right vagus in the neck and hoos aroun the sbclavia artery and ascends between the rachea nd esopagus.) The let recurent larngeal nrve rises fom the eft vags trunk as the nerve crosses the arch o the aora (Figs. 3-16 and 3-36). It hooks aound th ligametum artriosum nd ascends in th groov between the trachea and the esohagus o the let side ig. 3-6). It supplis all te muscls actin on the left voal cord (except the cricothyroi muscle a tensr of th cord, hich is supplie by the external laryngeal brach of te vagus).

hrenic erves The phrenic nerves rise frm the nck from the antrior rai of the third, ourth, nd fift cervicl nerve (see pae 771). The rght phrnic nerve decends i the thrax along the right side of the ight brchiocepalic ven and te superor vena cava (Figs. 3-6 and 3-6). It es in fron of the root of the ight lug and runs alon the riht side of the pericarium, whch sepaates the nerve from the ight atium. It then dscends n the rght side of the inferior vena cava to th diaphrgm. It terminl brances through the cavl openig in th diaphrgm to supply the centra part o the peitoneum on its nderaspct. The eft phrnic nere decends i the thrax alog the left side of the eft subclavian artery. It crosse the let side f the artic arh (Fig. -16) and here crosses the lef side of the let vagus nerve. t e in front of the roo of the left lug and ten descnds over the let surface of th pericadium, wich seprates te nerve from th left ventricle. On eaching the diapragm, te termina branche pierce he musce and spply the central part of he peritneum on ts underspect. The phrenic erves pssess eferent ad afferet fibers The efferent fibers are the sole neve supply to the musle of th diaphrgm. The afferent fibers arry seation o the cetral nevous systm from te peritoneum covring the central region o the udersurface of the diaphrag, the plura covering the central egion f the uper surfae of th diaphram, and te pericadium and mediasinal paietal peura.

Clinical Notes Paralyss of th Diaphram Th phreni nerve my be parlyzed beause of pressure from maignant umors in the medastinum Surgicl crushing or sectioing of he phrenic nerve in th neck, poducing aralysi of the diaphagm on one sie, was nce used as par of the treatmet of lug tuberculosis especilly of the lowr lobes The imobile dome of the diaphagm ress the lung.

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Thoracic Part of the Sypatheti Trunk The thracic prt of te sympahetic tunk is continuus aboe with he cervical and below wth the lumbar arts of th sympathetic trunk. It s the mst lateally plced strcture P.128

in he medistinum nd runs downwar on the heads o the ribs (Fig. -16). It leaes the horax on the side of the body of the 12t thoracc vertera by pssing behind th medial arcuate ligament. The ympathetic trunk has 12 often only 11) segmentally arrnged gaglia, ech with white and gra ramus ommunicns pssing t the correspondig spina nerve. The firt ganglon is oten fusd with he infeior cervical ganlion to form th stellate ganglion.

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ray rami communicantes o to al the toracic pinal nrves. Te postgnglioni fibers are disributed through the brnches of the spinal neres to the bloo vessel, sweat glads, an arrectr pili uscles f the sin. The firt five anglia ve postganglionic fibers to the heart, orta, lngs, an esophaus. The lower eght gangia mainy give preganglonic fiers, whch are rouped ogether to form the splnchnic erves (Fig. 3-16) and supply he abdoinal viscera. Thy enter the abdmen by iercing the crua of th diaphrgm. The reater planchnc nerve ariss from anglia to 9, he lesse splanchnic nere arses fro gangli 10 and 11, and the lowet splanhnic neve aises frm ganglon 12. or detas of th distriution o these erves i the abomen, se page 29.

Cliical Noes Symathetic Trunk in the Tretment of Raynau Diseas Peganglinic sympathectomy of th second and thid thorcic ganlia can be performed to increas the blod flow to the fingers for such conditins as Rynaud dsease. he sympthectomy causes vasodilatation of the rterioles in the upper lmb.

Spnal Anethesia and the Smpathec Nervous Syste A igh spial aneshetic my block the preanglionc sympathetic fibers pasing ou from the lower thoraci segmens of th spina cord. his prouces temporary vsodilattion below ths level with consequent fal in blod pressre.

Esophagus The eophagus is a tubular structure about 10 in. (25 cm) lon that i continous aboe with he larygeal pat of the phary opposite the sxth cerical vetebra. t es through the diphragm at the level of the 10th thoraci verteba to jon the tomach ig. 3-1).

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snell In te neck, the esophagus lis in fnt of the vertbral coumn; laerally, it is rlated t the loes of te thyroid gland; and aneriorly it is n contat with he tracea and the recurent layngeal erves (ee page 95). In the thoax, it asses dwnward nd to te left through the suprior an then the posterior mediastinum. At the evel of the strnal anle, the aortic rch puses the sophagus over to the miline (Fi 3-6. The relatons of the thoraic part of the sophagu from aove dowward ar as follows: 

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Anterorly: The tachea ad the lft recurent layngeal erve; te left principal broncus, which constricts it; and the pericarium, whch sepaates th esophgus from the lef atrium (Figs. 36 an 3-40) Posteriory: he bodies of the thorac vertebae; the thoraci duct; he azygs vein; the rght poserior intercostal arteris; and, at its ower en, the escendig thoracic aorta (Figs. 3-6 and 3-40) Right ide: The medastinal pleura nd the erminal part of he azygos vein ig. 3-1) Left sie: Te left subclavian artey, the ortic ach, th thoracic duct, and the mediastnal plea (Fig. 3-16)

Iferiorl to the level of the roots of the lungs, the vaus nervs leave the pulonary pexus an wth sympthetic erves to form te esophageal plexus. The lef vagus ies antrior to the esohagus ad the rght vags lies posterir. At the openin in the diaphram, the sophagu is acompanied by the two vagi branchs of th left gstric bood vessels, ad lymphtic vesels. Fibers from the right crus of the diaphram round the esophaus in te form of a sling. n the adomen, he esopagus decends fr about 0.5 in. (1.3 cm) and then enter the stomach. It is related to he left lobe of the lier anteiorly ad to th left crus of th diaphrgm postriorly.

Blod Suppl of the Esophags The upper thrd of te esophgus is upplied by the inferior thyroid artery, the midle third by branches frm the escendig thoraic aort, and th lower third by branche from te left gastric artery. The veis from he uppe third drain into the iferior hyroid eins, fom the iddle tird into the azyos vein, and rom the lower tird int the left gastric vein, tributry of te portl vein.

ymph Drinage o the Esphagus Lymp vessel from te upper third o the esphagus drain ito the deep cervcal nods, from the middle thir into te supeior and posterir mediatinal nodes, and from th lower hird ino node along he left gastric blood vssels and the ceiac nods (Fig. 3-27)

Neve Suppy of the Esophaus The sophagus is suppied by arasympthetic nd symathetic efferen and aferent fibers via the vai and mpathetic truns. In te lower part of its thoacic corse, the esophagus is srrounde by the esophagal nerv plexus

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Clincal Notes Esophgeal Costrictins The esophagus has thre anatoic and physioloic contrictios. The irst is where te pharyx s the upper end, the secod is whre the ortic ach and he left bronchus cross its anteior surace, and the third occrs wher the esophagus es hrough he diapragm ino the somach. hese constrictios are o consierable linical importace because they re site where wallowe forein bodie can lodge or though which it y be difficult o an esopagoscope. Because a ight delay in he ge of fod or fuid occurs at tse leves, stritures evelop ere aftr the drinking o causti fluids Those onstricions ae also the common sites f carcioma of he esopagus. I is useul to that their respecive disances fom the pper inisor teth are 6 in. (5 cm), 0 in. (25 cm), and 16 in (41 cm, respctively (Fig. -51).

Potal–Sstemic enous Aastomoss At he lowe third f the esophagus is an important portalâ“systemic venou anastoosis. (or othe portal€“systeic anatomoses see page 246). Here, the esophagea tributries of the azyos vein (systeic vein) anastmose wth the sophageal tributries of the lef gastri vein (hich drins into the portal vei). Shoud the prtal ven becom obstructed, as, for exmple, i cirrhosis of th liver, portal hypertension develos, resuling in he dilaation and varicoity of he poral–sytemic aastomoss. Varicosed esohageal eins ma ruptur durin the pasage of food, casing heatemesi (voiting of blod), whch may e fatal

arcinom of the Lower Tird of he Esopagus The lymh drainage of the lower third o the esophagus descends through the esohageal pening n the daphragm and end in the celiac nodes arund the celiac rtery (Fg. 3-27). A malignant tumor of thi area of the esohagus wuld theefore tnd to pread below the diaphragm along this roue. Consquently surgicl remoal of th lesion would iclude nt only he primry lesion, but also the celiac lymph noes and ll regions that drain to thes nodes namely the stmach, the upper half of he duodnum, th spleen and te oment. Restoration of continuty of te gut i accompished b performing an esophagoejunostmy.

The Esophags and te Left trium o the Heart The close relationhip beteen the anterio wall o the eophagus and the posterir wall f the left atri has already ben emphsized. barium swallow may hel a physiian assess the ize of the lef atrium in case of lef-sided eart falure, in which the left atrium ecomes istende becaus of bac pressure of venous bloo. P.29

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Thymu Te thymu is a flattened, bilobed structure (Fig. 3-6) lying etween he sternum and the pericardium i the anerior ediastium. In he newbrn infant, it reches it larges size elative to the ize of he body at which time it may exend up through the suprior meiastinu in frot of th great vssels ito the root of the nec. The tymus continues grow until pberty bt thereafter undergoes nvolutin. It hs a pink, lobulated apparance and is he site for devlopment of T (tymic) lymphocyte.

Blood Supply he bloo supply of the hymus i from te inferior thyroid and iternal horacic arterie.

Clinica Notes Chest Pin The preenting ymptom f chest pain is a commn problem in clinical pactice. Unfortuately, hest pan is a ymptom ommon t many condition and ma be caued by dsease i the thracic and abdominal walls or in many diferent horacic and abdminal vscera. The severity of the pain is often unrelated to te seriosness o the cuse. Mycardial ain may mimic eophagits, muscloskeleal chest wall in, and other non–lie-threaening causes. Uness the physicin is atute, a patient may be ischargd with a more sious cndition than te symptms indicate. It s not god enouh to hae a corect diagnosis only 99% o the tie with hest pan. A undersanding of ches pain hlps the physicin in th systemtic conideration of the differetial dignosis.

Somatic Chest Pin Pain rising rom the chest or abdominal wall is intnse and discretly locaized. Smatic ain rises i sensor nerve ending in thee structres and is condcted to the cenral nerous system by egmenta spinal nerves.

Visceal Ches Pain Viseral pan is difuse an poorly localizd. It i conduted to the centrl nervos syste along fferent autonomc nervs. Most visceral pain fiers ascnd to te spina cord along ympathetic neves and enter te cord hrough he poserior nerve roots of semental pinal nrves. Sme pain fibers rom the pharynx nd uppe part f the eophagus and the trachea enter the centra nervou system throug the paasympatetic nerves via the glosopharygeal an vagus nerves.

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Fiure 3-5 The approxiate resective istance from te incisr teeth (black) and te nostils (red) to the noral three constritions o the esphagus. To assit in th age of a tube to te duodum, the distancs to th first art of the duoenum are also iluded.

Referred Chest Pain

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snell Referred chet pain s the feling o pain a a locaion oter than the site of origin of the stimulus, but in an aea supplied by he same or adjaent segents of the spial cord Both somaic and viscera structres can produce referre pain.

Thoraci Dermatmes To understand chest pin, a wrking knowledge of the horacic dermatoes is esential (see pages 27 and 28).

Pain an Lung Dsease Fo a full discusson, see page 103.

Crdiac Pin For a ll discussion, ee page 16. .130

P.131

Cross-Sectional Anatomy of the Thrax To assist in the interpretation of CT scas of the thorax, study te labeld cross section of the thorax hown in igure 352. he sectons hav been potographed on their infrior sufaces (ee Figs. 3-53 and 3-54 for CT scans.

Radiogaphic atomy Only the more imortant eatures seen on standar posteoanterir and olique lateral rdiograps of th chest re disussed hre.

osteroanterior Radiograh A poseroanteior radograph is take with te anteror wal of the patient's chest touching the cassette holder and with th x-rays travrsing te thora from the posteror to te anteror aspet (Figs 3-55 and 3-5). irst chck to mke sure that the radiogrph is a true poteroantrior rdiograp and is not slightly oblque. Lok at th sterna ends o both lavicles; they should be equidisant fro the vrtebral spines. Now examin the folowing n a sysematic rder:

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Superficial soft tissues. The nipples in both sexes ad the beasts in the female may e seen superimpsed on P.132

P.13

te lung fields. The pecoralis ajor may also cat a sof shadow

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Fiure 3-5 Crss sections of the thorx viewe from below. A. At the level of the ody of the third thoracic vertera. B At th level f the eghth thracic vrtebra. Note that in th living, the peural cavity is only a ptential space. he larg space een her is an artifact and results fro the emalming rocess.

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Figure 3-53 Compute tomograhy scan of the uper part of the thorax at the leve of th third thoracic vrtebra. he secton is viewed fro below.

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Fiure 3-54 Comuted tomgraphy scan of the middle part of he thora at the evel of the sith thoraic vertera. The ection i viewed rom belo.

Figure -55 osteroaterior radiograph of he ches of a nrmal adult man.

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Bones. The thoracic vertebae are mperfecly seen The cototranserse jonts and each rb should be examined in rder frm above downwar and copared o the fellows of the oppsite sie (Fig. 3-55. The costal cartilages are nt usualy seen, but if alcifie, they ill be

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visible. The claicles ae cleary seen rossing the uppr part of each lung field. The medial borders of the sulae my overlp the eripher of eah lung ield. Diaphrgm. The diaphragm casts dome-shaped shadows on each side; te one o the rght is lightly higher han the one on he left Note the costophrenic ngle, were the diaphram meets the thoacic wall (Fig. 3-55). Beneath the righ dome is the homogeneous dense hadow o the lier, an beneath the left dome a gas buble may e seen n the fndus of the stmach. Tachea. The rdiotranlucent, air-filed shadw of the trachea is seen in the midline of the eck as a dark area (Fig. 3-55) This i supermposed on the lwer cerical an upper horacic vertebre. Lungs. Looing firt at th lung rots, on sees relativel dense shadows caused b the presence o the blod-filld pulmoary and bronchil vessels, the arge brnchi, ad the lmph nods (Fig. -55) The lng fields, by vtue of he air hey conain, redily pemit the age of x-ras. For his reaon, the lungs ae more ranslucent on ll inspration han on xpiratin. The ulmonay blood vessels are sen as a series o shadow radiating from he lun root. Wen seen end on they .134

ppear s small round, white sadows. he larg bronchi, if see end on also ast simlar roud shados. The maller bronchi ae not sen.

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Fgure 3-6 Main featres observable in the posteroanerior rdiograp of the chest sown in

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Fgure 3-5. Nte the osition of the atient n relation to th x-ray ource ad cassete holdr.

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Meiastinu. Th shadow is prodced by he varius strutures wthin the mediastinum, superimposed one o the oter (Figs 3-49 and 3-5). ote the outline of the eart an great vessels. The tranverse diamete of the heart shuld not exceed half the width o the thracic age. Reember tat on dep inspiration, when the diaphragm desceds, th verticl lengt of the heart icreases and the transverse diameter is arrowed In infnts, th heart s alway wider nd more globula in shpe than in aduls.

The right border f the mdiastinl shadow from above dowward cosists o the riht braciocephaic vein the superior vena cava the riht atrum, and sometims the iferior ena cava (Figs. -55 nd 356). The left border consists of a prominence, the aortic knuckle, caused by t aortic arch; blow thi are th left mrgin of the pulmonary trnk, the left auicle, ad the lft venticle (Fis. 3-55 and 356). The inferior boder of he medistinal shadow (lower borer of te heart blends with th diaphrgm and liver. Note the cardiophrnic angles.

Riht Obliue Radiograph A ight obique raiograph is obtaned by otating the paient so tha the riht anteior chet wall s touchng the assette holder and the x-rays traverse the thorx from osterio to antrior in an oblque dirction (Fgs. 3-5 and -58) The P.135

hert shadow is largely mad up by he righ ventrcle. A mall prt of he postrior boder is ormed b the riht atrim. For urther details f strucures sen on ths view, see Figues 3-57 and 358.

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igure 357 Rght oblque radograph f the cest of normal adult mn after a barium swallow.

Let Obliqe Radioraph A left obique raiograp is obtined by rotatio of the patien so tha the let anteror ches wall i touchig the cssette holder ad the x-rays trverse te thora from psterior to anteor in an obliue

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snell direction. The heart hadow i largel made u of the right entricle anteriorly and the left ventrile postriorly. Above te hear, the artic arch and th pulmonry trun may be seen. An example of a let laterl radioraph of the chet is shwn in Fiures 3-9 an 3-60

Broncography and Conrast Viualizaton of te Esophgus Bronchography is a specal stud of the bronchil tree by mean of the introdution of iodized oil or ther cotrast mdium into a paricular ronchus or bronhi, usully undr fluoroscopic control. The contrast media are onirritating an sufficently adiopaqe to allow good visualiztion of the brochi (Fig 3-61). After the raiographc examination s complted, the patient is aske to couh and epectorae the cntrast edium. P.36

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Fiure 3-58 Man features observable in the right obliqe radioraph of the chest shon in Figure 357. Noe the position of the paient in relatio to the x-ray surce an cassette holder.

Cotrast vsualization of te esophgus (Fig. 3-57 and 3-9) s accomlished y giving the paient a creamy paste of arium sulfate and waer to swallow. he aortc arch nd the left bronchus caue a sooth indentation on the nterior border f the brium-filed esphagus. This procedure cn also e

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snell used o outle the psterior border of the eft atrum in a right oblique vew. An enlarged left atium causes a smoth indentation of the nterior border f the arium-flled esphagus.

oronary Angiogrphy The coronary arterie can be visualied by te intrduction of radipaque material into ther lumen Under fluoroscopic control, a ong narow cathter is assed ito the ascendig aorta via the femoral artery n the lg. The ip of te cathter is carefully guided nto the orifice of a coonary atery an a smal amount of radipaque mterial s injeced to rveal the lumen of the atery an its brnches. he infomation an be rcorded n radigraphs Fig. 3-2) P.13

or by cineradiograhy. Usig this echniqu, pathoogic narowing r blockage of a oronary artery can be dentifid.

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igure 359 Lft lateal radigraph o the chst of a normal dult man after a barium swallow.

CT canning of the horax CT scannig relies on the ame phsics as conventional x-ays but combine it wit computr technlogy. A source f x-ray moves in an ar around the thoax and ends ou a beam of x-rays The beams of x-rays, having ed hrough the thoric wall and the thoracc viscea, are onverte into electronic impulses that poduce eadings of the ensity f the tssue in a 1-cm slice of the body

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snell From hese redings, he compter assmbles a picture of the horax clled a CT scan which n be viwed on fluorecent sceen and then photograpd (Fis. 3-53 and 354). P.13

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Figre 3-60 Main feature observable in left lteral rdiograp of the chest sown in Fgure 3-9. Nte

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the position of the ptient i relatin to th x-ray ource ad cassette holde.

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Figre 3-61 Posteroanteror bronhogram f the cest.

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Figure 3-62 Coronary angiograms. A. An area of etreme nrrowing of the circumfle branch of the eft cornary arery (whie arrow). B. The ame artry afte percutneous tansluminal coronary angiplasty. Inflaton of te luminl ballon has damatically improved the rea of stenosis (whit arrow).

Clinial Probem Solvng Study the folowing case histoies and select the best answer to the qestion ollowin them. A 5-year-od man sates tht he ha notice an altration n his voice. He has los 40 lb 18 kg) nd has persisent couh with lood-stained sputum. He smokes 50 cigarttes a ay. On xaminaton, the left voal fol is immbile an lies i the aducted position. A posteanterio chest radiogrph revels a lage mass in the pper lob of the left lng with an incrase in idth of the medastinal shadow n the lft sid. 1. The symtoms an signs isplaye by this patient can be xplaine by the followig stateents exept whih? (a) Ths patiet has avanced arcinom of th bronchus n the upper lobe of the left lung, whih was seen as a mass on the chet radioraph. (b) The carcinma has etastaszed to he brochomedistinal ymph nodes, causing their enlargement and producng a wdening f the mdiastinl shadow seen on the chet radioraph. c) The nlarged lymph ndes had pressed on the eft recrrent lryngeal nerve. 260

snell (d) Patial inury to the recurrent laryngeal nerve reulted i paralyis of te abducor mucles o the vcal cords leavin the aductor mscles uopposed (e) The enlarge lymph odes prssed on the lef recurrnt nerv as it ascended to the neck antrior to the arch of the orta. View Answer 1. E. The lef recurent layngeal nerve asends to the nec by pasing uner the rch of he aort; it ascends in the grooe betwen the rachea nd the sophagu. A 35-ear-old woman hd difficulty in breathig and sleeping a night. She sas she flls aslep only to wake up with a chokig sensation. Sh finds hat she has to leep prpped up in bed n pillos with er neck flexed to the ight. 2. The folloing statments cncerning this cas are corect excet which (a) Vens in te skin a the roo of the neck ar congested. (b The Ushaped artilagnous rings in he wall of the trachea prevent it from being inked or comprssed. (c The lft lobe of the thyroid glad is larger than the rigt lobe. (d) On fallin asleep, the patent tend to flx her nck latelly over the enlrged left thyroi lobe. (e) The enlaged thyid glan extend down the neck ino the serior mdiastinu. (f The brachiocephac veins in the uperior ediastinm were partially obstruced by the enlarged thyroid glan. Viw Answe 2. B The trahea is a mobile, fibroelstic tub that ca be kinkd or cmpressed despite the presnce of the cartilaginous rings. A 15year-ol boy was rescued from a lke after falling through thin ic. The ext day he devloped a severe old, an 3 days later hs generl condition detriorate. He beame febile and started to coug up blod-staied sputm. At first, he ad no cest pai, but lter, whn he coughed, he experinced seere pai over te right fifth itercostal space in the idclaviular lie. 3. The followig stateents wold explin the atient' signs and symptoms excet which (a The paient ha develoed loba pneumoia and leurisy in the rght lun. (b) Disease of the ung does not case pain until t parietl pleur is invlved. (c) The pneumona was lcated in the riht midde lobe. (d The viceral peura is innervaed by atonomic nerves that contin pai fibers

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snell (e) Pain assciated with the pleuris was acentuated when movement f the vsceral nd parital plerae ocurred, or example, on deep inspration r coughng. iew Anser 3. D. Lung tissue nd the isceral pleura re not nnervated with pin fibrs. The costal arietal pleura s innerated by the intrcostal nerves, which hve pain endings in the leura. A 2-ear-old boy was playing with hi toy ca when hs baby-sitter noticed tat a smll meta nut wa missin from te car. wo days later the child developd a couh and bcame ferile. 4. This chld's ilness cold be eplained by the ollowin statements excet which (a) The chid had ihaled te nut. (b) The meta nut could easily be seen on poteroanteior and right olique rdiograps. () The left pricipal bonchus s the more verical an wider f the to principal brochi, an inhale foreign bodies tend to become odged i it. (d) Te nut ws succesfully emoved hrough bronchoscope. (e) Childen who are teethng tend to suck on hard toys. View Anwer 4. C. The right principal (main) ronchus is the mre vertcal and wider f the to prinal brochi and for thi reason an inhaed foreign body es own the trachea and tens to ener the ight man bronchus, whre it was lodged in this patient A 23-yer-old wman was examind in th emergecy depatment bcause of the sudden onset of rspiratory distress. The hysicia was litening to breah sound over the right hemithorx and ws concened whe no sonds wer heard n the front of the hest at the levl of th 10th rib in the midclaicular ine. . The fllowing comment concering thi patien are correct ext whic? (a) In a healthy individual, the loer border of the right lung in the midlaviculr line n the idrespiratory position is at the level of the sith rib. (b The paietal peura in the midlaviculr line rosses he 10th rib. (c) The cotodiaphagmatic recess s situaed between the lower borer of te lung nd the arietal pleura. (d The lug on extreme inpiratio could escend n the cstodiapragmati recess only as far as the eighth rib. (e) No brath souds were heard bcause te stethoscope was locate over te liver View Anwer

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snell 5. . The prietal leura i the miclavicuar line only exends do as far as the eighth rib. A 1-year-ld man as seen in the mergenc departent comlaining of a feling of pressur within his chet. On qestionig, he sid tat he ad seveal attaks befoe and tat they had alwys occured whe he wa climbig stair or diging in the garden. He fond that the dicomfort disappered wit rest after abot 5 minues. The reason e came to the mergenc department was that th chest discomfor had ocurred ith muc less eertion. 6 The folowing omments concernng this case ar correc except which? (a) The diagnoss is a classic case of ngina pectoris. (b) The udden cange i histor, that is, pan caused by less exertio, shoul cause he phyician cncern that the patient ow has nstable angina r an acual myoardial infarction. (c) The aferent pain fibes from he heart ascend to the entral ervous ystem trough te cardic brances of he sympathetic trunk to nter th spinal cord. (d) The afferent pin fibes enter the spnal cord via th posterir roots of the 0th to he 12th thoraci nerves (e) Pai is refrred to dermatoes suppied by he uppe four intercostal nerves and th intercstal brachial nerve. View Anwer 6. D. The afferen pain fbers frm the hart entr the spinal cord via te posteior nerve roots of the upper for thoraic spina neves. A 55-year-old woman has evere aortic iompetene, with the blod retuning to the cavty of te left entricl during ventricular diatole. . To her the artic vave with the leat intererence from the other heart souds, the best plce to pace you stethocope o the chst wall is (a) the ight half of the lower end of t body of the strnum. (b the meial end of the econd rght intrcstal spce. (c) the medial nd of the second left intercostal space. d) the pex of he heart. (e) he fift left itercostl space 3.5 in. (9 cm) rom the midline. Viw Answe 7. B 33-yer-old wman was jogging across he park at 11 pm. when she was attacked by a gang of youths. Ater she was brually muged and raped, one of the youths decied to sab her n the hart to keep her silent Later in the mergenc department she was unconscious and in 263

snell extremey poor shape. small ound abut 0.5 n. in dameter as presnt in te left fifth itercostal space about 0.5 in. rom the lateral sternal margin. Her caotid pulse was rapid ad weak, and her neck vens were distened. No vidence of a left-sided pneumothorax existed. dignosis of cardac tampnade was made. 8. The following observation are i agreemnt with the dianosis ecept which? () The tp of th knife ad piered the ericardum. (b) Te knife had pierced the nterio wall of the lef ventrile. (c) he blod in th pericadial caity was under rght venricular pressure. (d) he bloo in the pericardial cavty pressed on the thin-alled aria and large vins as hey traersed te periardium to enter the heart. () The bcked-up venous lood cased conestion of the vens seen in the eck. () The por venos retur severey comprmised te cardiac output (g) A eft-sided pneumothorax did not occur bcause te knife ed trough te cardic notch View nswer 8 B. The knife hd piercd the aterior wal of the right vntricle A 36-year-old oman wih a knon histoy of emhysema dilataton of lveoli and destruction of alveolar walls with a tendency to form cystic spaces) suddenl experinces a evere pin in the left ide of her chest, is breathless and is obviouly in a state o shock. 9. xaminaton of this patint revels the following finding except which? (a) The trachea is dispaced to the rigt in th suprasernal notch. (b The apx beat f the heart can be felt in the fifth let intercostal sace just laterl to the sternum. c) The ight lug is colapsed. (d) The air pressure in the left plural caity is at atmosperic prssure. (e) The air has entered the left pleural cavity as the result of ruptur of one of the mphysemtous cyts of he left lung (lft-sided pneumothorax). (f) The elastic recoil of th lung ssue cased the lung to collaps. Vew Answr 9. . The lft lung collapsed immedately when air etered te left pleural cavity ecause the air pressurs withi the brnchial tree and in the pleural cavity wre then equal. A wife as told that her husban was suffering from cancr of th lower nd of he esophagus The phsician old her that to save hi life, he sureon woud have to remov the lowr part f the

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snell eophagus the somach, he splen, and he upper part of the duoenum. Te wife ould not undestan why suh a dratic opeation was requird to rmove suh a smll tumo. 1. The fllowing statements explin this extensive operation excet which (a) arcinom of the esophags tends to spred via te lymphatic vessels. (b The lyphatic essels escend hrough he aortc openig in th diaphrgm to eter the celiac ymph nods. (c) The tuor of te esophgus an an are f norma adjacet eophagus ave to be remoed. (d) The lyphatic vessels and nodes that drain the iseased area hae to be removed (e) Because of the rsk that retrogrde sprad had ccurred the oter organs draining into the lymh nodes also hae to be removed View Answer 0. B. he lympatic vesels daining he esophagus accompany te left gastric blood vssels trough te esophgeal opning in the diaphragm reach he celic nodes A 50-yer-old man with cronic alcoholim was told by his physican that he had irrhosi of the liver wth portl hyperension. 1. The following statements explain why the patint recetly vomted a ful of blood ecept whch? (a) The lower third of the esophagus s the se of a portalâ€systemi anastoosis. (b) At he lowe third f the eophagus the esphageal veins o the left gastric vein anastomose with he esophageal veins of he infeior ven cava. (c) n cirrhsis of the live the prtal circulation throug the lier is ostructe by fibous tisue, prducing portal hypertensin. (d Many of the diated vens that le withi the muous memrane an submucsa are easily dmaged by swallod food. e) Copius hemorhage fom thes veins s diffiult to reat and is oft terminl. View Answer 1. B. The esophaeal veis of th azygos system f veins anastomse with the esohageal eins of the lef gastric vein. A 5-year-ld boy as seen in the mergenc departent after an attck of reathlesness dring whch he hd lost onsciouness. The mother said tat her hild ha had seeral atacks before and sometims his skin had become luish. ecently, she had noticed that he breathe more asily wen he ws playing in a squatting positio; he alo seeme to slep more easily ith his knees

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snell drawn up. n extenive worup, inluding ngiograhy, demnstrated that the patiet had svere cngenita heart disease. 12. The fllowing observatons in this patent are consistnt with the dianosis o tetralgy of Fllot except whih? (a) The child was thiner and shorter than normal. (b) is lips finger, and tes were cyanoti. () A sysolic mumur was present down th left brder of the stenum. (d The hert was consideraly enlarged to he left () Pulmoary steosis imairs th pulmoary cirulation so that a right to left hunt occurs an the arerial bood is oorly oygenate. (f) A large ventriclar septal defect was present. (g) The aorti opening into the heart was common to boh ventrcles. View Answer 2. D. Beause o the pumonary stenosi and th ventriular setal defct, riht venricular hypertophy is causing the heart to elarge t the ight.

Review uestion Multiple-hoice Qestions Selec the bet answe for eah quesion. 1. Th followng statments cncerning the trachea are true except wich? (a) It ies antrior t the esphagus in the uperior mediastnum. (b) In dep inspiation, he carna may escend as far s the lvel of he sixt thoracic vertebra. (c) The left pincipal bronchu is widr than t right principl broncus. () The rch of he aorta lies o its anteior and left sies in te superor medistinum. (e) Te sensoy inneration o the mcus membrane lning th trache is derved fro branches of te vagi nd the recurrent laryngeal neves. View Answer 1. C The right prinipal brnchus i wider than th left. his is learly seen in the noral poseroanteior bronchogram shwn in Figure 3-54. 2. The followig stateents concernin the rot of th right ung are true ecept whch?

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snell (a) The right hrenic erve pases anterior t the lug root (b) The azygo vein aches ovr the sperior argin of the lng root (c) Te righ pulmonry artey lies osterio to th princial bronhus. () The ight vaus nerv es posterior to the lung ot. (e) The vesels and nerves orming the lug root re enclosed by a cuff f pleur. View nswer 2. C. he rigt pulmoary artry lies anterir to the principal brochus. 3. he follwing statements concering the right lung are true exept whih? (a) It posesses horizotal and an oblque fisure. (b) Its coverin of viseral plura is sensitie to pan and tmperatue. () The lymph frm the sbstance of the lung reches th hilum y the sperficil and dep lymphatic pexuses. (d) The pulmonry ligaent perits th vessel and neves of he lung root t move during he ovemens of rspiratin. (e) The brochial vins drain into the azgos and hemiazygos veis. View nswer 3. B. The viseral plura is nnervaed by smpathetc and vgal afferent ibers va the ulmonar plexus and is ot senstive to pain ad temprature, but it s sensitive to the senation f stretch. . The aterior surface of the heart i formed by the ollowin structres ext whic? () Righ ventrile (b) Right trium () Left ventrice (d) eft atrum (e) Right aricle Vie Answer 4. D The let atriu lies bhind te heart 5. In posteoanterir radioraph of the thorax, th followng strutures frm the left magin of the heart shado except which? (a) Left auricle

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snell () Pulmonary trnk (c) Arch of aorta () Left ventrice (e) uperior vena cva Vie Answer 5. E 6. ll of he follwing sttements concering the esophaus are orrect xcept which? (a) I receies an rterial blood supply from both the desending horacic aorta and the eft gatric arery. (b) It i constrcted by the presence o the lft prinipal bronchus. (c) It crosss from ight to left psterior to the descendng aort. (d) It piercs the daphragm with te left vagus o its anerior surface and th right vagus on its psterior surfac. (e It jois the omach about 16 in. (41 cm) fro the inisor teth. View nswer . C. Te esophgus croses from ight to left anerior t the decending aorta. 7. All of he follwing sttements concering the mediastnum are correct except which? (a) The mediastinum forms a patition between the two pleural spaces cavitie). (b The meiastina pleura demarcaes the ateral boundaries of th mediasinum. (c) Th heart ccupies the midle medistinum. (d) Shoul air enter the left peural cavity, he structures forming he medistinum re defected to the rght. (e) The anterior bundary f the mediastium extnds to lower evel tha the posterior bundary. View Answer 7. E. The anteior boundary of the medastinum xtends own to te xiphsternal oint aneriorlyâ”that i, to th level f the nith thoacic vertebral bdy. The posteror bounary extds down farther, o the leel of t 12th tracic vrtebra. All of the follwing sttements regarding the coducting system o the hert are tue excet which? a) The mpulse for cardiac conraction spontaneusly begns in th sinuatial node

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snell (b The atioventricular bundle is the soe pathwa for conucton of te wave of ion etween the atr and th ventrices. (c) The sinuatrial node i frequently upplied by the right and left cornary arteries. (d The symathetic erves to the heat slow he rate of dischage from the sinuaial nod. () The atrioventricular bndle deends beind the eptal cup of the tricuspd valve View Aswer 8 D. Th sympathtic neres to th heart ncrease he rate f dischage from the sinuatrial noe. 9. Al of the ollowing statemets regaring the echanic of inspration ae true xcept wch? (a) The diaphragm i the mos importnt muscl of inspiration. (b) Te supraleural mmbrane can be aised. (c) Th sternu moves teriorly. (d) The ribs are raised uperiorl. (e The tone of the muscles f the anerior abominal ll is dinished. Viw Answe 9. B. The supapleural membrane is comped of fbrous tssue an is attached t the transverse process of the sventh crvical vertebra; it cnnot b raised during inspiration. 10. The folowing statement concerning te lungs re corret except which? (a) Inhaled foreign odies mot frequntly entr the riht lung. () The lft lung is in direct cntact th the arch of he aort and th descening thoacic aota. (c) There are o lymph nodes wthin the lungs. (d The stucture f the lungs receives its blood supply frm the bonchial arterie. () The cstodiapragmati recesss are lned with parieta pleura Vew Answr 10. 1. The fllowing statemets concrning te blood supply o the heart are correct except hich? (a) Te coronry arteies are branche of the ascendin aorta. b) The right coronary tery suplies both the right atium and the rigt ventrcle. (c) The circumfex branh of th left oronary artery descends n the aterior ntervenricular groove nd pases aroud the apex of the heart.

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snell (d) Arrhythmias (abrmal heart beats) can occur aftr occluion of coronay arter. (e) Coronar arteris can b classiied as unctionl end arteries. Vie Answer 11. C The circumflex branch o the left coroary artry winds around the left margin of the heart in the atroventriular grove. 12 The folowing tatemens concening th bronchpulmonar segmens are crrect ecept whch? (a) The veins ae intersegmental. (b) The sements are separaed by connectiv tissue septa. () The ateries re intrsegmentl. () Each egment is supplied by secondry bronchus. (e) Ech pyraid-shapd segment has is base ointing oward te lung urface. Viw Answer 12. D Each sgment o the lun is suplied by a segmental brochus. Cmpletio Questins Math each tructur listed below wth the egion i which t is found. Each lettere answer may be sed mor than oce. 13. Coronar sinus opening 14. and 15. Aulus ovlis 16. Rght pulonary vins (opnings) (a) Lft atrim (b) Right ventricle () Right atrium () Left entricle (e) Riht auricle View Answer 13. C 1. B

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snell 15. C 16. ultipleChoice uetions Read th case histories and select the est answr to th questin folloing the. On performng a rotine exminatio of a 7year-ol girl, a pediatrcian hard a cntinuou machinrylike murmur n the scond left intercstal sace. Th murmur occupie both sstole and diastole. The child ws not yanotic the heart was of normal size, ad there was no lubbing of the fingers Radiographic examinatin of th chest evealed slight enlargeent of he left atrium, left vetricle, and pulonary trunk. A diagnoss of patent ducts arterosus wa made. 17. Based on th clinicl histoy and te diagnsis, th followng statements cocerning the case are correct exept whih? (a) he patet ductu represnts the distal ortion f the ixth let aortic arch artery. (b) The dutus conects th right pulmonay arter to the decending thoracic aota. () The ductus i fetal ife is the noral bypas of bood to he aort from te pulmoary trnk. (d) At irth, te ductu arterisus norally costricts in respose to a rise in arteria oxygen. (e) Th ductus arterious closs to beome the ligamentum arterosum. View Answer 17. B. The ducus arteiosus rpresent the dital porion of he sixt left aortic arch artery and connects te left ulmonar artery at its origin rom the pulmonary trunk o the jnction f the aortic arch and the descending thoracic orta. 18. he presence of a patent uctus presents he follwing phsiologi and pahologic consequnces except whi? (a) Aotic blod es into the pulmonary artery, prodcing th machinry-like murmur. (b) The shuning of bood occrs only during systole as the esult o the hiher blod pressre in te aorta and the lower bood presure in the pulonary atery. (c) The left ventrile show hypertophy beause of the lea from te aorta. (d) Te pulmonary trunk become enlargd and he righ ventrile hypetrophie owing to the rised pressure in the pumonary circulaton. e) Becase of te risk f bacteial inection of the wal of th pulmonry artey (bactrial enarterits) caused by t pulmonary hypetension the paent ducus should be lated an divide surgially. Vew Answr

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snell 18. B. The achinery-like murmur occurs during both ystole nd diasole an is caued by te shuntng of blood from the aora to th pulmonry artry owin to the higher blood pressure in the aorta during both phases of the cardiac cyle. A 12-yea-old bo was examined b a pediatrician and foun to hav absent femora pulses in both femoral arteris. The ood pressure in both uper lims was hgher than in boh lower limbs. The diagnosis was coarctation of the aora. 19. Te folloing staements bout ths case re corrct except which? (a) Th aorta s narrowed just proxima to the site of origin of the let commo caroti artery (b There s no feoral puse becase the mall aortic pulse wave des not each th femora arteris. (c) The high blood presure in he artries of the uppr limbs and the cerebra circultion is an attept by the hear to forc blood hrough he narrwed aora. (d) To compenste for the diminished lood flow into the lower limbs, he intenal thoacic, sbclavia, and osterior intercotal artries beome dilaed. (e) Th raised bloo pressue proxmal to the aoic narrwing ma later esult i cerebrl hemorhage and heart ailure. Viw Answe 19. A P.140

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Fotnote *The occurence of speciazed inernodal pathways has been dismised by sme reserchers, who laim that it is the pacaging ad arranement of ordinary atria myocardial fibers that are resonsibl for the more rpid conction. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

5. 4. The Abdomen: Part I - The Abdominal Wall A 6-year-ld man omplaining of a painful swellin in the right groin was seen by his physician he had vomited four times in the previus 3 hors. On xaminaton, he s dehydrated an his abomen was moderately distended A large, tense swelling which as very tender n palpaton, was een in the left roin and extended down ino the srotum. A attempt to genty push te contets of the swellin back ito the bdomen as impossible. A iagnosis of a riht complete, ireducible indirec inguinal hernia was made The vomting an abdomial distetion wer secondry to the intestinal obstruction cause by the herniation of soe bowel loops ino the henial sac An indirect inuinal hrnia is caused by a conenital persistnce of a sac formd from he lining of the abdomen This sac has a narrow neck, ad its avity emains n free communiation with the abdominl cavit. Hernias of the abdominl wall re commn. It is necessay to know the anaomy of he abdomen in the regio of the roin beore one can make a diagnois or unerstand he diffeent hernal typs that cn exist Moreovr, withot this kowledge t is impossible to appreiate th complictions tht can ocur or to plan tratment. herni may strt as a simple welling, but it an end s a lie-threaning prblem.

Chapter Objecties 

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Acute abdominl pain, abdominal swelings, ad blunt and penetrating trauma to the abdominal wall ar commo problems facing the phyician. he probems are complicted by the fact that the abdomen contains multiple organ system, and kowing he spatal relaionship of these organs to one another and to te anteior abdminal wll is essential before an accurate and cmplete diagnoss can b made. Th abdomial wall is a flexible tructue throuh which the physician ca often eel disased orans tht lie wthin th abdominal cavity. An inact abdminal wll is ssentia for the of the abdominal contents. A dect or malfuncion of he wall can allw the adominal content to bulge forward and frm a henia. Th abdomial wall provide the surgeon with a sit for to eep-lyig diseaed structres. For the aove reaons, the anatomy of te anteior abdominal all mus be leaned in detail. Because of its reat cinical mportane, examners ask many questions n this rea.

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Basic natomy Th abdomen is the region f the trunk that lies between te diaphagm aboe and te inlet of the elvis blow.

Structure f the Anterior Adominal Wall The anerior adominal wall is made up of skin, superfcial fascia, dep fasci, muscls, extraperitoneal fasca, and parieta peritoeum.

Skin The skin is losely atached o the uderlyin strucures exept at the umbilicus, whre it is tetherd to the scar issue. he natual lines of cleaage in the skin are onstant and run downwar and foward lmost hrizontaly around the trnk. The umbilics is a scar representing the site of attachmnt of te umbilcal cor in the fetus; t is situated in the lina alba see belw).

Clnical Ntes Sugical Incisions I possibe, all urgical incisios shoul be mad in the lines of cleavae where the bunles of ollagen fibers n the ermis rn in parallel rows. An icision long a leavage line wil heal as a narow sca, wheres one that crosses the line will hea as wie or eaped-u scars.

Clinial Note Infecion of he Umbilicus In th adult, te umbilcus oftn receies scan attenton in te showe and is consequntly a ommon ste of ifection. P.147

Nere Supply The cutaeous nere supply to the anterior abdominal wal is derved fro the anerior rmi of te lower six thoacic and the fist lumbr nerve (see Fi. 4-16). The thoracc nerve are th lower ive intrcostal and the subcostl nervs; the rst lumar nerv is repesented by the liohypogastric and the ilioinguinal neres.

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snell The dermatome o T7 is ocated in the epigastium ove the iphoid rocess. The deratome o T10 inludes te umbilcus, and that o L1 lie just aove the inguina ligamet and the symphyis pubs. The ermatoms and dstributon of ctaneous nerves are shown in Figre 4-16.

Blood Supply Arteris Te skin ear the midline is suppied by branche of the superior and th inferir epigatric areries. he skin of the flanks is supplied by branches f the itercostl, the umbar, nd the deep cicumflex iliac ateries (see Fig. 4-15. In addition, the skin in the nguinal region s suppled by te supeficial epigastri, the superficil circuflex ilac, and the superficia externa pudendl arteres, braches of the femral artry.

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Figure -1 A. Arangemet of th fatty ayer and the mebranous layer o the superficil fascia in the lower pat of th anterir abdomnal wal. Note the line of fusin betwen the mmbranous layer and the deep facia of he thig (fasci lata). . Noe the ttachmet of the membranus laye to the posterir margi of the perinel membrane. Arros indicte path taken y urine in case of ruptured urethra.

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Veins he venos drainge s above mainly nto the axilla vein via the lteral toracic ein and below ito the emoral vein vi the suerficial epigastic and he grea saphenus vein (see Fi. 4-18).

Suerficia Fascia he supeficial ascia is dividd into a superficial fatty layer (fscia of Camper) and a dep membrnous laer (Scapa's facia) (Fig. 41). The faty layer is contiuous wih the sperficil fat oer the est of the bod and may be extrmely thick (3 i. [8 cm or mor in obee patients). T membraous layr is thn and fdes out laterally and above, P.14

where it becomes cotinuous with th superfcial facia of he back and the thorax respecively. nferiory, the embranous layer asses oto the front o the thgh, whee it fuses with the dep fasci one fngerbreadth below the inuinal lgament. In the idline nferiory, the membranous layer of fasca is no attachd to th pubis ut forms a tubular sheath for te penis (or clioris). elow in the perneum, it enters the wal of th scrotu (or laia majoa). From there it es to be ttached on each side to the magins of the pubi arch; t is hre refered to s Colles' fascia. Posteriorly, it fues with he perineal bod and th posteror margn of th perinel membrane (Fig 4-1B).

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Figre 4-2 External oblique internl oblique, and transverss muscles of th anterir abdomnal wal.

In the scrotum the faty laye of the superfiial fasia is represented as a tin laye of smoth musce, the dartos mscle The mebranous layer o the suerficial fascia persists as a searate lyer. .149

Fgure 4- Antrior viw of th rectus abdomins muscl and th rectus sheath. eft: The antrior wal of th sheath has bee partly removed, revealing the rctus mucle wit its tedinous ntersecions. Riht: The poserior wll of te rectus sheath is show. The ege of te arcute line is show at the level of

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the antrior suerior iiac spie.

Clinicl Notes Membranous Layer of Suprficial Fascia and the xtravastion of Urine Th membraous layr of the superfcial fascia is importan cliniclly becuse benath it s a potntial cosed spce tha does not open into the high bt is cotinuous with th superficial peineal pouch via the pens and srotum. upture f the enile uethra may be followed by extravaation o urine nto the scrotu, perinum, and penis an then u into te lower part of the anerior adominal wall dep to th membranous layr of fascia. The urine s exclued from the thih becaue of th attachent of the fascia to the fascia lata (Fg. 4-1). When closing abdominal wounds it is uual for a surgeo to pu in a cntinuou suture uniting the divded memranous ayer of superficial fascia. Thi strenghens th healin wound, prevent strething of the ski scar, and makes for a mre cosmtically acceptble reslt.

Deep Fascia The deep fascia in the anteior abominal wall is merely a thin laer of cnnectiv tissue coverin the mucles; i lies immediatly deep to the embranos layer of supeficial fascia.

uscles f the Aterior bdomina Wall The musles of the anteror abdoinal wall consit of tree brod thin heets that are poneuroic in font; from exterior to iterior hey are the extrnal obique, iternal oblique, nd trasversus (Fig. 42). On either side of the midine antriorly s, in adition, a wide ertical muscle, the rectus abdomnis (Fig 4-3). As he aponuroses f the tree shets forward they enclose the rectu abdomiis to frm the rectus heath. The lower part of the retus sheth might contai a smal muscle called te pyramidalis.

Cliical Noes Generl Appearnces of the Abdominal Wall Te norma abdomial wall is soft and plible and undergos inwad and ouward exursion wth respration. The cntour i subjet to cnsiderabe variation and depends on the one of ts musles and the amont of ft in th subcutneous tssue. Wll-deveoped mucles or an abunance of fat can prove t be a severe obtacle t the papation f the abdominal viscera. P150

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Exteral Obliqe The extenal obliue muscle is a road, thn, muscuar shet that rises frm the ouer surfces of e lower eight ris and fns out t be inseted into the xipoid procss, the linea alba, the pubic cest, the pubic tbercle, nd the nterior half of the ilic cres (Fig. 4-2 Most of the fibers are insertd by mens of a broad aoneuross. Note that the most poterior fibers assing own to he ilia crest orm a psterior free border. trianglar-shaped defect in the eternal oblique poneurois lies mmediatey above and medil to the pubic tbercle. This is nown as the supeficial iguinal ring (Fgs. 4-2 and 4-3). Th spermatc cord or round ligamen of the terus) psses though thi opening and caries the xternal spermatc fascia (o the exernal cvering of the round ligament of the uters) from the marins of he ring (Figs. 44 an 4-5)

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Figue 4-4 A. Cntinuit of the differet layer of the anterio abdomial wall with coerings f the sermatic cord. B. The sin and superfical fasca of th abdomial wall and scrtum hav been icluded, and the tunica vaginalis is show.

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Figre 4-5 Scrotm disseted fro in frot. Note the spermatic cord and is coverngs.

Betwee the anerior superior iliac spine and the pubic tuberce, the ower boder of he aponurosis s folde backward on itelf, foming th inguinal ligament (Figs. 4-2 and 4-6). From the medial end of the ligamet, the lcunar ligament extends backwrd and pward t the petineal ine on the superior rams of th pubis ig. 4-6). It sharp, free crscentic edge foms the edial mrgin of the femral rin (see page 57). P.151

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On raching he pectneal lie, the acunar igament becomes continuus with a thickning of the perosteum alled te pectinal ligaent ig. 4-6).

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Figure 46 Boy pelvi viewed from abve. Note the attachments of the nguinal lacuna, and pctineal ligamens.

The ateral art of he postrior ede of th inguinl ligamnt give origin to part of the nternal oblique and trasversus abdomiis muscles. To the inferor rouned bordr of th inguinl ligaent is ttached the deep fascia of the high, te fascia lata (Fig. 4-).

nternal Oblique Te interal oblique muscle is also a broad, thin muscuar shee that les deep to the xternal oblique most of its fibers run at right angles to thos of the externa obliqu (Fig. 2). It aries from the lumar fascia, the anterior wo thirds of th iliac crest, nd the ateral wo thir of the inguina ligamet. The uscle ibers radiate as they pas upwad and frward. he musce is inserted into the ower boders o the loer thre ribs ad their costal artilags, the iphoid rocess, the lina alba, and the symphysi pubis The inernal olique hs a lowr free border tht arche over he speratic cod (or round ligament of he uters) and hen desends bhind it to be atached to the puic cres and th

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Figue 4-7 Anteror view of the elvis sowing the attachent of he conjint tedon to he pubi crest nd the ding part of the pecineal lne.

Transversus The tansverss muscle is a thin sheet of muscle that lies dep to th internl obliqe, and ts fibes run hrizontaly forwrd (Fig 4-2). It arises from the dee surfae of th lower ix costl cartiages (iterdigitating wth the iaphragm), the umbar fscia, te anteror two thirds o the iliac crest, and te laterl third of the nguinal ligamen It is inserted into te xiphod proces, the inea ala, and he sympysis puis. The lowest tendinos fibers siilar ibers fom the nternal oblique to form the cooint tedon, whch is fxed to he pubic crest and the ectinea line (Fgs. 4-7 and 48). ote tha the poterior order o the exernal olique muscle is free, wereas te posteior borers of he intenal oblque and transvesus musles are attache to the lumbar ertebrae by the lumbar fascia igs. 4- and 4-9).

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ectus Adominis Te rectu abdomiis is a long stap musce that xtends along te whole length of the anterior abdominal wall. I is broder abve and ies cloe to the midline, being eparate from is fello by th linea lba.

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Fgure 4- Inginal caal showng the rrangemnt of the exterl obliqe musce (A) the inernal olique mscle (B), the transvesus muscle (C), and te fasci transversalis (). Note that the antrior wal of th canal s forme by the externa obliqe and te internal oblique and te posteior wal is fored by the fasc transversalis nd the ont tendon. The dee inguinl ring lies lateral to the infrior epigastric artery.

Fgure 4- Cros sectin of th abdome showin the corses of the lower thoracic and first lubar nerves.

The rctus abominis uscle aises by two heas, from the front of the symphyss pubis and fro the puic cres (Figs. -6 ad 4-10). It i inserted into the fifth sixth, and sevnth cosal cartlages ad the xphoid pocess (Fg. 4-3). When it s, ts lateal margn forms a curve ridge hat can be palpted and often sen and i termed the line semiluaris (Figs. 43, 4-1, ad 4-12). This extends from the tip of he ninth costal cartilae to th pubic ubercle P.13

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The rectu abdomiis musce is diided ino distict segmnts by hree transverse tendinous itersectons: one a the leel of te xiphod process, one at the leel of te umbilicus, and one halway beteen thee two (Fg. 4-3). Thee interections are stongly atached to the anterior wall o the rectus sheth (ee below). The retus abdminis i enclosd betwen the poneuroses of the external olique, nternal obliqu, and tansversus, whic form he rects sheat.

Pyraidalis Th pyramialis mucle is often abent. It arises y its ase fro the anterior surface f the pbis and is inseted int the lnea alb (Fig. -3). It lies in fron of the lower prt of te rectu abdomiis.

Rectus Sheath Th rectus sheath s a lon fibrou sheath that encloses the rectus abdominis muscle and pyramidlis musle (if resent) and cotains te anteror rami of the ower si thoracc nerve and the superor and nferior epigastic vessls and ymph vesels. It is fomed mainy by the aponeuoses of the three lateral abdominal mucles (igs. 4-, 4-3, and -10) For ease of descripton the ectus sheath is consideed at tree levls (Fig. 4-13. 





Above the cosal margin, the anterior wall i formed by the aponeurosis of the exteral oblque. Th posteior wall is formed by the thoracc wallâ”that i, the ffth, sxth, an seventh costal cartilages and he intecostal spaces. Beteen the costal argin ad the level of the antrior superior iiac spie, the poneurois of te interal oblque splts to enclose the rectu muscle the exernal olique aponeurosis is directed in front of the muscle, d the tansverss aponurosis s direced behind the muscle. Betwen the lvel of the anteosuperir ilia spine and the pubis, th aponeuoses of all thee musces form the anterior wll. The posterir wall is abset, and he rects muscl lies in contac with the fasc transversalis.

It should be oted tht where the aponeurose formin the psterior wall pas in frnt of te rectu at the level o the aterior superior iliac spine, th posteror wall has a fee, cured lower borde called the arcate lin (Fig. 4-3 and 4-1). A this ste, the inferior epigastic vessls ente the P.15

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rectus sheath nd upward to anastomose with the sperior pigastrc vesses. 289

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Figure 4-10 Rects sheat in antrior viw (A) and in sagittal section (B). Note the arrangment of the apoeuroses forming the recus sheah.

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Figre 4-11 Antrior abominal all of a 27-yer-old mn.

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Figur 4-12 Surface landmarks and egions f the aterior abdomina wall.

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snell The rctus shath is eparated from is fellow on the opposite side by a fibrous band alled he linea alba (Figs. 43, 4-, an 4-13. This extend from te xiphod process down t the syphysis ubis an is fored by te fusio of th aponeuoses of the lateral musces of he two ides. Wder aboe the ubilicus, it narrows dow below he umblicus t be attched to the symhysis pbis. The posterir wall f the rctus shath is ot attahed to the recus abdoinis mucle. Th anterir wall s firml attachd to it by the muscle's tendinus intesections (Figs. -3 ad 4-10).

Clincal Nots Hemaoma of the Rectus Sheat Hematoa of th rectus sheath s uncomon but mportan, since it is often ovelooked. It occrs most often o the riht side below he leve of the umbilics. The ource o the bleeding is the inerior eigastri vein o, more arely, he infeior epiastric artery. These vessels my be stetched uring a severe out of oughing or in he late months of pregancy, which may predispse to te condtion. The cause is usually blun trauma to the bdomina wall, such as a fall r a kick. The syptoms tat follw the tauma inlude mdline adominal pain. An acutely tender mass cofined t one retus shath is iagnostc. P.157

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Figure 4-13 Transverse sections of the rectus sheath seen three levels. A. Abve the ostal mrgin. B. Betwen the costal mrgin and the levl of th anteror superior ilic spine. C. Below the level o the anerior superior iliac spie and aove the pubis.

Functin of th Anterior Abdomnal Wal Muscls Te obliue musces lateally flx and rtate th trunk (ig. 4-4). The recus abdoinis flxes the trunk ad stabilizes th pelvis, and the pyramialis keps the inea ala taut uring te proces.

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Figure 4-14 Actin of th muscle of the anterio and lateral abdominal wlls. Arrows inicate lne of pull of different uscles.

The mscles o the anerior a latera abdominal walls assist he diaphagm durig inspirtion by relaxing as the daphragm descend so that the abdoinal viera can be accomodated. The muscles assist in th act of forced expiraton that occurs during oughing and sneezing by ulling dwn the rbs and sternum. Their tne plays a important part in ing and protcting te abdoinal vicera. B contrating smultaneusly wih the iaphrag, with the glottis of th larynx closed, they inrease te intr-abdomial presure and help in micturiion, decation, vomitin, and arturiton.

Nerve Supply of Anteri Abdominal Wal Muscle The oblique and trasversus abdomiis musces are supplid by th lower ix thorcic nerves and the ilioypogastic and ilioinginal neves (L1. The rctus mucle is upplied by the lower six thoraic nervs (Figs. 4-9 and 4-15). Th pyramialis is supplid by th 12th toracic erve. A summary of the mucles of the antrior abominal wall, thr nerve supply, and ther actin is gien in Tale 4-1.

Fscia Transvrsalis The facia trasversais is a thin laer of fscia that line the trasversus abdomins musce and i continuous wit a simar laer linig the daphragm and the iliacus muscle ig. 4-10).

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snell he femral sheth for the femoral vesels in the lower limbs s formed from te fasci transversalis nd the ascia iiaca tat coves the iiacus mscle (see page 59). P158

Figur 4-15 Segmenal innevation f the aterior abdominal wall (left) ad arteral supply to te anteror abdoinal wal (rigt). Tabe 4-1 Muscle of the Anterio Abdomial Wall

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ame of uscle

Orign

Insrtion

Nerve Supply

Actio

Exernal olique

Lower eight ribs

iphoid process, linea aba, pubic crest, pubic tubercle iliac crest

Loer six horacic nerves nd iliohypogastric and ilioinguinal nerves (L1)

Suppors abdomnal conents; ompreses abdoinalconents; asists in flexing and rottion of trunk; assist inforcd expiration, micturitio, defection, prturitin, and vomitin

Interna obliqu

Lumbar fascia, iliac cest, laeral tw thirds of ingunal ligment

Lower thre ribs and costal cartilages, xihoid process, linea alba, symphysis pubi

Lowe six thracic nrves an iliohyogastri and iioinguial nerves (L1)

As abov

Transversus

Lower six cosal cartlages, umbar fscia, iiac crest, lateral third of inginal ligament

Xiphoi proces linea lba, syphysis ubis

Lower ix thorcic neres and liohypoastric nd ilionguinal nerves L1)

Comresses abdominal contens

Rectus

Symphysis

Ffth, sixth,

Lwer six

Compresses

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abdomiis

pubis and pubic cest

and seventh costal cartilages and iphoid rocess

thoraci nerves

abdominal cntents nd flexs verteral colmn; accssory mscle of expiration

Pyramidalis (if presnt)

Aterior urface f pubis

Linea alba

12th thoraci nerve

enses te linea alba

Clnical Ntes Abominal uscles, Abdominthoraci Rhythm and Viceroptois The abdominal mscles contract and relax with espiraton, and the abominal all conorms to the volme of te abdoinal vicera. Tere is an abdomiothoracc rhyth. Nrmally, during nspiraton, whe the strnum moes forwrd and he chet expans, the nterior abdominl wall lso movs forward. If, hen th chest expands, the anteior abdminal wll remns statonary or contracts inard, it is highly probabe that he paretal peitoneum is inflamed and has caued a relex conraction of the bdomina muscle. Th shape f the aterior abdominl wall epends on the tone of its muscls. A middle-aged woman with poor abdomial musces who has had multipl pregnacies is often icapable of suppoting he abdominal viscera. The lowr part f the aterior bdomina wall rotrude forwar, a condition kown as visceroptosis. his should not be confued with an abdoinal tuor such as an oarian cst or wth the excessie accumlation f fat i the faty layer of the superfiial faia. .159

Extaperitneal Fat he extrperitoeal fat is a thn layer of connctive issue that contans a vaiable mount o fat an lies btween te fasca transersalis and the parieta peritoeum (Fig 4-10).

Paretal Peitoneum

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snell The wall of the abdomen are lind with arietal peritoneum (Fig. 4-10. This s a thi serous membran and is continuus belo with te parieal perioneum lining the pelvis see pages 359 and 376).

linical Notes bdominl Pain Se also page 280.

Musle Rigiity and Referre Pain Sometims it is difficut for a physicin to deide whether th muscle of the anterio abdominal wall of a ptient are rigi because of underlying iflammaton of te parieal perioneum o whethr the ptient is voluntarily contracting the mucles beause he or she resents being eamined r becaue the pysicians hand is cold. This problem i usuall easily solved y askin the paient, who is lying supine on te examiation tble, to rest th arms by the sies and draw up the knes to flex the hp t. It is practiclly impossible or a patient to keep th abdomial musclature ensed wen the thighs re flexed. Needless to say, the xaminers hand hould b warm. A plerisy inolving he lowe costal parieta pleura causes pain in the ovelying skin that may radate dow into te abdomen. Although it s unlikly to cuse rigdity of the abdminal uscles, it may ause cofusion n makin a diagosis uness thee anatmic facts are ed. It is seful t remembr the fllowing Dermtomes oer:   

The xipoid process: T7 Te umbilcus: T1 T pubis L1

Anterir Abdomnal Nere Block Area of Anesthesia Th area o anesthesia is he skin of the nterior abdominal wall. The nerves of the anteior and lateral abdominal walls are the anterio rami o the 7t throug the 12h thoraic nerves and the first lumbar nerve (lioinguinal and iliohypoastric erves).

Indcations A anterir abdomnal nere block is perfrmed to repair aceratins of te anterior abdoinal wal.

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Figure 4-6 Dematomes and ditributin of cuaneous erves o the anterior abdominal wall.

Proedure The nterior ends of intercotal nerves T7 through T11 ente the abdminal all by ing osterio to the costal artilags (Fig. 4-17) An abominal ield blck is mst easiy carrid out aong the lower order of the costal marin and hen infiltrating the neres as tey emege betwen the iphoid rocess nd the 0th or 1th rib along te costl margi.

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snell The ilioinginal neve es forward in th inguina canal and emeges thrugh the superfiial inginal rig. The iliohypgastric nerve psses foward arund the abdominl wall nd pieces the externa obliqu aponeurosis abve the superficial inguial rin. The to nerve are eaily bloked by inserting the anethetic needle in. (25 cm) aove the anterio superir iliac spine o the sinoumbilical lie (Fig. -17)

Nerves of the nterior Abdominal Wall The nerves of he anteior abdomina wall are the anterior rami of te lower six thoacic and the first lumbr nerve (Figs 4-9 4-15 and 4-16). hey pas forward in the interval between the internal olique and the ansversus muscles. The thoracic nerves re the ower fie interostal erves ad the sbcostal nerves, and the first lmbar nerve is represented by the iliohyogastric and ilioinguial nervs, branhes of the lumar plexs. They supply he skin of the nterior abdominal wall, the mucles, ad the prietal eritoneum. (Compare with the intrcostal nerves which un forwrd in te interostal saces between the interal intecostal nd the nnermost intercostal musles; se page 5). The lower six thoracic nrves pierce the posterir wall of the retus shath to upply te rectu muscle and the pyramidlis (T1 only). They erminat by piecing th anterir wall of the sheath and supplying th skin. Te first lumbar nerve hs a simlar couse, but it does not enter the rectus shath (Fis. 4-9, 4-15, and 416). It is presented by the iliohypogastri nerve, which perces te extenal oblque apoeurosis above te superficial iguinal ing, an by th ilioinguinal nerve, which emergs throuh the rng. The end by supplyng the skin just above e ingunal ligment an symphyis pubi. Th dermatme of T is located in he epigstrium over the xiphoi proces, that f T10 icludes the umbilicus, and that of L1 ies jus above he ingunal ligment and the symphysis pbis. Fo the dermatomes of the anterior abdominal wall see Fiure 4-1. P.160

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Figure 4-17 Anteior abdminal wll nerv blocks T7 though T11 are blockd (X as thy emere from eneath he costl margi. The iiohypogastric lioingunal neres are locked y insering the needle bout 1 n. (2. cm) abve the anterior superior iliac spine on he spinoumbilicl line (X). he termnal braches of the geitofemoal nerv are blcked by insertig the nedle though the skin just lateral to te pubic tubercle nd infltrating the subcutaneous tissue with aneshetic slution X)

P.161

Artries of the Anterior Abominal Wall Te superor epigstric artery one o the teminal banches f the iternal horacic artery, enters the uper part of the rectus heath etween the sternal and costal rigins the diaphragm ig. 4-5). t descends behd the rectus mucle, suplying he uppe central part o the aterior bdomina wall, nd anasomoses ith the inferio epigatric arery. he infeior epigastric artery i a branh of the external iliac artery ust aboe the iguinal ligament. It rus upward and medially aong the medial ide of he deep inguina ring (Figs. 4-4, 4-8, ad 4-15). It perces the fasci transvesalis to enter the rects sheat anterir to th arcuat line (Fg. 4-10). It ascend behind the recus musce, suppying th lower entral art of the anterior abminal wall, and anastomoses with the superior pigastrc arter. The deep circumflex iliac atery i a branh of th externl iliac artery ust aboe the iguinal igament (Fig. 415). It runs upward and lateally toward the anterosperior liac spne and then cotinues long th iliac rest. I supplies the lower lateral pat of th abdomial wall The loer two osterio intercstal areries, ranches of the descendng thorcic aorta, and he four lumbar rteries brances of te abdomnal aorta, forward between the musle layes and upply te laterl part f the adominal wall (Fig. 4-15). P.162

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Figre 4-18 Superficial veins of the anterior abdominal wall. On the left are anastomoses between systemic veis and he portl vein ia parumbilicl veins Arrows indicat the diection aken by venous blood when the portal vein is structed. On th right s an enarged nastomois betwen the ateral thoracic vein an the suerficial epigasric vei. This ccurs i either the suprior or the intrior vna cava is obstructed.

Veis of th Anterir Abdominal Wal Suerficial Veins Te supericial vins for a netwrk that radiates out from the ubilicus (Fig. 4-8). Above, he netwrk is dained ito the xillary vein via the lateral thracic vin and, below, into te femoral vein ia the superficil epigstric ad great saphenos veins A few mall vens, the paraumilical eins connet the ntwork trough te umbilcus and along the ligametum tees to te porta vein. his fors an imortant ortalâ€systemi venou anastoosis.

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Porta Vein Ostructin In cases of prtl vein bstructon (Fig 4-19), the superfiial veis aroun the umilicus nd the araumbiical vens becme grosly distnded. The distended subctaneous veins rdiate ot from the umblicus, roducin in sevre case the clnical picture referred o as caut meduae.

Deep Veis he deep veis of th abdomial wal, the sperior epigastic, infrior epgastric and dep circumflex ilac vein, follw the ateries f the sme name and drain into the interal thoacic an externl iliac veins. he postrior intercostl veins drain into th azygos veins, nd the umbar veins drain into te infrior ve cava.

Clnical Ntes Caal Obtruction f the superior or inferor vena cava is obstruced, the venous blood cuses ditention of the veins running fom the nterior chest all to he thig. The lteral thoracic ein anatomoses with th supericial eigastri vein, a tributay of the great saphenou vein o the lg. In tese cirumstancs, a totuous varicose vin may xtend rom the axilla o the lwer abdmen (Fig 4-18).

Lymp Drainae of th Anterir Abdomnal Wal Superficial Lymph Vessels The lyph draiage of he skin of the nterior abdominl wall above te level of the mbilicus is upward to the anterior axilary (petoral) roup of nodes, hich ca be palpated just beneat the lower border of the pectoralis mjor musle. Belw the lvel of he umbilicus, te lymph drains ownward and latrally t the suerficia inguinal node (Fig. 4-19). The lymph of the skin f the bck abov the leel of te iliac crests is draied upward to the posteror axilary grop of noes, palated on the poterior wall of the axila; belo the leel of te iliac crests, it drais downward to e superficial iguinal odes (Fi. 4-19). P.163

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Figur 4-19 Lymph drainag of the skin of the antrior ad posteior abdminal alls. Also show is an

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xample f caput medusae in a cae of potal obtructio caused by cirrosis of the livr.

Clinial Note Skin nd Its egional Lymph Ndes Kowledge of the reas of the ski that dain int a paricular roup of lymph ndes is linicaly imporant. For example, it s possible to find a sweling in the gron (enlaged suprficial inguinl node) caused y an inection r malignant tumor of th skin o the lower part of the nterior abdominal wall or that of the buttock.

Deep Lyph Vessls The dep lymp vessels follow the artries an drain into th internl thoraic, external ilac, poserior mediastinl, and para-aortic (lumbar) nodes.

Inguinl Canal Te inguial cana is an blique assage through he lower part of the nterior abdominal wall In the males, t allow structures to to nd from the tesis to te abdomn. In P.164

feales it allows he roun ligamet of the uterus to from the uterus to the labium majus. The cnal is about 1.5 in. (4 m) lon in the adult an extens from he deep inguina ring, hole in the fascia trasversals (see page 17), dwnward nd medilly to he supeficial nguinal ring, a hole in the aponeurosis of the external oblique muscle Figs 4-3 and 4-). t lies parallel to and imediatey above the inginal liament. n the ewborn hild, te deep ing lis almos directy posteior to he suprficia ring so that the canal s consierably horter t this ge. Laer, as the result of growth, the deep rig moves lateraly. The dep ingunal rin,* an ova opening in the fascia ransveralis, les abou 0.5 in (1.3 m) abov the inuinal liament midway beween th anterir superor ilic spine and the symphyss pubis (Figs. 4-4 and 4-8. Relaed to i medialy are te inferior epigatric vesels, wich pas upwar from te external iliac vessels. The magins of the rin give ttachmet to th internl spermtic fasia (r the iternal overing of the round lgament of the uterus). The suerficial inguinal ring* is a triangular-haped dfect in the aponeurosis of the xternal obliqu muscle and lie immeditely abov and medial to the pubc tubecle (Figs 4-3 4-5, and 4-8). Te margis of the ring, sometims calle the crra, ive attchment o the eternal permati fascia

Walls of the Inguina Canal

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Anterior all: Externl obliqe aponerosis, einforcd laterlly by he orign of th internal obliue from the inguinal liament (Fgs. 4-3 and 48). This wal is threfore tronges where it lies opposite the weaest pat of th posterior wall, namely the dep inguial ring Poterior all: Con tendon mediall, fasci transvrsalis aterally (Figs. 4-4 nd 4-8). Thi wall i therefre strogest where it lies opposite the weakest part of the anterior wll, namly, the superfiial inginal rig. Roof or superior wall: Arching lowet fiber of the interna oblique and transversus abdomiis musces (Fig. 4-7) Floor or inferior wal: Upturned lower edge of the inguina ligament and, t its mdial en, the lcunar lgament Fig. 4-7).

Fnction f the Iguinal anal Te inguial cana allows structues of te spermtic cod to pas to an from te testi to the abdomen in the ale. (Nrmal spermatogenesis taes plac only i the tetis leaes the bdominal cavit to entr a cooler envionment n the srotum.) In the emale, the smaller canal permit the pasage of the roud ligamnt of te uters from the uter to the labium ajus.

Mecanics o the Inuinal Cnal Th inguinal cana in the lower prt of the anterior abdminal wll is a site of potental weakess in oth sexs. It is interesting to conside how th design of this canal atempts o lesse this eakness    



Excep in the newborn infant, the caal is n oblique a with the weakst areas, namel, the sperficial and dep ring, lying some ditance aart. Te anteror wall of the anal is reinfored by he fibes of the internal obliqu muscle immediately in ront of the dee ring. Th posteror wall of the anal is reinfored by te stron conjoit tendo immediately beind the superficial ring On coughin and staining, as in icturiton, defcation, and parturition, the arching loest fibrs of the internal oblique and ransverus abdoinis mucles cotract, flattenng out the arched roof o that t is loered toard the floor. The roof may actually mpress he contnts of he cana agains the floor so that the anal is virtualy close (Fig. 4-20). When reat staining fforts may be ecessary, as in defecatin and parturitin, the erson nturally tends o assum the sqatting osition the hip ts are flexd, and he antrior sufaces o the thighs are brought up agaist the nterior abdomial wall By thi means, the lowr part of the aterior bdomina wall s protected by the thigh (Fig. -20).

Speratic Cord The sprmatic ord is collecion of tructurs that through the nguinal canal t and frm the testis (Fg. 4-21). It begins a the dep inguial ring lateral to the nferior epigastic artey and eds at te testi.

Strutures o the Sprmatic ord The structures ar as folows:  

Vas eferens Testicular artery

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Testiular vens (paminiform plexus) Testicular lymp vessel Autonomi nerves Remains of e procesus vagnalis Geital brnch of he geniofemora nerve, which spplies he cremster mucle

as Defeens (Dutus Deferen) Te vas eferens is a crdlike tructur (Figs. -5 ad 4-21) that can be alpated between finger and thub in the upper part of te scroum. It s a thik-walle musculr duct hat trasports permatooa fro the epdidymis to the rethra.

Testiclar Artry A brach of te abdominal aorta (at the level of the econd lmbar vetebra), the tesicular artery is long and sleder and descens on the posterior abdominal wall. It taverses the inginal cnal and supplies the testis and the epiidymis Fig. -21). P165

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Figur 4-20 Action of the muscles on the nguinal canal. ote tha the canal is “oblierated╠when the musles contract. Note also hat the anterio surfae of the thigh protects the inguinal region whn one asumes te squating poition.

Tticula Veins An extensie venou plexus the pampiniform plexus, leaves the posterior border f the testis (Fi. 4-21). As the pleus asceds, it ecomes educed n size o that t about the leel of te deep inguina ring, single testicuar vein is formd. Thi runs up on the posterior abdomial wall and drans into the lef renal vein on the left side and into he infeior ven cava o the rght sid.

Lymp Vessel

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snell he testcular lmph vesels ascnd throgh the nguinal canal nd up over the poserior adominal wall to reach th lumbar (para-ortic) ymph noes on te side f the arta at he level of the first umbar vrtebra ig. 4-2).

Atonomic Nerves Sympathetc fibers run wit the testicula artery rom th renal r aorti sympatetic plxuses. fferent sensory nerves accompay the efferent smpathetc fiber.

Processs Vaginlis The emains of the processus vaginals are present within the cord (ee below).

Genial Branch of th Genitoemoral erve his nere supples the remaste muscle (Fig. 4-1) (ee page 78).

Coverigs of te Spermtic Cor (the Sermatic Fasciae Th coverigs of te spermtic cor are thee concntric ayers o fascia derived from th layers of the nterior abdominl wall Each cvering s acquied as the processus vagialis decends nto the scrotum throug the laers of he abdoinal wall (Fig. 4-2).   

Externa spermaic fasca deived from the external oblique aponeursis and attache to the margins of the superfiial inginal rig remastric fascia derived from the nternal oblique uscle Internal spermaic fasca derived from the fscia trnsversais and ttached to the argins f the dep ingunal rin

To understand te coverngs of he speratic cod, one ust firt consier the development of the inguial canal.

Develpment o the Inuinal Cnal Beore the descent of the estis ad the oary fro their site of origin igh on he postrior abominal all (L1), a pertoneal ivertiulum caled the rocessus vaginais i formed (Fig. 4-23). The proessus vaginalis es rough te layer of the lower prt of te anteror abdoinal wal P166

and, a it doe so, acuires a tubular coverin from ech laye. It taverses the fasia tranversali at the deep inguinal ring and acquires a tubulr coverng, the interna spermatic fasci (Fi. 4-4). As it es through the lower part of the ternal blique uscle, t take with i some of its lowest fibs, whih form he cremater musle. he musce fiber are emedded i fascia, and thus the second tublar sheth is known as he cremsteric fascia (Fig. 44). The proessus vginalis es nder the archin fibers of the transvesus abdominis muscle and therefoe does not acquire a overing from tis abdominal layer. On eaching the aponeurosis of the xternal oblique, it evainates his to

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snell orm the superfiial inginal rig and cquires a third tubular fascial coat, te externl spermtic fasia (Figs. 4- and -5). It is n this anner tat the nguinal canal i formed in both sexes. (In the female he term spermatc fasci should be replced by he covring of the roud ligamnt of te uteru.)

Figure 4-21 Testis nd epiddymis, permatic cord, nd scrotum. Also sown s the testis ad epidiymis cu across in horiontal section.

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snell Meanwile, a and of esenchye, exteding frm the lower poe of the developing gonad through the inguinal canal to the laboscrota swellig, has ondense to for the guernaculm (Fig. 4-23). I the male, the testis descends through the pelis and inguina canal uring te sevenh and eghth moths of etal lie. The normal stimulus or the escent f the tstis is testostrone, wich is secreted by the fetal tstes. Te testi follows the guernaculm and escends behind e peritoneum on the poserior adominal wall. Te tests then asses behind the processus vaginalis and pulls dwn its duct, bood vesels, nerves, an lymph essels. The tesis P.16

taes up is final position in the developng scroum by te end o the eihth month.

Figre 4-22 Lymp drainae of th testis and the skin of the scrtum.

ecause he tests and is accomanying essels, ducts, and so on follow the course previously taken b the prcessus vaginalis, they cquire the sam three overing as the dwn the inguina canal. Thus, the spermatic cord is coveed by tree conentric layers f fasci: the eternal permati fascia the crmasteri fascia, and te interal speratic facia. In th female the ovary descds int the pelvis following th gubernculum (Fg. 4-23). he gubenaculum becomes attache to the side of the devloping uterus, and the onad decends n

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snell farthe. That part of the gubrnaculu extening from the uterus into the devloping abium mjus perists as the roud ligamnt of te uteru. Ths, in he femae, the nly structures hat pas through the inguinal caal from the abdominal cavity re the ound liament o the utrus and a few lmph vesels. Th lymph essels onvey a small aount of lymph rom the ody of the uteus to te superficial inguinal ndes.

Clinicl Notes Vasectmy Bilaterl vasecomy is simple operatin perfomed to produce infertility. Undr local anesthesia, a sall incsion is made i the uper part of the crotal all, an the va deferes is diided btween lgatures. Spermaozoa ma be present in the first few potoperatve ejaclations but tht is siply an emptying rocess. Now ony the scretion of the seminal vesicle and prstate cnstitut the sminal fuid, whch can e ejacuated as before.

Scrtum, Tetis, an Epididmides Scroum The scrtum is n outpoching o the loer part of the anterio abdomial wall. It contains the testes, the epididymids, and the lowr ends f the sermatic cords (Figs. 4-4 and 4-21) The all of he scroum has he following layers: 

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kin: The sin of the scrotum is thin, wrinked, an pigmened and orms a ingle ouch. A slightly raise ridge n the mdline idicates the lin of fuion of the two ateral abioscrtal swellings. In the emale, he swelings rmain searate ad form he labi majora) Suerficia fasci: his is ontinuos with he fatt and mebranous layers f the aterior abdominal wall; the fat is, howver, relaced b smooth muscle alled he dartos muscl This i innervated by sympathetic nerve fibers and is responsble for the wrikling o the ovrlying kin. The membrnous lyer of he superficial ascia (ften reerred t as Coles' fasia) is continuous in front with the memranous ayer of the anerior bdomina wall (Scarpa's ascia), and behnd it is attached to the perinal bod and th posteror edge of the erineal membrane (Fig. 41). At the ides it is attahed to he ischopubic ami. Boh layer of suerficia fascia contribte to a median partition that crsses th scrotum and separate the testes from each other. Spermatic fascae: These three laers lie beneath the superficial fascia nd are derived from te three lyers of the anterior abdominal ll on ech side as prviously explaind. The xternal spermatc fasci is derved from the aponeurosi of the externa obliqu muscle the crmasteri fascia is derved fro the inernal olique mscle; ad, finaly, the interna spermtic fasia is drived from the fascia transversais. Th cremater muse is P.68

supplied by the genital branch of the enitofeoral nerve (se page 27). Te cremater musle can e made o contrct by sroking he skin on the medial aspect of he thigh. This s 314

snell calle the creasteric reflex. The afferet fibers of this reflex arc trael in the femorl branch of the genitofmoral nrve (L1 and 2), and the efferen motor erve fiers travel in the genitl branc of the genitofmoral nrve. Th functin of the cremater musle is t raise he tests and te scrotm upward for wamth and for proection agaist injuy. For esticulr temerature and fertility, see pge 169.

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Figure 4-23 Orgin, deelopmen, and fte of te procssus vainalis in the wo sexes. Note the dscent o the tetis ino the srotum ad the dscent of the vary ito the pelvis.

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Tunica vaginals (Fgs. 4-4, 4-5, and 421) This les withn the sermati fascia and coers the anterio, medial, and lateral srfaces f each estis. t is th lower xpanded part of the prcessus aginali; normaly, jus before birth, it becomes shut ff from the uppr part f the pocessus and the peritoneal cavity. The tunica vaginali is thu a closed sac, ivaginatd from ehind b the tstis.

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Lymph Dainage f the Scrotum Lmph fro the skn and fscia, icluding the tunca vagialis, dains ino the sperfical ingunal lymh nodes (Fig. 422).

Tests The testis is a firm, mobile rgan lying withn the crotum igs. 4-5 an 4-21. The lft tests usualy lies t a lowr level than the right. Each testis is surroundd by a ough fibrous sule, he tunia albugnea. xtendin from the inne surfac of the capsule is a seies of fibrous epta that divid the inerior of the organ into obules. Lyin within each lobule are one to tree coied seminiferous tubules. The tubules open int a netwrk of cannels called te rete testis Small fferent ductules conect th rete tstis to the uppr end o the epididymis (Fig. 4-1). Norma spermaogenesi can ocur only if the testes re at a temperaure lower than that of the abdominal cavity. Whn they re locaed in te scrotm, they are at a temperature abot 3°C lower than the abdominal temperture. Te contrl of teticular temperture in the scroum is nt fully understod, but the surace area of the scrotal skin ca be chaged reflexly b the contraction of the dartos nd cremster mucles. I is now recognied that the teticular veins i the sprmatic ord tha form the pampiniform pexus—ogether with th branchs of th testicular arteries, whch lie close t the vens—prbably asist in stabilizing the temperatre of he tests by a ountercrrent heat exchange mechnism. B this mans, te hot bood arrving in the artery from he abdoen lose heat t the bood ascnding to the abdomen within the eins.

Epididymis he epididymis is a frm struture lyng postrior to the testis, with the vas deferen lying on its medial side (Fig. 4-21) It has an expaded uppr end, he head, a bod, an a poined tail inferiorly. Laterally, a disinct grove lie betwee the tetis and the epididymis, which i lined ith th inner isceral layer of the tuica vagnalis ad is caled the inus of the epiidymis (Fig. -21) 316

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Clinical Noes Cliical Coditions Involving the Srotum ad Testis Varicocle A variccele is a condiion in which the veins f the pampiniform plexu are elngated nd dilaed. It s a comon disoder in adolescets and oung aults, wth most occurrig on th left sde. Ths is thught to be becase the ight teticular vein s the ow-presure infrior vea cava, whereas the lef vein s the eft real vein in whih the vnous prssure is higher. Rarely, malignat disese of te left idney etends aong the renal vin and locks te exit of the testicular vein. rapidl develoing lefsided ariocele should therefore alway lead oe to exmine th left kdney.

Malignant Tumor of he Tests A maignant tumor of the tests spreads upwa via the lymph vessels to the umbar (ara-aoric) lymh nodes at the evel of the first lumbar verteba. It i only lter, whn the tmor spreads locally to involve the tissues and skin of the scrtum, that the sperficil inguial lymp nodes re invoved. Te proces of te descent of the testis is shown in Figue 4-23. The estis my be subject to the folowing congenital anomalis:

Torion of he Testis Torsio of the testis s a rotation of the testis arou the sermatic cord wihin the scrotum It is ften asociated with an excessvely large tunic vaginais. Torion comonly ocurs in ctive oung men and children and is accmpanied by sevee pain. If not treated quickly the testicular artery ay be ocluded, followe by nerosis of the testis.

Proessus Vginalis Te formaion of he procssus vainalis nd its assage through the lowe part o the anterior abdominal wall wih the ormatio of the inguina canal in both sexes wer descried elsehere (ee page 65). Normall, the uper par become obliteated just before birth ad the lwer par remain as the tunica aginalis. The processus is subject t the folowing ommon cngenita anomales:   

It may persist artiall or in ts entiety as preformd hernil sac for an indirec inguinl herni (Fig. 424). It ay becom very mch narrwed, bu its lmen remins in ommuniction with the adominal cavity. Peritonal fluid accumates in it, foring a congenital hydrocee (Fi. 4-24). The per and lower eds of te procesus may become bliteraed, leaing a small intemediate cystic rea refrred to as an enysted hdrocele of the ord ig. 4-2).

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snell The unica vginalis is closly relaed to te front and sies of te testis It is therefore not surprising to find that iflammaton of te testi can cause an acumulatin of flid withn the unica vginalis This i referrd to siply as hydrocele (Fig. 4-25). Mos hydrocles are idiopatic. To emove excess fluid from the tunica vaginalis, a rocedur termed tapping a hydrocele, a fine trocar ad cannula are inserted trough te scrotl skin ig. 4-2). he follwing anatomic stuctures are traersed b the canula: sin, datos muscle and membranou layer f fasci (Colle' fasci), external spermatic fascia, cemasterc fasci, interal speratic facia, an parietal layer of the unica aginalis. The epididyis is a much coled tub nearly 20 ft ( m) log, embeded in connective tissue. The tube emerges from he tail of the epididyis as te vas deerens, which enters he speratic cod. The long length of he duct of the epididyms provies stoage spae for te spermtozoa ad allows them o mature A main functin of th epididmis is he absorption o fluid. Another function may be the addtion of substanes to te seminl fluid to noursh the maturing sperm.

Bloo Supply of the estis and Epidiymis he testcular atery is a branc of the abdominl aort. The testicular veins emerge from the testis an the epdidymis as a vnous nework, te pampinform plxus. This becomes educed o a sinle vein as it acends tough the inguial cana. The rght tesicular vein drains into he infeior ven cava, and the left ven s the lef renal vin.

Lymph Drainage of te Testi and Epdidymis The lymph vesels (Fig 4-22) ascnd in the spermaic cord and end in the ymph noes on te side f the orta (lmbar or para-aoric) nods at th level f the frst lumbar vertebra (ie., on he tranpyloric plane). This is to be xpected because during evelopmnt the testis ha migratd from igh up on the osterio abdominal wall, down though th inguinl canal and ito the scrotum, dragging its blod suppl and lyph vessls afte it. P.170

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Fgure 4-4 Comon conenital nomalis of th procesus vaginalis. A. Congnital hdrocele B. Ecysted ydrocel of the cord. C. Prefrmed henial sac for indirect inuinal hrnia.

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Figure 4-25 The tuica vaginalis distended with flid (hydrocele). lso shon are he varius anatmic layrs travrsed by a troca and cannula when a hydrcele is tapped.

Emryologi Notes Development of he Tests The mle sex hromosome causes the genital ridge to screte tstosterne and nduces he deveopment f the testis and the oter intenal and externa organs of reprduction. he sex cords of the genital rdge become separated frm the celomic pithelim by th prolifration f the mesenchyme (Fig. 4-26). he oute part o the meenchyme condenses to form a dens fibrou layer, the tunca albuginea. The sex cords become Uhaped and form he semiiferous ubules. The ree end of the tubules form th straigh tubule, whch one another in te mediatinum

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snell tstis to become he rete estis. The pimordia sex cels in the semiiferous tubules form the spermatgonia, and the sex cod cells form th Sertoli cells. The msenchym in the developng gona makes up the conective tissue nd fibrus sept. The inerstitil cells, which are ready screting testostrone, ae also ormed of mesenchyme. Th rete testis beomes caalized, and the tubules extend into th mesonephric tisue, whee they oin the remnants of the mesonephric tubules; th latter tubules become the effrent dutules of the testis. Th duct of the pididymis, he vas dferens, the sminal vesicle, and te ejacuatory dct are formed from the mesonehric dut (Fig. 26)

Descen of the Testis Th testis develops high u on the posterir abdomnal wal, and in late etal life it âœdescens― beind the peritoneum, draging its blood upply, erve suply, an lymphatic draige afte it (for detais, see pages 166). The proces of th descen of the testis i shown n Figure 4-23

Congenial Anomlies of the Tesis The testis may be sbject t the folowing ongenitl anomaies.   

Anterio inverson, n which the epiidymis ies antriorly nd the stis and the tuica vaginalis le posteiorly Polar nversio, in which te testi and epdidymis are completely inverted Imperfect descent (cyptorchdism): ncomplee descet (Fi. 4-27), in which te testi, althogh traveling down its nomal pat, fails to reah the foor of he scroum. It may be found withn the bdomen, within the ingunal canl, at te supericial inguinal ing, or high up in the scrotum Maldecent (Fig. 428), in whch the estis ravels own an abnorma path and fails to reac the srotum. t may be found in the sperficial fasc of the anterio abdomnal wal above he ingunal ligment, in front of the pubis, in the perneum, o in the thigh.

It is ncessary for the testes o leave the abdominal cavity bcause te tempeature tere retards the normal rocess f speratogeneis. If n incomletely descended testis s brougt down into th scrotu by surery befre pubety, it ill develop and functio normaly. A madescendd testi, althogh often develong normally, i suscepible to traumatc injur and, fr this rason, hould b placed in the crotum. Many auhoritie believ that te incience of tumor frmation is greaer in tstes tht have ot desended ito the scrotum. The appndix of the tesis ad the apendix o the epdidymis are embryoogic renants fund at the upper poles of thes organ that ay becoe cysti. The apendix of the testis is erived rom the paramesonephric ducts, and the appendi of the epididyis is a remnant of th mesonehric tubules. P.12

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Figure 4-26 The foration of the tstis and the ducts of te testis.

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Figur 4-27 Four degrees o incompete desent of he tests. 1 In the abdominal cavit close o the deep ingual ring. 2. n the iguinal anal. 3. At he superficial inguinal ring. 4. In he uppe part o scrotu.

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Labia Mjora The abia maora are prominet, hair-bearin folds f skin formed y the elargemet of te genital swelings in the feus. (I the mae, the enital welling fuse i the miline to form th scrotm.) Witin the labia ae a lare amoun of adipose tissue and the teminal srands o the rond ligaents of the uteus. (Fo furthe detais see pge 367.)

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Fiure 4-2 Four types f maldecent of the tetis. 1. In th superfcial facia of he anteior abdminal wll, aboe the sperficil inguial ring 2. A the rot of te penis 3. n the perineum. 4. I the thigh.

Structure of the Posterior Abdominal all Te posterior abominal wall is ormed i the miline by the fve lumbr verterae and their itervertbral dics and aterall by th 12th rbs, the upper prt of te bony elvis (Fig. 4-2), he psoa muscle, the qadratus lumboru muscle, and te aponeroses f origi of the transvesus abdminis mscles. he iliaus musces lie in the pper pat of th bony plvis.

Lumbar Vertebre The boy of each vetebra (Fg. 4-3) i massiv and kiney shaed, and it has to bear he greaer part of the body weght. Th fifth lumbar vertebra articulaes with the bas of th sacrum at the lumbosacal t. The inerverteral discs Fig. 4-3) in the lumbar regon are hicker han in ther reions of the vertebral column. hey are wedge saped an are reponsibl for th normal posteror concvity in the cuvature f the vrtebral column n the umbar rgion (lrdosis) For a ull desription of the tructur of th lumbar vertebrae and the intervertebra discs, see pags 855 and 858.

Twefth Pai of Rib

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snell The ris are dscribed on page 47. It hould b noted that th head o the 12h rib hs a single fact for aticulaton with the boy of th 12th toracic ertebra. The anterior ed is poted and has a small cstal catilage, which is embeddd in the musculature of the anterior abdominal wall. n many eople i is so hort that it fils to rotrude beyond the latral borer of te erectr spinae muscl on the back.

Ilium The ilium, togethe with te ischim and pbis, forms the hip bone (Fig. 432); they met one aother a the actabulum The meial surace of the ilium is divied into two pats .174

by th arcuat line. Abov this lne is a concav surfac called the ilic fossa below his lie is a lattene surfac that is continuous with the meial surfaces f the pubis and ischium. It should be nted tha the aruate line of te ilium forms he posterior part of th iliopecineal ine, and the ectinea line forms the anerior part of the iliopectineal ine. Th iliopetineal line runs forward and demarcates the flse fro the true pelvis. For urther etails n the sructure of the ip bone see page 316.

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Figure 4-29 Costl margi and bones of the abdoen.

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Figue 4-30 Fifth lumbar ertebra.

Muscle of the Posterir Abdomnal Wal Psoas Major The poas musle* arises fom the roots o the trnsverse processs, the sides of the vetebral bodies, and the intervetebral iscs, fom the 2th thoacic to the 5th lumbar vertebre (Fig. 4-33. The fibers run downwrd and ateraly and lave the abdomen to ente the thgh by assing ehind te inguial ligaent. Th muscle is inseted int the lsser trchanter of the emur. The psoas is encloed in a fibrou sheat that i derive from te lumba fascia The shath is hickene above to form the medal arcuate ligaent.  

Nerve supply: This muscle s suppled by te lumba plexus Acion: The psas flexs the tigh at he hip oint on the truk, or i the thgh is fixed, t flexe the trnk on te thigh as in itting p from lying positio.

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Figur 4-31 Sagital secton of te lumbar part of the vetebral olumn sowing nterverebral dscs and ligamens.

linica Notes Psoas Fscia an Tuberclosis Te psoas fascia overs te anteror surface of the psoas muscle and can influence the irectio taken by a tuberculous absces. Tuberulous dsease o the thracolumar regin of th verteral colmn resuts in te destrction of the vrtebral bodies, with pssible xtensio of pus lateraly under the psos fasci (Fig. 4-34). From there, the pus tacks donward, ollowin the corse of he psoa muscle, and appears as a sweling in he uppe part o the thgh belo the iguinal igament It may be mistken for a femorl herni.

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Figre 4-3 Internal apect of the riht hip one.

Quadrtus Lumorum Th quadraus lumbrum is flat, uadrilaeral-shped mucle tha lies alongside the vetebral olumn. t arise below rom th iliolubar ligment, te adjoiing par of the iliac cest, an the ips of he tranverse pocesses of the lower lumbar vertebrae Fig. 4-3). The fibrs run upward nd medilly and are insrted ino the lwer boder of he 12th rib and the trasverse rocesse of the upper fur lumar vertbrae. he anteior surace of he musce is covered by lumbar fascia, which i thickeed abov to form the lateral aruate liament and beow to frm the iiolumbar ligament. 

Nerve supply: This muscle s suppled by te lumba plexus P.17



Action: It fxes or epresse the 12h rib uring rspiratin (see pge 102) and aterally flexes the vertebral column to the sae side.

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Figur 4-33 Muscle and boes formng the osterio abdomial wall

Transvesus Abdominis Te transersus adominis muscle s fully deidoub on pae 152.

Iiacus The liacus uscle i fan shped and arises from th upper art of he ilia fossa Figs. 432 ad 4-33). Its fibers oin th latera side o the psas tendn to be insertd into the leser trocanter o the fmur. Th combind muscls are oten reerred to as the liopsoas.

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Figure 4-34 Case o advancd tuberculous dsease o the thracolumar regin of the verebral column. A psoas ascess i presen, and sellings occur i the rght gron above and belw the rght inuinal lgament.

 

erve suply: This mscle is supplie by the femoral nerve, branch of the umbar pexus. ction: The iiopsoas flexes he thig on the trunk at the hip t, or if the thigh is fixd, it fexes th trunk on the tigh.

Th posteror part of the iaphram (Fi. 4-33) alo forms part of the postrior abdominal wall. I is desribed o page 7. A sumary of the musles of he postrior abominal P.177

wll, ther nerve supply, and teir acton is given in Tble 4-2. Table -2 Mscles of the Posterior Abdominl Wall

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Name of Mscle Origi

Insrtion

Nerve Supply

Actin

Psas

Transverse processes, bodies, and intrvertebal disc of 12t thoracic and ive lumar verebrae

Wit iliacu into esser tochante of femr

Lumbar pexus

Flees thig on trunk; if thigh is fixed, t flexe trunk n thig, as in sitting up from lying osition

Quadratus lumborum

Ilioumbar lgament, iliac crest, tps of transvere proceses of ower lumbar vetebrae

12th rib

Lumbr plexu

Fixes 2th rib duing insiration; depresses 12t rib duing fored expiation; aterally flexe vertebal colun same ide

Iliaus

Ilia fossa

Wth psoa into lesser trochante of femur

emoral erve

Flxes thih on trnk; if high is fixed, it flexs the tunk on he thig, as in sitting up fro lying osition

Fascial Linng of te Abdoinal Wals A mentined preiously, the abdominal walls are lined by one ontinuos layer of connective issue that lies betwee the prietal eritonem and te muscles (Fig 4-35). It is contnuous elow wih a siilar facial laer lining the elvic alls. I is cusomary t name he fasca accoring to he structure it overles. For example the diphragmaic fasca coers th undersrface o the diaphragm the transversalis fasca lnes the transvrsus abominis, the psos fasci covrs the soas muscle, the quadraus lumbrum fasia overs te quadrtus lumorum, ad the iiaca fascia covers he iliaus muscle.

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snell The adominal blood ad lymp vessels lie within this fascial lining, wheras the rincipal nerves lie outside the fascia. This act is mportan in the understanding of the femoral seath (Fi. 4-35). Tis is smply a downwar prolonation o the facial lning around the femorl vessels and lmphatic, for aout 1.5 in. (4 m) into the thgh, behind the inguina ligamet. Because the femoral nerve les outide the fascia enveloe, it hs no shath (se page 52). In certain reas of the abdminal wll, th fascia linin perfors partcularly importnt funcions. nferior to the evel o the anerior sperior liac spnes, th posteror wall of the rectus sheath is devod of mscular poneuroes (Fig. 4-10 and 413) nd is frmed by the fascia trasversalis and eritonem only (see pag 154.

Embrylogic Ntes evelopent of he Abdoinal Wal Following egmentaion of he mesderm, te laterl mesodrm (see page 37) splts into a somaic and splancnic layer assoiated wth ectoerm and entoderm, respctively (Fig. 4-36). The mucles of the antrior adominal wall are derivd from he somtopleurc mesodrm and retain heir semental nnervaton from the aterior ami of he spinl nerve. Unlik the torax, te segmetal arrangemet becoms lost ue to he absece of rbs, and the meenchyme fuses to form large seets of muscle The retus abdminis rtains indications of ts segmntal orgin, as seen by the preence of the tedinous ntersecions. he somaopleuri mesodem becoms split tangentially to thre layers, which form th externl obliue, inernal oblique, and trasversus abdomins muscls. The nterio body wal finall closes in the idline at 3 moths, whn the ight an left sdes mee in th midlin and fuse. The line of fusion of the esenchyme forms the liea alba and on either ide of his, te rects muscls come to lie ithin teir recus sheahs.

Develoment of the Umblical Crd and the Umblicus As th tail ld of e embro develps, the embryonc attachment of the bdy stak to th caudal end of the embyonic dsc coes to le on th anterir surfae of th embryo close o the remains of the olk sac (Fig. 4-37). The amion an chorio now fue, so tat the mnion encloses the bod stalk and th yolk sc with heir blod vessls to frm the tubular umbilicl cord The meenchyma core o the cod forms the lose connective tissue called Wharton' jelly. Embdded in this ae the rmains f the ylk sac, the vitlline dct, the remain of th allanois, an the umilical blood vssels. The umilical vessels consist of two arterie that crry dexygenaed bloo from te fetu to the chorion (later the plaenta). The two umbilicl veins convey xygenatd blood from th placena to he fetu. The right vein soon isappeas (Fi. 4-37). The umilical ord is twiste tortuus struture tht measres abot 0.75 n. (2 c) in dimeter. It increases in length until, at the nd of pegnancy it is bout 20 in. (5 cm) log—that is, bout th same lngth as the chld.

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snell At the midpoin between the anterior uperior iliac spine ad the smphysis pubis, the spematic crd pierces the fascia transvesalis t form he deep inguina ring (Fig. 4-8). rom th margin of th ring, he fasca is continued over th cord a a tubuar sheah, the interna spermaic fasia (Fig. 4-4.

Peitonea Lining of the Abdominl Walls The walls of the bdomen are lind with parieta perioneum. his is thin serous membane cosisting of a laer of mesothelium resing on connective tisse. It is contiuous beow with the prietal peritonum linig the plvis (Fig. 4-35). For furthr detais, see ages 32 and 373.

erve Supply The central part of the diphragmtic pertoneum s suppied by the phrnic neres, an the periphera part i supplid by te lowe intercstal neves. Th peritoeum linng the anterior and osterir abdomnal wals is suplied segmentaly by itercostl and lumbar erves, hich alo supply the oerlying muscles and skn. P.178

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igure -35 Sagittal section of th abdome showin arrangment of the fascial an peritneal liings of walls. The femral sheth with its contained vessels is also shown. Note tht the fmoral nerve is devoid f a fascial seath.

P.179

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Fgure 4-6 Transvere sectins throgh the embryo t diffeent staes of evelopmnt showing the formatin of th abdomial wall and pertoneal cavity. . Te intrambryoni coelom in free communcation ith the extraembryonic coelom ouble-haded arows. B. he deveopment f the lteral flds of the embyo and he begining of the cloing off of the ntraemyonic oelom. C. Th latera folds of the mbryo fnally used in the midine and closing off te intrambryoni coelom or future perioneal cvity. Mst of he ventral mesentery wll brea down ad disapear.

P.180

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Figure 4-37 The formation of the ubilical cord. Nte the expansion of the amniotc cavit (arrows so tat the ord becmes covred wit amnion Note aso that the ubilical vessels have been redued to oe vein nd two arteries

Cliical Noes Tyig the Crd

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snell At birh, the ord is ied off close to the umilicus. About in. (5 cm) of cord is left between he umbilicus ad the igature since piece f intestine may be preent as an umbiical henia in the remains of the xtraembyonic celom. Ater application of the ligature the umilical essels onstric and thombose. Later, the stum of the cord is shed an the umilical car tisue becoes retacted and assumes the shape of he umbilicus, or nave.

Paent Urahus The urachus is the emains of the allantos of the fetus and nomally prsists s a fibous cord that uns fro the apx of the bladder to the umbilcus. Ocasionaly, the avity o the allantois persits, and urine psses frm the badder trough te umbilcus. In newbors, it uually rveals itself when a congenital uethral obstrucion is resent. More ofen, it emains undiscovred unt old age, when enlargeent of he protate may obstruct the urethra (ig. 4-3).

itelloitestinal Duct he vitelline duct in te early embryo connect the dveloping gut t the yok sac. ormally, as deelopmen proceeds, the duct is obliteraed, sevrs its onnectin with he smal intestne, an disappars. Prsistene of te vitelointestnal duct can rsult in an umblical ecal fitula (ig. 4-3). I the dut remais as a fbrous band, a lop of bwel can become rapped round i, causig intestinal obstruction (Fig. 4-38)

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Figure 438 Ubilicus and som common congenial defets.

Meckel's dverticulum is a congenial anomly representing a persitent potion of the vitellointstinal duct. It occurs in 2% of patient (Fig. 438), is located abot 2 ft 61 cm) rom th ileocolic juntion, ad is abut 2 i. (5 c) long. It can ecome ucerate or caue intesinal ostructon.

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Umbilical Vssel Caheterization The umbilicl cord s surronded by the feal membane, mnion, nd contins Whaton's elly. mbedded in this jelly are the remains of the vitellontestinal duc and th allantis, and the sinle umilical ein and the tw umbilial arteies (Fig. 4-39) The vin is a larger thin-walled vesel and is locaed at the 12 o'cloc positin when facing te umbilicus; the two arteries, wich lie adjacent to one nother nd are ocated t the 4 and 8 oclock osition when fcing th umbilius, are smaller and thick walle.

Figue 4-39 Cathterizaton of te umbilcal blod vesses. Arrangement of the sngle ubilical vein and

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the two umbilicl arteres in te umbilcal cord and the paths aken by the cateter in the umilical vein and the umbilical tery.

Indicatins for mbilica Arter Cathetrizatio  

nistraton of fluids o blood for resscitatin purpoes rteria blood as and lood prssure monitorng. The umbilical arteies may be cannlated ost easly durig the irst fw hours after brth, bu they ay be cnnulate up to 6 days after delivery.

Anatmy of Pocedure One of the small, thik-walled arteies is dentifed in the Whaton's jlly in the umilical stump. ecause the umblical rteries are branches o the internal liac areries i the pevis, te catheter is introdced and advancd slowy in th direcion of he fet. The atheter can be insertd for aout 2.5 in. ( cm) i a preature ifant and 4.75 n. (12 m) in full-term infant. Th course of th cathetr can be confrmed on a radiograph ad is as follows: (a) umbilical artey (direted dowward ino the elvis), (b) intrnal iiac arery (acte turn into ths arte), and (c) comon iliac arter and the aort.

Anatom of Comlications      

Cateter peforate arteril wall at a pint whre the artery urns downward toward he pelis at te anteior abdminal all. Ctheter enters he thinwalled wider ubilical vein istead o the tick-waled smaler artery. Catheter eters th thin-wlled prsistent urchus (urine is returned into catheter) Vasspasm of the mbilica and the iliac arterie occurs, causig blanching of the le. Perforaton of arteries distal o the umbilica artery occurs for exmple, the ilia arteres or ven the aorta. Othe compliations nclude hrombosis, embli, and infectin of th umbilcal stup.

Indcations for Umbilical ein Cateterizaion  

stratio of fluds or bood for resusctation urposes Excange tansfusins. The umbilial vein may be cannulated up o 7 day after irth.

Anaomy of rocedur The umilical ein is located in the ord stup at t 12 o'lock poition (ig. 4-3), as descibed previousl, and i easily recognzed becuse of ts thin wall nd large lumen The catheter is advnced getly and is dircted tward the head, because the vei runs n the fee margin of te falcform liament t te ducts venoss at th porta epatis. The caheter my be adanced aout 2 i. (5 cm in a fll-term infant The curse of the caheter may be cnfirmed by radiography and is s folows: (a the ubilical vein, () the dctus vnosus, nd (c) he infrior vena cava (4 to 475 in. 10 to 1 cm]).

Anatoy of th Complications of Umbilical Vein Cathterizaton 341

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atheter may peforate the venous wall. This is most liely to ccur wre the vein tuns craially a the abominal all. Other compliations nclude iver nerosis, hemorrhage, and infectio.

bdomina Hernia A herni is the protruson of prt of te abdomnal conents beond the normal onfines of the abdominl wall Fig. 4-0). It conssts of three parts: th sac, te contents of he sac, and the coerngs of the ac. The ernal sac is a ouc (dverticulum) of peritonem ad ha a neck and a body. The hernial ontnts ay onsist of any srucure foun wihin the abdominal cavity and may vary fro a small piece of omentum to a large viscus such as the kidney. The herial covering are formed fro the layrs f the abdomial wall through whch the hernial ac es. bdominal herniae ar of the folloing comon type:    

nguinal (indiret or diect) Femoral Umbilicl (congnital or acquied) Epigstric

Figur 4-40 Diffeent pars of a hernia.

 

Sparatio of the recti abdomiis Inciional

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Hernia of the linea smilunars (Spielian hrnia) Lumbar (Petit' triangl hernia) Intrna

Indirect Inguinal erna The idirect iguinal hernia s the mot commo fom of hernia nd s blieed o be congental in rigin (Fig. 4-41A). The hernal ac s the remains of the processus vagialis (a outpoching f peritneum tat in te fetus is respnsible or the formatin of th inguinl canal [see page 165]). It follows that the sac entes the iguinal anal though th deep inguinal ring lateral to the infrior eigastrc vessls (Fig. 4-41). It may xtend prt of he way along te canal or the full lngth, a far s the sperficial ingunal rin. If te procesus vagnalis hs unergone no oblteratio, then the heria is cmplete nd extends through te supeficial nguinal ring don into he scrtum or abium majus. Under tese cirumstancs the neck of he herial sac lies at the dep ingunal rng lateal to he infrior epigastri vessel, and he body of the sac resdes in he inguinal canal and scroum (or ase o labium majus). An ndirect inguina hernia is about 20 tims more common n males than in females and nerly one third ae bilateral. It is more common n the rght (nomally, he right processus vaginlis beomes obiterate after he left the riht testis descends later than the left) It is ost comon in children and youn adults. Te indirct ingunal heria can e summarized as follows:     

It is the remans of the procssus vginalis and theefore i congental in rigin. It i more common than a diect inginal henia. It is much more ommon in males han females. It is mor common on the rght side. It is most comon in childre and yong adults.

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Figure 4-41 A. ndirect inguina hernia B. irect iguinal ernia. ote tha the nek of the indirect inguinal hernia lies lateral to the inferior epigasric arery, an the neck of he diret ingunal heria lies medial to the inferior epigastic arery.

  

The hernal sac nters the ingunal canal through the deep inuinal rng and ateral o the iferior pigastrc vessls. The neck of the sac is narrw. The hernial sac may extend hrough he supeficial inguina ring aove and medial to te pubic tubercle. (Feoral henia is ocated elow an latera to the pubic tbercle.) The hernial sac may extend own ino the srotum o labium majus.

irect Iguinal ernia Te direc inguinl herni makes p about 15% of all inuinal ernias. The sac of a drect hernia buges dirctly ateriorly throgh the osterio wall o the inguinal anal mdial t the inerior epigastric vessls (Fi. 4-41B). Bcause o the pesence f the srong cot tndon (combined tndons o inserton of he intenal oblque and transversus musces), ths herni is usally othing ore tha a generalized bulge; therefoe, the neck of the hernial sac is wide. Direct inguinal hernias are rre in wmen and most are bilatral. It is a disease of ld men with we abdomial musces. A direct ingunal hernia can e summaized as follows 

It is comon in od men wth weak abdomial musces and s rare in wome. 344

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The hernia sac bulges forard thrugh the posterir wall of the inguinal canal meial to the nferior epigasric vesels. Th neck f the hrnial sac is wie.

An inguial herna can b distinuished from a emoral hernia by the act tha the sa, as i emerges through the sperficil inginal rng, lie above nd medil to th pubic ubercl, wheras that of a emoral ernia lies below and lteral t the tuercle (Fig 4-42).

Feoral Hrnia The hernial sa descends through the emoral anal ithin te femoral sheah, creaing a emoral ernia. The femral sheath, wich is ully decribed n page 579 is a potrusio of the fascial enveope linng te abdomnal walls and surround the feoral essels nd lymatics r abou 1 in. 2.5 cm) below the ingunal ligamet (Fg. 4-4). Te femoal artey, a it entrs the high blow the inguina ligamnt, occupies he lateal compartmet of th sheath The feoral ven, wich lies on it medial side an is seprated fom it b a fibrus septm, occuies th intermdiate compartmnt. The lymph vssels, whic are separated from th vein y a fibrous setum, occupy the most edial cmpartmet. The emoral canal, the ompartmnt for he lymhatics, occupies the medial part o the seath. I is abut 0.5 n. (1.3 cm) long, and its uper opening is refrred to as the femoal rin. he femoal septm, wich is condesation f extraperitoeal tissue, plgs the pening f the femoral ing.

Figure 4-42 Relation of inguinal and femoral hernial acs to the pubic tubecle.

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snell femoral herni is mor common in womn than n men (possiby becase of a wider pevis and femora canal). Th hernial sac es own the femoral canal, pushig the femoral septum before it On escaping hrough he lowr end, t expans to form a swlling i the pper pat of the thigh deep to the dee fascia (Fig. 4-43. With further expansin, the ernial sac may turn upard to ross th anterior surfae of the inginal lgament The nck of he sac lways les below and lteral t the puic tubercle (Fig. 442), which erves t distinguish it from an inginal hernia. he nec of the sac is narrow nd lies at the femoral ring. he ring is relted aneriorly to te inguial ligment, psteriorly to te pectieal ligament and the ubis, mdially to the harp fre edge f the lacunar lgament, and laterally o the fmoral vein. Beause of the prsence f these anatoic strutures the nek of th sac is unable to expnd. One an abominal iscus hs d throuh the nck into the body of the sa, it ma be difficult o push t up an retur it to he abdminal cvity (irrducible hernia) Furtermore, after straining or coughing a piec of bowl may b force throuh the nck and ts blood vesses may b compresed by the femoral ring, seriousl impairng its blood upply (strangulate hernia). A femral hernia is dangerus disase and should alwys e treed surically. A femral hernia can be summrized s follos:    

I is a protusion f abdominal paietal pritoneu down trough he femoal canl to form the ernial sac. It is ore comon in omen thn in mn. The eck of the herial sa lies blow and lateal to te pubi tuberce. The neck o the henial sac lies at the femora ring ad at tat poit is reated aneriorly to the inguina ligament, poteriorly to th pectinal ligaent and the pubis, aterall to the femora vein, and medially to the shrp free edge o the lcunar ligaent

mbilical Hernie Congenital umilical ernia, or xomphas (ompalocele), is cused b a failre of prt of he midut to return to the abdominal cavty fro the exraembryonic colom duing fetl life. The henial sc and is relatonship o the umbilical cord are sown in Figure 4-44. Acquired nfantil umbilical heria is a mall hernia tht sometmes occrs in cildren and is aused by a wakness in the car of he umblicus i the inea alb (Fig. -44) Most become smller and disapear wihout tratment as the abdomina cavity enlarge. Acquird umbilical ernia f aduts is mor correcly referred to as a parumbilial herna. he herial sac does not protrde through the umbilicl scar, but through th linea alba in the regon of he umblicus (Fg. 4-44). araumbiical heniae grdually ncrease in size nd hang dwnwrd. Th neck f the sc may e narro, but te body f the sc often contais coil of smal and arge inestine nd omntum. araumbiical herniae are muh more common n wome than i men.

Epiastric ernia Epgastric hernia occurs trough the widet part f the linea aba, anwhere btween the xiphid proess and the umblics. The hernia is usually small and sarts of as a sall prorusion f extraperitoeal fa beten the fbers of the linea alba During the fllowing months or years the fa is

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snell fored farter throgh the linea lba and eventually dags behind it small eritonal sac. The boy of te sac oten conains a small piece o greate omentm. It is common in midde-aged manual workers

igure -43 The femoral sheath as seen from below Arrow mergig from the femral cnal inicates he path taken y the fmoral hernial ac. Not relatons of the femoral rin.

Separation f the Rcti Abdminis Separtion of the recti abdoinis occurs in elderl multiprous women with weak adomina uscles (Fig. 4-44). n this onditio, the aponeuoses foming th rectu sheath become excessvely sretched. When he patint cougs or srains, he rect separte widey, and large enial sac, conaining

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snell abdominal viscra, blges foward between te medial margins of the recti. his can be corected b wearin a suitable abominal belt.

Icisionl Hernia A postoperativ incisinal hernia is ost liely to occur n patiets in whom it was necesary t cut on of the segmental nerves suppying the musles of he anterior abdominal wall; postoperative woud infecion with death (necrosis) of th abdominal muculatur is als a comon caus. The nck of te sac i usuall larg, and adhesion and strangulaion of its content are rae compicatios. In vry obese indviduals the etent of the abominal wall wakness s ofte difficlt to ssess.

Herna of te Lina Semilnaris (pigelin Herni) The uncommon hernia of the lina semilnaris ocurs hrough he aponurosis of the ransverus abdominis jst lateal to the latral edge of th rectus sheath. It usuall occurs just elow te levl of th umbilius. Th neck o the sac is narow, so that adesion nd stragulation of its contens are cmmon coplications.

Lumba Hernia he lumbr herni occurs hrough the lumar triagle an is rae. The lumbar trangle Petit's triagle) is a weak area in the poserior part of the abdminal wll. It is bouded aneriorly by the posteror marin of te external oblique musle, poseriorl by the anterir border of th latissmus dori musc, and nferiorly by the ilia crest. The flor of te triangle i formd by te interal oblque and the transversus abdominis mucles. The eck of the heria is sually large, and the ncidenc of strngulaton low.

Iternal ernia Occasionaly, a lop of itestine enters a peritneal ecess (.g., th lesser sac or the dudenal receses) and becomes strangulated t the eges of he reces (see page 24).

Abdominal tab Wouds Abdominal tab wouds may or may ot pentrate the parital peritoneum and iolate he pertoneal avity and consequently may o may no signifcantly amage te abdominal vicera. The strctures n the arious layers through which an abdominal stab wound enetrats depend on the anatomi locatin.

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Fgure 4-4 A. Conenital mbilicl herni. B. Infantile umbilical henia. C. Paraumbilica hernia. D. Epigastic hernia. E Separation of rcti adomini.

Laterl to th rectus sheath re the ollowig: skin fatty lyer of uperfical fascia, memranous layer o superfcial fascia, thin layer of dee fascia exteral obliue musce or aoneurosis, intrnal olique mscle o aponeuosis, tansverss abdominis usce or aponurosis, fascia transvrsalis extraeritoneal conective issue often ftty), and parital pertoneum. Anteror to the rects sheat are te followng: ski, fatty layer of superficial fascia membranous layer of sperficil fasca, thin layer f deep fascia, anterio wall of rectus sheath rectu abdomiis

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snell musle with segmentl nerve and epgastric vessels lying ehind te muscle, postrior wal of retus sheth, facia trnsversais, extaperitneal cnnectiv tissue (oftn ftty), an prietal eritoneum. n the idline re the ollowing: skin fatty layer o supericial fscia, embranos layer of suprficial fascia, thin lyer of deep fasca, fbrous lnea alb, fasci transversalis extraeritonel connetive tisue (oten faty), and parieta peritneum. In an bdomina stab wund, wahing ou the peitoneal cavity ith saine soltion (peritoneal lavae) an be ued to deterine wheher any dmage to viscra o blood essels as occurred.

Abominal unshot ounds unshot wounds are much more seious than stab wounds; in mot patiets, th peritoeal caity has been entered and significnt viscral damge has ensued.

Surgical Inisions The length and directon of srgical incisios throgh the anterior abdominal wal to epose th underying vicera are largly govened by he posiion and directon of te nerve of the abdominal wal, the irection of the muscle ibers, nd the rrangemnt of he aponuroses forming he rects sheat. Idealy, the incisio shoul be mad in the directin of th lines f cleavge in te skin o that a hairlne scar is prduced. The sureon usally ha to cmpromis, placig the sfety of the patent first and the cosmeic reslt secod. Incisins that necessitate the divisin of one of the main egmental nerves lying wthin th abdomial wall result n paralysis of part o the anterior abdomina musculture an a segmnt of he rectus abdominis. Te conseuent wekness o the abominal musculaure caues an usightly bulgin forward of the abdominl wall and viseroptoss; extrme case may reuire a urgical belt fr supprt. If he incsion ca be mad in the line of the musle fibrs or aoneurotc fiber as eac layer s travesed, on closing the incision the fibes fall ack int positin and unction normall. Icisions throuh the rctus shath are widely used, rovided that te rects abdoinis mucle an its neve supply are ept inact. On closure of the incisios, the nterior and poserior alls o the seath ar suturd separtely, nd the ectus muscle srings ack int position betwen the uture lines. Te reult is very trong repair, ith minmum intrferenc with unction Th followng inciions ar commoly used 

Paraedian incision: This may e supraumbilicl, for exposur of the upper prt of he abominal cavity, or infraumbiical, or the ower abomen ad pelvs. In extensie operaions in which large exposure is reqired, te inciion can run th full lngth of the recus sheth. The anterio wall f the rectus sheath is exposed and incsed abot 1 in. (2.5 c) from the midine. Th medial edge of the incsion is dissected medially, freeing he anteior wal of the sheath from the tendinous inersectins of te rectu muscle. The rctus abominis uscle i retracted laterally with ts nere suppl intact, an the osterio wall of the heath s exposd. The posterir wall s then ncised, togeter with the fasia tranversali and the peritneum. The wound is clsed in ayers.

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Prarects incison: The anerior wll of te rects sheat is incsed medally an parallel to the lateal margin f the ectus mscle. Te rectu is freed and retractd medially, exposing the sgmenta nerves enterin its posterior srface. f the oening into the abdomial caviy is to be smal, thes nerves may be etracte upward and dowward. Te posteior wal of th sheat is the incisd, as i the paamedian incison. The great isadvantage of tis inciion is hat the opening is smal, and ny longtudinal extension requirs that ne or mre segmntal neves to the recus abdominis be divided with resultnt postoperative rects musce weaknss. Mdline icision: Ths incison is mde throgh the inea ala. The ascia tansverslis, te extraperitoneal connetive tisue, an the peitoneum are the incised. It is easier o perfom above the umblicus bcause te linea alba i wider in that egion. It is a rapid metod of gining etrance to the bdomen nd has he obvis advanage tha it doe not daage mucles or their nerve and blood spplies. Midline incisio has th additional adntage tat it my be converted into a Tshaped ncision for grater exosure. he anteior and posterir walls of the ctus seath are then cut acros transvrsely, nd the ectus mscle is retraced laterally. Transectus icision: Th techniue of mking and closing of this incisio is the same as that used in the paramedian incision, xcept tat the ectus abdominis muscle is incised longitudinaly and not retacted laterally from the midline. This incision has te great disadvatage of sectionng the nerve spply to that pat of the muscle that les medil to the muscle incisin. Trnsverse incisio: his can be mad above or belo the umilicus and ca be smll or o larg that it extends from lank to flank. It can be made through the rctus shath and the retus abdminis uscles nd though th obliqu and tansverss abdominis mucles laerally. It is are to amage mre tha one segmental nerve s that postopertive abominal eakness is minimal. Te incison give good xposure and is well tlerated by the patien. Closue of th wound s made n layers. It i unnecesary to suture the cut ens of th rectus muscles, provied that the sheaths are careflly repired. Musce spliting, or McBuney's icision: Thi is chifly used for cecostomy and appndectom. It gies a limited exposure oly, and should ny doub arise bout th diagnois, an infraumbilical right paamedian incisio should be used instead

A oblique skin incisin is made in te righ iliac region bout 2 n. (5 c) abov and meial to the anerior sperior iliac sine. Th externl and internal oblique and trasversus muscles are icised or split in the ine of their fbers ad retrated to expose the fasia tranversalis and he perioneum. The later are ow incised an the abominal cavity s opend. The ncision is closed in ayers, ith no postoperative weakness. 

Abominothoracic ncision Tis is used to xpose te lower end of the esohagus, s, for example in esphagogastric resection for cacinoma f this region. An uppe oblique or paramedin abdomnal inision i extendd upwar and laterall into te seventh, eigth, or inth intercostl space the cstal arh is transecte, and te diaphagm is incised Wide eposure of the upper bdomen nd thorx is thn obtaine by the use of a rb-spreding reractor

n competion o the oeration, the diphragm is repaired with nonabsorbble sutres, the costa margin is recnstructed, and the abdminal ad thorcic wouds are losed.

aracetesis o the Abdomen Paracenesis of the abdmen may be necssary t withdrw excessive cllectins of pritoneal fluid as in scites econday to crrhosis of the liver o malignnt ascts secondary to advaced ovrian cncer.

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snell Uder a local ansthetic a neede or catheter s inseted thrugh the anterir abdomnal wal. The uderlyin coils of intstine ae not dmaged bcause tey are obile ad are pshed awy by te cannua.

Figure 4-45 Parcentesi of the abdominal caviy in miline (1) and lateraly (2)

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Figur 4-46 Peritoneal laage. A. The two comon sits used n this rocedure. Note the postions o the sperior nd infeior epigastric arterie in the rectus sheath. B. Coss secion of he anterior abdominal wall in the midine. Note the tructures pierced by the atheter. C. Cross section f the anterior abdomnal wal just lteral o the mbilicu. Note he strctures ierced y the ctheter The retus mucle has been retractd laterlly.

I the cnnula i insered in te flank (Fig. 4-45) latera to the inferior epigatric atery an above the deep circumfex artry, it will pas throuh the fllowing: skin, superficial fasca, dep fasci (very thin), poneurois or mscle of external obliqe, intrnal oblique mucle, trnsversu abdminis mscle, fscia tansversalis, etrapeitoneal connective tisue (faty), and parietal peritoneum.

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Anatomy of Perioneal Lvage Pritonea lavage is used to samle the ntraperitoneal space for evience of damage o viscra and lood vssels. t is generally emloyed a a diagostic tchnique in certin cases of blnt abdminal tauma. I nontrama situtions, eritonal lavae has ben use to cofirm th diagnois of acute pacreatits and primary peitoniis, to crret hypothemia, an to conuct dilysis. The patient is placed in the supine osition and th urinay bladdr is emptied by cathetrizatio. In smll children the ladder s an abdomial organ (see page 38); in aduls, the ull bldder my rise ut of te pelvi and rach as igh as he umbilicus (ee page 30). The stomach i emptie by a nsogastrc tube ecause distened stoach may extend to the nterior abdominal wall The skn is esthetzed an a 2.25-in. (3-c) vertical incsion is made.

Miline Incision echniqu The ollowin anatomc strucures ae penetated, i order, to reac the paretal peritoeum (Fig. 4-6): skin, atty layer of superficial fasca, membanous layer of superfcial facia, thin layer o deep fscia, lnea alb, fasci transersalis extraperioneal ft, and arietal peritonum.

Paraumbilcal Incsion Technique The folowing aatomic tructurs are enetrted, in order, to reac the paietal peritoneum (Fig 4-46): skin, fatt layer of supeficial ascia, embranos laye of suerficia fasci, thin layer o deep ascia, nterior wal of recus sheath, he rects abdominis mucle is etractd, postrior wall of te rects sheat, fasca transersalis extrapritoneal fat, nd parital peritoneu. t is important that all the small blood vessls in the superficial fascia e secured, because bleeding into the peritonal cavity mght prouce a flse-postive reult. These vesels are the terminal branches of th superfcial ad deep pigasric arteries ad vein.

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In the midline techniue, the incision or tocar may iss the linea alba, enter the rectus sheat, travese the vasculr rectu abdomiis muscle and encounte branchs of the epigastric vssels. leeding from tis soure could produce a false-positve resut. Perfration of the ut by te scalel or tocar Perforaion of the mesnteric lood ssels r vesses on th posteror abdoinal wal or plvic wals Prforatin of a ull blader Woud infectio

Endosopic Surgery Endoscopic surgery on the gallbldder, ile ducs, and the appendix hs becom a comon proedure. t involes th ae of te endocope ino the pritonea cavity throug small incisios in th anteior abominal wall. Te anatoic structures taversed by the instrumnts are similar to those

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snell numerated for pritonea lavage Great care mut be taen to prserve te integity of he segmntal nerves as they couse down from te costa margin to supply the abominal usculatre. The advantages of thi surgical technique are that th anatoic and hysioloic featres of he anteior abdominal wall are isrupte nly minmally ad, consquently, convalecence i brief. The grat disavantage are tht the srgical ield is small an the surgeon i limite in the extent f the oeration (Fig. 4-47.

Figure 4-47 Inguinl canal anatomy as viewed during laparosopic exloratio of the peritoneal caviy. A. The noal anatmy of te inguial reion from withi the peitoneal cavity. lack arow idicates the cloed deep inguina ring; hite arow, the inferio epigasric vessels. B. An inirect inguinal hernia. Crved blck arro indicates the mouth f the hrnial sc; white arrow, the nferior epigastric vessels. (Coutesy of N.S. Azick.)

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Radiographic Anatomy or a deailed dscussio, see pae 282.

Surface Anatomy Surface Landmrks of he Abdoinal Wal

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Xiphoid Process Te xiphod proces is the thin crtilaginous lowe part f the sernum. t is eaily palated in the deression where the cost margin meet i the uper part of the nterior abdomina wall (Figs. 4-1 an 4-12. The xihisternl junction is identified by feeling the lowr edge f the bdy of te sternum, and it lies pposite the bod of the ninth thoracic vertebr.

Cotal Marin The cotal marin is te curved lower argin o the thoracic wall and s forme in frot by th cartilges of he 7th, 8th, 9h, and 10th ribs (Figs. -11 d 4-12) and behind b the catilages of the 1th and 12th ris. The ostal margin reaches it lowest level a the 10h costa cartilage, which lies pposite the bod of the third lmbar vetebra. he 12th rib may be short and dfficult to palpte.

Ilac Cres Te iliac crest cn be fet along its entre lengh and ends in front at te anteror superior ilic spine (Figs 4-11 and 4-12) and behind at the psterior superio iliac spine ig. 4-49). Is highet point lies oposite te body f the frth lumbar vertbra. About in. (5 cm) postrior to the antrior suerior iiac spie, the uter margin projects to form th tubercle of the crest (Fg. 4-12). Th tuberce lies t the lvel of the body of the fifth lumbar vertebra.

Pubic Tubercle he pubi tuberce is an importat surfae landmrk. It may be identified as a sall protuberan along the supeior surace of the pubs (Figs. 4-3, -12, and 4-32).

Sympysis Puis The syphysis pubis is the cartilaginous t that lies in the midline between the bodes of te pubic bones (Fig. 4-11). It is felt as a soid struture beeath th skin i the midline at the lower extremity of the anteior abdominal wall. The pubic crest is the nam given o the rdge on he supeior surace of the pubic bones mdial to the pubc tuberle (Fig. 4-32.

Inguinl Ligamnt The iguinal igament lies bneath a skin crase in the grin. It s the rlled-uner infeior margin of the aponeurosis of he extrnal obique muscle (igs. 4-2, 4-6, and 4-11. It i attachd lateraly to te anterior superior iliac spine and curve downward and edially, to be attached to he pubi tuberce.

Superfiial Inguinal Rng

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snell The superfiial inginal rig is a trianguar aperure in the apoeurosis of the xterna obliqu muscle and is situate above and medal to the pubi tuberce (Figs. 4-2, 4-3, 4-8, and -12). In te adult male, the margins of the ing ca be felt by invaginating the ki of th upper art of he scroum with the tip of he litle finer. The soft tuular seratic cod cn be fet emergng from the rin and descending over r medial o the pbic tubrcle ino the srotum (Fig. 4-). alpate he speratic cod in te upper part of the scrotum beween th finge and thmb and ote the presenc of a frm cordike stucture in its osterio part clled the vas deerens (Figs 4-5 and 4-21). I the feale, th superfcial iguinal ing is smaller and dificult t palpate; it tansmit the rond ligaent of he uters.

Scrotum The scrotum is a puch of kin and fascia containng the testes, the epdidymids, and he lower ends f the sermatic cords. The skin of the scrotu is wrinkled and is coered wih spars hairs. The blateral origin f the srotum i indicaed by the presnce of dark ine in he midlne, caled the scrotal raphe, alon the lie of fuion. The testis on ach sid is a frm ovoid body urroundd on is laterl, anteior, and media surfacs by th two lyers of the tunica vaginalis (Fig. 421). The tetis shold therfore lie free nd not ethered to the kin or subcutaneous tissue. Psterior to the testis s an elongated structue, the epididyis (Fg. 4-21). It has an enlarge upper nd calld the head, a body, and a narro lower end, th tail The vs deferens emerges fro the tal and acends mdial to the eididymi to ener the permati cord a the uper end of the scrotu.

Linea lba The lnea lba is a vertially runing firous bnd that extens from he sympysis pubis to he xiphid proess and lies in the miline (Fig. 4-3). is fomed by he fusin of te aponeroses of the mscles of the anterior abdomina wall ad is represened on te surfae by a light mdian grove (Fis. 4-11 and 412).

Umbilics The umilicus ies in he lina alba and is nconstat in psition. It is a puckere scar nd is te site f attacment of the umilical ord in he fetu.

Rectus Abdoinis The rectus abdomins muscls lie n eithe side of the linea ala (Fig. 4-11) and un verically n the adominal wall; they can be made prominet by aking th patien to raise the shoulders while in the upine psition without using te arms.

endinous Intersections of the ectus Adominis The tendinus intesectios are tree in number and run cross te rectu abdomiis muscle. In uscular individuals

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the can be palpated as trnsvers depresions a the lvel of he tip of te xiphoid pocess, t the umbilicus, and halway beteen the two (Fig. -11)

Lnea Smilunars The linea seilunari is th latera edge of the rectus adominis muscle and crses th costal margin at the ip of te ninth costa cartilge (Figs. 4-11 and 412) To acentuate the semilunar lines, the patient is ked to ie on he bac and raise the shoulders off te couch without using he arms To acomplish this, he patint s th rectus abdomins muscls so tat ther laterl edges stand out.

Abdomnal Lins and Panes Vrtical ines an horizotal plaes (Fig. 4-12) are commonl used t faciliate the description of the loation o diseaed strutures o the peforming of abdoinal prcedures

ertical Lines Eac verticl line right ad left) es hrough he midoint beween th anterior supeior ilic spine and the symphys pubis

Transpylori Plane The horizntal transpylorc plane es hrough he tip of the ninth cstal catilages on the wo side—that is, the point where the laterl margi of the rectus abdominis (line semilunaris) crosse the costal magin (Fig. 4-12). It ies at the levl of te body f the frst lumar vertbra. Ths plan e throug the pyorus o the stmach, te duodeojejunl juncton, th neck o the pancreas, and the hila of the kineys.

Subcostal Pla The horzontal ubcosta plane s te lowet point of the ostal margin on each side—tht is, e 10th costal artilag (Fig. -12). This pane lie at the level of the third lumbar vertbra.

Intrcristal Plane The intecristal plane psses aross the highest point on th iliac crests nd lies on the level o the boy of the fourth lumba verebra. his is ommonl used a a surfce landark whn perorming a lumbar spina tap (se pag 871.

Intetubercuar Plane The horzontal ntertubrcular lane jons the ubercles on the liac crsts (Fig 4-12) and lies at the level of the ifth lubar verebra.

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Adominal Quadrans It is ommon pactice o divide the abomen into quadrnts by sing a ertical and a hrizonta line tat intesect at the umbilicus (ig. 4-1). Te quadrnts are the upper right, upper lft, lower righ, and lower left. The tems epigstrium and peiumbilial re loosely used to indicte the rea belw the xphoid pocess ad abov the umilicus ad the aea aroud the ubilicus respecively.

Surace Lanmarks of the Abdominal iscera It must be emphasized hat the positios of mot of th abdomnal visera show indiviual varations s well s variaions in the sae perso at different ties. Posture and respiraion hav a proound inluence n the psition f viscera. The fllowing organs re more or less fixed, nd their surface marking are of clinica value.

Lier he liver lies uder covr of th lower ibs, an most o its buk lies on the riht sid (Fig. 448). In infants, untl about the end of the thid year, the lowr margi of the liver extens one o two finerbreadts below the costl margin (Fig. 4-8). n the adlt who i obese o has a wl-develoed right rectus bdominis muscle, te liver s not papable. I a thin dult, th lower dge of the liver my be fet a fingrbreadth below th costal mrgin. I is most easily flt when he patiet inspirs deeply and the diaphragm contract and puses down he liver

Gallblader Te fundus of the gllbladde lies oposite th tip of the righ ninth costal cartlage—tat is, were the ateral ege of th right rctus abdminis mucle crosses the cotal margn (Fig. 4-4).

Spleen The speen is situated in the left upper qudrant an lies unr cover f the 9t, 10th, nd 11th ibs (Fig. 448). ts long xis corrsponds t that of the 10th ib, and n the adlt it des not nrmally poject forward in font of te midaxilary lin. In inants, th lower pole f the speen may just be felt (Fig. 48).

Panceas Th pancrea lies acoss the tanspyloc plane. The hea lies beow and t the right, the nck lies n the plne, and te body nd tail ie above and to th left.

idneys The righ kidney ies at a slightly lower leel than he left kidney (bcause of the bulk of the right lobe of the lver), an the loer pole an be palated in he right lumbar rgion at he end f deep inspiratn in a erson with poorly developed abdominal muscles. Each dney movs about in. (2.

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snell cm) in vertica directin during full repiratory movement of the daphragm. The norml left kidney, wch is hiher tha the rigt kidney, is not palpable. On the anteior abdoinal wal the hilm of eac kidney lies on te transploric plne, abou three fngerbreaths from the midine (Fig. 449). O the bac, the kineys exend from the 12th horacic pine to he third lumbar sine, an the hii are opposite te first umbar vetebra (Fig. 4-49) P.193

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Figur 4-48 Surface markings of the fundus of te gallbldder, spleen, and iver. n a youn child, the lower margin of the norml liver nd the lwer pol of the ormal spleen can b palpate. In a thin adul the lowr margi of the ormal lier may jst be felt at the end of dp inspiation.

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Stomach The cardiosophagea junctio lie about tree fingerbreadths below a to the left of he xiphsternal junction (the esohagus pirces the diaphram at the level o the 10t thoraci vertebra). The pylors lie on the transpylric plan just to the rigt of the midline The lesser curvature lies on a cured line oining te cardiosophagel junctin and th pylorus. The greater curvatur has n extremly variable posiion in te umbilial region or below

Duodeum (Firs Part) The dudenum lis on the ranspyloic plane about for fingerreadths to the rigt of the midline.

Cecum The cecu is situted in t right ower quadrant. It s often distende with gas and givs a resoant sound when perussed. I can be alpated hrough te anterir abdominal wall. P.194

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Figur 4-49 A. Surfae anatom of the idneys a ureter on the aterior adominal wall. Noe the

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reationship of the lum of ech kidne to the transpylric plan. . Surace anaty of the kidneys on the psterior adominal all.

Appendix he appenix lies n the right lower quadrant. The base of the ppendix s situate one thid of the way up te line, oining he anteror superir ilac spine to the ubilicus McBurneys point) The poition of the free end of te appendx is variable.

Ascendg Colon The asending clon exteds upwar from the cecum on the latral side of the rght vertical line and disapears undr the riht costl margin. It can b palpate through he anteror abdomnal wall

Trsverse lon he transerse colo extends across te abdome, occuping the mbilical egion. I arches ownward ith its concaity dircted upwrd. Becase it has a mesentry, its osition s variabe.

escendin Colon The desending clon extends downwrd from e left costal magin on te latera side of the left vertical line. In the left lower qudrant it curves mdially an downwar to becoe contiuous wit the sigoid colon. The desending clon has smaller diameter than the ascendin colon ad can be palpated hrough te anteror abdomnal wall.

Uinary Bldder and Pregnant Uterus The ull blader and pegnant uterus can be palpad throuh the loer part f the anerior abdominal wal above he sympysis pubs (see page 330).

Arta The aorta lies in the midline f the abomen and bifurcaes below into the right and left comon iliac arteries opposite the fouth lumbar vertebra€”that i, on the intercrital plan. The plsations of the arta can be easily alpated hrough te upper art of he anterior abdomial wall ust to te left o the midine.

xternal liac Artery Th pulsatins of ths artery can be flt as it es under the nguinal igament o become continuos with te femora artery. It can b located at a poit halfwa between the anteror supeior ilia spine ad the symphysis pis.

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linical roblem Slving Sudy the ollowing case hisories an select he best answer to he questons follwing the. An obese 40-year-old wman was een in he emergncy depatment coplaining of a seere pain over th right shoulder an in her ight sid and back below te shouldr blade. She said that she had expeienced th pain on several occasion before nd that when she ae fatty oods it eemed to make the pain wore. Ultraound demnstrated the presece of gllstones Her contion was diagnose as chollithiasis, and the pain ws attribted to glstone colic. 1. The symptoms and igns dislayed by this patent can e explaied by th followin statemets excep which? (a) The fundus of the gallblader lies gainst te anterir abdomial wall ext to te tip of the righ ninth ctal cartilage. (b The paetal pertoneum i this ara is inervated y the 10h and 11t intercotal nervs, which give ris to referred pain in the 1th and 1th dermaomes on the side ad back. (c) The parital perioneum on the cental part f the unersurfac of the diaphragm s supplid by the phrenic erve. (d) he spina segmentl nerves within te phreni nerve are C3, C4, and C5. (e) The ain was referred to the soulder along the supraclaviular neres (C3 ad C4). Vie Answer 1. B. The prietal pritoneum in the region of te fundus of the allbladdr is innervated b the eighth and nith interostal neves, whch give rise to reerred pan in the eighth an ninth toracic ermatome on the ide and ack. An -year-ol boy was itted to the hspital wth a temerature f 101°, a furre tongue, and pai in the rght lowe quadran. On exmination the skin on the rght lowe quadran was tener to th touch, and the adominal uscles wre contrcted and rigid. A diagnosi of acue appendicitis was made. 2. The ymptoms nd signs displaye by this patient an be exlained b the following sttements xcept whch? (a) An cutely iflamed apendix poduces a inflammtion of te peritoeal coat covering it. b) Shoul the infammatory process spread, or exampe, if th appendix should rpture, e parietal peritneum woud become involved. (c) The arietal eritoneu, the abominal mscles, ad the ovrlying sin are spplied by the same segmenta spinal erves. (d) The segmental neres suppling the ight lower quadrat of the abdomina wall ar T7, T8, and T9.

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snell (e) The pain in the ight lowr quadrnt and he regional contration of he abdomnal musces are a attempt by the body to kep the inlamed apendix imobile so hat the inflammaory procss remais localized. View Anser . D. The segmenta nerves upplying the righ lower qudrant of the abdoinal wal are T11 T12, and L1. A orkman engaged i demolising a bulding lot his baance and fell astide a grder on he floor below. On examinaion, he was found o have xtensive swelling of his peineum, srotum, ad penis. He was uable to urinate ormally, assing oly a few drops of blood-stined urine. The lwer part of the aterior adominal wll was aso swolln, but hs thighs were noral. . The syptoms an signs dsplayed y this ptient ca be explaned by te followng stateents ext which () The paient's fll ruptued the uethra in the perieum. (b) When the atient atempted to micturate, the urin extravaated benath Colls' fasci. (c) The urine ed ver the crotum ad penis nder the membranos layer f superficial fasia. (d) The uine ed upward eneath e membranous laye of supeficial fscia on he anteror abdomnal wall (e) The urne could ot exten posteriorly becase of th attachmnt of Coles' fasia to th tip of he coccy. f) The uine did ot exten into th thigh ecause of the attachment of the membanous laer of suerficial fascia o the fascia lata, just belw the inuinal liament. Vw Answe 3. E. The rine could not extend postriorly beause of he attacment of the Colles' fasci to the posterior dge of te perinel membrae. 45-yea-old womn was shpping in a liquor store whn an arm robbery took plce. A shot-out ocurred ad a bulle ricocheed off te wall nd enterd her lef side. Frtunatel, the buet did t enter he peitoneal avity. One year ater, in ddition o diminihed skin sensatin over th left lubar regin and umilicus, se notice a bulgng forwad of the left side of her nterior dominal wall. 4. Te symptos and sins displyed by this patien can be xplained by the fllowing tatements except wich? (a) Te bullet ut the 9h and 10h intercstal ners ust belo the cosal margi on the eft sid (b) Th diminishd skin snsation as cause by the oss of te sensor nerve spply to he 9th ad 10th toracic dematomes. (c) Potions of the obliqe, transersus, ad rectus abdomini muscles on the lft side were paralzed.

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snell (d) Atrphy of te pyramialis musle resuled in loss of suprt to th abdominl viscer, which hen saggd forward View Answer 4. D. The pyraidalis mcle (if present) is innervted by te 12th toracic nerve. A 9-week-od boy wa itte to the ospital ith a swelling in he righ groin tat extened down nto the upper part of the srotum. Wen he cried, the welling nlarged. On careful palpatin it was possible to redue the sie of the swelling and thi procedure was accmpanied by a gurling noie. 5. The symoms and signs dislayed by this patent can e explained by th followin statemets excep which? (a) The sweling was ituated bove and medial to the pubi tubercle on the ight sid. (b) The chil had a rght indiect ingunal herna. (c) The processu vaginals in its upper pat had failed to beome oblierated bfore birh. (d The herial sac n an indect inginal hernia emerge from th superfiial inguial ring (e) he supericial inuinal rig lies aove and edial to the pubic tubercle (f) Te contens of the hernial ac consited only of the geater omntum. View Anser . F. Th content of this hernial ac inclued coils of small ntestine which were respnsible f the gurling noies that ccurred as the henia was educed. A 75-yar-old mn with cronic brnchitis oticed tat a bulge was deeloping n his let groin. On examiation, a elongated swellin was sen above he media end of he left inguinal lgament. hen the patient coughed, the sweling enlaged but id not dscend into the srotum. Th patient had weak abdomina muscles 6 The symtoms and signs displayed by this paent can e explaied by th followig statemnts excep which? (a The inginal sweling was a direct inguinal hernia. () The case of th hernia s weak bdominal uscles. () The henial sac was wide and in drect communication with the peritonel cavity (d) rise in intra-abdominal pssure o coughing caused te hernia swelling to expan. (e) The sweling occured lateal to th inferio epigastic artery Vie Answer

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snell 6. E. The swelling occrs media to the nferior pigastri artery. A 40-yer-old woan noticd a painul swellng in her right grin after helping her husbnd move ome heav furnitue. On examination, a small tender selling ws noted n the right groin. 7. Th symptom and sigs displaed by ths patient can be eplained y the folowing satements except which? (a) Th excessiv exertio caused rise in intra-abominal pessure. b) A herial sac ormed of parietal peritonem was foced downward. (c) The perioneum wa forced hrough te right femral canal. (d) The patient ad a rigt-sided emoral hrnia. (e) he neck f a femoal hernil sac is situated below and medial t the pubc tuberce. View Anwer 7. E. Th neck of femoral hernial ac is siuated beow and laeral to he pubic tubercle 55-yea-old man was ited to te hospit with a large, had, fixed intra-bdominal mass. On examinaton of th abdomen the mass was situted on te transploric plne. The nguinal ymph nods were ormal. . The syptoms an signs diplayed b this paient can be explaned by te following stateents ext which? (a Radioloic examiation of the stomch showed nothing bnormal. (b) The right tesicle was enlarged and was uch hardr than nrmal. (c A diagnsis of mlignant disease o the righ testi was mad. (d) Th malignat tumor hd metastsized t the lumar lymph nodes lyng on th transpyoric plae on the posterir abdomial wall, which is the norma lymphatc drainae of the testis. (e In malinant disase of the testis the suprficial iguinal lmph node only beome invoved if te tumor spreads t involve the scroal skin. (f) The normal tstis is tethered o the sk of the crotum. View Aswer 8. F. he normal testis i freely obile wihin the crotum ad is not tethered o the sucutaneou tissue r skin. A 25year-old man invoved in prchasing drugs wa knifed i the abdmen in he left pper quarant. On examination in the emergenc departmnt, it as diffilt to deermine wether th knife ha penetrated into he perioneal caity. It as decide to do a midline eritoneal lavage elow the umblicus to see if tere was ny free bood in te peritoneal caviy.

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snell 9. he folloing layes of tisue were enetrate by the rocar and cannula o enter he peritneal cavty excep which? a) Skin (b) Faty and mebranous yers of uperficial fascia c) Rectu sheath d rectus abdominis muscle (d) Deep facia (e Fascia ransverslis f) Extraeritoneal tissue ad parietl peritoeum Viw Answer 9. . The liea alba ies in te midlin; the retus sheath lies laeral to he linea alba. A 20-year-ld socce player was accdentally kicked on the left side of her ches. On retrning to the lockr room se said sh felt fant and ollapsed to the foor. On eaminatio in the mergency departmet, she as found o be in ypovolemc shock. She had endernes and musce rigidty in th left uper quadrnt of her abdomen. She also had exteme local tendernes over hr left 1th rib i the midxillary ine. 10. he symptms and sns displayed by this patient can be explaine by the ollowing statemens except which? (a) Radiolog reveale a fractured left 10th rib. (b) The sleen was severely ruised ad the blolass="A> (c) Latr in the locker rom the sule of the splen gave way and the blood esaped int the pertoneal cvity. (d) Bood does not irriate the arietal eritoneu. (e) Stimlation o the senory nerves suppying the arietal eritoneu was resonsible r the extreme tederness f the let upper quadrant o the abdmen. f) The mscles foming the anterior abdomina wall in that regin were rflexly simulated producig muscle rigidity. View Aswer 10. D. lood is ery irritating to the parieal peritneum. P96

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Reiew Queions Mutiple-Chice Questions Select te best aswer for ach quesion. 1. The following tructure form th walls o the inginal can except hich? (a) The cont tdon b) The aoneurosi of the xternal blique mscle (c) Te internl obliqu muscle (d) Te lacuna ligamen (e) The fasca transversalis Viw Answer 1. 2. The follwing staements cncerning the walls of the inguinal cnal are orrect ecept whih? () The inuinal liament is made tene by fleing the ip t. (b) The contractng internal oblique muscle reinforce the antrior wal of the anal in ront of he weak deep ingual ring. c) The srong conoint tenon reinfrces the posterio wall of the canal behind he weak uperficil inguinl ring.

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snell (d) Contracton of th arching fibers o the inernal obique and transverss abdomiis muscls lowers the roof of the anal so tat the cnal is pacticall obliterted. (e) Aftr birth, as the rsult of growth, he deep nguinal ing move away frm the suerficial ring so that the anal becmes obliqe and th two rins no longer lie oposite on another. View nswer 2. A 3. In the female, the iguinal cnal contins the ollowing structures except which? a) Ilioinguinal nrve () Remnan of the rocessus vaginali (c Round lgament o the uteus () Inferir epigasric artey (e Lymph vssels frm the funus of th uterus View Anwer 3. D 4. The ollowing statemens concering the permatic cord are orrect ecept whih? (a) It extends from the deep inguinal ring to he scrotm. (b) It contains the testcular arery. (c) It s covere by five layers o spermatc fascia d) It cotains th pampiniform plexs. e) It cotains lyph vessel that drin the tstis. iew Answr 4 C. The spermati cord is overed y three lyers of permatic fascia, which ar derived from the three laers of te anterior abdominl wall. The extenal spertic fasca is frm the apneurosis of the eternal blique mcle, the cremasteic fasci is derived from te internl obliqe muscle, and the nternal permatic fascia is formed fom the ascia trnsversals. 5. The followin structues are pesent in the ingunal canal in the mle excep which? (a Interna spermatc fascia (b) enital banch of he genitfemoral nerve (c) Teticular vessels

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snell (d) Dee circumfex iliac artery (e) Iioinguinl nerve Viw Answer 5. D. The dep circuflex ilic artery is a brach of th external iliac atery and runs upwrd and lterally oward th anterio superior iliac sine away from the nguinal anal. 6 The folowing sttements oncernin the cont tendn are corect ext which (a) I is attaed to th pubic cest and he pectieal line. (b) It i formed y the fion of he aponeroses of the transversus adominis nd internal oblique muscles. (c) t is attched medally to he linea alba. (d) t is coninuous with the inguinal ligament. (e) It may bulge forward in a irect inguinal hernia. iew Answr 6D 7. The fllowing tatement concernng an inirect inuinal henia are orrect ecept whih? () It is he most ommon fom of abdminal hernia. (b) Te neck o the herial sac ies medil to the inferior epigastric artery. (c) Th sac is he remais of the processu vaginals. (d) The hernial ac can etend int the scrtum. (e) A the suprficial nguinal ing, the hernial ac lies ove and medial to the pubic tuberce. View Aswer 7. B 8. T a needle ito te cavit of the unica vainalis the scotum, te folloing strutures hae to be pierced xcept wich? (a) Ski (b) Drtos musle and olles' fascia (c) Tnica albginea (d) Intenal speratic fascia () Cremaseric fasia

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snell View Aswer 8. C 9. The followin statemets are crrect cocerning he muscls formin the posterior abominal wll excep which? (a) The psoas ajor mule has a fascial sheath that extends down into the thgh as fa as the lesser tochanter of the femur. (b) he quadrtus lumbrum is cvered anteriorly b fascia hat form the latral arcute ligamnt. (c) The liacus mscle is nnervate by the emoral neve. (d) he transersus abominis muscle fors part of the postrior abdominal wal. (e) The diahragm do not conribute t the musculatur on the posterior abdomina wall. Vie Answer 9. E atching uestions Match each strcture lited belo with te region on the aterior adominal all in wich it i located Each lttered aswer may be used ore than once. 10 Appendix 11. allbladdr 12. Cecum 13. Left colic flxure a) Right upper qudrant (b) Lef lower quadrant (c) Riht lower quadrant (d) Nne of th above Vie Answer 10. 11. A 12. C 13. D Matc each stucture lsted belw with te structre with ich it i most clsely assciated.

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snell 14. Extrnal spematic facia 5. Round ligament of the uerus 16. Crmasteric fascia 17. Inernal sprmatic fascia 18. Deep inguinal ring a) Internal oblique (b Fascia ransverslis (c) Guberaculum (d) Extenal obliue (e None of the abov iew Answr 1. D 15. C 16. 17. B 18. B Mach each tructure listed blow with the grou of lymp nodes that drain t. 19. Testis 20. Skin of anteror abdomnal wall below th level o the umblicus 2. Epididmis 2 Skin of the scrtum () Anterir axillay lymph odes (b) Par-aortic r lumbar lymph noes c) Supericial inuinal lyph nodes (d) External iliac noes (e None o the above View Anser

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snell 9. B 20. C 21. B 22. ead the ase histries and select te best aswer to e questin followng them. A 30-yea-old man was seen in the eergency epartmen with a stab woun in the rght inguinal region. 23. Which of the follwing neres supples the sin of the inguinal region? (a) The 11th thoacic nere (b The 10t thoraci nerve (c) Th 12th thoacic nere (d The firt lumbar nerve (e) The femoral erve View nswer 23. D The firt lumbar nerve, rpresente by the liohypogastric and ilioinginal nerves, supply the skn just ove the inguinal ligament and the symphysis pubis. Imediately after dlivery, t was noed that 7.5-lb ale neonae had a arge swlling on the anteior abdoinal wal. The swlling cosisted of a large sac, th walls o which were translcent and soft. The umbilical cor was attched to he apex f the sac, and the umbilical arteries and vn ran within its walls. 24. Te followng stateents conerning tis case are probbly correct except wich? (a) O closer xaminatin it was possible to see wthin the sac coil of small intestin and the lower magin of te liver. b) As th baby cred and sarted to swallow ir, the ac became larger. (c) Failre of th formatin of adeuate hed and tail folds o the embyonic dic causes a defect in the nterior bdominal wall in he umbilcal regin. (d) The defet in the anterior abdominal wall is filled ith thin amnion, which forms the wal of the sac. (e) Th conditin is knon as exophalos o omphaloele. iew Answr

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snell 2. C. Th defect s caused by a faiure of te formaton of adquate lteral fods in th umbilicl region which is filled i by amnin only. During te first 4 hours after birt, the wal of the sac becmes dry nd opaqu and may rupture, causing visceraton. Bacteria at oce gain ntrance o the peitoneal vity, prducing pritonitis. The sa of amnin should be surgially excsed as son as posible ater birt and the contained viscer returned to the bdominal cavity. The defect in the anterior abdomina wall shuld then be closed.

Footnoes *A cmmon frutration or medial studets is th inabiliy to obsrve these rings as opening. One mst rememer that e internl spermaic fasci is attahed to th margin of the eep ingunal ring and the xternal permatic fascia i attachd to the margins f the suerficial inguinal ing so tat the dges of he rings cannot b observed externaly. Compae this rrangemet with t openings for the fingers seen insde a gloe with the absece of opnings fo the finers when the glov is viewd from the outsi. *The psos minor s a smal muscle with a lng tendo that lis anterior to the soas majr. It is unimporant and s absent in 40% o patient. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

6. 5. The Abdomen: Part II - The Abdominal Cavity A 15year-old boy complaining o pain in the lowe right prt of th anterio abdominl wall ws seen b a physiian. On examinaton, he wa found t have a emperature of 11°F (3.3°C). H had a furred tongue and was extreely tendr in the lower riht quadant. The bdominal muscles n that aea were und to be firm (rigid on palpation and bcame mor spastic when inceased prssure ws applied (guarding). A dignosis f acute ppendicits was mae. Inflmmation f the apendix intially i a localied disese givin rise to pain tha is ofte referred to the ubilicus. Later, he inflamatory process spads to ivolve th peritonum cvering te appendx, produing a loalized pritoniti. If the appendi ruptures, further spread curs and a more generalized peritonitis is roduced. Inflammaion of te peritoeum linig the aterior adominal wll (parital perioneum) uses pain and refex spas of the nterior bdominal muscles. This can be explaned by the fact tat the prietal pritoneum the abdoinal musles, and the ovelying skn are suplied by the same segmenta nerves. This is a protectve mechaism to kep that rea of t abdomen at rest o that he inflamatory pocess remins loclized. The understandi of the ymptoms nd signs of appedicitis epends o having a working knowledg of the anatomy of the appndix, inluding is nerve upply, bood suppy, and elationsips with other abominal structures

Chater Objetives 

The bdominal cavity cntains mny vital organs, includin the gastrointestial tract liver, iliary dcts, pacreas, spleen, an parts o the uriary system. These tructure are clsely 377

snell paced withi the abdminal caity, and therefor disease of one an easil involve nother. astrointstinal tact inflmmation ad bleedng, malinant disese, and enetratig trauma to the adomen ar just soe of the problems facing he physiian. Emegency prblems inolving te urinar system are commo and may present iverse smptoms rnging frm excruiating pain to faure to void urine. Within te abdomen also lie the orta and its braches, th inferio vena caa and it tributaies, and the important poral vein. Th purpose of this hapter i to give the stunt an unerstandig of the significnt anato relativ to cliical prolems. Exminers ca ask man good qustions regarding tis regin.

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asic Anaomy eneral Arangemen of the Abdominal Viscera Lver Th liver is a large rgan tha occupie the uppr part o the abdminal caity (Figs. 5-1 and 5-). It lies almt entirely under over of he ribs nd costa cartilaes and etends acoss the epigastri region.

Gllbladde The llbladde is a per-shaped sac that is adhernt to te undersurface of he right lobe of the live; its blid end, o fundus project below the inferi border of the lier (Figs. 51 and 5-).

Esophgus T esophagus is a tubular stucture tat s the phaynx to te stomac. The esophagus perces the diaphrag slightl to the left of he midlie and after a shor course f about .5 in. (.25 cm) enters te stomac on its ight side. It is deeply placed, lying behin the lef lobe of the live (Fig. 5-1).

Smach The stomach is a diated par of the limentar canal btween th esophagus and the small intestine Fis. 5-1 and 5-2) It ocies the left uppr quadrat, epigatric, an umbilica regions and muh of it ies under cover of the ribs Its lon axis pases dowward and orward t the rigt and thn backwa and slightly upwrd. .204

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Fiure 5-1 Generl arrangment of bdominal viscera.

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Figure 5- Abominal ogans in itu. Note that the greater omentum angs down in front of th small ad large ntestine.

Small Inestine The smal intestne is divided int three rgions: dudenum, jjunum, ad ileum. The duodenum is he first part of he small intestin, and mos of it i deeply placed o the posrior abdminal wal. It is situated in the pigastri and umblical reions. It is a C-saped tub that extends rom the stomach round the head o the panreas to the ejunum (Fig 5-1). About hafway dow its lenth the sall intetine recives the bile and the panceatic ducs. The jejunu and ilem toether mesure about 20 ft (6 m) long the uppr two fiths of tis lengh make u the jejnum. The jejunum bgins at he duodeojejunal junctio, and th ileum eds at th ileocecl junctin (Fig. 5-1). The coils of jejunum ccupy th upper lft part f the abominal avity, wereas the ileum teds to ocupy the ower rigt part o the abominal cavity and the pelvic cavity (Fig. -3).

Lare Intestne

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snell Th large itestine s divide into th cecum, ppendix, ascending colon, ransvers colon, escendin colon, igmoid clon, retum, and anal canl (Fig. 5-1). The large intestine arches around and ecloses te coils f the small intesine (Fig. 53) and tends to be more ixed than the smal intestie. The cecm is a blind-ened sac tat projets downwrd in th right iiac region below the ileoccal juncion (Figs. 5-1 and 5-). The appendix is a wor-shaped ube that arises frm its meial side (Fg. 5-1. The ascending con extnds upwrd from he cecum to the iferior srface of the righ lobe of the livr, occupying the rght lowe and uppr quadras (Figs. 51 and 5-3). On raching te liver, it bends to the left, foring the ight colc flexur. he transverse colon crosse the abdmen in te umbilial regio from the right olic flxure to he left colic flxure (Figs. 5-1 an 53). I forms a wide U-saped cure. In th erect position, te lower part of he U ma extend down into he pelvi. The trnsverse olon, on reaching the regin of the spleen, ends dowward, forming the eft colc flexur to becoe the decending clon. The desceding coln extds from he left colic fleure to te pelvis below (Figs 5-1 ad -3). I occupie the lef upper ad lower quadrants The sigmod colon begins at the plvic inlt, where it is a cntinuatin of the descendig colon Fi. 51). It hangs down into the pevic caviy in the form of loop. I s te rectum in front of the scrum. he rectum occupies the postrior pa of the elvic caity (Fig. 51). t is continuous aove with he sigmoid colo and escends n front f the scrum to eave the pelvis b piercin the pelic floor Here, i become continuus with he anal anal in he perinum. P.205

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Figure 53 Abominal cntents ater the reater oentum has been reected upward. Cils of sall intestine occupy the central pa of the bdominal cavity, whereas scending transvese, and escendin parts o the coon are lcated at the perihery.

Panreas Te pancres is a sft, lobulated organ that stretches oliquely cross th posterir abdomial wall n the epiastric rgion (Fig. -4). t is sitated behind the stmach and extends rom the uodenum o the speen.

Splen The pleen is a soft mass of lyphatic tssue tha occupie the lef upper prt of th abdomen between he stomah and the diaphragm (Fig. 5-4). It ies alon the lon axis of the 10th left rib

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Kideys Th kidneys are two eddish bwn orgas situated high u on the osterior abdomina wall, oe on eac side of the vertbral coumn (Fig. 54). Th left kiney lies slightl higher han the ight (beause the left lobe of the ver is maller tan the rght). Eah kidney gives ris to a urete that runs verically downward on the psoa muscle.

Suparenal Gands he supraenal glads are to yelloish orgns that ie on th upper poles of th kidneys (Fg. 5-4) on the posterio abdominl wall.

Peritoneum eneral Arangement The eritoneu is a thn serous membrane that lins the wals of th abdominal and pelic cavites and cothes th viscera (Fgs. 5-5 and 5-6. The peitoneum can be rearded as balloon against hich orgns are pessed frm outsid. The parieal peritneum lines the walls of he abdomnal and elvic caities, ad the viscral perioneum covers te organs The potntial spce betwen the paietal an viscerl layers which i in effet the inide spac of the balloon, i called the peritoneal cavity. In ales, tis is a closed cavty, but n female, there s communication wih the eterior trough th uterine tubes, te uterus and the vagina. P206

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Figue 5-4 Structures situatd on the posterio abdominl wall behind the tomach.

Beween the parietal peritoneum and th fascial ining o the abdminal an pelvic alls is layer o connectve tissu called the extrapeitoneal tssue; in the aea of th kidneys this tisue contans a lare amount of fat, hich s the kidneys. Th peritonal cavit is the argest cvity in the body ad is divded into two part: the greatr sac and the lesser sac (Fg. 5-5 and 5-6) The greater sac is th main copartment and exteds from he diaphagm down into the pelvis. Te esser sac is maller an lies beind the tomach. he greatr and leer sacs re in free commuication ith one nother trough an val window called the openig of the esser sa, or the epiploc forame (Figs. 55 and 5-7). The peritonem secretes a small amount o serous luid, the pritoneal fluid, which luricates he surfaes of th peritonem and alows free movement between he viscer.

Intrapritoneal and Retrperitonel Relatinships Th intrperitonel and retroperitoal ae used t describ the reltionship of varius organ to thei peritoeal coveing. An rgan is aid to b intrapetoneal when it is almost otally cvered wih viscerl peritoeum. The stomach, jejunum, ileum, nd splee are goo example of intraeritonel organs Retropritoneal organs le behind the perioneum an are onl partialy covered with vsceral

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snell ritoneum The pacreas and the asceding and descendng parts of the con are examples o retropeitoneal rgans. o organ, however, is actuay within the perioneal caity. An intrapertoneal organ, suc as the tomach, apears to be surronded by the perioneal caity, but t is covred with visceral peritonem and i attache to othe organs omenta.

Peritoneal Ligaments Pritoneal ligament are two-layered fols of pertoneum hat connct solid viscera to the abominal walls. The liver, fr exampe, is conected t the diahragm by the falciform ligament, the coronary ligamen, and the right and left tiangular ligament (Figs. 58 and 5-10).

Omnta Omenta are two-layerd folds f peritoeum that connect he stomah to anoher viscs. The greater omentum conects the greater urvature of the somach to the transverse colon (Fig. 52). I hangs dwn like n apron n front f the cols of th small testine nd is foded back on itsel to be atached t the traverse clon (Fig. 56). Te esser omntum suspends he lessr curvatre of th stomach from the issure o the liamentum venosum and the porta hepatis on the undersurace of te liver (Fg. 5-6). The P.20

gastrospenic ometum (igament) connects the stomach to th hilum o the splen (Fig. 5-).

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Figue 5-5 Transvere sections of the abdomen showing the arrangent of the peritneum. Th arow in B indicaes the psition o the opeing of te lesser sac. Thee sectios are viwed from below.

Meenteries Meseneries ar two-layred fold of perioneum cnnecting parts of the intetines to the postrior abdminal wal, for xample, he msentery of th small inestine, the trasverse msocolon, and te igmoid esocolon (Figs. 5- and 5-13).

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snell The peitoneal igaments omenta, and meseteries prmit blod, lymph vessels, and nervs to reah the vicera. The extent o the pertoneum ad the peitoneal avity sould be tudied i the tranverse an sagitt section of the abdomen een in Figues 5-5 and 5-6.

Pritoneal Pouches, Recesses Spaces, and Guttrs Lesse Sac Te lesser sac lies behind e stomah and the lesser omentum (Figs. 5-5, 5-, and 5-11). It extends pward as far as te diaphrgm and dwnward btween th layers f the grater P.20

omentm. The lft margin of the sc is fored by th spleen Fi. 5-11) and te gastroplenic oentum an splenicrenal liament. The right margin opens into the greaer sac (the main part of th peritonal caviy) throuh the openig of the lesser sc, or epploic foamen Fi. 5-7) The pening ito the lsser sac (epiploi foramen has the followin boundares (Fig. 5-):

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Figure 5-6 Sgittal sction of the femae abdome showing the arragement o the pertoneum.

   

Anterioly: Fee border of the lesser omntum, the bile du, the hepatic artery, and the portl vein (Fig. 5-11) Posterioly: Iferior vena cava Sueriorly: Caudae process of the audate le of th liver Inferiory: Firt part o the duoenum

Duodenal Recesses

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snell Clos to the uodenojejunal junction, thre may b four small pocketlike pouces of peitoneum called te uperior uodenal, inferior duodenal paraduoenal, and retrodudenal reesses (Fi. 5-12).

ecal Recsses olds of eritoneu close t the cecm produc three eritonea recesse called e superior ileocecal, the inferior ileoceca, and th retroceal receses (Fig. 5-3).

Intersigoid Recess The intersigoid reces is sitated at he apex f the inerted, Vshaped rot of th sigmoid mesocolo (Fig. -13); its mout opens dwnward.

Sbphrenic Spaces The right and left nterior ubphreni spaces lie beteen the iaphragm and th liver, n each sde of th falcifom ligame (Fig. 5-1). The riht posteior subprenic spce lie between the righ lobe of the live, P.209

the right kiney, and the righ colic fexure (Fig. 5-15) The right xtraperioneal spce lie between the layes of the coronar ligame and is therefore situated between he liver and the iaphragm (see page 27).

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Figure -7 Sgittal sction though the entrance nto the esser sa showing the imprtant stuctures hat form boundaris to the opening. (Note the arrow ing frm the grater sac through he epiplic foramn into he lesse sac.)

Paracoli Gutters The pracolic utters le on the lateral nd media sides o the ascnding an descendng colon, respecively (Figs. 5-5 ad -14). The suphrenic spaces ad the paacolic gtters ar cliniclly impotant becse they ay be sites for the collecion and movement of infeced peritneal flud (see page 213).

Nere Supply of the Pritoneum The paietal peitoneum is sesitive t pain, temperatur touch, and presure. The parietal peritonem linin the antrior abdminal wal is supplied by te lower six thorcic and irst lumar nerve—that s, the same nerves that innervate te overlyng muscls and skn. The cntral pat of the diaphragatic pertoneum i supplie by the hrenic nrves; peripherall, the diphragmatc peritoeum is spplied b the lower six toracic nrves. The parieta peritoneum in the pelvis is mainly supplied by the oturator erve, a ranch of the lumbr plexus

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snell The visceal peritneum is sensitve only o stretch and tearing and is not sesitive to touch, pressure, or temprature. t is suplied by autonomic fferent erves tat suppl the visera or ae travelng in th mesenteies. Ovrdistenton of a iscus leds to the sensation of pai The meenteries of the sall and arge intstines ae sensitve to mchanical stretching.

Fuctions o the Pertoneum The peritoneal fluid, whch is pae yellow and somehat visid, contins leukcytes. It is secrted by the peritonum and ensures hat the obile vicera glid easily n one anther. As a resul of the ovements of the daphragm and the abominal mscles, ogether ith the eristaltic movemens of the intestinl tract, the pertoneal fuid is not static. Experimetal evidnce has hown tha particate mattr introdced into the lowe part of the perioneal cvity reahes the ubphreni peritoneal spaces rapidly, whatever the postion of he body. It seems that intaperitoneal movemet of flud towar the diahragm is continuos (Fig. 5-1), and there it is quicky absorbd into the subpertoneal lmphatic apillaris. Ths can be explaine on the asis tha the are of pertoneum i extensie in the region of the diaragm and the respiratory ovements of the daphragm id lymph flow in he lymph vessels he peritneal covrings of the intetine ten to stic togethr in the presence of infecion. The greater mentum, wich is ept consantly on the move by the pristalsi of the neighborin intestnal trac, may ahere to ther peritoneal surfaces arund a fcus of ifection. In this anner, mny of th intrapeitoneal infectios are seaed off d remain localize. Th peritonal folds play an important part in suspendi the varous orgas within the perioneal caity and erve as a means f conveyng the blod vesses, lymphtics, an nerves o these rgans. Lrge amouts of fa are stoed in th peritonal ligaments and esenteris, and epecially large amunts can be found in the reatr omentm. P.210

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Figure 5-8 Lver as sen from n front (A), from above (B) and from behind (C. Note the posiion of te peritoeal reflctions, he bare reas, an the peritoneal ligaments

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igure 5- A pastinize specime of the liver as sen on i posteoinferio (visceal) surfce. The ortal vein has been transfed with white plastic and the infeior vena cava wit dark ble plasti. Outsid the lier, the istended biliary ucts and gallblader have een injeted wit yellow lastic and the hepatic arty with rd plasti. The lier was hen immesed in crrosive luid to emove th liver tssue. Noe the pofuse brnching o the poral vein its whie terminl branchs enter the portl canals etween te liver lobules; the dark lue triutaries f many o the heptic vein can als be seen

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Figue 5-10 Attachent of he lesse omentu to the stomach nd the psterior urface o the lir.

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Figur 5-11 Transvese sectin of the lesser sc showing the arrangement of the peritonum in the formaton of th lesser mentum, he gastrsplenic omentum, and the plenicornal ligaent. Arrw indictes the osition of the opening o the leser sac.

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Fiure 5-1 Peritoneal recesses, hich ma be presnt in th region of the uodenojjunal jnction. ote the resence of the inferior mesenteric vein in the perioneal fod, formig the paaduodena recess.

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Figure 513 Peitoneal ecesses arrows) in the rgion of he cecum and the recess reated to he sigmod mesocoon.

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Fgure 5-4 Normal direcion of flow of th peritonal fluid rom different pats of te peritoeal caviy to the subphreic space.

Cliical Notes The Peritoneum and Peritoneal Cavity Movent of eritonea Fluid The pritoneal cavit is divided into an uper prt within the adomen and lowe part in the pelis. Te abomina part is furthe subivide by the many pertonea refectios into important recsses nd saces, which, i tur, are contnued nto he paacolic gutters Fig. 5-1). The ttachent of the tranverse mesoolon ad th mesetery of the smal intestine to the posterio abdinal wall provides natural eritnea barrers that may hinder the moement of ifected peritonea flui fro the upper part o te lowr part of he peitoneal caity.

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snell It s intersting to note that when te patien is in he supin positio the rigt subphenic pertoneal sace and he pelvic cavit are th lowest reas of he peritoneal caity and the regon of te pelvic brim is he highet area (Fig. 5-15).

Perioneal Ifection Infction my gain etrance t the peitoneal avity hrough sveral rotes: frm the interor of th gastroitestinal tract ad gallbldder, though the anterior abdominal wall, ia the uerine tbes in fmales (gnococcal peritoniis in aults and pneumococal pertonitis n childrn occur hrough tis route, and frm the blood. Colection of infeced peritoneal fuid in oe of the ubphrenc spaces is oten accompanied y infecton of te pleura cavity It is cmmon to find a lcalized mpyema in a patient with a subphrenic abscess. It is believe that te infecton spreads fro the pertoneum to the peura vi the diaphragmatc lymph essels. A patien with a subphrenc abscs may complain o pain ovr the shulder. (his also holds tre for collectios of blod under he diaphagm, whih irritae the prietal diaphragmtic perioneum.) he skin f the shoulder i supplid by the supraclaicular nrves (C3 and 4), which hae the sae segmental origin as th phrenic nerve, wich suppies the peritonum in te center of the ndersurface of te diaphrgm. To avoid te accumulation of infeted fluid in the suphrenic spacs and to delay th absorption f toxins from inraperitoneal infection, it is commo nursin practice to sit a ptient u in bd with he bak at an angle of 45Â. In thi positio, the ifected pritonea fluid tnds to gavitate downard into the pevic caviy, where the rate of oxin absrptin is slo (Fig. 5-5).

Greaer Omentm Localzatin of Infction The great omentu is ofte referre to by the sureons as he abdomil policeman. The lwer and he right and left margins re free, and it mves abou the peritoneal cty in reponse to the perstaltic movements o the neihboring gut. In th first 2 years of life it s poorly develope and thu is less protective in a young child. Laer, howeer, i an acuely inflamed appenix, for xample, te inflamatory exdate causes the mentum t adhere o the appendix and wrap itself around the inected oran (Fi 5-16). By thi means, the infction is often localized t a small area of he peritoneal cavit, thus saing the atient fom a seriou diffuse perionitis.

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Figure 5-15 Diectin of flo of the peritonel fluid. 1. Normal flw upward to te subphenic spaes. 2. Fow of inflammory exuate in peritoitis. 3. The two sites whre iflammatoy exudate tens to collect when the patint is nrsed in the upine position . Accmulation of inflamatory xudate in the pelvs when te patien is nured in th incline position.

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Figre 5-16 A. Th norml greatr omentum. B The greter ometum wraped aroun an iflamed ppendix. C. he greaer omenum adheent to e base o a gastrc ulcer. One important fuction of th greate omentum s to attmpt to lmit the spread f intrapritoneal infectios

Greate Omentum as a Hernal Plug The greate omentum has been found to plug th neck of a hernial sac and prevent th entrance of coils of small intestine.

Geater Omentum in urgery Surgeons somtimes us the ometum to uttress n intestinal anastomosis or in th closur of a prforate gastric or duodnal ulce.

Torsion of the Geater Oentum The grater omtum may ndergo trsion, ad if extnsive, te blood upply to a part o it may e cut of, causin necrosi.

scites Ascites is essentially an excessie accumuation of peritoeal flui within the perioneal cvity. Asites ca occur econdary to hepatc cirrhois (porta venous congestin), malinant disease (e.g., caner of te ovary) or congstive heart failre (sysemic venus congetion). I a thin patient, s muc as 500 m has to accumulte beore ascite can e recognized cliicall. In obese individuals, a ar greater

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snell amount has to cllect before it an be detected. The ithdrwal of peritonea flui fro the eritoneal cavity is dscribed on page 88.

eritonal Pan rom te Parietal Peritonum The parital peritoneum lning the aterir abdminal wall is spplie by he loer six thoracic nervs and the first umbar nerve. Abominal pai orignating fro the arieal peitoneum is therfore o the soatic typ and can be precsely loclized; i is usally sevre (see Adominal Pain, pae 281. n inflamed parietal peritoneum is extremly senstive to stretchg. This fact is ade use of clincally in diagnosng perionitis. Pressure is appled to th abdominl wall wth a sigle finer over the site of th inflammtion. The pressue is the remove by sudenly witdrawing the fingr. The adominal wall rebunds, esulting in extrme local pain, wich is kown as reound tenerness. It shoul always e rememered th the paietal pritoneu in the elvis is innervatd by th obturatr nerve and can be palpated by mans of a rectal o vaginal examinaion. An nflamed appendix may han down ino the pelvis and irritate the paretal pritoneum A pelvic examination can detect etreme tnderness of the arietal eritoneu on the ight sie (see pag 345)

From the Viscral Peroneum The isceral peritoneum, incluing the mesenteres, is innervatd by autnomic aferent ners. Strech cause by ovedistensin of a vscus or ulling o a mesentry gives rise to he senstion of pain. Th sites o origin f visceal pain re show in Figure 5-1. Because he gastrintestinl tract arises mbryologially as midline structur and recives a blateral nerve spply, pin is reerred to the midlne. Pain arising fom an aominal viscus i dull ad poorly localizd (see Abdomial Pain, page 28).

Peritoneal Dialyis ecause the peritoneum is semipemeable mmbrane, t allos rapid idirectional trasfer of substancs acros tself. ecause the surfae area of the peritoneum i enormou, this transfer property has been made us of in ptients wth acute renal isufficiecy. The fficienc of thi method s only a fraction of that achieved by hemodalysis. A watry soluton, the ialysate is intrduced though a atheter hrough a small miline incsion thrugh the nterior abdominal wall belw the umilicus. he technque is the same as peritoneal lavge (see pae 189. The prducts o metabolsm, such as urea, diffuse hrough te peritoeal linig cells from the blood vesels int the diaysate and are remed from the patint.

Internl Abdominal Herni Ocasionall, a loop of intesine entes a perioneal puch or ecess (e.g., the lesser sc or th duodena recesse) and becomes srangulatd at th edges of the reess. tht impotant structures

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snell form the oundarie of the entrance into the lesser sac and that the nferior meseteric ven often lies in he antrior wal of the paraduodnal recess.

Figue 5-17 Some iportant kin areas involvd in refrred viceral pan.

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Emryologi Notes Deveopment o the Peritoneum nd the eritonea Cavity

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snell Once th laterl mesodem has split into somatic nd slanchnic layer, a cavity is fomed beteen the wo, called the intraemryonic celom The petoneal avity is derived rom that part of the embryonic colom sitated caudal to te septum transverum. In the earliet stage, the peritoneal cavity is in ee commnicatio with th extraemryonic coelom o each sie (see Fig. 436B). Later, with the develoment of he head tail, ad lateral folds of the mbryo, tis wide rea of ommunicaion becoes resticted to the sall area withi the umblical crd. Ealy in dvelopmen, the peitoneal cavity i divide into rght and eft halves by a centrl partiton forme by the orsal sentery the gut, and the small vetral mesentery (Fig. 5-18). However the venral mesentery extnds only for a short distnce alog the gt (see below), so that belw this vel the right and left haves of he perioneal cvity are in free communiction (ig. 5-18). As a result of the enormous growth f the liver and the enlarement of the developing idneys, he capacty of th abdominl cavit becomes reatly reduced a about he sixth week of evelopment. It i at this time tht the smll remaning comunicatin betwee the peritoneal cavity and extrambryonic coelom bcomes imortant. n intestnal loo is fored out o the abdminal cvity thrugh the mbilicus into the umbilial cord. This phyiologic erniatio of the idgut takes place durng the sxth wek of development

Foration of the Pertoneal Lgaments and Mesenteries The perioneal ligamens are developed rom the entral and dorsl mesentries. Th ventra mesentey is formed from the mesderm of the septm transersum (derived fom the crvical somites, which migrte downwrd). Th ventral mesenter forms te alcifor ligamen, th lsser ometum, nd the cornary nd triangulr ligamnts of te liver (Fig. 5-1). The dorsal esetery s formed from te fusio of the splanchopleuric mesoder on the wo side of the mbryo. extend from the posterior abdoinal wall to the posterio border f the bdominal part of the gut Figs. 4-3 and 5-8). Te dorsal mesentery forms te gastrophenic ligament, the gastroplenic oentum the splencorenal igament, the grater omentum, nd the mesenteies of te small nd larg intesties.

Frmation f the Lesser and Greater eritonea Sacs Th extensve growt of the ight lobe of th liver ulls the ventral esentery to the ight and causes otation of the stomach and duoenum (ig. 5-19). B this mans, the upper rght part of the eritonal cavit becoes incoporated nto the lesser sac. The ight fre border of the vntral msentery becomes he right borde of the esser omntum and the anerior bondary of the entrnce into the lessr sac. The remaiing par of the eritonea cavity, which is not inluded in the lesser sac, is clled the greater sac, and the two sacs ar in commnicatio through the epiploic foamen.

Foration of the Greater Omentum The speen is dveloped n the upper part of the dorsal msentery, and the grater omntum i formed as a reslt of th rapid and extesive groth of th dorsal esentery caudal to the speen. To

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snell begin wth, the reater oentum exends frm the grater curvature of the stmach to he posterior abdminal wall superor to th transvese mesoolon. With continued groth, it raches iferiorly as an apronlike doubl layer f peritoneum anerior to the trasverse olon. Late, the poterior lyer of te omentu fuses wth the transverse mesocolo; as a rsult, te greate omentum becomes ttahed to the antrior surface o the trasverse clon (Fi. 5-19). As evelopmnt proceds, the omentum ecomes lden wit fat. Th inferor reces of the lesser ac exteds inferiorly beween the anterir and the posteror layer of the old of the greatr omentu.

igure 5-18 Ventral and dorsl mesentries an the orgns that develop ithin tm.

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Figre 5-19 The rtation o the stomach and the frmation f the grater omentum ad lesser sac.

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Gastrintestinl Tract Esophagus Abdominal Portion Th esophags is a mscular, ollapsibe tube aout 10 n. (25 c) long tat s the pharnx to te stomac. The grater pat of the esophagu lies wiin the torax (se age 127). The esophagu enters he abdomen through an opeing in te right rus of the diaphagm (Fig. -4). fter a curse of about 0. in. (125 cm), it enter the stoach on its right side.

Relations

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snell Te esophgus is rlated ateriorly to the osterior surfac of the left lobe of the lver and osteriory to the left cru of the diaphrag. The let and riht vagi ie on it anterio and poterior surfaces, respectiely.

Blood Supply Arteries The arteies ar branche from the left gastric rtery (ig. 5-20).

Vei The vins drai into th left gatric vei, a tribuary of te portal vein (se prtal–systemic anastomosis, page 46).

Lyph Draiage he lymph vessels follo the arterie into th left gatric nods.

Nrve Suply Th nerve spply is the anterior and osterior gastric nerves (vgi) and ympathetc branchs of th thoracic prt of th sympatetic truk.

Functin The esophagus conducs food rom the harynx ito the somach. Wvelike cntractios of the muscula coat, clled perstalsis, prop the fo onward

astroesphageal phincter No natomic phincter exists a the loer end o the esphagus. owever, he circuar laye of smooh muscle in this region serves a a physilogic spincter. As the food desceds throuh the eophagus relaxaion of te muscle at the ower end occurs aead of he peristaltic wae so tha the foo enters the stomach. The toic ion o this spincter pevents te stomac content from rgurgitatng into he esophgus. The closure of the sphincter is under agal cotrol, an this an be aumented b the homone gasrin and educed i respone to seretin, holecystokinin, and glucag. P.28

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Figure 5-2 Artries tht supply the stomch. Note that all the arteries are derived rom braches of he celia artery.

Cinical otes he Esopagus Narrow Area of the sophageal Lumen Te esophagus is nrrowed a three stes: at the beinning, behind te cricod cartilge of th laryx; where the lft bonchus ad the arh of the aorta coss the ront of the esopagus; ad where the esopagus entrs the somach. Tese three sites may offer resistane to the age f a tube down the esophagu into th stomac (see ig. 3-4).

Ahalasia of the Crdia (Esphagogasric Junction) he cause of achalsia is uknown, but it is associatd with degenertion of he paraympathetic plexus (Auerbachs plexus in the wall of he esophgus. The primary ite of te disordr may b in the innervaion of te cardiesophagel sphinter by the vags nerve. Dysphaia (diffculty in swallwing) a

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snell regurgiation ae commo symptom that ar later acompanie by proimal diltation ad dista narrowig of the esophags.

Bleeding Esophagel Varice A the loer third of the sophags is an importan portalâsystemi venous nastomoss (se pge 246). Hre, the sophageal tributaries of the left astric vin (whic drains into th portal ein) anatomose wth the eophageal tributares of th azygos veins (sytemic vens). Shold the prtal vei become obstructed, as, for exampe, in cirhosis of the livr, prtal hypertensio develop, resuling in dlatation and varcosity o the potal–sytemic aastomose. Varicsed esophageal veins may rupture, causing svere vomting of ood (hematemesis).

Antomy of the Insertion of the Sengstaken-Bakemore alloon for Esophgeal Herrhage The Sngstake-Blakemoe balloon is usd for th control of massive esopheal hemrrhage from esopageal vaices. A astric alloon anchors t tube against the esophagel–gastic juncton. An sophage balloon occlude the esohageal vrices by counterpessure. The tub is insrted thrugh the nose or by using the oral route. Te luricaed tue is pssed dow into th stomach and th gastri balloon is inflaed. In he averae adult he distace betwen the eternal oifices o the nos and the stomach s 17.2 i. (44 c), and te distane betwee the incsor teet and the stomach is 16 in (41 cm)

natomy of the Complicaions    

Difficulty in ig the tue throuh the noe Dmage to he esopagus fro overinfation of the esopageal tue Pressure n neighbring medstinal tructures as the esophagus s expandd by the balloon ithin is lumen Persitent hicups caued by iritation of the diaphragm by the distende esophags and irritation of the somach b the blod

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Stmach ocation nd Descrption The stomach is he dilatd portin of th alimentry cana and ha three min funcions: t stores food (in the adut it has a capacty of abt 1500 mL), it mixes the food wit gastric secretios to frm a semfluid chyme, ad it conrols the rate o deliver of the hyme to the smal intestine so tht efficent dgestion and absoption ca take place.

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snell The stomach s siuated i the uppr part f the adomen, extending from benath the eft cosal margi region nto the epigastric ad umbilial regis. Much of the somach lis under over of the lowr ribs. t is roughly J-saped and has two penings, the cardiac and pyloic oriices; two curvtures, he greater and lessr curvatres; nd two urfaces, an anterior and a posterior surface (Fig. 5-21).

Figue 5-21 Stomch showig the parts, musular coats, and ucosal lning. Noe the increaed thickess of he circuar muscl forming the pyloic sphincter.

The stomah is reltively fxed at both ends but is ry moble in beween. It tends to be high and tnsversey arrangd in the short, bese peron (stee-horn smach) ad elongaed vrtically in the tall,

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snell thn persn (J-sped stomch). It shape udergoes considerable varation in the sam person nd depeds on th volume of its ontents, the posiion of he body, and the hase of respiraton. The tomach s divide into th followng parts (ig. 5-2):   

Fundus: Thi is domeshaped nd projets upwad and to the left of the ardic orific. It i usually full of gas. Body: This etends frm the leel of th cardic orifice to the level of the incisra anguaris, a constnt notch in the lwer prt of th lesser urvatur (Fig. 5-1). Pyloric ntrum: This etends frm the incisura angulari to the pylorus ig. 5-21). P.20

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Pylors This is the most tubular part of he stomch. The hick musular wal is caled the pyloric spincter, and th cavity f the pyorus s the pyloric canl (Fig. 5-21)

Th esser cuvature forms the rigt border of the tomach ad extends from te cardia orifice to the ylorus (Fig. 5-21). It is suspeded from the live by the lesser oentum. Te reater urvature is much longer than he lesse curvatre and etends frm the left of te cardia orifice over te dome o the fundus, and along th left order of the stomch to the pyloru (Fig. 5-2). Te gastroplenic omentum (igament) extend from th upper part of th greate curvatre to th spleen, and the reater oentum exends frm the lwer par of the reater crvature o the trnsverse colon (Fig 5-11) The cadiac oriice i where te esophgus entes the stmach (Fig. -21). Althoug no anaomic sphncter can be demostrated ere, a pysiologi mechansm exists that pevents rgurgitaton of stmach cotents ino the eophagus see page 27). Th yloric oifice is formd by the pyoric canal, hich is bout 1 i. (2.5 c) long. he circuar musce coat o the stmach is uch thicker here and form the anamic and physiologic pyloric sphincte (Fig. 21). The pylrus lies on the transpyloic plane and it positio can be recognizd by a sight contriction on the srface of the stomch.

unction f the Pyoric Spincter The pyloric sphincte control the outflow of gstric cntents ito the dodenum. he sphicter recives motr fibers from th sympathtic systm and inhibitory fibers fom the vgi. In ddition, the pylous is cntrolled by loca nervous and hormnal infuences om the tomach and duodeal walls For exmple, th stretcing of te stomch due t filling will stiulate th myenterc nerve plexus i its wall and reflexly cuse relaation of the sphicter. The mucou membran of te stomac is thic and vasular and is throw into nuerous fods, or ruga, tha are maily longiudinal n directon (Fig. 51). Te folds flatten ut when he stomah is ditended. The musclar wall of the tomach contais longitdinal fibers, circuar fibers, and olique fiers (Fig. 5-21).

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snell Te peritonem (vsceral peritoneum) competely surounds te stomah. It leves the lesser curvatur as the esser oentum an the greater curvature as the gastrospenic ometum and he greatr omentm.

Relaions  

nteriorl: The anterior abdominal wall, the left costal margin, the left pleura and lung the diahragm, ad the let lobe o the livr (Fis. 5-2 an 56) Poseriorly The lesser sa, the diaphragm, the splen, the eft suprrenal glnd, the upper prt of the left kidney, the splenic rtery, te pancreas, he transverse meocolo, and t transvrse colo (Figs 5-4, 5-, and 5-11

lood Suply Arteres The arteies are derived rom the branhes of te celiac artery (Fig. 5-2). The lft gastric arery rises frm the ceiac artery. I es pward an to the eft to reac the esohagus an then decends alng the lsser curature of the stomach It suppies the lowe third f the esphagus ad the upper right pat of the stomach. Te righ gastric artery arise from the hepaic arter at the uppe border f the porus an runs t the lef along te lesser curvture. I supplie the lower right part of the somach. he short gastric rteries arise fro the splnic artey at the hilum of the splen and orward i the gastrosplenc omentu (ligament) t supply he fundu. The let gastropiploic rtery arises from the splni artery at the ilum of he splen and pases forard in te gastroplenic mentum (igament) o supply the stoach alog the uppr part f the grater curvture. The rght gasroepiploc arter aries from the gastoduodenl branch of the patic atery. It es to the lft and spplies te stomac along he lower part of the greter curvture.

Veis The veins drin into the portl circulation (Fig. 5-22) The left and right gastric veins drain diectly ino the potal vein The short gastric veins ad the left astroepiloic veis joi the splnic vein The right gastroepploic ven jois th superior mesentric vei.

Lymph Draiage Te lymph vessels Fg. 5-23) follow the arteries into the lft and rght gastic node, the lft and ight gasroepiplic nodes and the short gatric nodes. All lymph fro the stmach evetually asses to the celac nodes located round th root f the ceiac artey on the posterir abdomial wall.

Nerv Supply 412

snell The nrve suppy includs sympatetic fiers deried from the celic plexu and parsympathtic fibes from the right and lef vagus nrves (Fig. 5-24) The aterior vgal trun, whch is fomed in te thorax mainly rom the left vags nerve enters the abdomen n the anterior srface of the esopagus. Te trunk, hich may be sine or mutiple, then divies into ranches that suply the nterior urface f the stmach. A arge heptic branh es up to th liver, nd from his a pyoric branch s down the pyorus (Fig. 5-2). Te posterio vagal tunk, which i formed n the thrax mainy from te right agus neve, entes the adomen on the postrior surace of te esophus. The trunk thn divids into banches tat supply mainly the postrior surace of te stomah. A large branc es o the cliac and superior mesenterc plexuses and is distriuted to he intesine as fr as the splenic flexure and to te pancreas (Fig. 5-2). The ympathetc innervtion of he stomch carries a roportin of pai-trasmitting nerve fibers, whreas th parasypathetic vagal fiers are ecretomoor to th gastri glands nd moto to the uscular wall of he stomch. The yloric sphincter receive motor fbers fro the symathetic ystem an inhibiory fibes from he vagi. .221

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igure 5-2 Trbutaries of the portal ven.

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Figure 5-23 Lymph drainag of the tomach. Note tha all th lymph eentuall es through he celia lymph nodes.

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Figure 524 istributon of th anterir and posterior agal truks withi the abomen. Nte that he celiac branch of the posterior vagal trnk is istributd with he sympahetic neves as fr down te intestnal trat as th left coic flexu.

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Clinica Notes Traum to the Stomach Apart rom its ttachmen to the esophagu at the cardiac rifice nd its cntinuity with th duodenu at the ylorus, the stoach is elativel mobile It is potected on the lft by the lower part of the rib age. Thee factor geatly potect th stomac from bunt trama to th abdomen However its lare size mkes it vulnerabe to gunhot wouns.

Gastric Ulcer The muous membane of te body o the stoach and, to a leser extt, that of the fundus prouce acid and pepsin. The secreti of the ntrum and pylori canal i mucous nd weakl alkalin (Fig. 5-5). Te secreton of acid an pepsin is controlled by two mechanisms: nevous and hormonal The vags nerves are resonsible or the nrvous cotrol, an the horone gastrin, produced by the atral muosa, is esponsibe for the hormonal contro. In th surgica treatmet of chrnic gastic and dodenal ucers, ttempts re made o reduce the amout of aci secretin by secioning he vagus nerves (agotomy) and by rmoving te gastri-bearing rea of ucosa, te antrum (partial gastrectmy). Gastric ulcers ocur in te alkalie-producng mucos of the stomach, usually n or cloe to the lesser crvature. A chronc ulcer invades the musclar coat and, in time, ivolves te peritoeum so hat the stomach dheres t neighboring structures. An ulcer siuate on te poterior wall of the stomach may prforate nto te lessr sac or become aherent t the panreas. Esion of the panceas prouces pai referre to the back. Th splenic artery rns along the uppr borde of the pancreas, nd erosin of this artery ay produe fatal hemorrhae. A penetrating ulcer o the anterior stoach wal may reult in he escap of stomch contets int the greatr sac, producing diffus peritonitis. Th anterior stomach all may, however, adhere to the liver, an the chrnic ulce may pentrate th liver ubstance

astric ain The senstion of ain in he stomach is cased by te strething or pasmodic ontraction of te smooth muscle i its wals and i referre to the pigastrim. It is believed hat the pain-trasmitting fibers lave

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snell the tomach i company with the sympatheic nerve. They pss throuh the celiac ganlia and each the spinal ord via he greaer splachnic neves.

Cancr of the Stomach Becase the lymphatic essels of the mucus membrne and ubmucosa of the somach ar in contnuity, i is possble for ancer clls to travel to dfferent arts of the stomch, some distanc away fom the pimary ste. Cancr cells lso often trough or by he local lymph noes and ar held u in the egional odes. Fo these reasons, malignan disease of the somach is treated y total gastrectmy, which include the remval of te lower nd of th esophaus and te first prt of th duodenm; the sleen and the gasrosplenc and spenicoreal ligaents an their associated lymph nodes; the splenic vessels; t tail ad body f the pacreas and their associatd nodes; the node along te lesser curvatue of the stomach; and the nodes alng the gater curature, aong with the greaer omenum. This radical peration is a deserate atempt to emove te stomah en boc and, ith it, its ymphati field. he continuity of the gut is restred by aastomosng the eophagus ith the jejunum.

astroscoy Gastroscop is the iewing of the muous membane of te stomch throuh an illminated tube fitted with lens sytem. T patie is aneshetized and the astroscoe is pased into he stomah, whih is the inflate with ai. With a lexible iberopti instrumt, diret visualzation o differet parts o the gasric mucos membrne is pssible. It is also possibl to perform a mucosal bipsy throgh a gatroscope

Naogastri Intubation asogastrc intubaion is a common rocedur and is performe to empt the stoach, to decomprss the omah in cases of intesinal obtruction, or befo operatns on te gastrointestinal tract; it may alo be peformed to obtain a sampl of gastic juice for bichemical analysi.    

Th patient is placed in te semiupright position or left ateral osition o avoid aspiratin. The ell-lubricated tube is inserted trough the wider nostil and i directed bakward aong the nasal flor. Onc the tub has pased the oft palte and ntered t oral prynx, decreased resistace is fet, and the consious patent will feel like gaggin. Some importan distnces in he adult may be seful. om the ostril (xternal nares) o the cadiac oriice of he stomch i about 1.2 in. (4 cm), ad from te cardic orifie to te pyloru of the stomach is 4.8 t 5.6 in. (12 to 1 cm). The curved course takn by he tube rom the ardiac oifice to the pylous is usully loner, 6.0 o 10.0 i. (15 to 25 cm) (ee Fig. 3-51).

Anatomic Strctures hat May mpede he ge of te Nasogatric Tub  

deviate nasal sptum makes the pssage f the tube diffiult on te narrowr side. Three sites of esophagal narrowing may offer rsistance to the nsogastri tube—at the beginning of the sophagus behind te cricoi cartilae (7.2 in. [18 cm]), where the left

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snell ronchus nd the rch of te aorta cross the front f the eophagus 11.2 in. [28 cm], and where the sohagus eters the stomach (17.2 in. [44 m]). The upper sophagel narrowng may e overcome by gntly graping the wings of the thyoid carilage ad pullng the lrynx foward. Ths maneuvr opens the normally colapsed esophagus and permits te tube t don withou further delay.

natomy o Complications   

Th nasogatric tue enters the larnx insted of th esophags. Rough insertin of the tube int the noe will cuse nasa bleeding from e mucou membrae. enetration of th wall of the esohagus o stomach Always aspirate tube for gstric cotents to confirm successul entrace into the stomah.

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Figure 5-25 Areas o the stmach tha produce acid and pepsin (ble) and alkali and gasrin (red).

Small Intestine The sall intetine is he longst part f the alimentar canal and extens from the pylorus of te stomac to th ileoceal juncton (Fig. -1). he greater part of digesion and fod absotion taes plac in the mall inestine. t is diided into three arts: th duodenm, the junum, nd th ileum.

Duoenum Locatio and Decription 418

snell The duodenum i a C-shaed tube, about 0 in. (25 cm) lng, whic s the stomch to te jejunu. It reeives th opening of th bile an pancreaic ducts The duoenum curvs around the head of the pancreas (Fig. 5-26) The firt inch 2.5 cm) f the dudenum rsembles he stomah in tha it is overed o its anerior an posterir surfaces with peritonem and has the lesser omentum atached t its uppr borde and te greaer omentum attaced to is lower border; he lesse sac lie behind this shot segmen. The remainder of the duodnum is rtroperitneal, being only partialy coverd by petoneum

Figre 5-26 Pancras and aterior elations of te kidnes.

Pats of te Duodenm The duodeum is siuated in th epigasric and mbilical regions and, for urposes of decriptio is divided into four pars.

Frst Part of the uodenum The irst part of the duodenu beins at te pylorus and rns upward and ackward on the transpyloic plane at the lvel of te firs lumbar ertebra Figs. 526 and 5-27. The reltions of this pat are as follows:  

Anteriorl: The quadrate lobe of the live and th gallbladder (Fig. 510) osteriory: Th lesser ac (firs inch only, the gatroduodeal artery, the bile duct and porta vein, nd the iferior vna cava (ig. 5-27)

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snell  

Superorly: The enance ino the lesser sc (the epiploic oramen) Fs. 5-7 and 5-11) Inferorly: The head of the pancrea (ig. 5-26)

Secon Part o the Dudenum The scond par of the uodenum runs verically ownward in front of th hilum f the riht kidny on th right sde of th second and thir lumbar ertebra (Figs. 5-2 and 5-2). bout halway dow its medal borde, the bile duct nd the min panceatic dt pirce the duodenal wall. Thy unite o form the amplla tha opens o the sumit of th major uodenal P.25

pailla (Fig. 5-28) The accssory pacreatic uct, if present, opens ito the dodenum little highr up on the minr duodenl papill (Figs. 5-7 and 5-28).

Fgure 527 Posterior reation of te duodenum and te pancres. The umbers represet the fur parts of the dodenum.

The relations of thi part ar as folows: 

Antriorly: The fundu of the gallbladder an the rigt lobe o the liver, the ransverse colon and the coils of the small intestine (Fig 5-29)

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snell   

Posterirly: The hilu of the ight kidey and te right ureter (Fi. 5-27) Laterally: The ascending colon, he right colic fexure, and he right lobe o the lier (ig. 527) Mdially: The had of te pancreas, the bile duct, and the main panreatic uct (Fgs. 5-2 and 5-28)

Figure 5-28 Entrance of the ile duct and the main and accessoy pancretic ducs into the secod part o the duoenum. Nte the sooth lining of th first par of te duodenum, the licae circulare of the econd part, and the majo duodenal papill.

Third Par of the Duodenum The thrd part f the dudenum rus horizntally t the let on the subcostl plane, ing in fron of the vertebral column and follwing th lower mrgin of he head f the pacreas Figs. -26 and 5-27). The elation of this part are as follws:    

Anteriory: The root o the mesntery f the sall intstine, te superir mesenric veels conained within it, nd coils of jejunum (Figs. -26 ad -27) osteriorly The right ureter, the righ psoas muscle, the inferi vena caa, and he aorta (Fig. 5-7) Speriorly The ead of te pancres (Fig. 5-26) Iferiorly: Coils of jejnum

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Fgure 5-2 The bile ducs and the gallbldder. Noe the reation of the gallladder to the tansverse colon an the dudenum.

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Figue 5-30 Attachment of he root f the msentery f the sall intetine to he postrior abominal wll. Not that it extends from the dodenojejnal fleure on lft of te aorta, downwar and to the rigt to the ileoceal juncton. The suprior mesnteric artery lies in the roo of the mesenter.

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Fourth Part of te Duodem he fourth part o the duoenm runs uward and to te left t the dodenojeunal flexure (Fgs. 5-26 and 5-27). The flexure s held i positin by a pritoneal fold, th lgament of Treit, whch is attached to the right crus o the diahragm (Fig. 5-12) The reations o this pat ar as follws:  

Anteriorly: The beginning f the oot of te mesentry and coils of jejunum (Fi. 5-30) Posterirly: he lef margin of the aorta an the medal borde of the left psos muscl (Fig. 27)

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Mcous embra and Dudenal Paillae The mcous mebrane of the dodenum s thick. In the irst par of the duodenu it is smooth (Fig 528). In he remaindr of the dudenum it is thrown int numerous circlar fold called the plcae circlares At the site whe the ble duct nd the min pancratic duc pierce the medal wall f the seond part is a smal, roundd elevaion calld the major duodnal papilla (Fig. 5-8). Te ry panceatic dut, if pesent, oens int the duoenum on smaller papilla about 0.5 in. (19 cm) abve the mjor duodnal paplla.

Blod Suppl Ateris The upper half s supplid by the suprior panreaticododenal atery, a branch o the gastroduodnal artery (Figs. -20 ad -26). he lower half is supplie by the nferior ancreaticoduodenl arter, a banch of he suerior meenteric rtery.

Veins he supeior panreaticododenal ein drais into te portal vein; the inerior vin s the superior mesenteric vin (Fig. -22).

Lyph Drainage The lymph vesels folow the rteries nd drai upward via pncreaticduodena nodes t the gatroduodeal nodes and then to the celiac nodes and downwar via panreaticododenal ndes to he supeior mesnteric ndes arond the oigin of the suprior mesenteric artery.

Nerve Suply e nerve are derved from sympatheic and parasympatheti (vagus) nerves from the eliac an superior mesentric plexses.

Cinical Notes Traua to the Duodenum Aprt from the firs inch, te duodenum is rigidly fied to te posteior abdoinal wal by pertoneum nd thereore cannt move way from crush ijuries. In sevee crush njuries o the anterir abdoinal all, the third prt of th duodenu may be everely rushed or torn gainst te third umbar vrtebra.

Dodenal cer s the stmach empies its ontents into the duodenu, the aid chym is squited agaist the nterolateral wall of the first part of the duodeum. Tis is thought t be an important actor i the productin of a dodenal ulcer at his site An ulcr of the anterior wall o the first inch of the duodenum my perforte into he upper part o the greter sac, above te transverse colon. Th

424

snell transvrse clon direts the ecaping fluid ino the riht latel paraolic guter and hus down to the rght ilia fossa. he diffential diagnosi betwee a perfoated duoenal ulcr and a perforatd appenix may e difficlt. A ulcr of the osteror wall f the frst part of the duodenm may pnetrate he wall and eroe the reatively arge gatroduodenal artey, causig a sevee hemorrhage. Te gastrduodenal artery i a branch of he hepatic artery, a banch of the celic trunk (Fig. 54).

Duodenal Recsses Te imporance of he duodenal receses and the ccurren of hernae of th intestie were lready aluded to on page 08.

Impotant Duoenal Relatios The reltion to he duodnum of he gallbladder the trnsverse olon, a the riht kidny should be rememered. Caes have been reprted in which a arge galstone ucerated through the gallbladder all into the duoenum. Oprations on he colon and righ kidne have reulted in damage o the dudenum.

Jejunu and Ilum ocation and Desciption The ejunum ad ileum easure bout 20 t (6 m) long; the upper wo fifths of this length make up the jejunum. Each has distictive fetures, bt there s a graual chnge from one to te other. The jeunum begns at te duodenjejunal lexure, and the leum ens at the ileoceca junctin. The coils of jejunum and ileum r freey mobile and are attache to the osterior abdominl wall y a fan-haped fld of pritoneum known as the meentery o the smll intesine Fig. 5-30). The ong free edge of the fold encloses he mobie intestne. The hort rot of th fold is continuus with he parital perioneum o the poterior abdminal wall alng a ine tht extnds donward and to he rigt from he left ide of the second lubar vertbra to te regio of the right saroiliac oint. The root o the mesntery pemits the entrane and ext of the branches of the sperior mesenterc artery and vei, lymp vessel and neves into the spae betwee the tw layers of perioneum foming th mesentey. In te living the jejnum can be distinguished from the ileum b the folowing fetures:  

The jejunum lies oiled in the upper part of the peritonel cavity below the left sde of th transverse mescolon; te ileum is in th lower prt of t cavity and in te pelvi (Fig. 5-3). he jejunum is wider boed, thicker waled, and redder han the leum. Th jejunal wall fels thicer becase the prmanent nfolding of the mucous mmbrane, he plica circuares, ae large, more nmerous, nd closey set in the jejnum, whereas in the upper part o the ilm P.228

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they are smaler and ore widly seprated and in the lower pat they are absen (Fig. 5-31).

Figre 5-31 Some external and internal diferences etween the jejunm and the ileum.

 





Te jejunl mesentry is atached to the poerior adominal wall abov and to he left of the arta, wheeas the ileal meentery i attache below nd to th right f the aota. The jeunal mesnteric vessels form only one r two arades, wth long nd infrequent brnches pssing to the inestinal wall. Th ileum rceives nmerous hort terinal vesels tha arise from a seies of tree or four or een more arcdes (Fig. 5-1). At he jejunl end of the mesetery, te fat i depositd near te root nd is scnty near the intetinal wll. At he ilea end of he mesentery the fat is deposited hroughou so tha it extends from the root to the intestina wall (Fig 5-31). Aggreations of lymphid tissue (Peyers patches) are present i the mucus membne of te lower leum alng the ntimeseneric border (Fig. 531). n the liing these may be visible though the wall of the leum fro the outide.

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Blod Suppl Areries The arteial suppy is from branchs of the superior mesenterc arter (Fig. 5-3). The intetinal brnches arse from he left side of the artery ad run in he msenter to reac the gut They aastomose wth one aother to form a series o arcades The lowst part f the ilum is alo supplied by he ileoolic artry.

Veins he veis correpond to the brances of th superio mesenteic artey and drin into he superor esenterc vein (ig. 5-22).

Lymph rainage The ymph vesels through many inermediat mesentric node and finlly reac the suerior meenteric node, which are situated around the origin of he superor meseneric artry.

Nerve Suply The neves are erived fom the ympathetc and paasympatetic (vgus) neres from he supeior meseteric plexus.

Clinial Notes Trauma to the Jejnum and leum Because of its extent ad positin, the sall inttine i commonl damaged by traum. The etreme mobility ad elastiity permit the oils to ove freey over one anothr in instanes of blun trauma. Smll, penetratin injuris may slf-seal s a result of th mucosa pluggin up the ole and he cntractio of the mooth mucle wall. Materal from arge wounds leak freely into the peritonl caviy. The pesence o the vrtebral column nd the prominent anterior margn of the first saral verebra may provide a firm bckgroun for inestinal crushing in case of midlne crush injuries Smallbowel contents hve nearl a neutal pH and produe only sight chemica irriatio to the perioneum.

Recogntion of the Jejnum and leum A phsician sould be able to istinguh betwen the lrge and mall intstine. H or she may be clled on to examie a case of posoperativ burst bdomen, here cols of gu are lying free in he bed. he macrscopic dfference are desribed on page 227.

Tumors ad Cysts f the Mesentery f the Smll Intesine

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snell The ine of atachmen of the mall intestine o the psterior bdominal wall should be emembere. It extnds from a poit jst to he left of th midlin about 2 in. (5 cm) belw the transpyloric plane (L1) downward to the righ iliac ossa. A tumor or cyst of the mesetery, whn palpaed throuh the anerior abominal wall, is more moile in a direction at rigt anges to th line o attachent than along th line o attachent.

Pain Fiber from e Jeunum and Ileum Pai fibers raverse he superior mesnteric smpathetc plexu and pas to the spinal crd via te splanhnic nees. Referred pan from this segment of the gastrointestial trac is felt in the dermatoes suppled by t 9th, 1th, and 1th thorcic nervs. Stragulation of a col of smal intestne in an inguinal hernia irst gies rise to pain in the rgion of he umbiicus. Ony later, when he parital perioneum of the henial sac becomes nflamed does th pain ecome moe intene and loalized t the inginal regon (see Abdoinal Pai, page 21).

Mesenteric Aterial Oclusion The superio mesenteic artery, a branch of the bdomina aorta, upplies n extensve terrtory of the gut, from hlfway don the scond par of the uodenum o the lef colic lexure. Occlusion of the artery r one f its ranches results n death f all r part o this sement of he gut. The occlsion ma occur a the reult of n embolu, a throbus, an ortic disection, or an abdominal aneurysm

esenteric Vein Thrombois The suerior meenteric ein, whch drain the sam area o the gu supplie by the superior mesenteic arter, may udergo trombosi after sasis of he venou bed. Cirrhosis f the lier wit portl hypertnsion my predisose to his condtion.

eckel's iverticulum eckel's diverticlum, a congenita anomaly of the leum, is deidoub on page 238. P.229

Lrge Inttine The lage intesine exteds from he ileum to the aus. It s divide into th cecum, ppendix, ascendig colon, transvere colon descendng colon and sigoid coln. The rctum an anal cnal are consideed in th sections on the pelvis ad perinem. The pimary fnction o the lare intestne is the absorpton of waer and lectrolyes and the storae of undgested mterial util it cn be exelled frm the boy as feces.

Cecum

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Locatio and Decription Th cecum i that pat of the large inestine tat lies elow the level of the juncion of the ileum with the large inestine (Fis. 5-32 and 5-33). It is a blid-ended ouch tha is situted in te right liac fosa. It i about .5 in. (6 cm) lon and is ompletel covered with pertoneum. It posseses a cosiderab amount of mobilty, althugh it des not have a msentery Attache to its posteromdial suface is he appndix. Th presen of pertoneal flds in the vicinity of the cecum (Fig 5-33) create the suprior ilececal, te inferir ileoceal, and he retroecal recsses (se pge 208). As in the colo, the logitudina muscle s restrited to hree fla bands, he teniae coli, which coverge on the bas of the appendix and proide for t a compete longtudinal uscle cot (Fig. 5-3). The cecum is often distended with ga and can then be palpated through the anteior abdoinal wal in the iving patient. The teminal pat of the ileum eners the large intestine t the juction of the cecu with the ascending colon. The oping is rovided ith two olds, or lips, whih form te so-caled ilececal vlve (see below). The appedix commnicates with the cavity of the ccum thrugh an oening loated belw and bhind the ileocecl openig.

Relaions   

Anterirly: oils of small inestine, sometime part o the greter omentum, an the anterior adominal all in te right liac regon Posterioly: Te psoas and the liacus uscles, he femoral nerve and the lateral utaneous nerve of the thih (Fig. 5-3). The appendi is commnly foun behind he cecu. Medialy: Te appenix arises from te cecum n its mdial side (Fig. 5-3).

Blood Spply Arterie Anteror and osterior cecal arteries orm te ileocolic artey, a brnch of the sperior esenteric arery (Fig. 533).

Veins Th veins corrpond to the arteries nd drain into the superior meseteric vn. P.230

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Figure 5-32 Superior mesenteri artery nd its banches. Note hat this artery supplie blood to the gut from halfway own the econ part of the duoenum to he distal thid of the transverse coon (arrow).

Lymph Drainage The lymph vssels pas throug several meseteric noes and inally rach the uperior meseteric noes.

Nerve Suply Banchs from the sympathetic an parsympatheic (vagu) nerves form the superir mesenteric lexus.

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Ileoecal Vale A rdimentar structue, the leocecal vlve consists of to horizotal fold of mucu membrane that pject arund the orfice of te ileum. The valv plays ittle or no part in he prevention of reflux cecal cntents ito the ieum. The crcular muscle of the lower end of th ileum (alled th ileocecl sphincter by pysiologits) servs as a spincter ad control the flw of contents fro the ilem into the colon. The smoth musce tone is eflexly increase when the cecum is distende; the homone gastrin, hich is poduced b the stomch, caues relaxtion of he muscle tone.

Appendix Loction and Descriptin he appenix (Fig. 51) is a narrow muscula tube ctaining a large aount of lymphoid tssue. It varies n length rom 3 to in. (8 o 13 cm) The base is attaced to he posteomedial surface of the cecu about 1 in. (2.5 m) below the iloecal juntion (Fig 5-33. The reainder o the appnix is fee. It hs a compete perioeal covring, whch is atached to he mesentery of e small ntestin by a shot mesetery of is own, te mesoappndix. The mesoapendix cntains th appendiular vesels and erves. The appendix ies in te right iliac fosa, and in relaion to e anteror abdoinal wall its bae is sitated one third f the wa up the line joiing the ight antrior suerior ilac spin to the umbilicu (McBurey's poit). Insie the abdomen, the base of the appendix is easily found by idetifying he teniae coli of the cecum and tracin them to he base of the appendix, here they convere to fom a coninuous lngitudial muscl coat (Figs. 532 nd 5-33) P.231

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Figur 5-33 Cecum nd appendix. Noe that te appendicular atery is a branch of the posterir cecal artery. he edge f the mesoappendx has ben cut to show te peritoeal layrs.

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Figure 5-3 Postrior abdminal wll showig posterior relaions of the kidnys and he colon

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Common ositions of the Tp of the Appendi The tip f the appendix i subject to a coniderable range o movemet and ma be foud in the following positions: (a) anging dwn into he pelvi agains the rigt pelvic wall, (b) coiled up behid the ccum, (c) projectng upward along he laterl side o the ceum, and (d) in font of r behind the terinal par of the ileum. The first and secod positions are the most common stes.

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snell Te appenicular atery is branch of the psterior ecal artry (Fig. 5-33).

Veins he appenicular vin drain into th posterir cecal ein.

Lymph rainage The lmph vessls drain into one or two odes lyig in the mesoappedix and then evetually nto the uperior mesenteric nodes.

Neve Suppl The ppendix is suppled by th sympathtic and parasympthetic vagus) nrves fro the suprior meenteric lexus. Afferent rve fibs concerned with the condction of visceral pain frm the apendix acompany he sympahetic nerves and enter th spinal cord at he leve of the 0th thorcic segmnt.

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Figue 5-35 Abdomial cavit showing the termnal part of the ieum, the cecum, the appndix, the ascendng colon the rigt colic lexure, he left colic fexure and the descendig colon. Note he teniae coli and th appendces epioicae.

Ascendig Colon Locaion and escriptin Te ascendng colon is about 5 in. (1 cm) lon and lie in the rght lowe quadran (Fg. 5-35). It extends upward fom the ccum to te inferor surfae of the right obe of the liver where it turns to the lft, formng the ight colic flexure, an becoms continous with the trasverse colon. Th peritoneum coves the font and e sides of the acending olon, biding it to the osterior abdomina wall.

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Anteriory: Cols of smll intesine, the greater mentum, nd the aterior adominal all (Figs. 5-2 ad -3) osterioly: The ilacus, te iliac crest, the qadratus umborum, the oriin of th transersus abominis mscle, ad the loer pole of the rght kidny. The iliohypoastric ad the iioinguinal nervs cross ehid it (Fig. -34)

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Bloo Supply Arteres Th ileocolc and riht colic branche of the uperior esenter artery (Fg. 5-32) suppy this rea.

Veins The vein correspnd to th arteries and drain into the superior mesenteric vei.

Lymph rainage The ymph vesels drain into lmph nodes lying along the course of the clic bloo vessel and ultmately rach the superior mesentric node.

Nere Supply Smpathetc and paympatheic (vagu) nerve from th superior mesenteic plexu supply this are of the colon.

Transvere Colon Locaion and scription Th transvese colon is about 15 in. (8 cm) log and etends aross the abdomen, occupying the umilical region. I begins at the ight colic flexue below he right lobe of the lver (Fig. -4) ad hags downward, uspended by the tansverse mesocoln from te pancres (Fig. 5-). It then ascends to the eft colic flexue belw the speen. The left colc flexur is high than te right olic fleure and s suspeded from the diahragm by the phrenicocoic ligamnt Fg. 5-35).

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Figure 5-36 Inferior meseneric arery and ts branches. Note that this atery spplies he large bowel frm the dstal thid of th transvese colon to halfay down the anal canal. t anastooses wih the midle coli branch of the uperior esenteri artery (arrow).

The transvrse mesocolon, r mesentry of t transvse colo, suspeds the tansverse colon fom the aterior order of the panceas (Fig. -6). he mesetery is ttached o the suerior boder of he transverse clon, and the postrior layrs of th greater omentum re attached to he inferor borde (Fig. 5-6). Becuse of te lengt of the ransvers mesocoln, the position of the transvere colon is extrmely varable and may sometime reach dwn as fr as the pelvis.

Reltions

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Anterirly: he grear omentm and th anterio abdominl wall (mbilical and hypoastric regions) (Fig. 5-6) osteriorly: Te secon part of the duoenum, th head of the pancreas, an the cois of the jejunum and ileu (Fig. 5-5)

Blod Suply rteries The proximal two thirs are supplied y the midle coli artery, a branc of the superior mesenteic arter (Fig. 5-2). Te distal third i supplie by the eft coli artery a branc of the nferior msenteri artery Fig. 5-3). .234

Vens The veins correspond to the ateries an drain ito the sperior ad inferir mesentric veis.

Lmph Draiage he proximal two thirds drin into he coli nodes ad then into the superior mesenterc nodes; the disal third drains nto the colic noes and ten into the infeior meseteric ndes.

Neve Suppy Th proxima two thids are inervate by sympthetic nd vaga nerves hrough te superir mesentric plexs; the dstal thrd is inervated by sympahetic and parasympathtic pelvc splanhnic nerves throuh the inerior msenteric plexus.

escendig Colon Loction and Description The desending colon s about 0 in. (5 cm long an lies in the left upper ad lower uadrant (Fig. 535). It exteds downwrd from the left colic flxure, to the pelc brim, where i become continuous with the sigmoid colo. (For te sigmoid colon, see page 38.) The peritneum covrs the font and he sides and bind it to te posteror abominal wall.

Relations  

Anterirly: oils of mall intestine, he greatr omentu, and th anterio abdominl wall Figs. 5-2 and 5-3) Posteriorly: The laeral borer of th left kdney, th origin f the tansversu abdomnis musle, the uadratus lumboru, the ilac cret, the iiacus, nd the lft poas. Th iliohypgastric and

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snell the ilioinguinal nervs, the lateral utaneous nerve o the thih, and te femora nerve Fig. 5-4) alo lie poteriorly

Blood upply Arteris The left colc and th sigmoid branche of the nferior mesenterc artery (Fig. 5-36) suppy this area.

eins Te veins orrespon to the arteries and drai into th inferio mesentric vein

ymp Drainag Lymh drains into the colic lyph node and the inferior mesenterc nodes around te origi of the inferior mesenterc arter.

erve Suply Te nerve upply is the symathetic and paraympathetc pelvic splanchnc nerves through the infeior meseteric pexus.

Clnical Notes olonoscopy Sine colorctal caner is a eading ause of eath in the Wesrn worl, colonocopy is now being extnsivly used or early detecton of maignant tmors. In this procedure, he mucou membran of th colon cn be directly viualized hrough a elongatd flexibe tube or endocope. Folowing a thoroug washing out of the large bowel, he patiet is seated, an the tu is genly insered into he anal canal. Te interior of te large owel can be obseved from the ans to the cecum (Fig. 5-37). Potograph of susicious areas, suc as polys, can e taken and biopy specimns can be removd for pahologic examinaion. Altough a relatvely expnsive pocedure, it provdes a moe complete screeing examnation fr colorctal cacer than combine fecal ocult blod testig and te examiation of the distal colon with sigoidoscop (see pge 339).

Variablity of osition f the Apendix Th inconstancy of he positon o the appndix shuld be orne in mind wen attempting to diagnose an appenicitis. retroccal appendix, for example may lie behind a cecum dstended ith gas, and thus t may be difficut to elcit tendrness on palpatin in th right iiac regin. Irrition of the psos muscle conversly, may cause te patiet to kee the rigt hip t flexd. An appendix hanging down in he pelvs may reult in bsent adominal endernes in the right lwer quadant, but deep tederness ay be exerience just abve the smphysis ubis. Retal or vaginal xaminatin may reeal tendrness of the perioneum in the pelis on th right sde.

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Predispsition f the Apendix to Infectio The follwing facors contibute to the appedix's predilection to infction:   

It i a long narrow, blind-eded tube, which ncourage stasis f large-owel conents. It has a large mount of lymphoid tissue n its wal. he lumen has a tedency to become obstructd by harened intstinal cntents (nterolits), whic leads o furthe stagnaton of it contens.

Predspositin of the Appendix o Perfoation he appenix is suplied by a long mall artry that does not anastomoe with oher arteies. Th blind e of the appendix is suppled by th terminal branchs of the ppendiclar artey. Infammator edema o the appndicula wall copresses he blood supply o the apendix an ftn leads o thrombosis of he appenicular artery. hese coditions ommonly result i necrosi or gangrene of he appedicular wall, wih perfoation. Perforation of te appendx or trnsmigration of acteria hrough the iflamed appendicuar wall result in infction of the peritoneum f the gater sa The pat that te greate omentm may pay in aresting he spred of the peritonel infecion is escribe on page 213.

Pain of Apendiciti Vsceral ain in te appendx is prouced by distentin of it lumen o spasm o its musle. The afferent pain fiers ente the spnal cord at the lvel of te 10th thoracic egment, nd a vagu referrd pain is fel in the egion o the umblicus. ater, th pain sifts to here the inflamed appendi irritates the parietal peitoneum. Here the pain is pecise, svere, and localizd (se Adominal Pain, pae 281)

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Fgure 5-37 Seies of te interior of th large bwel take during a colonocopy prcedure. A. The ectal muosa shows a smal benign polyp (arowhead). B. The sigmid mucous membran shows evidence of a mild divertculosis. Arrowhads indicate the entrances into t mucosa pouches. . The splenic lexure i normal. Note the light reflections from th drops o mucus o the mucos membre. D. The transverse coln shows he charcteristic normal lds or ridges (arroheads) between the sacculations of the wll of th colon. E. The ieocecal alve shos the uer lip arowheads) of te valve, which has a norml appearace. . Finlly, the mucous membane lining th

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inferior wall o floor of the ccum loos normal (Courtsy of M.. Brand.

Trauma o the Cecum and Clon Blunt o penetraing injuries to he colon occur. lunt inuries mot commoly occur where mbile parts of th colon transvere and sgmoid) jin the fxed part (ascending and descending). Pentrating injuries follwing stb wounds are comon. Th multipl anatomic relatinships o the diferent prts of te colon explain why islated clonic truma is uusual.

Cncer of the Large Bowel Cancr of the large bwel is relativel common in persns older than 50 ears. The growth is resticted to the bowe wall fr a consderable ime befre it speads via the lympatics. loodstrem sprea via the portal irculatin to the liver ocurs late If a dagnosis is made arly an a partil colectmy is peformed, accompaied by rmoval of the lymp vessels and lymph nodes draining the area then a ure can e antiated.

Diveticulosi Divrticuloss of the colon i a commo clinica conditon. It onsists f a hernation of the liing mucoa throug the crcular mscle beteen the eniae cli and ocurs at oints whre the circular muscle s weakes—that is, where the blod vesses pierce the musle (Fig. -38). he commo site fo herniaion is sown in Figre 5-38.

Ceostomy ad Colostmy ecause o the antomic moility o the cecum, trasverse clon, and sigmoid olon, they may b brought to the urface hrough a small oning in the anteior abdoinal wal. If th cecum o transerse coln is thn opened the boel contets may b allowed to dran by thi route. hese proedures ae referrd to as ceostomy or colosomy, espectivly, and re used to relive large-bowel obstructios.

Volulus ecause o its exteme mobility, th sigmoid colon smetimes otates aound it mesentery. This may corrct itsef spontneously r the rotation my contine until he bloo supply f the gt is cu off comletely.

Intussuseption Intussusceptin is the telescoing of a proxima segment of the bowel ino the lmen of n ading distl segmen. Needlss to sy, ther is a grve risk f cuttin off th blood spply to he gut nd deveoping gagrene. t is comon in chldren. Ieocolic, colocoic, and leoileal forms d occur, but ileoolic is he most common.

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snell The hih incidnce in cildren ay be cased by the relatively large size of the lrge bowl compared with he small intestie at thi time of life. Aother fator may e the possible welling f Peyer' patche seconday to inection. In the ltter cas, the sollen pach protdes int the lumn and vilent perstalsis f the leal wal tries t it distall along te gut luen. P.235

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Figure 538 Blood suppy to the colon (A) and fomation f the dverticulm (B). Note th age of the ucosal divericulum through te muscle coat alng the curse of the artey.

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Embrologic Ntes Developmnt of th Digestie Syste he digesive tub is formd from he yolk ac. The entoder forms te epitheial lining, and he splanhnic mesnchyme orms the surrouning musce and seous coat. The deeloping gut is ivided nto the forgut, migut, nd hindgut (Fig. 5-39).

Deveopment o the Esohagus The esphagus dvelops fom the nrrow pat of the foregut hat succeds the pharynx (Fig 5-39. At first, it is a short tube, but hen the eart an diaphra descend, it elonates rapidly.

Atrsia of te Esophgus tresia o the esohagus, wth and wthout fitula, wih the trchea is onsidere in detail on pae 99.

Esophgeal Steosis Esophagel stenoss is a nrrowing f the lmen of te esophagus, whih commony occurs in the lower pat. It is treated by dilaation.

Congenial Short Esophagus Abnormal shrtness of the esohagus is caused b an esohageal hatus heria in th diaphram. Stomah contens flow into the eophagus resultig in esophagitis.

Develpment of the Stomch he stomah develos as a dlatation of the oregut (Fig 5-40. To bein with, it has ventral and dorsl mesentry. Very active rowth tkes plac along te dorsal border, hich becmes convx and orms the geater curvature. The anerior brder becmes concve and frms the lesser crvature. The fundus appear as a diatation t the uper end o the stoach. At his stag, the somach ha a right and lef surface o which the righ and let vagus nerves re attaced, resectively (Fg. 5-40). Wit the gret growth of the rght lobe of the lver, the stomach s gradlly rotaed to th right s that th left suface becoes antrior and he righ surface, posterir. The vetral an dorsal mesenteries now hange position as a result of rotation of the stomac, and tey form he omenta and vaious peritoneal lgaments. The pouch of peritonem behind he stomch is knwn as the lesser sa.

Congenitl Hypertophic Pyoric Steosis Hypetrophic pyloric tenosis is a relaively comon emergency in nfants etween th ages o 3 and 6 weeks. Te child ejects te stomach content with cosiderabl force. The exac cause o the stnosis is unknown, althoug evidenc suggest that th number of autoomic ganlion cell in the tomach

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snell wll is fwer than normal. This possibility eads to prenatal neuromucular inordinaton and ocalized muscular hypertrohy and hperplasi of the yloric phincte. It is mch more common in male chidren.

Deveopment f the Dudenum The dodenum i formed rom the most caual portion of th foregut and the ost cephlic end of the mdgut. Tis regio rapidl grows t form a oop. At his time the duodenum has a mesentery tha extend to the osterior abdominl wall and is par of th dorsal esentery A smal part of the vental mesetery is lso atached to the vental borde of the irst par of the uodenum d the uper half of the second par of the duodenm. When he stomah rotats, the uodenal oop is frced to rotate to he right where te secon, third and fouth parts adhere to the postrior abdminal wal. Now he peritneum behnd the dodenum dsappears However some smoth muscle and fibrous tissue that belong t the doral mesetery remin as te suspensry ligamnt of th duodenu (ligamet of Tretz), nd this ixes the terminal art of e duodenm and prvents it from movng infeiorly (Fig. 541) The liver and pncreas aise as entodermal buds fro the devloping duodenum.

Atresia and Stnosis During he development of he duodnum, the lining cls prolferate a such a ate that the lume becomes completey oblitrated. Lter, as a result o degenertion of hese cels, the g become recanaized. Falure of ecanaliztion coud produc atresia r stenosis. Diffrent fors of duoenal atrsia and tenosis ae shown n Figure 5-42. Voiting is the mos common resentin symptom and the vomitus sually i bile stined. Sugical reatment during te first fw days o life is essentia.

Devlopment f the Jeunum, Ilum, Cecu, Appendx, Ascening Colon, and Proimal Two Thirds o the Trasverse Clon Dista to the uodenum, the smal intestne and te large intstine, s far as the dital thid of the transvee colon develop from th midgut. The midut increses rapdly in length an forms loop t the ape, on whih is atched the itellin duct; this dct e throug the widly open mbilicus (Fg. 5-39). At te same me, the dorsal msentery elongate, and ing though it rom the orta to he yol sac ar the viteline arteries. hese artries no fuse to form the sperior msenteric artery, whic supplis the migut and ts derivtives. he rapidy growig liver and kidneys now encroach on the adominal avity, ausing te midgu loop t herniat into the umbilial cord. A diveticulum ppears t the cadal end of the bwel loop, and ths forms he cecum. At irst the diverticlum is conical; ater the upper prt expans and orms the cecum, hile the lower pat remais rudimtary an forms te appendi (Fig. -43). After birth, the wall of the ccum grows unequaly, and the appedix coms to lie on its mdial sie. Wile the loop of ut is in the umilical crd, its ephalic limb becmes gretly elongated an coiled nd forms th future ejunum and greter part of the ileum. he cauda limb o the loo also increases in lengt, but it remains uncoild and frms the uture dital part of the leum, th cecum, he appndix, th scending colon and th poximal to thirds of the transvers colon.

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Rotatio of the idgut Lop in th Umbilicl Cord nd Its Rturn to he Abdominal Cavty hile in the umbiical cord, the migut rotaes aroun an axi formed y the superior mesenteric rtery an the vitlline duct. As on views te embryo from the anterior aspect, counteclockwis rotatio of appoximatel 90° ccurs (Fig. -44). Later, as the gt return to the bdominal cavity, he midgu rotates counterlockwis an addiional 18°. Thus a total rotation of 270° counterclockwie has ocurred (Fig. 5-45. he rotaion of the gut results in art of te large intestin (transvese colo) coming in front of the sperior mesenteric artery d the second par of the uodenum; the thid part o the dudenum coes to li behind he arter. The ceum and apendix cme into close cotact wit the rigt lobe of the livr. Later the cecm and pendix escend ito the rght iliac fossa o that te ascening coln and rght coli flexue are fored. Thu, the roation o the gut has reulted in te large gut coming to li laterally and encircle the centrlly placed sall gut he primtive mesnteries f the duodenum, scending and desending clons now fuse with the paietal peitoneum n the posterior abdominl wall. his explains how these parts of the develing gut become retroperioneal. Te primitve meseneries of the jejnum and ileum, te transvrse colo, and the sigmoi colon prsist s the meentery f the small intetine, th trnsvere mesocolon, and he sigoid mesolon, rspectivly. The rotation of the stoach and uodenum to the rght is argely rought aout by te great growth o the right lobe f the lver. Th left suface of he stomach becomes antrior, and he righ surfae become posterior. A pouch of eritoneu becomes located ehind he stomah and is called te lesse sac.

Fae of the Vitelline Duct The mdgut is t first onnecte with te yolk sac by the vtellie dut. By the tim the gu returns to the bdomina cavity the duct becomes obliterted and evers it connecion with the gu.

Devlopment f the Left Colic Flexure, Descendig Colon, Sigmoid olon, Retum, and Upper Half of te Anal Cnal The lft colic flexure descendin coln, sgmoid colo, retum, and upper haf of the anal caal are developd from te hindgu (see page 23).

Divertiula of te Intestne All coas of the intestinal wall are found in the wll of a congenitl divertculum. n the dodenum, iverticua are fond on te medial wall of the secd and tird parts (Fig. 5-42) Usualy, thes are symptomless. Jejunal iverticula occasonally ocur and usually give ris to no smptoms. or Meckl's diveticulum of the leu, see net colun. A diverticulm of the cecum is commony situted on te medial side of the ceum clse to th ileocecl valve It may be subjct to acte inflmation nd then s confued with appendictis. Diverticula of the colo are acqired, no congental (se pag 236).

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Atresia and Stensis of te Intesine The ost common ste of an atretic or senotic bstruction is in the duoenum (se previos page). The next most cmmon sies are he ileum and jejuum, respectively (Fig. -42). Frequetly, the obstrucion ocurs at mltiple stes. The cause is possibl the faiure of the lumen to becoe recanaized aftr it has been bocked by epithelil proliferatio of he cells of he mucou membrae. Other causes have ben suggeted, sch as vacular dmage asociated ith twisting or olvulus of the itestine. Persistet bile-stained omiting ccurs frm birth. Surgica relief of the bstrution hould be carried out as oon as pssible.

Duplicaion of e Digesive Syse In uplicatin of th digestie syste, the nomal deeneratio of the mucous mmbrane ells, whch have proliferted to emporariy block he lume, occurs at two sites simltaneousy instea of a one. In this wa, two luina are formed sde by side. he addiional segment of bowel should b remove as soon as possble, sice it ma cause ostructin or be he site f hemorrage or perforaton.

Arrested Roation or Malrotation of the Midgu Loop Cmplete bsence o Rtation o Incomplete Rotation Complte absece of rtation i rare. In cases f incomlete rottion no urther rtation ccurs ater the nitial countercckwise rotation f 90° n the umbilical ord. Thu, the dodenum, ejunu, and ileum reain on te right ide of he abdomn, and the cecu and colon are on the lef side of the abdmen (Fg. 5-42). In other caes, a conterclokwise roation of 180° occurs, an although the duodenu may tke up is corret positon posteior to he supeior meseteric atery, te cecum omes to ie anterior nd to the le of the duodenum Abnorma adhesios fom, whic run acrss the nterior urface o the dudenum an cause bstructin to its second art.

Malotation of the Mdgut Loo ounterclckwise rtation of 90° fllowed b clockwe rotation of 9° or 18° may ocur. In hese ases, the duodenum coms to li anterio to the uperior esenteri artery, and the colon ma come to lie anterio to the esenter of the mall intstine. Rpeated vomiting is usual the preenting symptom ad is caused by duodenal bstructin. Surgial corretion of he incoplete rotation o malroation of the gut is perfomed, and al adhesins are divided.

Persistence of the Vtellointestinal uct The itellin duct in the eary embryo connects the dveloping gut t the yol sac (Fig. 5-46). Nrmally, s develoment prceeds, te duct i obliterted, sevrs its onnectio with th intestne, and disappeas. Persitence of the vitllointetinal dut can result i an umblical fstula (se Fig. 4-38. If the duct remains as a fibrou band, a loop of small inestine cn become wrappe around t, causig intesinal obsruction (see Fig. 4-38).

Meckel' Diverticulum 447

snell Mecel's dierticulu, congental aomaly, represent a persstent prtion of the vitllointesinal dut The dierticulu is locted on te antimeenteric bordr of th ileum about 2 ft (61 cm) from the ileocecl juncton. It i about 2 in. (5 cm) long nd occurs in abut 2% of individals. The divertiulum is mportant clinicaly, sine it may possess a sall area of gstric ucosa, nd bleedng may ccur from a “astric― ulcer in its ucous mebrane. Moreover, the pain from this ulcer may be cnfused wth the pain from appendicitis. Shuld a ibrous bnd connet the diverticum to the umbilicus, a loop of small bwel may ecome wrpped arond it, ausing itestinal obstrucion.

Undesceded Cec and Apendix In ases of undescened cecum an appedix, an inflamation o the appndix woud give ise to endernes in the right hpochondrum, whih may led to a mstaken dagnosis f inflamation f the galbladder

Anomalies the Apndix Ageness of the appendix (faire to evelop) is extremly rare; howevr, a few eampls of double apendix have ben repored (Fig. 5-42). The pssibiliy of left-ided appendix in indiiduals wth tranposition of thoracic and abdomina viscera or in cses of arrested otation f the midgut shuld alwas be emembere (Fig. 5-42)

Anomals of the Colon The cngenital anomaly of undeended ccum or failure f rotatin of the gut so tat the cum lie in the eft ilic fossa may give rise to onfusio in diagsis. Th pain of appenicitis, for example, alhough intially sarting i the umblical reion, may shift nt to the right ilac foss, but to the rigt upper uadrant or to th left wer quarant. P.238

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Figue 5-39 The oregu, midgu, and hidgut. Th positions of th ventral and dosal mesnteries, the hepaic bud and the ventral nd dorsl pancratic bud are als shown.

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Figure 5-40 Developent of te stomah in elation to the ventral nd doral meenteries. Note how the stomach otates s that th left vus nerv comes o lie on the antrior surace of he stomach. Note also the positin of the lesser ac.

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igure 5-41 Th developent of he pancras and te extrahepatic biliary appratus.

Bloo Supply f the Gatrointesinal Trct Arerial Suply he arteral supply to the gut and ts relaionship o the developmet of the differet parts of the t are ilustrate diagrammatially in Figure 5-46. The celac artey is the artery of the fregut ad supplies the gstrointestinal ract fro the lowr one thrd of te esophaus down s far as the midle of th second part of he duodeum. The uperior mesenterc arter is the rtery o the midut and upplies he gastrointestnal tract from the mddle of the econd pat of the duodenu as far as the dstal one third of the tansvere colon. The infeior meseteric rtery is the artey of the hindgut and suppies the large inestine rom the istal on third f the trnsverse colon to halfway own the anal canal.

Celac Arter

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snell The celiac atery or runk is ery shor and arises from the commncement f the abominal orta a the levl of the 12th thracic vrtebra (Fg. 5-20). It s surrouded by the celic plexus and lies behid the lesser sac of peitoneum. It hs three erminal branches the let gastri, splenc, and hpatic ateries.

Lt Gastric Arter The small lft gastrc artery runs o the ardiac ed of te stomac, gives off a fe esophaeal branhes, then turns to the right alon the leser curvaure of te stomac. It anstomoses with the rigt gastri artery Fig. 520).

Spenic Arery Te large splenic rtery rns o th left in a wavy curse aong th upper order of the pancreas and behind te stomac (Fig. 5-4). On reachng the lft kidne the artry entes the spenicoreal ligamnt and rns to th hilum f the speen (Fig. 5-11).

ranches  

Panreatic ranches The left gastroepiploic artery rises ner the hium of th spleen and reaces the greater crvature of the stomach i the gasrosplenic omentu. It es to the right P.24

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alng the reater crvature of the somach btween th layers of the geater oentum. I anastomoses with the right gasroepipoic arter (Fig 5-20.

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Fiure 5-42 Some ommon cogenital anomalie of the ntestinal tract. 1â“3. ongenita atresias of the small intestine. 4. Divericulum of the dodenm or jejunum 5. Mesnteric yst of te small ntestin. 6. Abence of he appenix. 7. Duble appndix. 8. Malrotaton of te gut, wth the appendix ying in the left iliac fossa. For Meckel's diverticulum, see Figure 4-38.

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Figure 5-43 Stages n the development of the cecum an appendx. The fnal stags of dvelopmen (stages 4, 5, nd 6) tae place fter birh.

Figure 5-44 eft side views of the couterclockise 90° rotation of the midgut lop while

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it is i the extembryonc colom in te umblical cod.

Fiure 5-45 Left side views (A B) o the couterclockise 180Â rotation of the midgut oop as it is witdrawn ino the abominal cvity. C. The descet of the cecum takes lace laer.

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Fiure 5-46 Formtion of he midgt loop (shaded). ote how the supeior mesenteic artery and vitellin duct fom an axi for the future tation f the migut loop



The short gstric ateries, ive or sx in number, aris from the end of the spleic artey and reach the fndus of he stomah in th gastroslenic omntum. Tey anastomose wit the let gastri artery and the eft gasroepipoic artry (Fig. 5-2).

Hepatic Artery The edium-sie hepati artery* runs foward and to the ight and then asends beeen the layers o the lesser omentum (Figs. -7 and 5-11). It lies in front of the opening ito the lesser sa and is laced to the lef of the ile duct and in ront of the portl vein. t the pota hepatis it diides int right ad left branches o supply the corespondig lobes f the ler.

Brances 



The righ gastric artery arises from th hepatic artery t the uper borde of the ylorus and run to the eft in te lesse omentum along th lesser urvature o the stmach. It anasomoses ith the left gasric artey (Fig. -20). The gastoduodena artery is a lrge branch that escends behind the first part of th duodenum. It diides ino the right gastroeiploic atery hat run along the greater curvatre of he somach etwee the ayers of the greater oentum and the supeior

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

panceaticodudenal arery that descends beteen the econd pat of the duodenum and the ead of te pancres (Figs. 5- and 5-0). he right and left epatic ateries enter te porta epatis. he righ hepatc artery usually gives of the cystic artery, which runs to he neck of the gllbladdr (Fig. 5-47).

Supeior Mesenteic Arery The suerior msenterc artey supplies the distal pat of th duodenu, the jjunum, he ileum the cecm, the apendix, he ascnding clon, an most o the trasverse clon. It rises fom the front o the abdminal aota jut below he celia artery (Fig. 5-32) and rus downwad and to the righ behind he neck of the pncreas and i fron of the hird part of the duodenum It contnues ownwrd to he right between he layes of the mesentery of th small itestine and end by anasomosing ith the leal brach of its ow ileocolic branch.

Brances 

The inferor pancraticoduoenal arery asses to the righ as a sngle or ouble brnch along the uper borer of te third art of te duodenum and the head o the panreas. It supplis the pacreas ad the aing art of e duodeum. P.244

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Figure -47 Sructures ntering and leaving the prta hpatis

  



The middl colic artery uns forard in te transvrse mesoolon to upply te transvrse coln and diides into right nd left ranches. The right colic artery is oftn a branh of the ileocoli artery. It pases to th right to suppl the ascnding coon and ivides ito asceding and descending branhes. The ileoclic artey pases downard and o the riht. It ives ris to a superior brach tht anastooses with the right colic arter and n inferior branc tha anastooses wih the nd of th superir mesentric artey. The iferior ranch gies rise o the anteior and osterior cecal areries; the appenicular atery is a brach o the poserior ceal arter (Fig. -33). he ejunal nd ileal branches are 2 to 15 n numbe and arie from te left sde of the superir mesentric artey (Fig. 5-2). ach artey divides into t vessel, which nite with adjacent banches to form a series of arades. Brnches frm the arcades ivide ad unite to form a second third, nd fourth series of arcads. Fewer arcade supply he jejunm than spply the ileum. Fom the trminal arcades, small sraight vessels supply he intestine.

Inferior Mesentec Arter Th inferior mesentric artery supplis the dital thir of the transvere colon, the lef colic lexure, he desceding colon, the sigmoid olon, th rectum and the upper hlf of the anal canal. It arise from te abdoinal aora about 1.5 in. 3.8 cm) bove its ifurcatin (Fig 5-36. The atery run downwrd and t the lef and croses the left comon ilia artery. Here, t become the suprior rectal arery.

Braches 

 

The lef colic atery runs upward and o the let and suplies th distal hird of the trnsverse olon, th left coic flexre, and he upper part of the decending olon. It divides into ascndig and descending brances. Te sigmoid rteries are to or thre in nuber and upply te descening and igmoid colon. Te superior rectal tery is a cotinuatio of the inferio mesentric artey as it rosses he left common iiac artey. It decends ito the elvis beind the rectum. The artery supplis the retum and upper haf of the anal canl and aastomoss with te middle rectal nd infeior rectl arteris.

Marginal Arery The anatomosis f the clic arteies arond the cncave margin of the large intestne foms a single artrial truk called the maginal arery. Thi begins at the ieocecal juction, were it nastomoes with he ilea branche of the superior mesenteric arter, and it ends were it anastomoes less freel with th superio rectal artery (Fig. -36)

Embryologi Notes Exlanation fo the Blood Supply to the astrointstinal Tact

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Forgut Artries The cepalic end of the fregut (hich incudes the pharyn) and th cervicl and thracic prtions o the esphagus ae supplied by te ascendng pharngeal areries, platin arteries, sperior nd infeior thyrid arteies, brochial ateries, nd esopageal brnches fom the aorta The caual end o the forgut (wich incldes the distl third f the esphagus, he stomah, and te proximal half of the dodenum) is suppied by a number f vessel that use to frm a sngle truk, the celiac arery (Fig. 5-46. It s intersting to note that this atery als supplie the livr and pancreas, which ar glandulr derivaives of this par of the ut. The spleen s also spplied b the sam artery, which is not surprisig, sine this ogan deveops in the dorsa mesentey of the foregut the arter to the spleen rns in te spleniorenal igament.

Midgt Artery The idgut, wich exteds from alfway long the second prt of th duodenm to the left coic flexue, is spplied b the superior meseteric arery, hich repesents he fused pair of itelline arteris (Fig. 46).

Hindgut Artery The indgut, hich exends fro the let colic lexure t halfwa down te anal cnal, is supplie by the inerior msenteric artery (ig. 5-46). This reresents number of ventral braches of he aort that fue to fom a single artery. P.245

Venous rainage The vnos blood rom the greater art of te gastrintestinl tract nd its ccessory organs rains to the live by th portal enous sytem. The roximal ributaris drain directly into the portal vein, but the veis formig the dtal triutaries orrespon to the branches of the celac arter and the superior and inferior mesenteric arteres.

Prtal Vein (epatic Prtal Vei) The poral vein Fg. 5-22) drains blood frm the abominal prt of the gastrotestina tract fom the ower third of th esophags to hafway don the anl canal; it also drains bood fro the splen, paneas, and gallblader. The portal vein entrs the lver and breaks u into sinusoids, from whih blood es ito the hpatic vens that oin the inferior vena cav. The prtal ven is abot 2 in. (5 cm) lng and is formed behind the nec of the ancreas by the nion of he superor meseneric and splenic veins (Fi. 5-48). It asends to he righ, behind the firs part of the duodnum, and enters he lesse omentum (Fgs. 5-7 and 5-11). It then run upward in front of the oening ino the leser sac o the porta heptis, whee it divdes into right ad left trminal banches.

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Figre 5-48 Formaion of te porta vein beind the eck of te pancreas.

The portl circulation beins as a capillar plexus n the ogans it rains and ends b emptyin its bld into inusoid within the liver. For the relation of the portal ven in the lesser entum, e Figures -7 an 5-11

Trbutarie of the ortal Ven he tribuaries o the poral vein are the plenic ein, superior meenteric ein, lef gastri vein, rght gastic vein, and cystic vein. 





 

Spenic ven: Tis vein eaves the hilum f the speen and es t the rigt in th splenicorenal igament. It unites with the superor meseneric vei behind the neck of the pncreas t form te porta vein (Fig 5-48). It receives te short gastric, left gasroepiploc, inferor mesenteric, ad pancretic veis. Inerior meenteric vein: This vein ascend on the osterior abdomina wall an s the splenc vein bhind the body of he pancras (Fig. 548). t receivs the suerior retal vein, the sgmoid vens, and the left colic vin. Superior mesnteric vin: This vei ascends in the oot of te mesentry of th small ntestine It pases in front of th third part of te duodenm and jons the plenic vin behin the nec of the ancreas Fig. 5-48). It ceives the jejual, ileal, ileoclic, rigt colic, middle clic, iferior pncreatioduodena, and right gastoepiploi veins. Left gastric vein: This vein dains the left porion of he lesse curvature of the tomach and th distal art of he esophagus. It opens diectly ino the prtal vei (Fig. 522). Right astric vin: his vein drains he right portion of the lser curture o the stoach and drains irectly nto the ortal ven (Fig. 5-2).

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Cysti veins: Thes veins ether drain the gllbladder directy into te liver or he porta vein (Fig 5-22.

Clincal Notes Portalâ“Systemi Anastomoses Under ormal coditions, the portal venous blood traverses the liver and rains ino the nferior ena cav of the systemic venous crculatio by way f the hepatic vins. Thi is the direct oute. Hwever, ther, saller comunicatins exis between the poral and stemic stems, nd they ecome imortant wen the drect route becoes bloced (Fig. 5-49). Thee communcations are as ollows: 







At the lower thrd of th esophags, the sophagea branches o the lef gastric vein (potal tritary) anastomose with the esophageal veins raining he middl third o the esphagus ito the aygos veis (systeic tribuary). alfway down the aal cana the suerior rectal veins (portal tributary) drainig the uper half of the aal cana anastomose with the middle and inferior recl veins (systemic tributaries), which are ributaris of the internal iliac an interna pudendl veins, respectiely. The parumbilic veins connec the lef branch f the potal vein with the superfical veins of the nterior bdominal wall (sytemic triutaries) The paaumbilicl veins ravel in the falcform ligment and accompan the liamentum eres. he vein of the scending colon, descendig colon, duodenum pancrea, and lier (poral tribuary) anstomose ith the enal, lbar, and phrenic veins (sstemic ributaris).

Porta Hypertnsion Porta hypertesion is common clinical conditio; thus the lis of poral–sysemic anstomoses should e remembred. Enargement of the ortal–ystemic connectins is fequently accompaied by ongestiv enlargeent of te splee. Portacaval shnts or the teatment of porta hypertnsion ma involve the anasomosis f the prtal ven, becaue it lis within the leser omentm, to th anterior wall f the inerior ena cav behin the entance into the lesser sac. The splenic vein ma be anatomosed o the let renal vein afer removng the sleen.

Blood Fow in the Portal Vein and Malignat Disea The potal vein conveys bout 70 of the lood to he live. The reaining 0% is oxgenated blood, hich pases to te liver via the hepatic rtery. he wide ngle of union of the splnic vein with the superir mesentric vein to fom the potal vein leads t streamng of th blood fow in te portal vein. Th right lobe of the liver receives blood mainly from the inestine, whereas he left obe plu the quarate an caudat lobes rceive blood from the stoach and the splen. This istributon of blod may eplain th distribtion of seconday malignnt deposts in th liver. .246

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Dfferenc Betwee the Smal and Lage Intesine Exernal Diferences (ig. 5-50    

 

The small intestine (with the exception of the duodenum is mobie, wheres the asending nd desceding parts of te colon are fixe. Th caliber of the fll small intestie is smler tha that of the filld large ntestin. The sall intetine (with the exception f the dudenum) hs a mesetery that es downward across he midine into the righ iliac fssa. The longitudnal musce of the small ntestine forms a cntinuous layer around the ut. In he large intestie (with the excetion of the appenx) the ngitudinl muscle is collected int three ands, th teniae coli. Te small ntestin has no atty tag attached to its wall. Th large itestine as fatty tags, clled the appendice epiploiae. The wall of he small intestine is smth, wheeas that of the lrge intetine is sacculatd.

nternal Differenes (Fig. 550)   

The mucos membrne of th small itestine as permaent fold, called picae cirulares, which are abset in the large ntestin. The mucos membrne of th small intestin has villi, which ae absent in the lage intetine. Aggreations o lymphoi tissue alled Pyer's paches are found in te mucous membane of te small intestie; these are abset in the large intestine.

ory Ogans of he Gastrintestial Trac Liver Locatin and Dscriptio Th liver i the larest glan in the ody and has a wde variey of funtions. Tre of it basic fnctions re prodution an secretin of bie, which is ed into the intestial tract involvment in many metaolic activities lated t carbohyrate, fa, and proten metaboism; and filtratin of th blood, emoving acteria and oth foreig particls that hve gained entranc to the lood frm the lmen of te intestine. Th liver snthesize hepari an antcoagulan substance, and as an imortant dtoxicating functon. It poduces ble pigmnts from the hemolobin of worn-out red blo corpuscles and secretes bile salts; thes together are coveyed to the duodnum by te biliay ducts. The liver is sot and pliable an occupis the uper part f the abominal city just beneath the diahragm (Fig. 5-1). The greater art of te liver is situaed under cover of the righ costa margin, and the ight heidiaphram separtes it fom the leura, lungs, pericardium and heat. The lver exteds to th left to reach te left hmidiaphrgm. The onvex uper surfae of the liver is molded o the unrsurfac of the domes of the diapragm. Th posteroinferior, P247

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o isceral surface, is mlded to djacent viscera nd is therefore regular in shape it lis in conact with the abdoinal pa of the sophagus, the stmach, te duodeum, the ight colc flexur, the riht kidne and suparenal land, and the gallbladder

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Figre 5-49 Importnt porta–systemic anastomoses.

The live may be ivided ito a lare right loe and a small left lobe by the atachment of the ritoneum of the flciform igament Fi. 5-8. The riht lobe s furthe divided into a quarate lob and cudate le by the presence of the gallladder, the fissre for te ligamntum tees, the nferior ena cava and the fissure for the igamentu venosm. Experiments hve shown that, i fact, te quadrae and cadate loes are functional part f the let lobe o the lier. Thus the riht and lft branches f th hepatic artery ad portal vein, an the riht and lft hepatc ducts, are distibuted t the rigt lobe ad the lft lobe plus quarate pls caudat lobes), respectiely. Apprently, the two ides ovrlap very little The prta heptis, o hilum of the lier, is fund on te posterinferior surface nd lies between he caudae and qudrate loes (Figs. 58 and 5-9). The upper pat of th free ede of the lesser oentum i attache to its argins. n it P.28

lie the righ and lef hepatic ducts, te right and left branches of the hepatic artery, te portal vein, an sympathtic and parasymathetic erve fibrs (Fig. 5-7). A few heatic lyph nodes lie here they drin the lver and gallblaer and send their efferent vessels o the ceiac lymp nodes.

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Fiure 5-50 Some external and intenal diffrences tween the small and the large intetine.

The iver is ompletel surrouned by a fibrous apsule bt only prtially covered y peritoeum. The liver is made up f liver loules. he central vein of each lbule is tributary of the epatic veins. In the spacs betwee the lobles are he portal cnals, which contain braches of he hepatc artery portal ein, and a tribuary of a bile duct (portal triad). The arteral and vnous blod e between the live cells b means o snusoids and drins into he centrl vein.

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Imprtant Relations  

Anterorly: Diaphrag, right nd left ostal magins, riht and lft pleur and loer margis of both lungs, xphoid prcess, an anterio abdominal wall i the subostal anle Posteiorly: Diaphram, right kidney, epatic fexure of the colo, duodenum, gallbladdr, inferor vena cava, and sophagus and funds of the stomach

Perioneal Liments of the Liver he falciform ligament, whic is a tw-layered fold of the peritoneum, ascnds fro the umblicus to the live (ig. 5-8). It hs a sicke-shaped free marin that ontains he ligamentum tere, the rmains o the umbiical vei. The faciform lgament psses on o the aterior ad then te P.249

sperior srfaces o the liver and th splits nto two ayers. Te right ayer fors the uper layer of the coroary ligaent; he left ayer fors the uper layer of the left triangulr ligamet (Fig. -8). he right extremit of the oronary igament is known as the right triangulr ligamet of he liver It shoud be notd that the peritoal layer formig the cronary lgament ae widely separated leaving an area f liver evoid o peritonum. Such an area s referr to as a bre area of the liver (Fig. -8). The ligmentum tres psses int a fissue on the visceral surface f the lier and s the eft branch of the ortal vin in th porta heatis (Figs. 5-9 ad -22). he ligamenum venosu, a fbrous bad that is the remans of th dctus vensus, is ttached o the left branch of the rtal ve and scends in a fisure on the viscra surfac of the iver to be attaced above to the nferior ena cva (Fis. 5-8 and 5-22). In he fetus oxygenaed blood is brough to the iver in he umbilcal vei (ligamentum teres. The grater proortion o the blod byasses te liver n the dutus venous (ligaentum venosum) an s te inferior vena cava. At birth, the umbilical vein a ductus enosus close and become fbrous cods. The lesser omentum arses fro the edgs of the porta heatis and the fissre for te ligametum vensum and asses don to the lesser crvature f the stmach (Fig. -10).

Blod Supply Arteris The hepatic rtery, a branch o the celac artery, divides into rigt and let terminl branchs that eter the orta hepatis.

Clinial Notes Live and Surgry he liver is held n positin in th upper prt of the abdominl cavity by the atachment of the hpatic vens to th inferior vena caa. The pritoneal ligament and the tone of the abdomial musces play

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Liver Trauma The lier is a oft, frible struture encosed in fibrou capsule Its close relationship to the lowe ribs must be empasized. ractures of the lwer ribs or penetting wounds of th thorax or upper abdomen re commo causes o liver ijury. Blnt trauatic injries from automobie accidets are aso commo, and svere hemorhage acompanies tears of this orga. Becaus anatomi researc has shon that te bile dcts, hepatic arteies, and portal vein are dstribute in a semental anner, apropriate ligation of these structurs allows the surgen to reove larg portion of the iver in atients ith sevee traumaic laceations o the liv or with a liver umor. (Een large localize carcinmatous mtastatic tumors hve been uccessfuly remove.)

Liver Bipsy Lier biops is a comon diagostic prcedure. ith he patint holdig his or her breah in ful expiraton—to educe th size o the costdiaphragatic recess and th likelihod of daage to te lungâ”a needl is inseted throgh the rght eigh or nint intercotal spae in the midaxillry line. he needl es hrough te diaphrgm into he liver and a sall specmen of lver tiss is remoed for icroscopc examintion.

bphrenic Spaces The imortant sbphrenic spaces ad their elationsip to te liver are described on pge 208. nder noral condiions these are pential spaces onl, and th peritonal surfaes are i An abnrmal accmulation of gas o fluid i necessar for sepration o the peitoneal urfaces. The anteror surfae of the liver is normally dull on percussin. Perforation of gastric ulcer is often acompanied by a loss of livr dullnes caused by the acumulatin of gas over the anterio surface of the lver and n the subphrenic ace.

Veins The poral vein divides ino right nd left erminal ranches hat ente the pora hepati behind he arteres. The heptic vein (thre or more) emerge rom the osterior surface f the lier and dain into the infeior vena cava.

Blood Ciculation through the Liver Th blood vssels (Fig. 5-47) conveyig blood o the liver are te hepati artery (30) and potal vei (70%). he hepatc artery brings oxygenated blood to he liver and th portal ein brins venous blood rih in the products of digetion, whch have een aborbed frm the gatrointesinal trat. The rterial nd venou blood is conducted to the central vin of eah liver lobule b the livr sinusods. The entral vins drai into th right and left hepatic eins, an these lave the posterior surface the liver and open direcly into he inferor vena ava.

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Lyph Drainge Th liver poduces a large amount of lmph—about one ird to oe half o all bod lymph. he lymph vessels eave the liver ad enter everal lmph nodes in the prta hepais. The efferent vessels ass to te celiac nodes. A few vessls from the bare area of the iver throgh the daphragm o the poterior mdiastinal lymph des.

Nrve Suppy Sympathetic ad parasypathetic nerves frm the cliac plxus. The antrior vagl trunk ives ris to a lage hepatc branch which asses diectly to the live. .250

Bil Ducts o the Liver Bie is seceted by he liver cells at a constant rate about 4 mL per our. Whe digestin is not taking pace, the bile is stored ad concenrated in the gallbladder; later, it s deliveed to e duodenum. The ile duct of the iver conist of te ight nd left heptic duct, the comon hepatc duct, the bile duct, the gallladder, and th cstic duc. The smallet interlbular trbutaries of the ble ducts are sitated in the portal canals o the livr; they eceive te bile analicul. The inerlobular ducts jon one anther to orm proressivey large ducts ad, evntually, at te porta epatis, orm the right an left hepatic ducts. The right hepatc duct dains the right lbe of th liver ad the let duct dains the left lob, caudat lobe, nd quadrte lobe.

Hepati Ducts The rigt and let hepatic ducts eerge from the right and le lobes o the livr in the porta heatis (Fig. -47). After a hort couse, the epatic ducts unite to form he commo hepatic duct (Fig. -29). The common hepatic uct is about .5 in. (4 cm) long and descnds withn the fre margin of the esser omntum. It s ed on the rght side by the cstic duc from te gallbladder to orm the ile duct (Fig 5-29).

Bile Duct Th bile dut (commo bile dut) is abut 3 in. 8 cm) lng. In te first art of is course it lies in the rght free margin f the leser omenum in frnt of th opening into the esser sa. Here, it lies n front f the riht margi of the ortal ven and on the right of the epatic atery (Fig. 5-11). In the scond par of its ourse, it is situed behin the firt part o the duoenum (Fig. -7) t the righ of the astrodudenal artry (Fig. 54). n the thrd part of its course, t lies in a groove on the osterior surface f the hed of the pancreas (Fig. 5-29). Hee, the ble duct omes int with the main panreatic dut.

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Figur 5-51 Terminal parts o the bil and panreatic dcts as tey enter the secnd part f the dudenum. Nte the shincter f Oddi and the smooth mucle aroud the ens of the bile duc and the main panreatic dct.

Th bile dut ends blow by percing te medial wall of he secon part of the duodnum abou halfway down its ength (Fig 5-51) It is sually jined by he main ncreatic duct, an togethe they oen into small ampulla in he duodeal wall, called te epatopanreatic apulla (apulla of Vater). The amulla opens into th lumen o the duoenum by eans of small papilla, the ajor duoenal papilla (Fig. 551). he termial parts of both ucts and the ampula are srrounded by circular musce, known as the sphncter of the hepaopancreaic ampula (sphincter of Oddi) (Fig 5-51. Occasonally, he bile nd pancratic duts open eparatey into te duodeum. The ommon vriations of this rrangemet are swn in igure 5-52.

Gallbladder Locion and Descriptin Te gallbldder is pear-shped sac lying on the undesurface o the livr (Figs. 5-, 5-9 and 5-29. It ha a capacty of 30 to 50 mL and stors bile, hich it concentrats by aborbing wter. The gallblader is diided int the funus, body, and neck. The funds is runded an projecs below he inferior margin of the liver, whe it comes in cotact wit the antrior abdminal wal a the levl of the tip of the nint right cstal carilage. Te body ies in cntact 469

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wih the viceral surface of the livr and is directed upward, ackward, and to te left. he neck becomes ontinuous with the cystic dct, whic turns ito the lsser omntum to oin the ommon heatic duc, to form the bile duct (Fig. 5-29).

Figue 5-52 Three cmmon varations o terminaions of he bile nd main pancreatic ducts a they ener the scond par of the uodenum.

The peritoneum completely urrounds the funs of the gallblader and inds the body and neck to he visceal surfae of the liver.

Reations  

Anterioly: The anerior abominal wll and te inferir surfac of the liver (Fig. -2) Postriorly: The tranverse colon and the first ad second parts of the duodnum (Fig. 529)

Functio of the allbladdr Wen digesion is nt taking lace, te sphincter of Oddi remains closed nd bile ccumulats in the gallblader. The gallblader concentrates ile; stos bile; electivey absorb bile slts, keeing the bile acid; excrete cholesteol; and ecretes ucus. T aid in these funcions, th mucous embrane s

470

snell thrown into permanent fods that nite wit each oter, givig the surface a hoeycombe appearace. The olumnar ells linng the srface hae numeros microilli on teir free surface. Bile i deliverd to the duodenum as the rsult of contracton and prtial emtying of the gallbladder. This mechanism is initiat by the entrance of ftty oods int the duoenum. Th fat cases relese of th hormone colecystoinin rom the ucous mebrane of the duodnum; the hormone hen enters the bood, causng the gllbladde to . At he same time, the smooth musle aroun the disal end o the bile duct an the amplla is elaxed, hus alloing the assage o concentrated bile into th duodenum. The bile salts in the bie are imortant i emulsifing the fat in te intestne and i assistig with its digestion and aorption.

Blood Supply The cystic artery, a branh of the right heatic artry (Fig. 5-7), supplies th gallblader. The ctic vei drain directl into th portal ein. Sevral very small areries an veins aso run btween th liver ad gallbldder.

Lmph Draiage Te lymph rains ino a cystic lymph nod sitated nea the nec of the allbladde. From hre, the ymph vesels pas to the epatic ndes along the coure of the hepatic rtery an then t the celac nodes

Nrve Suppy Symathetic nd parasmpatheti vagal fbers for the ceiac plexus. The galbladder contract in respnse t the hormone cholecysokinin, hich is roduced y the muous membane of te duodeum on th arrival of fatt food frm the stoach.

Clinical Notes Gallstoes Galstones ae usuall asymptoatic; hoever, thy can gie rise t gallstoe colic or produce acute chlecystits.

Biliar Colic Biliary colic is usually aused by spasm of the smoot muscle of the wll of th gallblader in a attempt to expel a gallsone. Affrent nere fibers ascend tough the celiac plexus and the greter splachnic neves to te thoracc segmens of the spinal ord. Refrred pain is felt n the riht upper quadrant or the pigastriu (T7, 8, and 9 dematomes) Obstction o the bilary duct with a gallston or by compresson by a umor of the panceas resuts in bakup of ile in te ducts and deveopment of aundice. The mpaction of a stoe in the ampulla of Vater may resut in the age of infeced bile nto the ancretic duct producig pancretitis The antomic arangement of the trminal prt of th bile dut and th main pncreatic duct is ubject o

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snell considerable vaiation. he type f duct ystem prsent detrmines wether inected bie is likly to ener the ancreati duct. Gallstone have ben known o ulcerate through the galbladder wall int the trasverse clon or te duodenm. In th former case, thy are pased natully per the rectum, but i the latter case they my be hel up at he ileoccal juncion, proucing itestinal obstructon.

Aute Choecystiti Acue cholecystitis produces iscomfor in the right uper quadant or pigastium. Infammation of the allbladdr may cause irrtation o the subiaphragmtic parital perioneum, wich is upplied n part b the phrnic nerv (C3, 4, and 5). his may ive ris to refered pain over the shoulder becaus the ski in this area is supplied by the spraclaviular neres (C3 nd 4).

Cholecystectomy ad the Arerial Spply to he Gallbadder Before attmpting cholecytectomy operatio, the urgeon mst be aare of he many variations in th arteria supply to the allbladder and th relatioship of the vessls to th bile duts (Fig. 5-53) Unfortnately, here hae been sveral reorted caes in whch the ommon hpatic dut or the main bil duct hae been icluded i the arerial liature wih disastous conequences

Gangree of the Gallblader Unlike te appendx, which has a sngle artrial supply, th gallblader rarey become gangrenus. In addition o the ysic arter, the gallbladder also recives smll vesses from te visceal surace of te liver. Soograms cn now be used to emonstrte the gllbladde (Fig. 5-5). P.252

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Fure 5-5 Some common ariation of blood supply to the gllbladde.

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Fiure 5-5 Longudinal sonogram f the uper part f the abomen shoing the umen of the gallbladder. (Courtes of Dr. M.C. Hill.

P.253

ystic Dct Th ystic dut is bout 1.5 in. (3.8 cm) lon and conects the neck of the galbladder o the common heptic duct to form he bile uct (Fig. -29). It usualy is somwhat S-saped and descends for a vaiable ditance in the rigt free argin of he lesser omentum The muous memrane of he cysti duct is raised t form a spiral fld that is contiuous with a simiar fold n the neck of the gallblader. The fold is ommonly nown as the “spral valv.― The functin of the spiral valve is o keep te lumen onstantl open.

Embryoloic Note 474

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Deelopment of the iver and Bile Ducs Liver The livr arises from the distal ed of the foregut a a solid bud of etodermal cells (Fig. 5-41 and 5-55). The ste of orgin lies at the aex of th loop of the deveoping dodenum ad corresnds to point halfway alog the seond part of the ully fored duodeum. The heatic bud grow anteriorly into e mass of splancnic mesoerm calld the setum transversum. The end f the bu now divdes into right and left branches, rom whic columns f entodemal cell grow ino the vacular mesoderm. Te paired vitellin veins ad umbilial veins that course throuh the setum tranversum bcome broen up by the invaing columns of lier cells and form the liver sinusoid. The columns f entodemal cell form th liver cords. The connective tissue of the lver is frmed fro the mesenchyme of the septm transersum. Th main heatic bud and its ight and left terinal braches now become cnalized to form te ommon heatic duc and he right nd left heptic duct. Th liver gows rapily in sie and comes to occupy the reater pt of the abdominl cavity the rigt lobe bcomes much larger han the eft lob.

Gllbladde and Cysic Duct The gallblader develops from he hepatc bud as a solid utgrowth of cells (ig. 5-41). The end of te outgroth expans to for the galbladder, while the narrow tem remans as th cystic uct. Latr, the gllbladde and cytic duct ecome caalized. he cysti duct no opens ito the commn hepati duct o form te ile duct

Biliry Atresia Faiure of te bile dcts to cnalize dring devlopment auses atresia. The various orms of tresia ae shown n igure 5-6. Jaundice apears soo after rth; cla-colored stools ad very drk coloed urine are also present. urgical orrectio of the tresia hould be attempted when poible. If the atreia canno be corrcted, the child wll die o liver filure.

Absence f the Gallbladder Occaionally, the outgowth of ells fro the heptic bud fails to develop. In these cases, tere is n gallblader and no cystic duct (Fig. 5-57).

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Fiure 5-55 Deveopment o the duoenum in elation o the ventral and orsal msenteris. Stipped area, foregut; crosshatced area, midgut.

Doble Gallladder Rarely, the outgowth of ells fro the heptic bud ifurcate so that two gallladders re forme (ig. 557).

Asence of the Cystc Duct In abence of the cystic duct, the entire outgrowth of cell from th hepatic bud deveops into the gallladder ad fails o leave the narrow stem tht would ormally orm the ystic dut. The allbladdr drains directly into the bile duc. The coition ma not be recognizd when prforming a cholecstectomy, and the ile duct may be eriously damaged y the sugeon (Fig. -57).

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Accessoy Bile Dct A mall accssory bie duct my open directly from the liver ino the galbladder which ay cause leakage f bile ito the eritonea cavity after cholcystectoy if it s not reognized t he time of surgey (Fig. 5-7).

ongenita Choledochal Cyst Rarly, a chledochal cyst develops becuse of a area o weakness in the wall of th bile duct. A cyt can conain 1 to 2 L of ile. The anomaly s importnt in tht it ma press o the bil duct ad cause obstructve jaunice (Fig. 5-57). P.254

P.255

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Figue 5-56 Some common conenital nomalies of the iliary dcts.

Figre 5-57 Some common cogenital nomalie of the allbladdr.

P.26

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Pancreas ocation nd Descrption The pacreas is both an exocrine and an ndocrine gland. he exocrne portin of the gland poduces a secretio that cotains ezymes caable of ydrolyzing proteins, fats and carohydrate. The edocrine portion f the glnd, the pacreatic islets (islets of Langerhas), prduces th hormone nsulin and glucagn, whch play key rol in carbhydrate etabolis. Th pancreas is an longated structue that les in he epiastrium nd the lft upper quadran. It i soft an lobulatd and situated n the poterior adominal wall behnd the eritoneu. It crosses th transpyoric plne. The ancreas is dividd into a head, eck, bo, and til (Fi. 5-58). The head of te pancreas is dic shaped and lies within te concavty of the duodenum (Fig. 5-58). A prt of the head extnds to te left bhind the superior mesenterc vessel and is alled the uncinate process. he neck is the cstricted portion of the pncreas ad connecs the hed to the body. It lies in front of the begining of he portal vein and the orign of the superio mesenteic arter from th aorta (Fig 5-26.

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Figure -58 Dfferent arts of he pancras disseced to reeal the uct systm.

The body run upward nd to the left across the midline (Fig. 5-4. It is omewhat riangula in cros section Te ail psses forward in the spleniorenal liament an comes i with the hilum of the splen (Fig. 5-4).

Relatios  

Antriorly: From rght to lft: the ransverse colon an the attchment o the trasverse msocolon, the lessr sac, and the stomach (Figs. 5-4 an 56) Posterorly: From riht to left: the ble duct, the porta and splnic vein, the iferior vna cava, the aorta, the oigin of he superior meseteric atery, th left psas muscl, the let supraenal glad, the lft kidny, and te hilum f the speen (Figs. 5-4 an 527)

Pancreati Ducts 480

snell The mai duct o the panreas egins in the tai and run the legth of te gland, receivin numeros tributries on he way (Fig 5-58. It opes into te secon part o the duonum at bout it middle ith the ile duct on the maor duodeal papila (Fig. 551). ometimes the mai duct drans separtely int the duoenum. P.257

The ry duct of th pancras, when present, drains te upper art of he head nd then opens ito the dodenum a short ditance abve the man duct n the minor duodenal papilla (Figs. 5-1 and 5-8). Te accessry duct requentl communiates wit the mai duct.

Blood Suply Areries The spleic and te superir and iferior pncreaticduodenal arterie (Fig. 5-6) suply the pancreas

Veis he corrsponding veins drin into the portl system

Lymp Drainage Lyph node are sitated alng the rteries hat supply the land. Th efferen vessels ultimatly drain into the celiac ad superor meseneric lymh nodes.

Nerve pply Sympatheic and prasympatetic (vaal) nerv fibers upply th area.

Cinical Ntes Diagnosis f Pancretic Disease The deep loation of the panceas sometimes gives rise to problem of diagosis for the folowing resons:   

Pin from he pancras is comonly reerred to the back Bcause th pancrea lies beind the stomach nd transerse coln, diseae of the gland ca be confsed with that of the stomch or trnsverse olon. Infammation of the pancreas can sprea to the peritoneum forming the posrior wall of the lesser sc. This n turn an lead o adhesins and t closing off of the lesser sac to orm a psudocyst

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Truma of te Pancres Te pancres is deely place within he abdomn and is well prtected b the costal margin and the anterior bdominal wall. However, bunt traua, such s in a sorts injry when sudden low to he abdomn occurs can comress and tear the pancreas against he vertbral colmn. The pancreas is most commony damage by gunsot or sab wound. Damaed pancratic tisue releaes activted panceatic enymes tha produce the sign and symtoms of cute pertonitis.

Cncer of he Head f the Pacreas an the Bil Duct Becuse of te close relation of the ead of te panceas to te bile dct, cancr of th head of the panreas oftn cause obstructive jaudice.

The Pancreatc Tail ad Splenectomy The presence f the tal of the pancreas in the splenicorenal ligament smetimes esults n its dage durng splenectomy. The damaed pancras releaes enzyes that tart to igest srroundig tissus, with erious cnsequencs. P.258

Embryoloic Notes Deelopment of the Pncreas The ancreas evelops rom a dorsl and vetral bud of entoderml cells hat aris from te foregut The doral bud riginate a short disance aboe the vntral bu and grows into te dorsa mesentry. The entral bd arise in commn with te hepati bud, cose to e juncton of th foregut with the midgut (Fig. 5-1). A canalied duct ystem now develops in each ud. The otation of the tomach ad duodenm, together with he rapid growth o the lef side o the duoenum, reults in he ventrl bud's oming ino contac with te dorsal bud, and fusion ocurs (Fig. 5-59). Fsion also occurs between the ducts so that the main pncreatic duct is derivd from te entire ventral ancreati duct an the distl part f the dosal panceatic dut. The min pancratic duc s he bile duct an enters he secon part of the duodnum. The proximal art of he dorsa pancreaic duct ay persit as an accssory dut, which may o may no open ino the dodenum aout 0.75 in. (2 c) above the openng of te main dct. Cotinue growth f the enodermal cells of the no-fused vntral an dorsal ancreatic buds etends into the surrounding mesencyme as clumns of cells. Tese coluns give ff side branches which lter becoe canalied to fo collecting ducts. Secretry acini appear at the ens of the ducts.

482

snell Th pancreatic ilets arise as small bds frm the dveloping ducts. ater, tese cell sever their cnnection with the duct sysem and frm isolaed group of cell that tart to ecrete insulin and glucagon at abou the fifh month. Th inferir part o the hed and th uncinae proces of th pancrea are fored from the ventral pancretic bud; the suprior art o the had, te nek, the bod, an the ail of te panceas are formed from the drsal panreatic ud (Fig 5-59).

Figre 5-59 The otation f the dodenum and the uequal grwth of te duodeal wall lead to the fusing of the ventral and dosal pancretic buds

Entranc of the ile Duct and Panceatic Dut into te Duodenm As sen from dvelopmen, the bie duct ad the man pancratic duct are ed to on another They pas obliqly throgh the wall of the secod part of th duodenum t open on te summit f te majr duodenl papila, whch is surounded by the sphncter of Oddi (Fig 5-52. In soe indiviuals, they sparately through he duodeal wall, althoug in clos and ope separatly on th summit f the dodenal apilla. n other individuls, the wo ducts an form a common ilatatio, the hepaopancratic ampula (ampula of Vater). This opens on th summit of the dodenal ppilla.

Anular Pancreas In aular panreas, th ventral pancreatc bud beomes fxed so tat, when the stomach and uodenum otate, the venral bud is pulld aroud the righ side of the duodenm to fuse wit the doral bud of the pancrea thus eircling the duodnum (Fg. 5-60). Thi may caue obstruction of he duodeum, and omiting ay start a few hurs afte birth. Early surgical relief of the obstruction is necessary

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Ectpic Panceas Etopi panreatic tissue ay be fond in the submuosa of he stomach, duodnum, smal intesine (incuding Mekel's dverticulm), and allbladdr, and in the sleen. It is imporant in hat it my protrue into te lumen f the gu and be esponsibe for cuing intususception.

Conenital ibrocysic Diseae asically congenial fibroystic disease in the panreas is caused b an abnormality n the scretion f mucus. The mucs producd is excessively viscid nd obstrcts the ancreati duct, hich leds to pancreatits with ubsequen fibrosis. The cndition also inolves the lungs, kidneys, and live.

Figure 560 Formation f the anlar panreas, prducing uodenal bstructin. Note he narowing of the duoenum.

P.259

Splee Location and Descripton The splen is redish and s the largest sigle mass of lympoid tisse in the body. I is ova shaped nd has notched anterir border It lie just beeath th left haf of the diaphrag close o th 9th, 10th,

484

snell and 11th ribs. he long xis lie along te shaf of the 0th rib, and its ower pol extends forward only as far as he midaxillary lne and cnnot b palpate on clincal exaination Fig. -61) The pleen is surroundd by peritoneum (Fgs. 5-5 and -61), which asses from it at the hilm as th gastroslenic omentum (igament) to the greater crvature of the somach (carrying he short gastri and lef gastropiploic essels). The peritoneum aso e to the left kdney as the splenicorena ligamen (carryig the spenic vesels an the tai of the panceas).

Relations 

Anterirly: he stomah, tail of th pancreas, ad left clic flexure. Th left kdney lis along ts medil border (Figs. 54 and 511).

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igure 5-1 Spleen, with its notched antrior borer, and its relaion to ajacent ructures.



Posteiorly: The diahragm; lft pleua (left ostodiapragmatic recess) left lug; and th, 10th and 11t ribs (Fig. 5-11 and 5-61)

Blood Supply Arteris

486

snell The large spenic arry is te larget branch of the eliac arery. It has a totuous corse as i runs along the pper border of he pancras. The splenic rtery thn divide into abut six branche, which enter th spleen t the hilum

Veins Th spleni vein leves the ilum an runs bhind the tail an the bod of the pancreas Behind the neck of the pncreas, he spleic vein s th superio mesentric vein to form he porta vein.

Lymph Dainage The lmph vessls emerg from the hilum nd hrough few lyph nodes along th course of the slenic arery and then dran nto the celia nodes.

Neve Suppl The nerves acompany he splenic arter and are derived rom the eliac plxus.

linical Notes Splenic Enlgement A pthologiclly enlrged splen exteds downwrd and mdially. he left olic flexure an the phrnicocolic ligament prevet a direct donward enargemen of the oran. As te enlargd spleen projecs below he left costal argin, is notche anterio border an be recogniz by palation trough th anterio abdominl wall. The splen is siuated at the begnning of the splic vei and in cases of portal hpertenson it ften enlrges frm venous congesion.

Trauma to the Spleen Altough anaomically the spleen gives the apperance of being ell protcted, automoble accidnts of the crushng or ru-over ype commnly prouce laceation of the spleen. Penerating wunds of the loer left horax cn also dmage the spleen. P.60

Embryologic Notes Develoment of he Splen

487

snell The speen deveps as a thickenig of the mesencyme in the drsal mesntery (Fig. 5-4). In the arliest stages, he spleen consiss of a number of mesenchyal masss that later fus. The notches alng its aterior brder are permannt and idicate tat the msenchyma masses nevr competely use. The part f the dosal mesetery tht extens betwee the hium of th spleen nd the geater curvature of the somach is called he gastrsplenic mentum; the prt that extends etween he splee and th left kiney on he posteior abdominl wal is alle the splnicorenl ligament. he splen is suplied by a branch of the oregut atery (ceiac artey), the slenic arery.

Supernumerary Spleen In 10% of peopl, one or more suernumeray spleen may be resent, ither in te gastrsplenic omentum r in the splenicrenal igament. Their clnical iportance is that hey may hypertrohy afte removl of the major sleen and be resonsibe for a ecurrenc of symtoms of the disease for hich splenectomy was initally perormed.

Retropritoneal Spac Te retoperitoneal spae lies on the posterir abdominal wall behind the arietal eritoneum. It exends from the 12h thoraic vertera and te 12th rb to th sacrum nd the liac crets belw (Fi. 562). he floor or postrior wal of the space is forme from edial to lateral by the poas and quadratu lumborum muscle and the origin of the tansverss abdomiis muscl. Each o these mscles is covered on the nterior surface y a defiite layer of fasia. In font of the fascal layes is a vriable mount of fatty connetive issue that forms a bed fo the surarenal glands, the kidnys, the ascendin and decending parts o the colon, and he duodeum. The retropritoneal space aso contans the ueters an the real and onadal bood vessls.

Clinical Note Truma to rgans in the Retperitoeal Space Palpation of the anterir abdominal wal in the lumbar and ilia regions may give rise to signs indicative of peritneal iritation the pertoneum frms the nterior oundary f the spce; Fi. 5-62). In other wods, tenderness ad muscle spasm (rigidiy) may b present Palpation of te back i the inrval beween the 12th rib and the vertebrl colum may reval tendeness sugestive f kidney disease Abominal radiograps may reeal air in the xtrapertoneal tssues, ndicatin perforaion of a viscus (e.g., scendin or descnding coon). Comuted tomgraphy sans can ften acurately efine te extent of the njury to the extraperitonal orgs.

Abscess Formation

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snell Infection oiginatig in rtropertoneal ogans, suh as te kidney, lymph nodes, ad retroecal appndix, may extend widely nto the retropritoneal space.

Leaking Aoric Aneursm The lood ma first b confind to the retropeitoneal pace beore ruptring into the peitoneal cavity.

Uriary Trac Kineys ocation nd Description The to kidney functio t excret most of the waste proucts f metaolism. The play major role in controllng the ter an electroyte balace within the body and in maintaiing the acid–ase baance of the blod. The waste proucts leae the kidneys as urie, which es wn the ureters o the urinry bladdr, loated witin the pelvis. Te urine eaves th body i th urethr. The kidneys re reddih brown nd lie ehind th peritoeum high p on the posterior adominal wall on eiher side of the vertebra column they re larely unde cover o the cosal margin (ig. 5-6). Te right kidney les slighly lowe than the left kdney becuse of te large size of the right lobe of the livr. With ontracton of th diaphram duing resiration both kdneys moe downwad in a vrtical drection y as mch as 1 in. (2. cm). On the medial concae border of each idney is a verticl slit tat is ounded b thick lps of real substnce and s called the ilum Fi. 5-64). The hlum extnds into a large avity calld the renal sinu. The hium transits, fro the frot backard, th renal vin, two branches of the enal artry, the ureter, and the tird branh of the renal atery (VUA). Lymh vessel and symathetic fibers also pas throug the hilum. P.26

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Figure 562 Rtroperitneal spce. A. Sructures presen on the osterio abdominl wall ehind th

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peritoneu. . Tansverse sectio of th posterior abdoinal wa showig structres in te retroperitoneal space s seen fom belo.

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Figure 5-63 osterior abdominl wall sowig the kidneys and th ureters in situ. Arows indicae three sites whre the ureter is narrowed.

Coverings 491

snell The kidneys hve the fllowng coerings (Fg. 5-6):   



Fibrus capsle: This surrunds the kidney nd is cloely applied to ts outer surface Perrenal ft: Ths cover the fibous casule. Rena fascia: This is a condensatio of connctive tissue that lies outside he perirenal ft and encloses the kidneys and suprrenal glnds; it s contiuous laerally wth the fascia trnsversals. Pararenl fat: This les external to the renal fascia and is often in lre quantity. It forms pt of th retropeitoneal at.

The perirena fat, real fasci, and prarenal at supprt the idneys ad hold tem in position o the poserior abdominl wall.

Renal Structure Each idney hs a dark brown ouer cortex and a light brwn inner mdulla. The medula is cmposed o about a dozen renl pyramis, eah having its base oriente toward he cortx and it apex, the renl papilla, pojectng meially (Fg. 5-6). Te cortex extends into the medulla between djacent pyramids as the renal colums. Etending rom the ases of he rena pyramid into th cortex are stritions knwn as medulary ray. Th renal sinus, whch is th space wthin th hilum, ontains he uppe expanded end of he ureter, the renl pelvis. This divides nto two or thre major cayces, each of which divides ino two or three minor calycs (Fi. 5-64). Eac mino calyx i indened by te apex of the rnal pyrmid, the renal apilla.

Iportant Relation, Right idney  

Ateriorl: The suprarnal glad, the iver, the second part of the duodnum, and the riht colic flexure Figs. 54 and 5-65) Posterirly: The diahragm; te costodaphragmaic recess of the pleura; the 12th rib; ad the psas, quadratus luborum, nd transersus abdomins mucles. Th subcosal (T12), ilioypogastic, and ilioinguinal nerves (L1) run downward and laterall (Fig 5-34.

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Figur 5-64 . Rigt kidne, anterir surfae. B. Rght kidny, coronal section showing the corex, medula, pyramids, renal papillae, and clyces. C. Sectio of the kidney sowing th positin of th nephron and the arangemen of he blod vesels witin the kdney.

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Imortant Relations, Left idney  

Anteriorly: The suparenal gland, th spleen, the stoach, the pancrea, the let colic flexure and cois of jejnum (Fgs. 54 an 565) Postriorly: The diapragm; te costodaphragmtic reces of th pleura; the 11th (the lft kidne is highr) and 1th ribs and th psoas, quadratu lumborum, and transversu abdomins musces. The subcotal (T1), ilihypogastic, and lioingunal nervs (L1) rn downwad and lterally Fig. 5-34)

Note tat many f the sructures are drectly in contat with the kidnys, wheeas othes are sparated y viscerl layer of pertoneum. or detals, see Figure -65.

Blood Suply Arteries The rnal artey arises from the aorta at the leel of the second lumbar vrtera. Ech rnal artery usually ivides into fie segmental rteries that enter he hilum of the idney. hey are istribued to different egments or areas of the kidney. Lbar arteris aise from each semetal arty, one or each enal pyrmid. Before etering te renal substance, each obar artery give off two or thre interobar artries (Fg. 5-64). Th interloar arteies run oward th cortex n each sde of th renal yramid. t the juction of the corex and te medulla, the interlobr artees give off the arcuate rteries, hich arh over te bass of the pyraids (Fig 5-65. The rcuate rteries ive off several intrlobula arterie that ascend i the corex. The aferent glmerular arteriols arse as branches o the intrlobula arterie.

Clinical Note Rnal Mobiity The kidns are mntained in thei normal osition y intr-abdominl pressre and by their onnectios with the prirenal fat an renal fscia. Each kidny moves slightl with repiration The rght kidny lies t a sligtly lowe level tan the eft kidny, and the lowe pole ma be palpted in he right lumbar egion at the end of dep inspiation n a pern with oorly deeloped adominal musculaure. Should the mount o perirenl fat be reduced, the moility of the kidey may bcome excssive an produce symptos of real colic caused b kinking of the reter. Ecessive obility of the idney leves the suprarenl gland undistured because the latr occupies a sparate comprtment in the ral fasci.

Kiney Traua The kidneys are well protecte by the lwer ribs the lumbar muscles, and the vertebral column. However, a sever blunt njury aplied to the abdoen may cush the idney against th last ri and te vertebal colun. Depening on te severiy of the blow, th injury varies from a mid bruisig to a omplete aceratin of the organ. Penetratng injuies are usualy caused by sta wouds or gunshot wounds ad often involve other viscera. Because 25% of te cardac outflw e through the kidneys, renl injury can resut in rapid bloo loss. A summary of the ijuries t the kideys is sown in igure 5-66.

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Kidey Tumor Malignant tuors of te kidney ave a srong tendency to spread aong the enal vei. The lft renal vein recives the left tsticular vein in he male, and this may rarey become bloced, prodcing lefsided vricocel (see pae 169.

Real Pain Rena pain varies fro a dull che to severe pain in the flan that ma radiae downwar into te lower bdomen. Renal pin cn reslt fom strething of he kidne capsul or spam of th smooth muscle in the rnal pelis. The fferent erve fibrs hrough he rena plexus round th renal atery an ascend o the spnal cor throug the loest splachnic neve in th thoax and he sympathetic trunk. They enter the spnal cord at the lvel of T2. Pain is commoly refered alog the ditributio of the subcosta nerve (12) to te flank and the nterior bdomina wall.

Translanted idneys The iliac fossa o the posterio abdomial wall is the usual ite chosn for trnsplanttion of the kidny. The fssa is xposed hrough a incisio in the nterior abdomina wall jt above the inuinal liament. Te iliac fossa in front of the ilicus musce is aproachd retropritonealy. The idney is positioed and te vasclar anasomosis onstructd. The rnal artry is anstomosed end-toend to te internl iliac artery ad the real vein s anastmosed en-to-sid to the xternal iliac ven (Fig. 5-67). Aastomosi of the ranches f the iternal iliac arteries on the two sides is ufficien so tha the plvic vicera on the sie of the renal arterial astomoss are no at ris Ureterocystostomy is thn perfomed by pening te bladder and prviding a wide entance of he ureer throuh the bldder wal.

Vens The renal vin emerge from th hilum i front o the renl artery and drans into he infeior vena cava.

Lymph Dranage Lymph drains to the lateral aoric lymh nodes around te origin of the enal artry.

Nrve Suply The nerve upply is the renal sympatetic plexus. The afferet fibers that trael throgh te renal plexu enter te spinal cord in the 10th, 11th, nd 12th thoracic nerves. .265

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Figure 5-65 Anterio relatins of boh kidnes. Visceal peritneum coering th kidnes has een eft in postion. Brown aeas indiate whee the kidney is in drect cntact wih the adacent vscera.

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Figre 5-66 Injures o the kiney. A. Cntusion, with heorrhage onfined to the crtex beeath the intact fibrous capsule. B. Tearing of the capsule nd cortx with beeding ocurring nto the erirena fat. C. Tearing of th capsule, the cotex, and the medlla. ote the escape of lood into he cayces an therefore the uine. Urie as wel as blod may xtravasae into te perireal and ararenal fat and into the peritoneal cavty. D. Shattered kidey with extensiv hemorrge and xtravasation f blood and uine into the perrenal an pararenl fat; bood also enters he calyces and apears i the urne. E. Injury to the enal pedcle invoving the renal vessels ad possiby the rnal pelvs.

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Figure 5-67 The tranplanted kidney.

reter Locatio and Decription Th two urters are muscular tubes tat exten from the kidneys to the posterior surface f the uinary bldder (Fg. 5-63). The urine i propelled along the ureter by peistaltic contracions of the muscle cat, assisted b the filration pessure o the gloeruli. Eac ureter easures about 10 in. (25 cm) ong and resemles the sophagus (also 10 in. lon) in havng three constrctions aong its ourse: were the renal pevis jois the ueter, were it i kinke as it rosses te pelvic brim, ad where t pierces the badder wll (Fig 5-63. The renal plvis is he funne-shaped xpanded upper end of th ureter. It lies ithin te hilum of the kdney an receive the maor calycs (Fig 5-64). The ureter emerges rom the hilum of the kidey and rns vertcally donward beind the parietal peritoneum (adheent to i) on th psoas mscle, hich searates it from te tips of the trnsverse rocesses of the lmbar vrtebrae It entes the pevis by crossing he bifrcation of the ommon iliac artery in ront of he sacroliac joit (Fig 5-63. The ueter the runs down the lteral wal of the pelvis to the rgion of the ichial sine and urns forard to eter the lateral ngle of the blader. The pelvic curse of he urete is desribed in detail n page 347 and 355.

Relatins, Right Ureter

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nteriorly: The duodeum, the trminal prt of th ileum, he righ colic ad ileocolic vesels, th right tsticular or ovaian vessls, and he roo of the esentery of the small intstine (ig. 5-27) Posteriorly: The ght psos muscl, which separate it frm the lmbar trsverse processes, and te bifurction of he right common iac artry (Fig 5-63)

Relatios, Left Ureter  

Aneriorly: The igmoid clon and igmoid esocolon the left colic essels, nd the lft testicular r ovarin vessels (Figs. 5-13 nd 5-27) Psteriory: Te left soas mucle, hich seprates it from th lumbar ransverse proceses, and the bifrcation of the lft commo iliac atery (Fig. 5-63)

The inferor mesenteric ein lie along te medial side of he left reter (ig. 5-27).

Blood Suply Arteries The aterial spply to he uretr is as ollows: pper ed, the rnal artey; middle portio, the testicular or ovarian artery; and in the pelvs, the sperior vsical arery.

Veins enous bood drais into vins that correspond to the arterie.

Lymph Drinage The lymh drains to the ateral artic nods and th iliac ndes.

Nerv Supply The nerve supply is the renal, esticulr (or ovrian), ad hypogstric plxuses (n the pevis). Aferent fiers travl with he sympahetic neves and enter the spinal cord in te first nd secod lumba segment.

Cinical Ntes raumatic Ureteral Injuries Because of its protected postion and small sie, injuies to te ureter are rare Most inuries ae caused by gunsht wounds and, i a few idividuals, penetating stb wounds. Because the urters are retroperitoneal in positin, urine may escae into te retroeritonea tissues on the psterior bdomina wall.

Ureeric Stoes

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snell Tere are hree sits of anatomic narowing o the urter wher stones ay be arested, nmely, te pelviureteral unction, the pelvc brim, nd wher the ureer enter the blader. Mot stones althoug radiopaue, are mall enogh to b impossile to ee defintely along the curse of the uretr on plan radiogaphic eaminatio. An inravenous pyelogra is usualy necessary. The ureter runs down in fron of the ips of the transerse proesses of the lumbar verterae, croses the egion of the sacoiliac jint, swigs out to the ichial spne, and hen turn mediall to the ladder.

Renal olic Th renal pelvis and the ureer send heir affrent nves into the spinal cord at segmens T11 an 12 and 1 and 2. In ren colic, strong perisaltic waes of ctraction don the ueter in an attemt to pas the stoe onward The spam of the smooth uscle cases an aonizing olicky pin, whic is refered to te skin reas tha are suplied by hese sements of the spinl cord, amely, he flank, loin, nd groin When a tone enters the ow part of the reter, te pain s felt t a lowe level ad is oft referrd to the testis or the tip of the pnis in he male ad the laium majus in the female. ometime uretera pain i referre along the feoral brach of te genitoemoral nerve (L1 and 2) so hat pain is exerienced in the frnt of th thigh. The pain is often so seere that afferent pain impuses spred within the cenral nervus systm, givin rise to ausea P.267

Embryogic Nots evelopmnt of the Kidneys and Uretrs Three sts of stuctures n the urinary system appar, calld the pronphros, msonephro, and metanephro. In he human, the meanephros i responsble for the permanent kidney. The metanephos devels from wo source: the urteric bu from the mesonepric duct and the etanephroenic cap from the ntermedate cell mass of mesenchye of he lower umbar an sacral regions.

reteric ud he ureterc bud arses as an outgrowt of the mesonephric duct igs. 5-68 and 5-9). I forms the ureter, which diates at is upper nd to frm the pelvs of the ureter The pelvis later ives off branche that fom the major calyces, and tese in trn divide and branh to for the minor calyces and the coecting tbules.

Meanephroenic Cap

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snell The metaneprgenic condenss around the ureteric bud (ig. 5-69) and frms the glomerular sules, the poximal and dista convoluted ubules, and th loops of Henle. The omerular capsule becoms invagnated by a cluster of capillari that frm the lomeruls. Each distal convoluted tbule fored from he metanephroenic cap tissue ecoms ed to a colecting ubule deived rom the ureteric bud. Te surface of he kidny is loblated at first, but afer birt, this obulation usully soon disappeas. The developig kidney is initally a plvic oran and eceives its bloo supply from the pelvic continuaton of th aorta, the midle sacra artery Later, he kidnes “ascnd― up the postrior abdominal all. Thi so-calld ascent is cause mainly y the grwth of he body n the lumbar and scral regons and y the staightenig of is curvature. The ureter elogates as the ascet contines. The kidney is vascularized at successivly highe levels by succesively hgher latral splachnic areries, banches o the aota. The idneys rach thei final position oposite te second lumba vertebra. Becaue of the large size of th right lbe of te liver the rigt kidney lies at slightly lower evel tha the let kidne.

Poycystic Kidney A herdiary disese, polcystic idneys can be tansmittd by eiter paret. It ma be assciated ith congnital csts of te liver pancre, and lng. Both kidneys are enorously nlarged nd ridled with cysts. Polycystic kidne is thouht to b caused by a faiure of nion beween the developng convouted tuules an collectng tubues. The ccumulaion of uine in he proxial tubles reslts in he formaion of etentio cysts.

Pelvic Kdney n pelvic kidney, the kidny is arested in some prt of its normal acent; it usually is found at the bim of th pelvis (Fig. 5-0). Such a kiney may resent wth no sins or smptoms ad may fuction ormally However should n ectopi kidney ecome inflamed, i may—ecause o its unuual posiion—gie rise t a mistaen diagnsis.

Horsshoe Kidey hen the caudal eds of boh kidney fuse as they devlop, the result s horsesoe kidne (Fig. 5-7). Both kidneys ommence o ascend from the pelvis, ut the nterconncting brdge becoes trapped behin the infrior mesnteric rtery so that the kidneys ome to rst in th low lumbar regio. Both reters ae kinked as they inferiorly ovr the bidge of enal tissue, prducing urinary sasis, whch may rsult in nfection and stone frmation. Surgical divisio of the bridge crrects he condiion.

Uilatera Double idney The kdney on ne side may be duble, wth separte uretrs and bood vesels. In nilaterl doble kidey, the reteric bud on ne side crosses he midlne as it ascends, and its pper ole fus with the lowe

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snell pole o the norally placed kidney (Fig. 5-70. Here aain, angulation f the urter may result i stasi of the rine and may reqire surgcal treament.

Rosett Kidney Both idneys my fuse ogether t their hila, an they usally remin in te pelvis The tw kidneys togethe form a osette (Fi 5-70). Thi is the result o the eary fusion of the wo uretric bud in the elvis.

Supernumeary Rena Arteris Suprnumeray renal rteries are reatively common. hey repesent pesistent fetal real arteies, whch grow n sequece from the aorta to suply the kdney as t ascends from he pelvi. Their ccurrene is cliically iportant because supernuerary arery ma cross the pelvureteral junctio and ostruct te outflo of urin, produng dilaation of the clyces an pelvis a condiion knwn as ydronephosis (Fg. 5-7).

Double Pelis Doble pelvs of th uretr is usully unilteral (Fg. 5-71). Th upper elvis is small ad drains the upper group f calyce; the larger ower pevis drans the mddle an lower goups of alyces. The case is a remature division of the ueteric bd near its termiation.

Biid Uretr In bifid urter, th ureters may in the lower thrd of their couse, may open though a common orfice int the bldder, or may opn indepedently nto the ladder (Fig. 5-71). In the later case one ureer crosss its felow and may produce uriary obstruction. The caus of bifd ureter is a premature ivision of the reteric bud. Cases o double pelvis ad doubl ureters may b found y chance on radiologc investigation of the rinary tact. The are moe liable to becoe infected or to be the seat of clculus formation than a normal reter.

Megaloueter egaloureter may e unilatral or ilateral and shos complee absenc of motilit (Fig. 5-71). The cause is uknown. ecause o the uriary stais, the reter i prone o infecton. Plasic surgry is required t improve the rate of drainage.

Postcaval reter The right ueter may ascend osterior to the inferior ena cava and may e obstruted by t (Fig. 571). Srgical rerouting of the ueter wih reimpantation of the dstal end into th bladder is the reatment of choie. .268 502

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Figure 5-68 he origins and psitions f the prnephros, mesonepros, and metanephros.

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igure 5-9 Te origin of the ueteric ud from he mesonphric dut and the fomatin of th major ad minor alyces and the cllecting tubules. Arrow indictes the point of union btween th collecing tubles and he convouted tuules.

Suparenal lands Locaon and Descripton he two sprarenal glands re yellowih retrperitoneal organs hat lie n the uper pols of th kidneys They ae surrouded by renal facia (but are sepaated frm the kineys by the perienal ft). Each gland has a yellw cortx and a dark rown medula. The cotex of he supraenal glads secrtes hormnes that include mneral coticoids, whic are cocerned wth the ontrol o fluid nd electolyte baance; glucocorticods, wich are concerned wih the cntrol of the metaolism of carbohyrates, fts, and roteins; and smal amounts of sex ormones, whic probab play a role in the prepbertal dvelopmen of the sex orgns. The medulla of the sprarenal glands scretes te cateholamins epinephrne and norepinephrin. The rght suprrenal glnd is pyramid shaped ad caps te upper pole of he right kidney Fg. 5-4. It les behind the right loe of the live and exends medally beind the inferio vena caa. It ests poseriorly n the diphragm.

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snell The let supraenal glad is rescentic in shpe and etends alng the edial boder of he left kiney from the uppe pole to the hils (Fig. 5-4). It lies behind te pancreas, the lesser sa, and te stomac and rests posteiorly on the diapragm.

Blood Supply Arteris The arteries supplying each gand are three in number: nferior hrenic atery, aorta, and renl arter.

Vein A single vein emerges from the hilum o each glnd and drains ito the iferior ven cava o the right and into th renal vin on he left.

Lyph Draiage The lymph drains ito the lteral artic nods.

Nerve Suply Preganglionic ympathetc fibers derived from the splancnic nervs suppl the glads. Mos of the nerves ed in the medulla of the gand.

Cliical Nots Cuhing's yndrome Supraenal corical hyperplasia s the mot common cause o Cushings syndro, the clnical maifestatins of whch inclue moon-haped fae, truncal obesity, abnormal hairiness (hirutism), nd hyprtension if the syndrome occurs ater in life, it may result fom an adenoma or carinoma of the crtex.

Adison's Disease Adrencortical insufficency (Adison's dsease), hich is characteized cliically b increaed pigmentaion, muscular weaknes, weight loss, an hypotesion, ma be caud by tuerulous dstruction or biateral atrophy of boh cotices

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Fiure 5-70 Some ommon cogenital nomalies of the kdney.

Phechromocyoma Peochroocytoma, a tumor of the mdulla, poduces a paroxysal or sstained hyperension. The symptom and sgns esult from the producion o a large amount catechoamines, which ae then oured ito the boodstrem. 506

snell Becaus of thei positio on the osterior abdomina wall, ew tumors of the sprarenal glands n be palpated. Coputed tmography (CT) scns can b used to visualiz the glndular nlargemnt; owever, hen inerpreting CT scans, remembe the close relatonship o the suparenal gands to he crura of the iaphrag

Surgical Signiicance o the Renl Fascia he suprarenal glands, togeter with the kidnys, are enclose within he renal fascia; the suprrenal glnds, hoever, li in a eparate ompartmet, which allows te to orans to be sparatd easily at opertion. P.20

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Fiure 5-71 Some ommon cogenital anomalie of the reter.

Ebryologic Notes Develpment of the Sprarenal Glands

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snell he cortex develos from the coelomc mesothlium covring the osterior abdomina wall. A first, etal cortex is formed; ater, it becomes overed by a seond fina cortex. After birth, th fetal cortex retrogresse, and is involuion is largely completd in the first few weeks f lie. The medla is formed fom the sympathohromaffi cells of the nural cret. These invade he cortx on it medial ide. By this meas, the mdulla coes to ocupy a entral psition ad is aranged in cords ad clustes. Prganglionc sympathetic nrve fibers grow nto the edulla ad influece the ctivity f the mdullary ells.

Susceptbility t Trauma t Birth A birth the suparenal gands are rlatively large because o the preence of he ftal cortx; later, when this part of te corte invlutes, he gland becomes educed n size. During te process of iolution the corex is frable and susceptile to daage an severe morrhage.

Arteies on he Posteior Abdoinal Wal Aorta Location an Descripion The aota enter the abomen thrugh the ortic oening of the diapragm in front of he 12th thoracic vertebra (ig. 5-72). It descends behind te peritoeum on the anteri surface of the odies o the lumar verterae. At the level of the furth lubar vertebra, it divides nto the wo commo iliac teries (Fig. 5-2). On it right side lie the infeior vena cava, th cistern chyli, and the beginnin of the azygos vin. On ts left ide lies the left sympatetic truk. Th surface markings of the arta are shown in Fgure 5-73.

Brnches (Fi. 5-72)  

hree antrior viseral braches: te celiac artery, superior mesenterc artery and infrior mesnteric atery Three ateral vsceral banches: the suprarenal artery, ren artery, and testcular or ovarian artery P.272

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Figure 5-72 orta and inferior vena cava.

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Figur 5-73 urface mrkings o the aora and it branches and th inferior vena cva on th anterior abdomial wall

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Diagra 5-1 ranches f Abdomial Aort

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 

Five lteral abominal wll branhes: the inferio phrenic artery ad four lmbar arries Three termina branche: the two ommon iliac arterie and the median acral artery

These branches are summrized in Diagram 5-1.

Clinicl Notes Aortc Aneuryms Lcalized r diffue dilataions of the abdoinl part f the aota (aeurysms) usually occr belw the orgin of te renal arteris. Most esult frm atheroclerosis which uses wekening of the arerial wal, and ccur mos commonl in eldely men. arge anurysms sould be surgically excised nd replaed with prosthtic gra.

Embolic Blckage of the bdominal Aorta The bifurcatin of the abdominal aorta here th lumen uddenly arrows my be a ldging ste for a embolus dischargd from he heart Severe ischemia of the ower lims result. 512

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ommon Iiac Arteies The rigt and let common iliac ateries re te termial brnches o the aorta. They arise a the levl of the fourth lumbar vrtebra ad run donward an lateraly along the P.274

medial border of the psoas mucle (Figs. 5-63 and 572). ach arty ends n front f the scroiliac t by dividin into th exteral and iternal liac artries. At the bifucation, the commn ilia artery on each ide is crossed anteriory by th ureter Fig. 5-7).

External Ilic Artery Th external iliac artery rns alon the medal bord of the psoas, following the pelvic brim Fg. -63. It gves off the inferor epigstric and deep cicumflex iiac banches (Fig 5-72. The artey enters the thig by pasing unde the iguinal ligament t become he femorl arter. The nferior epigastic artey arises just abve the inguinal igament. It es upward and medially along th medial margin o the dee inguina ring (Fg. 4-4) and enters the rectu sheath ehind the rectus abdomini muscle. The dep circumlex ilia artery arises cloe to th inferio epigastic artery (Fig. 5-72. It asends laerally t the anerior suerior ilac spin and the iliac cest, supplying te muscls of the anterior abdominl wall.

Intenal Ilic Artery he interal ilia artery asses dwn into he pelvs in frot of the sacoiliac jint (Fig. 572). ts further cours is descibed on page 328

Cliical Noes Oblitertion of he Abdonal Aora and Iliac Arteries Graual occlsion of he bifurcation o the abominal orta, prduced by atheroslerosis, results in the characteristic clinical symptoms of pain in the legs on waking (cludicaion) and imotence, the atter cused by lack of lood in the intenal iliac arteres. In oherwise healthy ndividuas, surgial treatent by hromboenarterecomy or a by gaft should be cosidered. Because the progess of he diseae is slow, sme collaeral ciculation estabished, but it is physilogicall inadequte. Howver, the collateal bloo flow dos preven tissue eath in both lowr limbs althouh skin ucers may occur. Th collateral circlation o the abominal arta is sown in Fiure 5-7.

Veins on the Postrior Abdminal Wll Inferor Vena ava 513

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ocation and Desiption The nferior ena cava conveys most of he blood from th body beow the daphragm to the right atrum of th heart. t is frmed by he union of the cmmon ilic veins behin the rigt common iliac rtery at the leve of the ifth lumar vertera (Fig. 5-72) It ascnds on te right ide of te aorta, pierces the cental tendn of th diaphram at the level of the eighh thoraic vertera, and drains nto the right atium of he hear. he righ sympathtic trun lies beind its ight marin and he righ ureter les clos to its ight boder. The entrance into te lesser sac sepaates the inferior vena cava from the portal vein (Fig. 5-7) The urface arkings f the inerior vea cava are shown in Figure 573.

Tributaries The nferior ena cava has the ollowing tributaies (Fig. 5-72)  

 

Two anterior visceral tributaies: the hepatic veins Three ateral isceral ributaris: the right suprarenal vein (the left vei drains nto the left renl vein), renal vins, and right testicular or ovarin vein the left vein drains int the lef renal vin) Five ateral abdominal wall triutaries: the inferior phreic vein nd four umbar vens Thre veins of origin: two commn iliac eins and the medin sacral vein

The tributaies of te inferir vena cva are smmarized in Diagrm 5-2. If one e that th venous lood frm the adomial porton of te gastrontestinl tract rains t the livr by mans of te tribuaries of the portal vein, and that the lef suprarnal and testiculr or ovaian vein drain frst int the left renal vein, then it is aparent tht the tributarie of the nferior vena caa correspond rather closely to the branches of the adominal portion of the arta.

Clnical Noes Trauma t the Infrior Ven Cava Injures to th inferio vena cava are cmmonly lthal, despite th fact tht the ntained blood i under lw pressue. The anatomic naccessibility o the vesel behnd the lver, duoenum, an mesenery of the small intestin and the bocking pesence of the righ costal margn make a surgial approch difficult Moreove, the hin wal of the vena caa makes t prone o extensve tears Because o the mutiple anstomoses of te tribuaries of the infeior vena cava (ig. 5-7) it is ipossible in an emrgency t ligate the essel. Mst patiets hae venous congeston of th lower imbs.

Cmpressio of he Inferor Vena Cava he infeior vena cava is ommonly compessed by the enlarged uterus dring th later sages f pregnancy. This poduces dema of the ankles and feet and temorary varicose vins.

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snell Malinant retoperitoeal tumos can cuse sevee comprssion an eventua blockage of the infeior vena cava. Ths reults in he dilattion of the extesive nastomoss of the tributaies (Fg. 5-75). Thi alternive patway for th blood t return t the right atriu of the eart is commonly referred to as te cavalâ“caval sunt. The same patway come into efct in paients wih a supeior meiastinal tumor compresing the superior vena cav. Clinically, the enlarged sucutaneou anastomsis between the lateral thoraci vein, a tributay of he axillry vein and the superficil epgastric ein, a ributar of the emoral vin, may be sen on the thorcoabdomal wall (Fig. 5-75). P275

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igure 5-74 Te possibe collateral circulatons of te abdomial aorta. Not the grat dilaation of the mesnteric ateries nd their branches which occurs i the aora is sloly bloced just below th level f the renal ateries (black bar).

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iagram 52 Triutaries of Inferor Vena ava

Inferior Mesenterc Vein The iferior msenteri vein is a tribuary of te porta circulation. It egins hfway don the aal canal as the superior rectal ein (Figs 5-22 526, ad -48). It pases up te posterior abdominal wal on th left sie of the inferio mesentric artey and the duodenjejunal lexure ad s he splenic vein behind te pancras. It rceives tibutaries that orrespon to the ranches of the atery.

Splnic Vein The splenic ein is a tributay of the portal circulaton. It bgins at the hilu of the spleen b the unin of seeral vens and is then jined by he shor gastric and the eft gasroepiploc veins (Figs. 5-2 and 5-8). t es to the rght witin the slenicoreal ligamnt and rns behid the pacreas. I s te superir meseneric vein behind the neck of te pancras to form the prtal vei. It is oined y veins from th pancrea and the inferior mesenteic vein.

Superior Mesenteric Vein The uperior mesenteic vein s a triutary of the poral circuation (Fis. 5-22, 5-26, and 5-48). It bgins at he ileoccal juncion and uns upwrd on th posterir abdoinal wal within the root of the msentery f the small inteine an on the ight side of the superior mesenteric arter. It pases in front of the third part of the duodeum and bhind the neck of the panreas, were it s the 517

snell splenic ein to frm the prtal vein. It receives tributaries that corespond o the banches o the suprior meenteric artery and also rceives te inferir pancreticoduoenal ven and the rigt gastroepiloic vein (Fi. 5-22).

Portal ein The porta vein is describe on pag 245.

Lymphatcs on th Posterir Abdomial Wall ymph Noes Th lymph ndes are closely elated o the aota and orm a praortic ad a righ and lef lateral aortic (para-aotic or umbar) hain (Fig 5-76. Th reaorti lymph ndes le around the orgins of he celia, superor mesenteric, and inferior meseteric ateries ad are referred t as the ceiac, suerior meenteric, and inerior mesenteric lymph ndes respetively. hey drai the lymph from the gastointestial tract extening from the lowr one thrd of the esophgus to halfway dwn the nal canl, and rom the pleen, pncreas, allblader, and reater art of the livr. The eferent lmph vesels form the large intestnal trk (see Fig. 1-18 and belo). The lateral aotic (para-aortic r lumbar lymph ndes rain lymh from te kidney and suparenals; from the testes i the mae and frm the ovries, utrine tubs, and fndus of he uteru in th female; from th deep lyph vessels of the abdominal walls; d from he common iliac nodes. he effernt lymph vessels orm the riht an lft lumbar trunks (see Fig 1-18 and belw).

Lymph Vessels The thorcic duc commnces in he abdomn as an longated lymph sa, the cistrna chyli. This lies just below he diaphagm in font of the first two lumbar vertebrae and o the right side f the aota (Fig. 576). P.277

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Figue 5-75 The possible colateral circulatons of te superior and iferior vnae caae. Note the altenative pathways that exist for blod to retrn to te right trium of the hear if the uperior vena ca become blocked below te entrane of the azygos vin (upper lack bar). Simlar pathays exis if the nferior na cava ecomes blocked below the renal veis (lower black bar). Note also the

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connections that exist btween th portal circulaton and te systemic vein in the nal cana.

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Fiure 5-76 Lymph vessels and nods on the posterir abdomina wall.

The citerna cyli receves the intestinl trunk, the rigt and let lumbar trunks, nd some small lyph vesses that dscend rom the ower pat of the thorax.

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Lymphic Drainge of th Gonads The importane of the lymph drinage of the tests was ephasized on page 169.

Nerves on the Psteror Abdominal Wal Lumbr Plexus The lmbar pexus, whch is on of the ain nervous pathways suppying the lower lib, is frmed in the psoa muscle rom the anterior rami of the uppe four lubar nervs (ig. 5-7). The anterir rami rceive gry rami cmmunicantes from he sympthetc trunk and t upper wo give ff white rami comunicantes to th sympatetic truk. The branches f the plexus emege from the lateal and edial brders o the mucle and from it anterir surfae. The iliohyogastric nerve, iioinguinl nerve, lateral cutaneos nerve f the thgh, and emoral nrve emege from he lateal bordr of the psoas, i that orer from bove dowward (Fi. 5-34). The ilohypgastric and ilioinguina nerves (L1) ener the teral ad anterir abdomial walls (see page 17). he iliopogastric erve suplies th skin of the ler part of the anterio abdominl wall, and the lioingunal nerv es through he inguinal canl to suply the sin of te groin nd the scrotum o labium majus. he ateral cutaneous nerve of the thih crsses th iliac fssa in fron of the lacus mule and nters te thigh behind the laterl end of the ingunal ligment (se page 56). It supplies the skin over th lateral surface of the tigh. Th fmoral nerve (L2, 3, and 4) i the larest branh of the lumbar pexus. It runs donward an lateraly betwee the poas and the iliacs muscle and enters the thigh behind the inguina ligamen and latral to te femorl vesses and th femora sheath. In the bdoen it suplies th iliacus muscl. P.279

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Figure 5-77 Lumbar lexus of nerves.

The obturtor nerve and the ourth lubar root of the umbosacral trunk eerge fro the meial bordr of the psoas at the bri of the pelvis. he obturator nerve (L2, , and 4) crosses the pelvc brim n front f the saroiliac oint ad behind the comon iliac vessels. It leaves the pelvis by pssing throuh the oturator oramen nto the high. (Fr a description f its ourse in the pelvs see page 36 and in the thigh se age 586). The fourth lumbr root o the lumosacral trunk takes pat in the formation of the sacral pexus (see age 325). It descends aterior t the ala of the acrum and s he first sacral nrve. Table 51 Branches of the Lumbr Plexu and Ther Distriution

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Banches

Distribuion

Iliohypogastrc nerve

Exernal obique, inernal oblique, ransverss abdomnis musces of anerior abominal all; skin over ower antrior abdominal wall and bttock

lioinguial nerv

Eternal blique, nternal oblique, transvesus abdoinis mscles of anterior abdomina wall; skin of pper medal aspet of thih; root f penis and scroum in te male; mons pubs and laia majoa in the female

ateral utaneous nerve of the thih

Skin f anterir and laeral sufaces of the thig

Geitofemorl nerve (L1, 2)

Crmaster mscle in crotum i male; kin over anterior surface f thigh nervous pathway for cresteric eflex

Femorl nerve L2, 3, )

Iliacus, ectineus sartoris, quariceps fmoris mucles, an intermeiate cutneous brnches to the skn of the anterior surface of the tigh ad by saenous banch to the skin of the mdial sid of the eg and fot; artcular brnches to hip and knee joits

Obtrator neve (L2, 3, 4)

Gracilis, addctor breis, addctor lous, obtrator exernus, pctineus, adductor magnus (adducto portion, and sin on mdial surace of thigh; aricular branches to hip a knee jints

Segmental branches

Quadrats lumborm and poas musces

Te genitofeoral neve (1 and 2 emerges on the aterior urface o the psas. It rns downard in font of te muscle and divdes into a genital branch which enters th spermatc cord ad supplies the cremaste muscle, and a femora branch, whih supplis a smal area o the ski of the thigh (se page 568). It the nervous pathway invoved in te remasteric refle, in which stimulation of the

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snell skin of he thig in the ale reults in reflex ontractin of the cremaste muscle nd the dawing upard of he testi within the scrotum. The branches of the umbar plxus and their distributio are sumarized i able 5-1.

Sypatheti Trunk (bdominal Part) The bdominal part of he sympathetic tunk is ontinuou aboe with te thoracic and blow wit the pelic parts of the sympatetic truk. It rus donward alng the edial boder of te psoas muscle on the bdies of he lumba vertebre (Fi. 5-78). It enters the abdomen from behnd the mdial arcate ligaent and ains ntrance o the pevis belo by ng behid the comon ilic vesses. The rigt sympaetic trk les behin the right border of the nferior vena cav; the left sympathtic trun lies close to the lef border f the aota. The sympathtic trun possesses four or five segmentaly arraned gangla, the frst and second ften beig fused ogether.

Braches  

White ami commnicante jon the fist two gnglia to the firt two lubar spinal nerve. A whte ramus contains pregangonic neve fiber and aferent sesory nrve fibes. Gra rami communicanes jin each anglion o a corrsponding lumbar sinal nere. A gry ramus contains postganlionic erve fibrs. The ostganglonic fibrs ar P.280

distribted thrugh the branches of the inal neves to he blood vessels, sweat lands, ad arrecor pili uscles o the skin (see Fig. 1-4).

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Figre 5-78 Aorta and relaed sympthetic pexuses.

 

bers pas medialy to the sympatheic plexuses on he abdominal aora and it branchs. (Thee plexuss also eceive fbers fom splachnic neves nd the vagus.) Fiers downward and medilly in ront of he common iliac vessels nto th pelvis, where, ogether ith brnches frm sympatetic neres in frnt of the aorta, they form a lage bundle of fibers alled th suprior hypgastric plexus (ig. 5-78).

Aortic Plexuse Preanglionic and potganglioic sympthetic ibers, reganlionic arasymathetic ibers, nd visceal afferent fibes form plexus f nerves, the aortic plexus, arund the bdominal part of the aorta (Fig. 5-7). Rgional cncentraions o this plexus arond the oigins o the ceiac, real, supeior meseteric, and inferir mesentric arteies fo the celiac plxus, real plexu, superor meseneric plexus, and inferior mesentric plexs, rspectivey.

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snell Th celiac lexus cosists minly of two celiac ganglia conncted togther by large network o fibers that surounds he orign of the celiac atery. Th ganglia receive he grear and lsser splanchnic nerves preganglonic sympathetic ibers). ostganglonic brnches acompany te branchs of the celiac rtery an follow hem to heir disribution Parasymathetic agal fibrs also ccompany the braches of the artey. The renal and superior mesenteric plexuse are smaler tha the celac plexu. They re distrbuted aong the ranches f the crrespondng arteres. The nferior esenteri plexus s simila but rceives prasympathetic fiers from the sacral parasympthetic.

Clinica Notes Lumbr Sympatectomy Lumbr sympatectoy is perormed manly to roduc a vasdilatatin of the arteries of the ower lim in patints with vasospatic disoders. Th pregangionic sypathetic fibers tat suppl the vesels of the lower limb leve the spinal cor from sgments T11 to L2 They synapse in the lumbr and saral gangia of th sympathetic tunks The posanglion fiers the lumbr and saral neres and re distibuted t the vssels of the limb as brances of thse nervs. Addiional pstganglinic fibrs irectly rom the umbar gnglia t the comon and eternal iiac arteies, but they folow the latter rtery only down s far as the inguinal ligment. In the mal a bilaeral lumbar sympathecomy may be folloed by lss of ejculator power, but erection is not impaied.

Abdoinal Pai Abdominal pan is on of the st impotant prolems facing the physicia. This sction prvides a anatomi basis fr the dfferent forms of abdominl pain fund in clinical ractice. hree distinct forms of pain exist: somatic, visceral and refrred pai.

Somtic Abdoinal Pai Soatic abdminal pan in the abdomina wall ca arise rom the kin, fascia, muscles, and parietal peritonem. It c be sere and precisely localize. When te origin is on one side o the mdline, he pain s also lteralized. The smatic pin impules from the abdoen reach the cenral nervus syste in the followig segmenal spinal nerve:    

Central art of e diaphagm: Phrenic erve (C3 4, and 5) Pripheral part of the diapragm: Intercotal nerves (T7 t 11) Anterior abdominl wall: Thoracc nerves (T7 to 1) and te first umbar nrve Pelic wall: Obturtor nerv (L2, 3, and 4)

Th inflame parieta peritonum is eremely ensitive and beause the full thikness of the abdminal wal is innrvated by the sae nerves it is ot surprsing to find cutneous hpersensiivity (yperestesia) an tenderess. Locl reflexs involving the ame ners bring about a rotectie phenomnon in wich

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snell the abdomin muscle increase in tone This inreased tone or igidity sometims called gurding is an attempt to rest ad locali the infammatory process. Rebound tendernes ocrs whe the parietal peitoneum s inflamd. Any mvement o that iflamed peritonem, even hen that movement is elicited by rmoving t examiing hand from a ste distant from the inflaed peritneum, brings abut tendeness. Examples of cute, seere, localize pain oiginatig in te paietal pritoneum are seen in the ater staes of apendiciti. Cutanous hypresthesia, tendeness, an muscula spasm or rigidity occu in the lower riht quadrnt of th anterir abdomial wall. A perfrated petic ulcr, in wich the parietal peritonum is chmically irritatd, prodes the same symptoms and signs bu involv the riht uppe and lowr quadrants.

Viceral Abominal Pain Visceral abdominal pain arses in bdominal organs, viscera peritonum, and he meseneries. he caus of viseral pain includ stretchng of a iscus or mesente, distention of a hollow viscus, impaire blood spply (ishemia) o a viscs, and cemical amage (eg., acid gastric uice) t a viscu or its overing peritonum. Pain arising from an abdominl viscus is dull and poory localized. Viseral pan is reerred to the midline, probabl because the vicera deveop embrylogically as midine strutures an receive a bilaral nere supply; many vscera laer move aterally as deveopment poceeds, aking thir nerve supply with them Colic is a fom of viceral pin produed by th violent contracton of sooth musle; it i commonly cause by lumial obstuction a in intetinal otructio in th ag of a gallstone i the biliary ducts, or i the pasage of a stone n the ureters. any viseral affrent fibrs that enter te spinal cord prticipae in refex activty. Reflx sweatng, salation, ausea, vomiting and inceased hert rate ay accoany viseral pan. The sesations hat arise in viscera reah the cetral nevous sysem in aferent neves tha accompay the sypathetic nrves nd enter the spina cord though the posterir roots. The signficance of thi pathwa is better undertood in he follwing disussion n refered visceal pain.

Refrred Abominal Pin eferred abdomina pain is the feeing of ain at a locatio other han the ite of oigin of he stimulus but in an are supplid by th same o adjacen segment of the pinal cord. Both somatic and visral strtures cn produc referre pain. In the case of rferred smatic pain the posible explanatio is that the nere fibers from th diseased structre and he area where th pain is felt asnd in th centra nervous system along a common pthway, ad the ceebral ortex i incapabe of dstinguising betwen the stes. Exples of referre somatic pain follow. Plurisy inolving te lower part of the costl parietl pleura can gie rise t referrd pain in the adomen because th lower arietal pleura eceives ts sensry inneration frm the loer five intercostal neres, whic also innervate the skin nd muscles of the anteror abdomnal wall

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snell Visceral pain fr the stach is ommonly referred to the epigastriu (Fig. 5-9). The affeent pai fibers rom the tomach acend in company ith the sympathtic nerves and throgh the celiac pxus and the greaer splachnic neves. Th sensory fibers enter the spinal cord at sgments T5 to 9 nd give ise to referred ain in drmatomes T5 to 9 on the ower chest and adominal walls. isceral pain frm the apendix (Fig. 5-79), which is produed by dstension of its lumen or pasm of its smooh muscl coat, ravels i nerve ibers tht accompny sympahetic neves thrugh the uperior esenteri plexus nd the lsser splnchnic nve to te spinal cord (T1 segment. The vaue refered pain s felt i the reion of the umbilicus (T10 drmatome) Later, f the inlammator proces involve the paretal pertoneum, he sever somati pain doinates te clinicl pictur and is ocalized precisel in the ight loer quadrnt. Visceral pain from the allbladdr, as ocurs in atients ith cholystitis r gallstne colic travels in nerve fibers hat accopany sympathetic nrves. Thy trough th celiac lexus and greate splanchnic nerves to the inal cor (segmens T5 to ). The ague refred pain is felt n the dematomes T5 to 9) on the lower chest and uppr abdomial walls (Fg. 5-79). If he inflamatory pocess spreads to inolve th parieta peritonum of te anterio abdominl wall o peripheal diaphagm, the severe omatic pin is fet in the right upr quadrant and through t the bak below the infeior angl of the capula. Involvement of th centra diaphramatic paietal peritoneum which i innervaed by the phrenc nerve C3, 4, ad 5), ca give rse to reerred pan over te shouer becae the sin in ths area is innerated by he suprclaviculr nerves (C3 and ).

igure 5-79 Sme impotant ski areas nvolved n referrd visceal pain

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P.22

Cross-ectional Anatomy f the Abomen To assist in iterpretaion of cmputed tmograph (CT) sans of te abdome, study he labeld cross ections f the abdmen shown in Figure 5-80 nd 5-81. The sectons have been phoographed on their iferior srfaces Also se Fgure 5-8 for a example of a CT can.

Raiographc Anatoy adiographic Appearances f the Adomen Ony the moe importnt featues seen in a stadard ateropostrior radograph f the abdomen, ith the patient the sine position, ae descried (Figs. 5-83 an 584). Examine the followin in a syematic rder. 

      

Bones. I the upper part of the adiograph the lower ribs ar seen. Rnning dwn the iddle of the radigraph ar the lower thoraci and lumar verterae and the sacrm and cocyx. On ither sie are te sacroiac ts, the plvic bons, and te hip ts. Diphragm This casts domehaped sadows on ach side the one on the rght is slghtly hgher tha the one on the left (not shown in ig. 5-83). Psoas muscle. On eithe side o the vetebral clumn, te latera borders of the soas musle cast shadow tat e downwar and latrally frm the 12h thoracc verteba. Liver. This orms a homogeneou opacity in the uper part of the abdomen. Spleen. This may cast a soft shadow, which can be seen in he left th and 0th intercostal spaces (not shown in Fi. 5-83). Kidnys. Thse are uually viible becuse the erirenal fat surrunding the kidneys produce a transadiant lne. Stomch and itestines. Gas ay be sen in the fundus of the stomch and i the intstines. Fecal matrial may also be een in te colon. Urinay bladde. If tis contans suffiient urie, it wil cast a shadow i the pelis.

Radographic Appearanes of th Gastroinestinal ract Stoach T stomach can be demonstratd radiolgically Fis. 5-85 and 5-86) by th isration o a water suspenson of baium sulfte (barium meal). With the patient n the erct positon, the irst few mouthful ito the somach an form a triangula shadow wth the aex downard. The gas bubbe in the fundus shws above the flui level a the to of the arium shdow. As the stoma is filld,

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snell the greater ad lesser curvatues are otlined ad the boy and pyoric porions are recognizd. The plorus is seen to ove downrd and come to lie at the level of the thir lumbar ertebra. Fluoroscopic xaminatin of the stomach s it is illed wth the barium emulion revels perisaltic waes of cotraction of the tomach wll, whic commence near the middle o the bod and pas to the pylorus. The respratory mvements of the diahragm case dispacement f the fudus.

Duodenum A barium mal e into th first prt of th duodenum and form a trianular homgeneous hadow, te duodenal cap, wich has ts base oward th pylorus (Fg. 5-87). P.283

Under he influnce of pristalss, the brium quckly leaes the uodena cap and es rpidly though the remainin portion of the duodenum The outline of te barium hadow in the firs part of the duoenum is mooth because of e absenc of mucsal folds In the remainde of the uodenum, the presce of plicae circulares braks up he bariu emulsion, giving t a flocular apparance.

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Figure 5-80 A Cross ection o the abdmen at te level f the boy of the 11th thoracic vetebra, vewed fro below. Nte that he large size of he pleual cavit is an aifact caused by he embaling proces. B. Crss sectin of the abdomen t the level of the body of he secon lumbar ertebra, viewed fom below

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Figure 5-81 Cross ection o the abdmen at te level f the boy of th third lmbar vetebra, viewed fro below.

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Figre 5-82 Computd tomogrphy scan of the abdomen at the leve of the econd lmbar verebra aftr intravnous pyeography. The radipaque material can be see in the nal pelvs and th ureters. The setion is iewed fom below

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igure 5-3 Antroposteror radiograph of the abdomen.

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Figu 5-84 Represenation of the main features seen in he anterposterio radiogrph in Figur 5-83.

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Fiure 5-85 Anterposterio radiogrph of th stomach and the sall inestine ater ingetion of arium mel.

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Figure -86 Reresentaton of th main fetures sen in the radiograh in Figure 5-85.

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Figur 5-87 nteroposerior raiograph f the dudenum afer ingesion of brium meal.

Jejuum and Ieum A barium eal entes the jeunum in few minutes and reaches the ileocal juncton in 30 minutes to 2 hours, and the greate part ha left th small itestine n 6 hour. In the jejunum and uppe part of the ileu, the muosal fols and th peristatic actvity scatter the arium shdow (Figs. -85 an 588). I the las part of the ileu, the baium meal tends to form a cntinuous mass of arium.

Large Intestine The large intstine ca be demostrated y the aministraion of a barium eema or a barium mal. The ormer is more saisfactor. The boel may b outline by the dministrtion of to 3 pnts (1 L of barim sulfat emulsion through the anal canal. When the rge intetine is illed, te entire outline an be sen in an anteropoterior pojection (Fgs. 5-89 and 5-90). Oblque and ateral vews of te colic lexures ay be necessary. Te charateristic sacculatons are ell seen when the bowel is filled, and, aftr the enma has ben evacuted, the mucosal attern i clearly demonstated. The ppendix requentl fills wth barium after a enema. he radiographic appearances of the sigmoid olon and rectum a described on pae 377.

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snell The artrial suply to th gastroitestinal tract ca be demonstrated y artergraphy. A catheter is inserted into the femoal artey and theaded upard unde direct ision on a screen into the abdominl aorta. The end f the caheter is then manpulated nto the opening of the apropriat artery. Radiopaqe materil is injcted though the catheter and an ateriogra is obtaned (Fig. 591).

Radiographi Appearances of th Biliary Ducts The bile pasages norally are not visile on a radiograh. Their lumina cn be outined by he stration of varius iodin-containng componds orally or by injection. When takn orall, the ound is absorbed from the small inestine, arried t the lier, and xcreted ith the ile. On eaching he gallbadder, i is concntrated ith the ile. The concentrted iodie compoud, mixed with th bile, i now radopaque ad reveal the galbladder s a pea-shaped pacity i the ange between the right 12th ri and the vertebral column (igs. 5-9 and 5-93). If the patint is gien a faty meal, e gallbldder conracts, ad the cstic and bile ducs become visible s the opque medim es down to the secod part o the duoenum. P.29

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Figur 5-88 nteroposerior raiograph f the smll intesine afte ingestin of barm meal.

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Figue 5-89 Anteropoterior rdiograph of the large intetine aftr a barim enema.

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Figur 5-90 Anteroposterior rdiograph of the lrge intetine aftr a barim enema. Air has been intoduced ito the itestine hrough te enema ube aftr evacution of ost of te barium This prcedure i referre to as contrat enema.

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Figre 5-91 An areriogram of the sperior meenteric rtery. Te cathetr has ben insered into he right femoral rtery an has ed up te externl and common iliac arteries to ascnd the aorta to te origin of the uperior esenteri artery. A nasogatric tub is also n positin.

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Figre 5-92 Anteroosterior radiograh of the gallblader after istation of an iodin-containng compond.

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Figur 5-93 Represntation f th main fatures sen in th radiogaph in Fgure 5-9.

A sonogam of the upper art of te abdomn can be used to show the lumen o the galbladder (g. 5-54).

Radiograhic Apperances o the Uriary Trac Kidneys The kineys are usually visible o a standrd anteroposterior rdiograp of the adomen beause the perirenl fat surroundig the kineys prouces a transradiat line.

Calyce, Renal elvis, ad Ureter

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snell Cayces, th renal plvis, an the ureer are nt normaly visibe on a sandard rdiograph The lumn can be demonstrated by te use of radiopaqe compouds in inravenous pyelograhy or rerograde yelograpy. Wih intravenus pyeloraphy, an iodne-contaiing compund is ijected ito a subutaneous arm vein It is xcreted nd concetrated b the kideys, thu rendering the cayces and ureter oaque to -rays (Figs 5-94 595, an 596). hen enouh of the opaque mdium has been exceted, the bladder is also revealed. The uretrs are sen supermposed o the trnsverse rocesses of the umbar vetebrae. hey cros the sacoiliac jints and enter th pelvis In the icinity f the ishial spines, they turn medilly to nter the bladder. The three normal onstrictons of te ureter (at th junctio of the enal pelis with he urete, at the elvic brm, and here the ureter eters the bladder) can be rcognized With retrograde pyelograpy, a cystoscoe is pased throuh the urthra int the blader, and a ureteic catheer is inerted ino the urter. A solution of sodium odide is then injected alng the ctheter ito the urter. Whe the mior calycs become filled wth the rdiopaque meium, the detailed anatomi feature of the inor and major cayces and the pelvs of the ureter an be clarly seen. Each minor calyx has a -shaped appearace cause by the enal paplla projcting ino it. P.296

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Figure 5-94 teroposterior radiograph o the ureer and rnal pelvis after ntravens injecion of a iodine-containing compound which i excretd by the kidne. Major and minor calyces are also shown.

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igure 5-5 Repesentatin of the main feaures see in the radiograph in Figure 594.

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Figure -96 Anteropostrior radograph o both kineys 15 inutes ater intrvenous njection of an ioine-containing compound. Te calyce, the renal pelvis, and te upper arts of he uretes are clarly see (5-yearold gir).

Surfce Anatomy of th Abdominl Viscra The suface anaomy of te abdomial viscea is fuly descried on pae 192.

Clinica Problem Solving Study te followng case istories and select the bes answers to the qestion flowing hem. A 45-yearold man as ited to th emergency departmnt complaiing of evere pan in the right loer quadrnt of the anterir abdomal wall. He had epeatedl vomited and his emperatue and puse rate ere elevated. Hi history indicate that he had acute appendictis and hat the pain had suddenly ncreased On examnation, the muscl of the lower pat of the anterior abdominal wall in he right lower qudrant sowed rigdity. Th diagnoss of peritonitis fter perration o the apendix wa made. 1. The ymptoms nd signs displaye by this patient cn be expained by the following statements eept whic?

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snell (a) The erforatin of the ppendix had reslted in te spread of the ifection rom the ppendix o involv the paietal pertoneum. (b) The arietal eritoneum in the ight ilac regio, the mucles of the anterir abdomial wall, and the overlyin skin ar all suplied by he segmetal erves T12 and L1 () Irritaion of te pariet peritoeum reflexly increses the one of te abdomial muscls, causig rigidiy. (d) The greater entum teds to beome stuc down to the appedix and estricts he spred of infction. (e) Th pain wa intensiied afte perfortion of he appenix becaus of stimlation o the autnomic pin endins in the parietal peritoneu. Vew Answe 1 E. In e parietal peritoneum linng the anerior abominal wll in th right liac fosa, the snsation f pain oiginates in the nrve endngs of smatic spial nerve (T12 an L1). A 63-year-old man with a long hstory of a duodenl ulcer as seen n the eergency departmen after vomiting blood-staind fluid nd exhibting al the sigs and syptoms of severe hpovolemic shock. 2 The following sttements oncernin duodena ulcers ould appl to the atient's conditio except hich? (a) Hmorrhage from a dudenal uler often reveals tself by the ge of blck stools on defecation. (b) Te pylori sphincter prevent most of the blod from the duodena lume from pa into the stomach. (c) The gastrodudenal arery lies behind te first art of te duodenm and wa probably eroded by the ulr. (d) The astroduoenal artey is a all branch of the hepatic rtery. e) The duodenal ulcer was ost likey to be ituated n the posterior wl of the first part of the duodenum View Anwer 2. D. Te gastrouodenal rtery is a large ranch of the hepaic arter. A 47-yer-old woan was oerated o for the treatmen of a chonic gatric ulcer that had not resonded to medical reatment At opertion fo partial astrectoy, it wa found tat the pterior all of te stomach was stuck down t the poserior abominal wll. The urgeon hd to prceed with great care to avod damagig importnt strucures lyig on th posterir abdomial wall. 3. The follong structures located on he posterior abdomnal wall were posibly invlved in he diseae proces except hich?

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snell (a) The righ kidney (b) The pancre (c) he left uprarena gland (d) Th left kiney () The leser sac f peritoeum f) The slenic arery View Aswer 3. A A 5-year-old man was n a resturant whn he sudenly stated to vmit blood. He wa taken uconsciou to the mergency departmet of a lcal hosital. On examination, he had all the signs o severe ypovolemic shock. On palpaion of te anterir abdomial wall, the righ lobe of the livr was fet three fingerbreadths bel the costal margi. Severl enlargd superfcial veis could e seen aound the umbilicu. His wife said hat he hd vomited blood 3 onths previously nd had early did. She amitted tat he wa a chronc alcohoic. The diagnosi was cirrhosis of the liver secondar to chroic alcohlism. 4. he symptoms and sns displayed by his patiet can be explaine by the ollowing statemens except which? (a) The norm flow of portal blood through the live is impared by crrhosis f the lier. (b) The portal–stemic anstomoses become elarged i this codition. (c) At te lower nd of th esophags, a brnch from the righ gastric vein anastomoses with an esophageal tributar of the zygos ven. (d) Rpture of a varicoed esophageal vein could poduce a evere heorrhage o that t patien would vmit up blood. (e) Wth porta hypertension the paraumbiical veis linkin the suprficial eins of he skin systemic veins) to the portal vein ecome cogested ad visibl. View Anser . C. At the lowe end of he esophgus, a banch fro the lef gastric vein anstomoses with an esophagea tributa of the zygos ven. A 55-year-old woman wih a hisory of flatulent dyspeps suddeny experienced a excrucating coicky pai across the uppe part o the abomen. On examinaton in the emergeny departnt, she was foun to hav some riidity an tendernes in th right upper quadrnt. A dagnosis f biliar colic ws made. 5. he following statments wold explan this ptient's symptoms except which?

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snell (a The pai of galltone colc is caued by sasm of te smooth muscle i the wall of the gallblader and istentin of the bile ducts by the stones. (b) Th pain fiers from the gallbladder and bile ducts ascd throug the suprior mesnteri plexus nd the greater splanchni nerves o enter he thoraic segments of te spinal cord. (c) eferred ain is elt in te right upper quadrant o the epiastrium (d) T7 through T9 dermomes ar involvd. (e) Th violent contractons of he gallbadder wal are atempts to expel the gallstoes. View Answer 5. B The pai fibers rom the allbladdr and bie ducts ascend through the celiac pexus. On examinaton of th abdomen of a 31-ear-old oman, a arge sweling was found t extend ownward nd medialy below the left costal mrgin. On percussion, a continuous bnd of dulness wa noted extend upward rom the lft of th umbilics to the left axilary regon. On alpation a notch was felt along th anterio border f the swlling. A diagnosi of spleic enlarement wa made. 6. Te signs isplayed by this atient cn be expained by the folloing statments exept whic? () The speen has notched anterior border cused by ncomplet fusion f its pats durin developent. (b) Becuse of te presene of the left coic flexue and th phreniccolic liament, te spleen is unabl to expnd vertially downward. (c) A pathologcally enlarged speen exteds downwrd and frward, toward the mbilicus (d) The spleen is situted in te upper eft quadant of te abdome beneath the diapragm. (e) The long axis of the sleen lie along te 12th rb. Viw Answer 6. . The log axis o the splen lies long the 10th rib A 48-yearold woma with a istory o repeate vomitin was tted to the hosptal with a diagnois of lage bowel obstructon. To dcompress the stoach a nasogastric tube was assed. 7. hen ng a nasgastric ube some importan anatomi statemens should be consiered ext which (a The wel-lubricaed tube s insertd throug the widr nostri. (b) Th tube is directed backward along th nasal foor and ot upwar because t may become caught on the nasal chanae. (c) The distance betwen the notril and the cardac orifie of the stomach is about 23 in. (7.5 cm).

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snell (d) The distnce betwen the cadiac oriice and he pylors is 4.8 to 5.6 i. (12 to 4 cm). (e) Eshageal narrowing ay offer resistane to the tube behnd the cicoid catilage, .21 in. (18 cm) frm the notril. (f) he left ronchus nd the ach of th aorta oss in font of te esophaus and my impede the descnt of th tube, 1.2 in. (8 cm) frm the notril. g) Where the esopagus entrs the somach is a slight resistance o the decent of he tube. Vew Answe 7. C. The dstance btween th nostril and the ardiac oifice of the stomch is abut 17.2 n. (44 c). A 16-yearold boy eceived severe ick in te right lank while playing footbal at schol. On exmination in the eergency epartmen, his riht flank was seveely bruised, and his righ costovetebral angle wa extremey tender on palpaion. A secimen f urine howed mcroscopi hematura. A diagnosis of damage t the right kidney as made 8. The followin statements concening blut trauma to the kidney are corect excet which? (a) The kidny tends o be cruhed betwen the 1h rib a the verebral coumn. () The kiney can e injure by fracures of he 12th ib (right kidney) r 11th ad 12th ribs (left kidney). (c) In ost patints the idney daage is mld and rsults in othing mre than icroscopc hematuia, as i this paient. (d In sevee kidney laceratis, exteive hemorhage an extravaation of blood an urine ito the paarenal ft occurs e) In seere kidny laceraions, a ass caued by exravasated blood an urine bhind the peritonem may be palpate, especilly on the right sde. () Both kdnes lie on the postrior abdminal all and are at the same verebral leel. View Aswer 8. F. Bcause of the larg size of the righ lobe of the live, the riht kidne lies at a lower evel tha the lef kidney. A 17year-old oy was ivolved i a gang ight. It started s an argment bu quickly worsened into a seet braw with th use of nives. H was exmined in the emerency deptment an found t have a leeding tab woud in his left flak. A urie specimn revealed frank bood. 9 Stab wonds of te kidneys involve other abdminal ogans in high pecentage f cases. Of the ogans lised, whic one is east likely to be damaged n this ptient? (a) Stomach b) Splee

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snell (c) Iferior vea cava (d) Let colic lexure (e) Left supraenal land (f) Cils of jjunum (g) Boy of the pancreas iew Answr 9. C A 56-yea-old man visited is physcian comlaining that he xperiencs sevee pain n both lgs when aking log walks. He noticd recenty that he crampike pain occurs afer walkig only a hundred ards. On questioning, he aid that the pain quickly isappear on rest only to return after he walks the sme distace. When the physcian askd about his sex life the ptient aditted tht he was experiening diffculty wth erection. 10. The smptoms an signs dsplayed by this atient cn be expained by the follwing staements ecept whih? (a) Arteriograph of the bdoinal arta reveled blocage in te region of the burcatio. (b) Only the right common ili artery was invoved by disease. ( The grdual blocage of te aorta as cause by advaced arteiosclerois. (d) An insuficient aount of lood was reaching both leg, causin pain (caudicatin) on waking. (e) Th lack of blood enering boh internl iliac rteries as responsible for the difficulty wth erecton. View Anser 10. B. he blockge of th aorta i the regon of th bifurcaton had ffectivey blocke the entances ino both cmmon ilic arteris. 23-year-old woman, who ws 8 monts pregnat, told er obsterician at she ad recenly noticd that her feet and ankles ere swolen at te end of the day. She said that the swelling was wors if s had ben standing for long periods. She alo notice that th veins aound he ankles ere becoing promnent. 11. Th symptoms and sign displad by thi patient can be eplained y the folowing satements except wich? (a) Th enlarge uterus an abdoinal organ and ofen comprsses the inferior vena cav. (b) Venous bck pressre cause the tisue fluid to accumlate in he subcuaneous tssues of the feet and ankl.

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snell (c) Venos back pessure ipairs th venous eturn in the supeficial vins in bth the legs, leadng to vricose vins. (d) Hgh level of progesterone in the blood durin pregnany cause he smoot muscle in the wal of the eins to relax, tus permiting the eins to dilate. (e) Th pregnan uterus resses o the symathetic tunks, casing vasdilatati of the blood vessels of the legs. View Anser 1. E. Th sympathtic truns are nt pressd on by the pregnant uterus. A 2-year-ol woman as involed in a head-on automobil acciden. When xamined n a neigboring hspital, he was i a state of sever shock, with a rpid puls and low blood prsure. Extensive ruising ws seen n the loer part f the anerior abominal wll. Furter examiation showed that the abdoen was bcoming rpidly ditended. xploratoy surgery reveale a ruptued abdomnal aort. 12. The followin statements concernng this ase would explain er clinial condiion excet which? (a) The atient wa wearing a seat blt, whic explaind the brising on the anteror abdomnal wall (b The aorta is locted on te posteror abdomnal wall lateral to the left side of the verteral colum. () The aorta lies ehind th peritonum in th retropeitoneal pace. (d The blod did no immediaely escae into he peritoeal caviy becaus it is retropertoneal i positio and th tear was small in size. e) A sea belt ma hold th patient securel in the eat, but in some idividual the kideys contnue forard afte impact and the real arter may be orn from the side of the orta. Vew Answe 12 B. The aorta decends though the abdomen ehind th peritonum on th anterir surfac of the odies of the lumbr vertebae. P.299

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Review Question Multipe-Choice uestions Selct the bst answe for eac questio. 1. The follwing staements concerning the live are correct excep which? (a) The uadrate obe drans into he right hepatic uct. (b) he lesse omentum uspends he stomah from te viscerl surfac of the iver. c) The lft trianular ligent of he liver ies anteior to te abdomial part of the eshagus. (d) Th attachmnt of th hepatic vein to the nferior vena cava is oe of th most important upports f the lier. (e) The lgamentum venosum s attaced to th left banch of the portl vein in the porta hepatis View Anser 1. A. Te quadrate lobe and the cudate lbe are i fact pats of th left lobe. Thus, the rigt and let branchs of the hepatic atery and portal ein and he right and left hepatic ucts are distribted to the right lobe and the left obe plus the quadrate and audate lbes. 556

snell 2. Th followi statemets concening the pancreas are corrct excep which? (a) The pancreas receive part of the artial suppy from te spleni artery. (b) Th main pacreatic uct open into the third part of the duodenu (c) The uncinat process of the pncreas pojects fom the had of th pancrea. (d) Te bile dct (commn bile dct) lies posterio to the ead of te pancre. (e) he transerse mescolon is attached to the aterior brder of he pancres. View Anwer 2. B. Te main pncreatic duct opes into te second part of he duodeum, at about its middle, ith the ile duct on the mjor duodeal papila. Someimes, th main dut drains separatey into te duodenm. . The following satemets concening the ileum are correct except wch? () The cicular smoth musce of the lower en of the leum seres as a phincter at the jnction o the ile and the cecum. (b The braches of he superor meseteric arery servng the ieum form more arces than those seving the jejunum. (c Peyer's patches re preset in the mucous mmbrane o the lowr ileum aong the ntimeseneric borer. (d) The licae ciculares re more rominent at the dstal end of the ieum than in the jjunum. (e) Th parasymathetic nnervatin of the ileum is from the vagus neves. View Anwer 3. D. Th plicae irculare are absnt from the distal end of he ileum 4 The hilm of the right kiney contins the ollowing importan structues excep which? (a) Th renal pelvis b) Tribuaries of the rena vein (c) Sypathetic nerve fiers d) Part f the riht supraenal glad () Branches of the renal aery View Answer 4. D The rigt suprarnal glan caps th upper ple of th right kidney an does not extend ownward to the hium of th kidney.

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snell 5. Te followng stateents concerning te left sprarenal gland are correct xcept whch? () The glnd extens along he media border f the let kidney from the upper poe to the hilus. (b) Th gland's vein drains into he left enal vein. (c) The land is eparated from the left kidey by perrenal fa. (d) Th gland lies behin the lessr sac of peritonem. (e) Th medulla is innerated by ostganglonic symathetic nrve fibes. iew Answer 5 E. The edulla o the suparenal gland is innervated by pregaglionic ympathetc nerve ibers. 6. The folowing statements concernig the abdominal aota are crrect exept whic? (a) he aorta bifurcats into te two comon ilia arterie in fron of the fourth lumar vertera. b) The arta lies on the rght side of the iferior vna cava. (c) From the aort's anteror surfae arise he celiac, superior mesenteic, and nferior esenteri arterie. ) The ata enters the abdmen in front of the 12th toracic vrtebra. (e) The horacic uct leavs the abomen thrugh the ortic opning of te diaphrgm on the right side of he aorta View Aswer 6. B. he abdominal aorta lies on the left side of he inferr vena cva. 7. Th followig statemnts concrning th abdominl part of the sympthetic tunk are orrect ecept whih? a) The unk entes the abomen fro behind he media arcuate ligament (b) The trunk posesses fur or fie segmenally arrnged ganlia. (c) All the anglia reive white rami communicanes. (d) Gy rami communicanes are given off to the lubar spinl nerves (e) Nere fibers medally to he sympahetic plexuses on he abdomnal aort and its branches. View Anwer 7. C. Th white rmi commuicantes oin the irst two ganglia o the first to lumbar spinal nrves. 8 The folowing sttements cncerning the lumbr plexus are corrct excep which? (a) The plexus lis within the psoa muscle.

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snell (b) The plxus is formed fro the poserior rai of the upper fou lumbar erves. (c) The emoral nerve emergs from te latera border of he psoas muscle. (d) Te obturaor nerve emerges from the mdial borer of th psoas mucle. (e The ilihypogastic nerve emerges rom the lteral boder of te psoas muscle. View Answer 8. B. The lumbr plexus is frmed fro the antrior rami of the uper four lumbar pinal nerves. 9. The followig veins orm important potal–systemic anastomoes excep which? (a) Eophageal branche of the left gasric vein and tribtaries of the azygs veins (b) Suerior retal vein and infeior vena cava (c) Praumbilial veins and supeficial vins of te anterir abdomial wall (d) Vein of the scending and descnding pats of th colon with the lumbar veis (e) Veins from the bare areas of the liv with the phrenic veins View Aswer 9. B The suprior rectal veins (tributries of he portal vein) anastomse with he middl and inerior retal vein (systemi tributries). 10. The follwing staements cncerning the uretrs are crrect exept which? (a) Bth uretes have tree anatmic site that are constriced. (b) Both ureers receive their blood suply from the testular or varian ateries. (c) Boh ureter are seprated frm the trnsverse processe of the lumbar veebrae by the psoas muscles. (d) Both ueters anterior to the testicular or ovaran vesses. (e) oth ureters lie anerior to the sacriliac jonts. iew Answr . D. Th ureters are crossd on ther anterir surfacs by the testiculr and ovrian vesels. 11. Th followig statements concerning the inferior mesentec artery are corrct excep which? (a) e meseneric artery's colic branch supplies the desceding coln. (b) he meseneric artry gives off the nferior ancreatioduodena artery. (c) The mesenterc artery supplies the sigmid colon

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snell (d) The esenteric artery's branches contribute to th marginal artery. (e) The esenteric artery rises frm the aota immediately below the thrd part f the ddenum. Vew Answe 11 B. The nferior ancreaticoduodena artery s a branh of the superior mesenterc artery 2. The fllowing tructure are preent withn the leser omenum excep which? (a) The ortal ven (b) The bil duct c) The iferior vna cava (d) Te hepatic artery (e) Th lymph ndes View Anwer 12. C. he inferor vena ava lies on the psterior bdominal wall behnd the arietal eritoneu. It is eparated from the lesser oentum by the epiloic formen. Matching Question Match the numbered structure shown n the poteroanteior radigraph of the stoach and small itestine€”after ngestion of a baium meal€”with the appropriate letered strctures (8-year-od male).

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13. Stucture 1 14. Sructure 15. tructure 3 16 Structue 4 1. Structre 5 () First art of dodenum (b) Seond part of duodeum 561

snell () Third at of duoenum (d) Air-illed fudus of somach (e) Jeunum (f) Pylorus of stomach (g None of the abov Vew Answe 1. B 14. F 15. 16. G The duonojejunal junctin 1. E Matc the numered strctures shown on he posteroanterior radiograh of the large inestineâ€after eacuation of a barum enema€”with te appropiate letered lymhatic dainage (2-year-ol female

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18. Sructure 19. tructue 2 2. Structre 3 1. Strucure 4

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snell 2. Struture 5 (a) Appedix (b Splenic flexure (c) Transverse olon (d) ecum (e Rectum (f) Sigoid colo (g) Dscending colon (h) None of the aove View Aswer 18. D 9. H. Rht colic flexure 20. G 21. F 22. E Match the nmbered stuctures hown o the intravenous pelogramâ”obtained 20 minuts after njectio of a sutable cotrast meium—wih the appropriate ettered tructure (5-yearold female)

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2. Strucre 1 24. Structure 2 25. Struture 3 26. Structue 4

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snell 2. Structre 5 () Rectum (b) Pevis of ueter (c) Sacru (d) Urter (e) Urinary ladder (f) Majo calyx (g) None of the aove Vie Answer 23. . Minor alyx 4. B 2. F 26. D 27. Multple-Choie Questins Rad the cse histoies and select th best answer to th questio followig them. A mother took her 0-day-o baby by to a pediatrician because he had sarted t vomit ater his eeds. Th baby wa breast-ed. For he first 15 days after bith, the by had tken his eeds ver well an had slet contetedly in his crib followin the noral afterfeed burp. However in the previous 5 days, he baby ad begun to vomit toward te end of each fe, shootig the mik out of his mout for a distance of 1 to 2 ft. Afte carefuly questioing the other an after a physical examinaion of te boy, te pediatrcian mad the dianosis of congenil hypertophic pyoric steosis. 28. He as able o ascertin the fllowing dditiona signs ad symptoms except which? (a) Onc the milk had bee vomited the chid immeditely woud feed aain, onl to repet the sae perforance. (b) O gentle alpation of the aterior bdominal wall, a mall firm swelling was felt just beow and mdial to the tip f the lef eighth ostal catilage. (c) On observing the anteior abdinal wal, an ocasional ave of gstric peristalsis was seen travelin across the epigstrium frm left t right. (d) The stools wre small n quantiy and inrequent. e) The hild shoed signs f dehydrtion as videnced by a depessed anerior fonanelle o the skul. 566

snell View nswer 28. B. In congital hyprtrophic pyloric tenosis, there is a localized muscar hyperophy and hyperplasia of the pylori sphinctr, which is largr than nrmal and can usually be palated jus below ad medial to the ip of th right nnth costal cartilae. A 6-year-ld girl as examied by a ediatrican becaue she ha a histry of reurrent pin in the region f the umilicus. he pain as dull and achin in natue and lated for bout 1 wek. It hd recurrd on four occasis in the previous 2 years. Then, 2 ays befoe the examination the chid had seere rectl bleedig and ha fainted. 29. On eaminatio of the hild, th pediatrcian foud the following signs and symptoms consiste with th diagnoss of Mekel's dierticulum except wich? (a) Tenderness of he anteror abdonal wall in the rght iliac region (b) Aneia (c) Stools sreaked with dark red blood (d) Pyrexia f 102°F Vew Answe 29 D. In any case of Mecke's diveticulum, a small rea of ectopic gatric mucsa is prsent, whch is caable of roducing hydrochloic acid and pepsn. In the adin mucous embrane, this chid had a chronic lcer tha was resonsible fr the umilical pin. Suddn sever hemorrhae from a artery n the flor of the ulcer wa the case of th rectal bleeding ad faintin attack. The condion is nt assocated wit a pyrexa. After restoraton of th blood vlume and hemogloin to a normal levl, a chid with tis condiion shou be operated on nd the dverticulm should be widel excised The cut ends of the ileu then ar ed by an end-o-end anstomosis

ootnote *For puposes o descripion, the hepatic artery s sometimes divied into he commo hepati artery, which extends rom its origin to he gastrduodenal branch, nd the hepaic arter proper, which is the remainder f the arery. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

7. 6. The Pelvis: Part I - The Pelvic Walls A 5-year-ol man was involved in a ligt-plane accident He was flying hom from a usiness trip whe, becaus of fog, he had o make a forced landing in plowed ield. On landing, the plae came abruptly to rest on its no. His cmpanion ws killed on impat, and h was thrwn from the cockp. On ission to the emegency deartment, he was uconsciou and shoed signs of sever hypovoemic (los of circlating bood) shck. He hd extensve bruiing of te lower art of te anterir abdomial wall, and the front of his pelvs was pominent n the riht side. During eaminatio of the

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snell penis, it was possble to epress a rop of bood-staied fluid from th externa orifice No evidnce of eternal hmorrhage was present. Radiogaphic exaination f the pevis showd a disocation f the syphysis pbis and linear racture hrough the later part of the sacrum on the right sie. The uethra wa damaged by the hearing orces aplied to he pelvi area, wich explaned the blood-stained flid from he external orific of the enis. Th pelvic radiograh (later confirmed on compued tomogaphy sca) also rvealed e presence of a lrge collction of blood in the loos connectve tisse outsid the pertoneum, hich was caused b the teang of th large, thin-waled pelvi veins b the fratured boe and acunted for the hypovolemic shock. his patint illusrates th fact tht in-deph knowldge of the anatom of the lvic reion is ncessary before a hysicia can even contempte makin an inital examiation and start treatment in cases of pelvi injury.

Chaper Objecives 

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The plvis is a bowl-shed bony structure that protects the terminal parts o the gasrointesnal trat and th urinary system ad the male and femle interal organ of repoduction It lso contins impotant nerves, blood vessels, and lympatic tisues. The prpose of this chater is t review the significant aatomy of the pelvc walls relative o clinicl problms. Partiular attntion is paid to ge and sxual diffrences nd to th anatomi feature associaed with elvic exainations

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Basic Anatomy The pevis* is he regio of the trunk tht lies blow the bdomen. Although he abdominal and pelvic cvities a continuus, the wo regios are decribed searately.

Th Pelvis The boy pelvis main function is to transit the eight of the body from the vertebra column o the feurs. In addition, it contans, supprts, and protects the pelvc viscer and provides attchment fr trunk nd lower limb musles. The bony pelvis is coposed of four bons: the to ip bones, whic form th lateral and anteror walls and the sarum ad the coccy, which are part of the vertebra column and form the back all (Fig. 61). The two hip bone articulte with ach othe anteriory at the sphysis bis ad posterorly wit the sacum at th scroiliac ts. The bony pelvis thus fors a strog basin-haped stucture tat contins and rotects he lower parts of the intestinal an urinary tracts ad the inernal orans of reproductio.

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snell he pelvi is divied into wo parts by the pelvc brim, which is formed by the sacrl promonory (anterior and upper argin of the firs sacral ertebra) behind, he iliopectneal lins (a ine that runs dowward and forward round the inner surface of he ileum lateraly, and te ymphysis pubis (t beween bodes of puic bones anteriorly. Above the bri is the false pelvis, whic forms prt of th abdominal cavity. Below te brim i the true plvis.

Orentation of the Plvis It is iortant fr the stdent, at the outst, to uderstand the corret orienttion of he bony elvis reative to the trun, with te indiviual staning in te anatomc position. The frnt of te symphyis pubis and the anterior uperior liac spies shoul lie in the same ertical lane. Ths means P.39

that he pelvic surface of the smphysis ubis facs upward and backward and the anterior surface of th sacrum s directd forwar and downard.

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Figure 61 Antrior vie of the ale pelvi A) and female plvis (B).

alse Pelis Th false plvis is f little clinical importane. It is bounded ehind by the lumbr vertebae, lateally by he iliac fossae nd the ilacus musles, and in front by the lwer part of the anterior bdominal wall. The false plvis flas out at its uppe end and should e considred as part of th abdominl cavity. It

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snell suppots the bdominal contents and afte the thid month f pregnacy helps the gravid uterus. During he early stages o labor, t helps uide the fetus ito the tue pelvi

True Pelvis Knowledge of the shape an dimensins of th female pelvis i of grea importace for ostetrics because it is th bony cnal throgh which the chil es uring bith. The true pelvis hs an inlt, an oulet, and a cavity 

The pelic inlet, or pelvic brim (ig. 6-2), is bunded posteriorly by the scral proontory, aterally by the iliopectneal lins, and ateriorly by the smphysis ubis (Fig. -1). P.310

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Figure 62 Rigt half o the pelis showig the pevic inle, pelvic outlet, nd sacrouberous nd sacrospinous lgaments.

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The pelvc outlet (Fig. 6-) is bunded poteriorly by the cccyx, laerally b the iscial tubeosities, and anteiorly by the pubic ach (Figs. 6-2 ad -3). he pelvi outlet as three wide nothes. Antriorly, he pubic arch is between he ischipubic rai, and lterally re the siatic noches. Te sciati notches are divied by the scrotuberus and sarospinous ligaments (Figs. 6-1 and 6-2) ino the greatr and leser sciaic foramna (se ge 318). From an obsteric stanpoint, bcause the sacroturous ligments ar strong and relaively inlexible, they shold be cosidered o form art of te perimeter of the pelvic utlet. Tus, the utlet is diamond shaped, ith the schiopubc rami ad the syphysis pbis formng the oundarie in fron and the sacrotubrous ligments and the coccyx forming the boundaries behind. The pelic cavit lie between the inle and the outlet. t is a sort, cured canal with a shallow nterior all and much deeper postrior wall (Fig. 6-2).

tructure of the Plvic Wals The wals of th pelvis are forme by bone and liaments tat are prtly lined with mscles coered with fascia ad parieal peritneum. Th pelvis has anterir, posteior, and lateral walls an an infeior wall or floor (Fg. 6-6).

nterior elvic Wal Th anterior pelvic wall is te shalloest wall and is ormed by the bodis of the pubic boes, the ubic rami and the symphyss pubis Fi. 6-7)

Posteior Pelvc Wall The poterior plvic wal is extesive and is forme by the acrum and coccyx (Fig. 6-8) and by the pirifomis musces (Fig. 6-) and their coring of arietal elvic facia.

Sacru The sarum conssts of fve rudimntary vetebrae fsed togeher to frm a single wedgeshaped bone with a forward concavit (Figs. 6-2 and 6-8. The uper bordr or bas of the one artiulates wth the ffth lumbr vertebra. The rrow infrior borer articlates wih the cocyx. Laerally, he sacru articulates with he two iiac bone to form the sacroilac t (Fig. 6-1). Th anterio and uppr margin of the irst sacral vertebra bulge foward as the posteror margi of the elvic inet—the saral promntory (Fi. 6-2—which is an imortant ostetric landmark used when easuring the size of the plvis. The ertebral foramina together form the sacral canal. Th laminae of the ffth sacrl verteba, and smetimes hose of he fourh, fail t meet in the midlne, formng the scral hiaus (Fig. 6-). Th sacral anal conains the anterior and postrior roos of the lumbar, acral, ad coccygal spina nerves; the

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snell filum terminal; and fbrofatty material It also contains the lower part of the subarachnoid space don as far as the lwer bordr of the second scral vertebra (Fig. 6-10). The anterior and posterio surface of the acrum pssess on each sid four foamina fo the paage of te anterir and psterior ami of he upper four saral nervs (Fig 6-8. P.11

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Figure 63 Riht hip bne. A. edial surface. B. Latera surfac. Note te lines of fusio between the

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thre bonesâ€the iliu, the ishium, an the pubs.

Clinicl Notes Clinial Concet: The Pelvis I a Basin with Hols in Its Walls he walls of the plvis are formed b bones ad ligamts; thes are parly lined with musles (obtrator inernus an pirifomis) covred with fascia ad parieta peritonum. On te outsid of the pelvis ae the atachments of the guteal mucles and the obtrator exernus mucle. The greater part of the bony pelvis is tus sandiched beween innr and ouer muscls. The basin has anterior, posterior, and lateral alls and an infeior wall or floor formed by the imrtant leator ani and cocygeus mucles and their coering facia. The basin has many holes: The postrior wal has holes on the anterior surface o the sacrum, the anerior saral foraina, or the age of the anterior rami of the sral spinal nerves. The sacrouberous and sacropinous lgaments convert the greaer and lsser sciatic notches into e greater and lesser sciatic foramina. The greater iatic foamen proides an xit from the true pelvis ito the luteal region fr the sciatic neve, the udendal erve, an the glteal neres and vessels; the lesser ciatic framen prvides an entranc into th perineu from th gluteal region for the pundal neve and te internl pudendl vessel. (One cn make a further analogy ere: For the wire to gain entrance to the apartment elow, whout goig throug the flor, they ave to perce the wall [grater scatic formen] to et outsie the bulding an then return throgh a seond hole [lesser sciatic framen]. n the cae of the human boy, the udendal erve and internal pudendal vssels ar the wirs and the levatr ani an the cocygeus mucles are the floo.) The lteral pevic wall has a lage hole, the obturaor foram, whih is cloed by th oturator embrane, excep for a sll opening that permits the obturator nerve o leave he pelvi and entr the tigh.

Pelic Measuements i Obstetrcs The capaity and hape of he femal pelvis re of fndamental importance in obetrics. The femae pelvis is well adapted for the process of hildbirt. The pevis is sallower nd the bnes are smoother than in he male. The size of the plvic inlt is simlar in he two sxes, but in the fmale, th cavity is larger nd cylidrical ad the pevic outlt is widr in bot the anteroposterir and te transvrse diamters. Fur relating to areas of the plvis are commonly used in linical ractice:  

Th elvic inet or brm of te true plvis (Fig. -4) i bounded anteriory by the symphysi pubis, aterally by the iiopectinl lines, and posteriorly y the saral promontory. The pelvic outlet of the tue pelvi (ig. 6-4) is bunded in front by the pubi arch, lterally y the ishial tuerosities, and posteriorly y the cocyx. Th sacrotuberous lgaments lso form part of he margi of the utlet.

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snell  

The elvic caity is the space between the inlet and the outlet (Fi 6-4) he axis of the pelvs is n imagiary line ing the central points f the aneroposteior diameters fom the inlet to th outlet nd is th curved ourse taen by te baby's head as it descends through the pelvs during childbirh (Figs. 6-4 and 6-5).

Interal Pelvi Assessnts Interna pelvic assessments are mae by vaginal exanation dring the later weks of prgnancy, hen the elvic tssues ar softer nd more ielding than in the newly pegnant ondition 

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Pubic arh: Sread the fingers nder the pubic arh and examine its shape. I it brod or anglar? The examiner's four fingers should be ae to res comfortably in he angle below th symphyss. Lateal walls Palate the ateral wlls and etermine whether they are concave, straiht, or onvergin. The pominence of the ichial spines and the postion of he sacrspinous igaments are note. Poserior wal: The sacrum is palpated to dermine wether it is straight or well curve. Finall, if the patient as relaxd the peineum sufficiently, an attmpt is mde to papate the promontoy of the sacrum. he secon finger of the eamining and is paced on he promontory, and the index finger of the fee hand, outside he vagin, is plaed at th point o the exmining hnd where it makes ith the ower borer of th symphyis. The ingers ae then wthdrawn nd the distance masured (Fig 6-5B) providig the mesurement of the diagnal conjgate, which i normall about 5 in. (13 m). The nteroposerior dimeter fom the scrococcygal t to the lwer bordr of the symphysi is the estimatd. Ischial tuberosities: Te distane betwee the iscial tubeosities ay be esimated b using te closed fist (Fig. 6-5D). It measues about 4 in. (1 cm), bu it is dfficult o measur exactly

eedless o say, cnsiderabe clinical experence is required to be able to asss the sape and ize of te pelvis by vaginl examintion.

The Femal Pelvis Deformities of he pelvi may be esponsibe for dystia (ifficult labor). contraced pelvi may obstruct the normal psage of the fetus. It ma be indiectly reponsible fo dystoca by cauing conitions sch as mapresentaion or mlpositio of the etus, pemature rupture of the fetal membrans, and uerine inrtia. The cause of pelvic deformities may be congenital (rare) or acqured from disease, poor posure, or ractures caused by injury. Pelvic formitis are more common n women ho have rown up n a poor environment and re underourished It is pobable tat these women sffered i their yuth from minor degrees of rickets. In 1933, Cadwell and Moloy clssified pelves into four roups: gnecoid, ndroid, anthropoi, and pltypelloi (ig. 6-5C). The gynecoid ype, preent in aout 41% f women, is the tpical female pelvs, which was prevously decribed. The andoid tpe, presnt in aout 33% of white females a 16% of lack females, is the male or funnel-shaped pelvis wih a ed oulet. Th anthropoid type, present in about 24% of wite femaes and 4% of black females, is long, narrow, and oval shped. 576

snell The pltypelloid type, present in only bout 2% f women, is a wid pelvis lattened at the rim, wit the proontory o the sacum pushe forward. P.312

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Figur 6-4 Pelvic ilet, pelic outle, diagonl conjugte, and xis of te pelvis. Some o the mai

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differeces betwen the feale and the male pelvis re also hown.

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Figure 6-5 A. Birth canal. Intrrupted ine indicates the axis of he canal. B. Proceure used in measuring the diagonal conjugate. . Diffrent typs of pelic inlet, accordng to Cadwell an Moloy. D. Estimaon of the width of the pelvic outle by mean of a clsed fist

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Figure 6-6 Right half f the pvis shoing the pelvic walls.

The sarum is uually wier in prportion o its lenth in te female than in he male. The sacrum is tilted forwad so tha it fors an ange with te fifth umbar vetebra, clled the lubosacral angle.

Coccyx The coccx consiss of fou vertebre fused ogether o form a small trangular bone, whih articuates at ts base ith the lower en of the acrum (Fig. 6-8).

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Figure 6-7 Anterior wall of he pelvi (posterior view)

he coccyeal vertbrae conist of bdies onl, but th first vrtebra pssesses rudimenary transvese proces and conua. he cornu are the remains f the peicles an superio articulr proceses and roject uward to rticulat with th sacral ornua (Fig. 6-8).

Piriormis Mucle he pirifrmis muscle arises from th front o the latral mass f the sarum and eaves th pelvis o enter e gluteal P.316

region y in lateraly throug the greter sciaic foramn (Fig. 6-9). It is insertd into th upper brder of he greatr trochater of te femur.

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Figure 6-8 Scrum. A. Anterior view. B. osterior view.

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Actin: It is a latral rotaor of th femur a the hip t. Nerve supply: t receivs branchs from te sacral plexus.

ateral Plvic Wal The lateral plvic wal is formd by par of the ip bone below th pelvic nlet, th obturatr membrae, the scrotuberus and acrospinus ligaments, and he obtutor intenus musce and it coverig fascia

Hip one In children each hip bone cosists of the iliu, which lies superiorly; te ischiu, which lies poseriorly nd inferirly; an the pubs, which lies antriorly ad inferirly (Fig. 63). The three eparate bones are ed by cartilage at the actabulum. At puerty, thse three bones fue togethr to for one lare, irregular bone. The hi bones aiculate with the acrum at the sacoiliac ts ad form te anteroateral P.317

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walls f the pevis; the also articulate with one nother aeriorly at the symphysis ubis.

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Figure 6-9 Psterior all of te pelvis

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Fiure 6-10 Sacrm from bhind. Lainae hav been reoved to how the acral neve root lying wthin the sacral canal. Not that in the adul the spinal cord ends below, at the level o the low border of the first lumbar vertebra.

O the outr surfac of the ip bone s a deep depressin, the acetbulum which aticulate with th hemisphrical hed of the femur (Figs 6-1 ad -3). ehind the acetabulum is a large notc, the greaer scatic notch, which is separted from the lesser ciatic ntch b the spine f the ischium. he sciac notche are conerted ino the greatr and leser sciaic foramna by he presece of th acrotubeous an scrospinos ligamets (Fig. 6-2). The ilum, whch is th upper fattened art of te hip boe, posseses the ilic crest (Fig. 6-3). The liac cret runs bween the aterior and posterir superir iliac pines Below hese spines are te corresponding anterior a posterir inferor iliac spines. n the iner surfae of the ilium is the larg aricular urface for artiulation ith the crum. Th liopectineal line runs downwad and foard aroud the iner surface of the ilium and serves to divide the fal from th true pevis. The ischiu is th inferio and posterior pat of the hip bone and posssses an ishial spie and n schial tberosity (Fig. 6-3).

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snell The pubis is the anteior part of the hp bone ad has a bod and supeior ad nferior ubic ram. The ody of te pubis ears te ubic crst an the pubic ubercle and ariculates with th pubic bone of te opposie side t the sympysis pubs (Fig. -1). n the loer part of the hp bone is a larg opening the obturaor foramn, whih is bouded by te parts f the ishium and pubis. Te obturaor foramn is filed in by the obtuator memrane (Fig. -3).

Ourator mbrane The oturator embrane s a fibrus sheet that almst compltly closs the oburator oramen, leaving a small ap, the obturaor canal, for the pasage of te obturaor nerv and vesels as hey leav the pelis to ener the tigh (Fig. 63).

Sacrotuberous Ligament The sacrotubrous ligment is trong an extends from th lateral part of he sacru and cocyx and te posteror inferior ilia spine t the ischial tuberosity (Figs 6-2 ad -9).

Sacrosinous Lgament The sarospinou ligamen is strog and trangle shped. It is attaced by it base to the lateal part f the sarum and occyx ad by its apex to te spine f the ishium (Figs. 6-2 ad -9). Th sacrotuerous and sacrospinous ligments prevent the lower en of the acrum an the cocyx from eing rotted upwad at the sacroilac t by the wight of he body Fi. 6-11. The tw ligamens also cnvert th greater and lessr sciati notches into formina, th geater nd lsser scitic foraina.

Obturaor Interus Muscl The obturato internu muscle rises frm the pevic surfce of th obturatr membrane and th adig part o the hip bone Fi. 6-12). The uscle fiers convrge to a tendon, hich leaes the plvis thrugh the lesser siatic foamen and s insertd into te greate trochaner of te femur.  

Actin: It laterall rotates the fer at the hip . Nere supply The rve to te obturaor interus, a brnch from the sacr plexus

Iferior Plvic Wal, or Pelic Floor Th floor o the pelis suppots the plvic visera and s formed by the elvic diphragm. The plvic flor stretces acros the pelvis and dvides i into the main pelic cavit above, hich conains the pelvic iscera, nd the prineum blow. The perineum is considred in dtail in Chpter 8.

Pelvic iaphragm The plvic diahragm is formed b the imprtant lvatores ni muscls and th small cccygeus uscles ad their covering fasciae Fi. 6-13. It is ncomplet anterioly to alow ae of the urethra n males nd the uthra and the vagina in females.

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Levatr Ani Mucle The levat ani musle is a wide thin sheet that has a linear oigin fro the bac of the ody of the pbis, a tndinous rch fored by a hickenin of the ascia coering the obturator internu, and the spine of the ichium (Fig. 6-13). From thi extensie origin groups f fibers sweep donward and medially to their insertio (ig. 6-14), as ollows: 

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Anterior fibers: The levatr prostaae or spincter vginae form a sing aroud the prstate or vagina ad are inserted int a mass f fibrou tissue, called te erineal ody, in front of the aal canal The levtor prosatae the rostate and stailize the perine body. Te sphincer vagine constrct the agina an stabilie the perneal bod. Inermediat fibers: The puboectalis forms a sling around the unction f the retum and nal cana. The puboccygeus es posterioly to be inserted into a sall fibrs mass, alled th anococcygel body, betwen the tip of the coccyx nd the aal canal. Posteror fiber: The iiococcygus is inserte into te anocoygeal body and te coccyx. Action: The lvatores ni muscls of the two side form an efficient muscula sling hat supprts and aintains the pelvc viscera in positon. They resist he rise n intraplvic presure durng the training and expusive eforts of he abdominal muscles (as ocurs in cughing). They als have a importat sphincer actio on the norectal junction and in the femae they srve also as a sphicter of the vagia. erve suply: The perineal branc of the fourth sacral nerve and fro the perineal brach of th pudenda nerve

Coccygus Muscl This small tangular uscle arses from the spin of the ischium nd is inerted ino the loer end o the sacum and ito the coccyx (Figs 6-13 nd 6-14) 

Actin: The two muscles assis the levtores an in supprting te pelvi viscera P.319

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Figure -11 Hrizontal section hrough te pelvis showing he sacroliac joits and he symphsis pubi. The loer diagrm shows he functon of th sacrotberous ad sacrosinous liaments i resistig the roation frce exered on th sacrum y the weght of te trunk.

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Nerve supply: A branh of the fourth ad fifth acral neves

A smmary of the attchments f the mscles of the pelvc walls nd floor their nrve suppy, and teir actin is givn in Table -1.

Pevic Fasca

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snell The pelvic fscia is ormed of connectie tissue and is ontinuou above wth the fscia linng the adominal alls. Beow, the fascia is continuos with te fascia of the prineum. he pelvi fascia can be dvided ino parietl and viceral lyers.

Parital Pelvc Fascia The arietal elvic facia line the wals of the pelvis ad is named according to the muscle t overlis (Fig. 6-17). Whre the plvic diahragm is deficien anteriorly, the parietal pelvic fascia becmes contnuous thugh the opening wth the fscia covring th inferio surface f the pvic diapragm, in the perieum. It covers te sphincer urethae muscl and the perineal membrane (see page 41) P.30

and orms the superior fascial yer of te urogental diapragm.

Figure -12 Lteral wal of the pelvis.

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Figure 6-13 Inferio wall or floor of the pelvs.

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Figure 6-14 Levator ani muscle and coccgeus musle seen n their nferior spects. Note tha the levtor ani s made u of seveal diffeent muscle groups The levtor ani nd coccyeus musces with heir fasial covrings fom a contnuous mucular floor to th pelvis, nown as the pelvic diaphrgm.

Viscral Laye of Pelv Fascia The visceral layer of pelvic fascia covrs and spports all the pevic viscra. In crtain lcations he fasci thicken and exends from the viscs to the pelvic wlls and rovides upport. Tese fasial ligaents are named acording t their aachments, for exmple, th pubovescal and he sacroervical gaments.

Clinica Notes Fascia Ligament of the terine Crvix

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snell In th female he fascil ligamets attaced to the uterine cervix ae of paricular cinical iportance because hey assst with he suppot of the uterus ad thus pevent utrine proapse (se age 366). The sceral plvic fasia aroun the uteine cervx and vaina is cmmonly rerred to as the parmetrium.

Pelv Peritoneum Te parietl peritoeum line the pelic walls and is eflected onto the elvic vicera and becomes ontinuou with th viscerl peritoeum (Fig. 617). For urther dtails, se ages 356 to 376

Clincal Notes Fractures of the Pelvs Factures f the Fase Pelvi Fractures of the fals pelvis aused by direct trauma ocasionall occur. he upper part of he ilium is seldo displacd becaue of the attachment of the iliacus scle on the inside and the gluteal muscles on the outside.

Frctures of the Tru Pelvis The mchanism f fractues of th true pevis can e bette understod if the pelvis is regarded not only as a bin but lso as a rigid rng (Fig. 615). Te ring i made of the pubic rmi, the schium, the acetbulum, te ilium and th sacrum, ed y stron ligaments at the sacroiliac and syhyseal oints. I the rin breaks t any on point, the fractue will b stable and no displacemet will ocur. Howver, if two brea occur n the ring, the fracture wll be untable an displacment wil occur, because he postvrtebral nd abdomnal musles will shorten and eleate the lteral part of th pelvis Fig. 615). The brea in the ring may occur not as e resul of a frcture bt as th result of disrution of he sacrliac or symphysal t. Fractre of boe on either side of the jnt is mre commo than disruptio of the t. The forces responsible for the isruptio of the bony ring ay be aneroposteior compession, lateral ompressin, or shearing. A heavy fll on th greater trochantr of the femur may drive te head o the femr throug the flor of the acebulum ino the plvic cavty.

Factures f the Sarum and occyx Fractres of te latera mass of the sacrm may ocur as pat of a plvic frature. Frctures o the cocyx are rre. However, coccydia i common nd is usally caued by direct trauma to the coccyx, s in faling dow a fligh of concrete steps The antrior surace of te coccy can be alpated ith a rectal examiation.

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Minor Fratures of the Pelvs The antrior suprior ilic spine ay be puled off y the forcible contraction f the storius uscle in thletes Fi. 6-15). In a similar anner th anterio inferior iliac spine may b avulsed by the contractin of the rectus fmoris mucle (orign of the straight head). he ischil tuberoity can b avulsed by the cntractio of the amstring muscles. Healing ay occur by fibros union, possibly resultin in elonation o the musle unit nd some reduction in muscuar efficency.

Aatomy of Complicaions of elvic Frctures Fratures of the true pelvis ae commony associted with injuries to the sot pelvic tissues. If amaged, he thin elvic vens—namly, the nternal iliac vens and teir tribtariesâ€that lie in the parietal pelvic faia beneath the parietal peitoneum an be th source f a massve hemorhage, wich may e life treatening. Th male urthra is ften damged, espcially i vertica shear factures hat may isrupt te urogental diapragm (se pge 407). The bladder, whch lies mmediately behind the pubi in bot sexes, s occasinally daaged by picules f bone; a full bladder is ore likey to be njured tan an emty bladdr (see page 353). he rectu lies witin the cncavity f the sarum and is proteted and arely daaged. Frctures o the sacum or ishial spne may b thrust nto the pelvic cavity, tearng the rctum. Nere injuris can folow sacrl fractues; the aying dwn of fibrous tisse around the anterior or psterior erve roos or th branche of the acral spial nerve can reslt in pesistent ain. Dame to the sciatic nerve may occur in fracture involvng the bundaries of the geater scatic noth. The peoneal prt of th sciatic nerve is most oftn involved, resulting in the inabilty of a onscious patient to dorsifex the akle or faiure of a unconscous patit to reflexly plantar-flex (ankle jrk) the foot (se pge 659).

Pelvic Floor The pelvc diaphrgm is a utter-shped shee of muscl formed by the lvatores ai and cocygeus mscles an their cvering asciae. From their origin, he muscl fibers n the tw sides sope dowward and backward to the mdline, poducing gutter hat slops downwrd and forward. rise in the intr-abdominl pressue, cause by the contractin of the diaphrag and the muscles f the anerior an latera abdominl walls, is counteracted b the ion o the mucles foring the elvic flor. By ts means, the pelvc viscer are ed an do not €œdrop ot― thrugh the elvic outlet. ion f the puorectalis fibers greatly asists the anal sphncters i maintaning coninence uder thes conditins by puling the anorecta junctin upward and forwrd. Durig the ac of defeation, however, the levator ani coninues t he pelvi viscera but the puborectlis fibes relax ith the nal sphicters.

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Functional Signicance of the Pelvic Floor in the Fmale The female plvic flor serves an imporant funcion durig the seond stag of labo (ig. 6-16). At the pelvic inlet, he wides diamete is tranverse so that the longest axis of he baby' head (ateroposterir) takes up the transverse position When the head rehes the pelvic flor, the utter shape of th floor tnds to cuse the aby's hed to rotte so tha its log axis cmes to le in the anteropoterior psition. he ocital prt of te head nw moves ownward nd forwad along he gutte until it lies uder the ubic arc. As the baby's had es through the lower part o the bir canal, the small gap that exists i the anerior pat of the pelvic daphragm ecomes eormously enlarged so that the head may slip through nto the erineum. Once the baby has ed through t perineum, the levatores ai muscle recoil nd take up their previous position

Injuy to the Pelvic Foor njury t the pelic floor uring a ifficult childbirh can reslt in th loss of or the plvic visera leading to uterie and vagnal prolapse, erniatio of the ladder (cysocele), and aleration n the postion of he bladdr neck ad urethr leading to stress incontinence. In the lattr condition, the ptient dribbles urne wheneer the itra-abdoinal presure is ised, as in coughng. Prolapse of the ectum may also occur.

Partial Fusion o the Sacal Vertbrae The frst sacrl verteba can be partly o completly sepaated fro the second sacral vertebr. Occasionally, o radiograhs of te vertebal colum, exampls are sen in which the fih lumba verteba has fused with the firs sacral vertbra.

Traua to the True Pelis Tauma to he true elvis ca result n fractue of the lateral ass of te sacrum (see preious colmn). P.32

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Fiure 6-15 A–C Differet types f fractues of th pelvic basin. D. Avulsion fracture of the elvis. The sartorius muscle is responsible or the aulsion o the antrior suprior iliac spine; he straiht head of the rctus femris musce, for te avulsio of the nterior inferior iliac spne; and e hamstrng muscls, for te avulsio of te ischia tuberosty.

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igure 6-6 Stges in rtation o the bab's head ring the second sage of lbor. Th shape o the pelvic floor lays an mportant part in his process.

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Table 6- Muscles of the Pelvic Wlls and loor

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Name o Muscle

Oigin

Inserion

Nerve Supply

Action

Piriforis

Frnt of sarum

reater ochanter of femur

Saral plexs

Laeral rottor of fmur at hp t

Obturatr interns

Oturator embrane ad adng part f hip boe

Greate trochaner of feur

Nerve to obturato internu from saral plexus

Lateral rotator f femur t hip jont

Levtor ani

Body f pubis, fascia o obturatr interns, spine of ischim

Perinal body; anococcyeal body walls o prostat, vagina rectum, nd anal anal

Fourth scral nere, pudenal nerve

Spports plvic visera; sphncter to anorecta junctio and vagina

occygeus

Spine of ischim

Lwer end f sacrum coccyx

Fourth and fith sacra nerve

Assits levatr ani to elvic vicera; flxes coccx

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Figue 6-17 Coronal section through te pelvis

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igure 618 Poterior plvic wal showing the sacrl plexus superior hypogastic plexus, and rght and eft infeior hypoastric pexuses. elvic pats of te sympattic truns are alo shown.

rves of the Pelvis Scral Pleus Th sacral plexus lis on the posterio pelvic all in font of te pirifomis muscl (Fig. 6-18). I is formd from te anterir rami o the fouth and fifth lumba nerves and the anteror rami f the first, secod, third and fouth sacrl nerves (ig. 6-19). The ourth lubar nerv s te fifth mbar nerve to for the lumboscral truk. Te lumboscral truk es down into the pevis and oins the sacral erves as they emege from he anteror sacra foramin.

Relatis  

Antriorly: The inernal ilac vesses and thir brances, and the rectum (Fg. 6-12) Posterioly: Te piriformis musc (ig. 6-18)

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Branchs to the lower lib that lave the elvis though the greater siatic foamen (Fig. -12):



The scatic nere (L4 and 5; S, 2, and 3), the argest banch of he plexus and the largest erve in he body (Fig. 6-9) The suprior glueal nerv, whih supplis the gluteus medus and mnimus and the tensor fasciae latae muscles The inferio gluteal nerve which spplies te gluteu maximus muscle The neve to th quadrats femori muscle, which also suppies the nferior emellus uscle Te erve to he obturtor intenus musce, which also supplies he superor gemelus muscl The posteror cutanous nerv of the high, which suplies the skin of he buttok and th back of the thig

    



ranches o the pevic musces, pelvc viscer, and perneum:



The pudenda nerve (S2, 3, and 4), which leves the elvis through the greater siatic foramen a enters he perinum throuh the leser sciaic foramn (Fig. 6-1) The nerve to the iriformi muscle The pelvc splancnic nervs, which constitute the sacral prt of th parasymathetic ystem an arise rom the econd, tird, and fourth saral nervs. They re distibuted t the pelic viscea.

 



The perorating utaneous nerve which spplies te skin o the lower medial art of te buttoc

The ranches of the sacal plexu and ther distriution ar summarized i Table -2.

Clinica Notes Sacral Plexus Pressur from th Fetal Head During the later sages of regnancy when th fetal head has descendd into the pelvis, the mothr often omplains of discmfort or aching ain exteding don one of the lowr limbs. The dicomfort caused by pressure from the feta head, s often elieved by changing position such as lying o the sid in bed.

Invasion by Malignnt Tumor T nerves of the sacral plexus can bcome invaded by malignant tumors etending from neigboring vscera. A carcinoma of the ectum, fr exampl, can case sever intractble pain down the ower lbs.

eferred ain from the Obtuator Nere The obturator nee lies o the lateral wall of the elvis an supplie the paretal pertoneum. n inflamd appendx hanging down into the pevic caviy could ause irrtation o the oburator nerve

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snell endings, leading to rerred pai down th inner sde of te right thigh. Infammation of the oaries ca produce similar symptoms.

Caual Anestesia (Anlgesia) Aneshetic soutions cn be injcted int the sacl canal through he sacra hiatus. The soluions the act on he spina roots of the scond, thrd, fourh, and fifth sacra and cocygeal sgments of the cord as they emerge fom the dra mater The roos of hiher spinl segmens can also be bloced by ths method The neele must be confied to th lower part of the sacral canal, beuse the meninges extend dwn as fa as the lower borer of th second acral vrtebra. audal ansthesia s used i obstetrics to blk pain fibers from the cevix of te uterus and to aesthetiz the perneum. P.326

Banches o the Lumar Plexu Lmbosacra Trunk Part of the anteior ramu of the ourth lubar nerv emerge from th medial order of the psoa muscle ad s he anteior ramu of the fth lumbr nerve o form te lumboscral trunk (Figs. 6-8 and 6-9). Ths trunk ow enter the pelvs by pasing down in front of the scroiliac t and s th sacral lexus.

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Fgure 6-1 Sacr plexus

Obturatr Nerve The oburator nrve is a branch o the lumar plexu (L2, 3, and 4), merges fom the mdial borer of th psoas mcle in he abdomn, and acompanie the lumbsacral tunk down into the pelvis. It crosss the frnt of the sacroilic t nd runs orward n the laeral pelvc wall i the ange betwee the intenal and external iliac vesels (Fig. -12). On reachig the oburator cnal (tha is, the upper pat of the obturator foramen, which devoid of the oburator P327

mebrane), t splits into antrior and posterio divisios that throh the caal to ener the aductor rgion of he thigh The ditributio of the bturator nerve in the thigh is considered on page 58.

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Tble 6-2 Branche of the acral Plxus and heir Disribution Banches

Ditribution

Superior gluteal nerve

Gluteus edius, guteus miimus, an tensor asciae ltae musces

Inferior gluteal erve

Gluteus maximus uscle

Nerve to piiformis

Piriormis mucle

Nerve o obturaor interus

Obturato internu and suprior gemllus musles

Nrve to qadratus emoris

Quadtus femoris and inferior emellus muscles

Perforating cutaneous nerve

Sin over edial asect of bttock

osterior cutaneou nerve o thigh

Ski over poterior srface of thigh an poplitel fossa, also ove lower prt of butock, scotum, or labium mjus

Scatic nere (L4, 5 S1, 2, ) Tibial portion

Hmstring uscles semitendnosus, bceps femris [lon head], dductor agnus [hamstring part]), astrocneius, solus, plantaris, popliteus, tbialis osterior flexor digitoru longus, flexor hllucis lngus, and via meial and ateral pantar branches to muscles of

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sole of foot; sual branh supplis skin o lateral side of eg and fot

Commn peronel portio

Bips femos muscle (short ead) and via deep peroneal branch: ibiali anterio, extensr halluci longus, extensor digitorm longus peroneu tertius and extensor digitorum revis mucles; skn over left beteen first and econd tos. The sperficia peronea branch supplies the perneus logus and brevis mscles an skin ovr lower hird of nterior urface f leg an dorsum f foot

Pudendal nerve

Musles of prineum icluding the extenal anal sphincte, mucous membrane f lower alf of anal canl, perianal skin, skin of nis, scrotum, clioris, an labia ajora an minora

Branches Sensory branches supply the parietal perioneum on he lateral wall of the pelvis.

Autnomic Neves elvic Pat of the Sympatheic Trunk Te pelvic part of he sympahetic trnk is cotinuous bove, beind the ommon ilc vesse, with the abdomial part Fi. 6-18). It rns down ehind th rectum n the frnt of the sacrum, medial t the anrior sacal foramina. The sympathetic trunk as four r five egmentaly arrangd gangli. Below, the two runks coverge and finally unite i front o the cocyx.

Branches  

Gray rami comunicante to the acral an coccygeal nerves Fibs that oin the hpogastri plexuse

elvic Spanchnic erves The pelic splanhnic neres form he parasmpatheti part o the autoomic nerous systm in the pelvis. he pregaglionic fibers arse from he secon, third, and fourh sacral nerves ad synape in ganlia in t inferior hypogasric plexs or in he walls of the iscera. Some of he parasympatheti fibers scend through the hypogastic plexues and tence via the aortc plexus to the iferior esenteri plexus. The fibes are thn distriuted along branches of the inferior mesenteric artery to supp the large bowel from the left colc flexur to the pper hal of the nal cana. 605

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Supeior Hypoastric Plexus The supeior hypoastric pexus is ituated n front of the promontory o the sacum (Fig. 6-8). t is formed as a continution of he aorti plexus nd from ranches of the tird and furth luar sympthetic gnglia. It contains sympathtic and acral paasympathic nerve fibers ad viscerl affernt nerve fibers. Te superir hypogatric pleus divids inferorly to form the rigt and let hypogatric nerves.

Infeior Hypoastric Pexuses The iferior hpogastri plexuse lie on ach side of the rctum, th base of the ladder, nd the vgina (Fig. 6-18). Each plxus is frmed fro a hypogstric neve (from the superior hypogastric lexus) ad from the pelvic splanchnc nerve. It contans postganglionic sympatheic fiber, preganlionic ad postgaglionic parasympthetic fibers, and visceral afferent fibers. ranches ass to he pelvi viscera via smal subsidiry plexues.

Arteris of the Pelvis Commn Iliac Artery Each cmmon iliac arter ends at the pelvc inlet in front f the saroiliac oint by ividing nto the xternal and interal iliac arteries (Figs. 6-1 and 6-18). P.328

ternal liac Artry Th externa iliac atery run along te medial border o the psos muscle, followin the pelic brim Fi. 6-12), and gves off he inferior epigastric and deep circumflex iliac brances. It laves the false pevis by pssing uner the iguinal ligament t become he femora artery.

Arterie of the rue Pelis he follwing artries enter the pelvic caity:    

nternal iliac arery Suprior retal arte Ovaria artery Mdian sacal arter

Internal Iliac Artery The iernal ilac arter es own into the pelvs to th upper mrgin of he greatr sciati foramen where i divides nto antrior and posterior divisions (Fig. 6-12) The brnches of these diisions

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snell spply the pelvic vscera, te perinem, the plvic wals, and te buttocs. The oigin of he termnal brances is suject to ariation but the usual arangement is show in Diagram 6-1.

Bnches of the Anterior Division    



Umbilcal artery: Fro the proimal patnt part f the umilical atery aries the supeior vesial arter, whih supplis the uper portion of the bladder (Fig. -12). Obtuator artry: is artey runs frward alng the lateral wall of the pelvis wth the bturator nerve an leaves he pelvis through he obturtor cana. nferior esical atery: his artry supplies the base of the bladder nd the postate ad semina vesicle in the ale; it lso give off the arery to te vas deerens. iddle retal artey: Commonly, this artery arises with the iferior sical rtery (Fig 6-12) It suppies the uscle of the lowe rectum nd anastmoses wih the suerior retal and nferior ctal areries. Interna pudenda artery: This artery leaves the plvis thrugh the reater siatic foamen and enters te glutea region elow the piriforms muscle (Fg. 6-12). It ten enter the perneum by assing trough th lesser ciatic oramen ad es forward in the pudndal canal with te pudendl nerve Its braches supply the mculature of the aal canal and the skin and uscles of the prineum. Diagram 6-1 ranches f the Inernal Ilac Arter







Inferio gluteal artery: This arery leavs the pevis throgh the gater scitic foraen below the piriormis mucle (Fig. 62). I es etween te first nd secon or second and thrd sacra nerves. Uterin artery: This artery rns medially n the foor of te pelvi and crosses the ureter sueriorly (see Fig 7-28. It es abov the latral fornx of the vagina t reach te uterus Here, t ascends between the layes of the broad liament alng the ateral mrgin of he uteru. It end by follwing the uterine ube latrally, were it aastomose with the ovarian artery. he uterie arter gives off a vagnal branh. Vagina artery: This artery uually taes the pace of he inferor vesicl artery present in the mle. It spplies te vagina and the ase of the bladder.

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Branhes of te Posteror Divison   

Iliolumbr artery This artery acends acss the lvic inlt posteror to th externa iliac vssels, poas, and iliacus uscles. Lateral sacral ateries: These rteries escend i front of the sacral plexus, giving ff branhes to nighborin structues (Fig. 6-1). Superir glutea artery: This rtery leves the pelvis trough th greater sciatic oramen aove the iriformi muscle. It supples the guteal reion.

Suprior Recal Arter The superior rectal atery is direct continuation of th inferio mesenteic arter. The name change as the atter arery croses the common ilc artery It suppies the ucous membrne of th rectum and the pper hal of the nal cana.

Ovaran Arter (The testicular artery enters te inguinl canal ad does nt enter he pelvi.) The oarian arery ariss from te P.329

abdominl part o the aora at the level of the firs lumbar rtebra. The artey is lon and sleder and asses downward and laterall behind the perioneum. It crosses he exteral iliac artery a the pelic inle and enters the supensory igament f the ovry. It ten e into te broad igament nd enter the ovary by way f the mesovarium.

Meian Sacrl Artery The edian saral artery is a small rtery tht arises at the burcation of the arta (Fig. 618). It descend over th anterio surface of the sarum and occyx. The ditributio of the isceral ranches f the pevic arteres is dicussed i detail ith the individual viscera n hapter 7.

Vins of te Pelvis Exernal Ilac Vein The eternal iiac vein egins beind the nguinal ligament as a continuation f the feoral vei. It runs along th medial side of he correponding artery and s th interna iliac vin to fom the commn iliac ein (Fig. 6-12) It receives the infeior epigstric and deep cicumflex liac veins.

Intrnal Ilic Vein

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snell The intrnal ilic vein bgins by he ig togethr of tributaries hat corrspond to the branhes of te internl iliac artery. It e upward n front f the saroiliac oint and oins the externa iliac vin to fom the comon iliac vein (Fig. -12).

Medin Sacral Veins The median sacral veins acompany te correspnding arery and nd by joning the eft commn iliac ein.

Lympatics of the Pelvs Th lymph ndes and essels ae arrangd in a cain alon the mai blood vssels. T nodes e named fter the blood vssels wih which tey are ssociate Thus, tere are extrnal ilic nodes, internal iliac noes, ad ommon ilac nodes

s of the Pelvis Sacroiiac s Th sacroilac t are strong synoval t and are formed btween th auriculr surfaces of the acrum an the ilic bones (Fg. 6-11). The scrum caries the eight of the trunk, and, aart from the intelocking f the irregular aricular urfaces, the shap of the bones contibutes lttle to he stabiity of he ts. The srong posteror an iterosseos sacroiliac ligamnts sspend th sacrum between th two iliac bones The anterir sacroiliac ligamnt is thin and ies in font of te t. The weght of te trunk ends to hrust th upper ed of the sacrum donward an rotate he lower end of te bone uward (Fig. 6-11). his rotaory movemnt is prvented b the strng sacrotubrous ad sacrospinous ligants dscribed reviously The iliolubar ligaent cnnects te tip o the fifh lumbar ransvers process to the ilac crest

Movemes A sall but imited aount of movement is possibl at thee ts In olde people, he synoval cavit disappers and te t becomes fbrosed. heir priary function is to transmit the weiht of th body frm the verebral coumn to te bony plvis.

erve Suply Th nerve spply is rom branhes of te sacral spinal neves.

Smphysis ubis The symphis pubis is a carilaginou t btween the two pubi bones (Fig 6-11. The aticular urfaces re covere by a laer of hyline carilage and are conected toether by a fibrocrtilaginous disc. he t is surrunded by ligaments that extnd from ne pubic bone to e other.

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Movemnts Alost no mvement i possible at this .

Sacrcoccygea t The sarococcygeal t s a cartlaginous t btween th bodies of the las sacral ertebra nd the frst coccgeal vetebra. Th cornua f the sarum and cccyx are ed b ligamen.

Movements Extnsive flxion and extension are possble at tis t

linical otes elvic Jonts Changes with Pregnacy Dring prenancy, he symphyis pubis and the igaments of the acroiliac and sacrcoccygea ts ndergo sftening n respose to horones, ths increaing the mobility ad increaing the potentia size of the pelvs during hildbirt. The homones rsponsible are estrgen and rogesterne producd by the ovary an the plcenta. An additionl hormon, called relaxin, produced y these organs cn also hve a relxing effct on the pelvic lgaments.

Change with Ag Oblieration f the caity in te sacroliac t occurs n both sxes afte middle ae.

Sacriliac t Diseas Th sacroiliac t s innervted by the loer lumba and saral nerv so that disease n the jont can poduce lo back pain and pan referrd along he sciatic nerve (ciatica) Te sacroiiac t is inaccssible t clinica examintion. Hoever, a sall area located ust medil to and below the posterir superir iliac pine is were the oint coms closest to the urface. In diseas of the umbosacrl regio, movemets of the vertebrl column in any drection cuse pain in the lmbosacral part of the colun. In saroiliac dsease, pin is extreme on rtation o the vetebral clumn and is worst at the ed of forwrd flexin. The ltter moement cases pain because te hamstrng muscls (see page 587) old the ip bones n positin while he sacru is rotang forwad as the vertebra column s flexed. P.30

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Sex ifferencs of the Pelvis The sx differnces of he bony elvis ar easily recognize. The moe obviou differeces result from th adaptaton of te female pelvis fo childbering. Th stronger muscles n the mae are rsponsibl for the hicker bones and ore promnent bon markings (Figs. 6-1 and 6-4).      

Te false elvis is hallow i the femle and dep in th male. The plvic inlt is trasversely oval in the femae but heat shaped in the mle becase of th indentaon prodced by te promonory of th sacrum n the mae. The plvic caviy is rooier in te female than in he male, and the dstance btween th inlet ad the oulet is mch shortr. The pelvic outlet is larger i the femle than in the mle. In th female he ischil tuberoities ar everted and in te male tey are trned in. Th sacrum s shorte, wider, nd flatter in th female tan in th male. The subpubic angle, o pubic arh, is mre roundd and ier in th female han in the ale.

Radiogaphic Antomy Radiogaphic antomy of the pelvs is fuly described on page 377.

Surface Anatom Suface Larks Iliac Crest The ilic crest an be fet throuh the skn along ts entir length Figs. 6-20, 6-21 and 6-22).

Anterio Superio Iliac Sine The anterior sperior iiac spine is sitated at he anteior end f the iliac cres and lies at the upper laeral end of the old of te groin (Figs. 6-2, 6-21, and 6-22).

Posteror Superor Iliac Spine The osterior superio iliac sine is stuated at the poterior ed of the iliac crst (Fig. 6-22). It lies at the bttom of a small skn dimple and on a level wth the econd scral spie, whic coincies with he lower limit of the suarachnoi space; it also oincides with the level o the midle of te sacroiiac .

Pubic Tbercle The pbic tubecle can e felt on the uper borde of the ubis (Figs 6-20 621, an 6-22). Attached to it s the meial end f the inuinal ligamnt. The tubercle an be papated eaily in te male b

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snell invaginting the scrotum rom belw with te examinng finge. In the emale, te pubic ubercle can b palpate throgh the lteral magin of te labium majus.

Pubi Crest The pubi crest i the ride of bon on the uperior urface o the pubc bone, edial to the pubi tubercl (igs. 6-1 and 6-22).

Symphyss Pubis he symphsis pubi (igs. 6-1 and 6-22) lies in the mdline beween the bodies o the pubc bones nd can b palpatd as a slid struture thrugh the at that is presen in this region.

Spinus Proceses of Scrum The spnous proesses of the sacrm (Fig. 6-2) are fused wih each oher in te midlin to form the medin sacral crest. he crest can be flt beneah the skn in the uppermos part of the clet betwee the butocks.

Sacra Hiatus The saral hiatus is siuated on the poserior asect of te lower nd of th sacrum, where te extradral spac terminaes (Fig. 622). he hiatus lies about 2 in. (5 cm) above the tip of te coccyx and beneth the sin of th cleft btween the buttocs.

Coccyx The iferior surface ad tip of the cocyx (Fig. -22) an be papated i the cleft betwen the buttocks out 1 i. (2.5 c) behin the ans. The aterior surfce of te coccyx can be palpated with th gloved finger n the anl canal.

Vicera Urinary Bladder In adlts, the empty badder is a pelvi organ and lies posterio to the ymphysis pubis. As the badder flls, it ises up out of he pelvs into te abdomn, where it can be palpatd throug the aterior adominal all abov the symhysis puis (Fig. 623). he peritneum covring the distende bladder becomes eeled off from th anterio abdominal wall so that the front of the blader is in direct ontact wth the adominal wall (se page 49). P.331

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Figre 6-20 Anterir view o the pelis of a 27-year-ol man.

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Fgure 6-2 Anteror view f the pevis of a 29-yer-old woan.

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Figre 6-22 Relationship between difrent parts of the pelvis ad the boy surfac.

In children, util the ge of 6 ears, th bladder is an adominal rgan eve when empty becaue the capacity of the pelv cavity is not geat enouh to conain it. he neck of the blder lies just blow the level of the upper order of the sympysis pubs.

Uterus Toward the end of the secon month o pregnany, the undus of the uters can be palpated through he lower part of e anteror abdomnal wall With th progressive enlarement of the uteus, the undus ries above the leve of the ubilicus nd reachs the rgion of he xiphod process by the nnth mont of pregancy (Fig. -23). Later, wen the pesenting part of he fetus usually the head descens into the pelvis, the fundus of the uterus escends so. 615

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ectal an Vaginal Examinatons as a Means of Palpatin the Pelic Viscera Bimanal rectobdominal and vagial–abdminal eaminatios are exremely vluable mehods of palpatin the pelvic viscea; they re descrbed in dtail on ages 397 and 412. P.333

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igure 6-3 A. Srface antomy of he empty bladder nd the full bladder . Heiht of th fundus f the utrus at vrious moths of pegnancy. Note th the peitoneum overing te distened bladdr become peeled ff from the anteior abdomnal wall so that he front of the bladder cos to li in diret

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contac with th abdominal wall.

Clnical Prblem Solving Stuy the folowing cse histoies and elect th best anwer to the questios followng them. A 65-ear-old an with history of prosttic enlagement cmplained that he ould not micturae. The lst time hat he pased urin had bee 6 hour previouy. He was found ling on hs bed in great ditress, clutching his anterior abdomnal wall with bot hands ad pleadig for soething be done quickly. On examiation, a large ovoid swellig could be palpaed throuh the abominal wll above the sympysis pubi. 1. In his patint the fllowing tatement are corect excet which? (a) In the adult, the uriary bladder is a elvic stucture. b) When he bladdr fills he superor wall f the bldder riss out of the pelvs. (c) When the bladder ecomes filled it never reahes a leel above the umbiicus. () The swlling is dull on ercussio. e) Pressre on th swellin exacerbtes the ymptoms. View Aswer 1. C. n extrem cases o urethra obstrucion in te male, he superor wall of the badder has been knn to reach the costal margin. A 43year-old woman wa operate on in te perinem to dran an iscial recal abscess. The ascess exended deply to t region of the aorectal unction. The surgon, to otain beter drainge, decied to cut the puborectalis muscle. hen, 3 dys later the patent compained o fecal icontinence. 2. The sympoms dispayed by his patint could be explaned by te followig statemnts excet which? (a) Anal coninence i maintaied by th tone of the intenal and xternal phincter and th puboectalis uscle. (b) The puborectalis fibers re a par of the levator ani muscle (c) Th puborecalis fibrs round th anorectl junctin. (d) Te puborctalis muscle sligs the aorectal unction up to the bak of th body of the pbis. (e) he puborctalis mscle plays only a minor ole in peserving anal coninence. View Anser 2. E. Te puboretalis mucle is oe of the most imortant shincters of the aal canal 618

snell A eavily uilt, midle-aged man runing down a flight of stone steps mijudged he posion of oe of the steps an fell sudenly ono his butocks. Followin the fal, he comlained o severe ruising of the rea of te cleft btween th buttock and peristent pin in ths area. 3. The followin statemets concening thi patient are correct excet which? (a) he lower end of he verteral colmn was taumatize by the stone stp. (b) The coccyx can b palpate beneath the ski in the atal clft. (c) The anteior surfce of th coccyx annot be felt cliically. (d) The occyx i usuall severel bruised or fracured. (e The pain is felt in the distribtion of ermatom S4 and S5. View Aswer 3. C The antrior surace of he coccyx can be palpate with a gloved fnger plaed in te ana canal. 28-yer-old prgnant wman was very frightened by the thught of oing trough th pain o childbith. She asked he obstetrcian if t was ossible o reliev the pai withou having a genera anesthtic. She was tod that se could ave a reatively simple pocedure called audal aesthesia 4. When peforming audal ansthesia the syrnge neele is iserted nto the acral cnal by percing he folloing anaomic stuctures xcept whch? (a) Skin (b) Fascia (c) Ligments (d) Sacrl hiatus (e) Dura mate iew Ansr 4. E The dura mater extends don in the sacral caal only s far as the lowr border of the second sacral vertra. It les about 2 in. (5 mm) abve the scral hiatus in the adul. An lderly oman was run over by an automobile s she was crosing the oad. Radiograhic examnation o the pelis in th emergenc departmnt of te local ospital revealed a fracture of the iium and iliac crst on the left sie. 5 The folowing sttements bout fractures o the pelvis are corect ext which (a) ractures of the iium have little dsplacemet. (b) Diplacemen is prevnted by he presnce of te iliacu and the gluteal uscles o the innr and ouer surfaes of ths bone, espectivly.

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snell (c) If two factures ccur in the ring forming te true plvis, th fractur will be nstable and displcement wll occur d) Fractres of te true plvis do ot cause injury t the pelc viscer. (e) he postertebra and abdminal uscles ar responsble for levating the lateral part f the pevis should two factures occur. (f) A heavy fall on te greate trochater of te femur ay drive the head of the femur through the floor of te acetablum and nto the elvic cavity. View Aswer 5. D. ractures of the tue pelvi are comonly assciated with injries to the sft pelvi viscera especialy the badder an the urehra. A prenant woan visitd an antnatal clnic. A vginal exmination revealed that th sacral romontor could b easily alpated nd that the diagonl conjuate measred less than 4 i. (10 cm. 6. The ollowing statemens concering this examinaton are crrect exept whic (a) Normally it is dificult o impossile to fel the saral promntory by means of vagina examinaton. (b) Th normal iagonal njugate measures bout 10 n. (25 c). (c) Tis patiet's pelvs was flttened ateropostriorly, and the scral proontory pojected oo far frward. (d) t is likly that his patint would have an bstructe labor. (e) This patient was advied to hve a cesarean setion. View Aswer 6. B. he norma diagona conjugae measurs about in. (11.5 cm). P.334

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snell ultiple-hoice Qustions Selec the bes answer or each uestion. 1. The following statments cocerning he pelvi are correct except which? (a) The ilium, ichium, ad pubis re three separate bones tht fuse tgether t form th hip bon in the 5th year of life. (b) The latypelloid type f pelvis occurs i about 2 of woen. (c) External pelvic masuremens have ittle prctical iportance in deterining whther a dsproporton betwen the sze of the fetal had and te size of the pelvic inlet is likely. d) The pelvic outet is fomed by te symphsis pubi anterioly, the schial tberositis lateraly, the sacrotubrous ligments laterally, and the cocyx postriorly. (e) he sacru is shorer, wide, and fltter in he femal than in the male iew Answr 1 A. At uberty te three separate ones—te ilium, ischium, and pubs—fuse together to form ne large irregula bone, te hip bone. 2. The following statements concernig structres that eave the pelvis are correct except which? (a) Th sciatic nerve leves the elvis though the greater ciatic framen. b) The priformis muscle laves the pelvis trough th greater sciatic oramen. (c) The external iliac arery s beneat the inginal ligment to ecome th femoral artery. (d) Te obturaor nerve leaves te pelvis through he lesse sciatic foramen. (e) Th inferio gluteal artery laves the pelvis trough th greater sciatic oramen. Vie Answer 2. . The obturator nerve leaves the pelvis throgh the oturator anal, wich is te upper art of te obturaor foramn, devoi of the bturator membrane. 3. The ollowing statement concerning the mscles an fascia n the pevis are orrect ecept whih? a) The lvator an muscle s innervted by the perineal branc of the urth sacal nerve and from the perieal brach of th pudenda nerve. (b) In te pelvis the fasia is diided int parieta and visceral layers. (c) The iliooccygeus muscle aises fro a thicking of the obturator internus fascia. (d) The pelvc diaphrgm is stong and has no opnings.

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snell (e The viseral layr of pelic fasci forms iportant igaments that hel the uters. View Aswer 3. D. he pelvi diaphram is a gtter-shaed sheet of muscle formed b the leatores ai and cocygeus mscles an their cvering fsciae. Is functon is to he pelvi viscera The pelvc diaphagm is ncomplet anterioly, formig an opening to allow age of the urethr in male and the urethra nd the vgina in emales. 4. The followng stateents conerning the nerves of the pelvic cavty are crrect exept whic? (a The infrior hypgastric lexus cotains boh sympatetic and parasymphetic neves. b) The sacral plexus lies ehind th rectum. () The pevic part of the smpatheti trunk pssesses oth whit and gra rami comunicants. (d The suprior hypgastric lexus is formed fom the artic symathetic lexus an branches of the lumbar sympathet ganglia (e) The anterior ami of te upper four sacral nerves emerge ito the plvis thrugh the nterior acral foamina. iew Ansr . C. Th pelvic part of he sympahetic trnk gives rise to only gray postgaglionic nerve fibers, whic are disributed o the pevic visera and lood vesels. 5. The follwing staements cncerning the bony pelvis ae correc except hich? a) When the patint is in the staning position, th anterio superio iliac spnes lie erticall above te anteror surfae of the symphysi pubis. (b) Ver little movement s possible at the sacrococygeal jont. (c) The false pelvis helps guie the fetus into the true pelvis dring labor. (d) he femal sex horones caue a relaation of the ligaents of the pelvi during pregnancy (e) bliteraton of th cavity f the saroiliac oint oftn occur in both sexes afer middl age. Viw Answe 5. B. The acrococcgeal joit is a crtilaginus t and can erform a great deal of movment. 6. The statments cocerning he segmetal orign of the followin nerves are correct except which? (a) Th sciatic nerve is derived rom the egments 4 and 5 nd S1, 2 and 3. (b) The udendal erve is erived fom the sgments L, 4, and 5. (c) Te pelvic splanchnc nerve is deried from he segments S2, , and 4 622

snell d) The bturator nerve is derived from the segments L2, 3, ad 4. (e) The lumbsacral tunk is drived frm the sements L4 and 5. View nswer 6. B. he pudenal nerve is a branch of the sacral lexus an is deried from 2, 3, and 4. 7 The staements concerning the oriin of the following arteris are corect ext which (a) The supeior rectl artery is derivd from te inferior mesenteric artery. (b) The ovarin artery is derivd from te renal rtery. (c) Te uterin artery s derive from th interna iliac atery. (d The midle recta artery s derive from th interna iliac atery. (e The suprior glueal artey is derved from the intenal ilia artery. Vie Answer 7. . Both te right nd the left ovarin arteris are brnches of he abdomnal aort. 8. The tatement concerning the mtor nerv supply f the muscles of the pelvic walls are correct except which? (a) The sacral erves or plexus pply the obturator internus muscle. (b) The obturato nerve spplies te pirifomis musce. (c) Th sacral erves, o plexus, supply te iliococygeus mscle. (d) The sacal nerves, or pleus, suppy the cocygeus mscle. (e) The perneal brach of the fourth acral nerve and the perieal branch o the pudndal nere supply the levaor ani mscle. View Anser . B. The pirifors muscle receives its moto nerve spply fro the sacal plexu. Read the case history nd selec the bes answer o the qustion folowing i. A 37-yar-old wman was nvolved n a severe automole accident in whch the car travelig at hig speed, werved of the rod and hi a tree. She was evaluate in the mergency departmet and fond to hae multile injures. Radigraphic xaminatin of her pelvis sowed a racture f her right ilium and ilia crest. 9 From yor knowlege of antomy, deermine wich of te following treatents was correct. (a) n attempt was mad to immoilize th bony fagments by encasing the patient in plaster cast extnding frm the subcostal region dow both highs to just aboe the kne.

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snell b) The rght glutal regio was strpped wit a stron Elastopast bandge. (c) The patint was oerated o and the bony framents wee replacd in their correct anatomi positio and secred with screws. ( Splintg of the fracture bone wa unnecesary. (e) ecause o the fea of avasular necrosis, the smaller bony framents wee surgically remoed. View Answer 9. . Most factures f the uper part f the ilum have ittle dsplacemet of the bone framents. Tis is beause the iliacus uscle i attache to the nner surface and e gluteal muscles are attched to the oute surface. Splintig the bos is unnecessary because o the atachment f these uscles. he muscuar attacments alo provid an adeqate bloo supply o the boe fragmets.

Footnote *The term elvis is loosey used t describ the regon where the trun and lowr limbs eet. The word pelvis means “a basn― and is more orrectly applied o the skleton of the regin—that is, the elvic gidle or bny pelvi. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

8. 7. The Pelvis: Part II - The Pelvic Cavity A 6-year-ol man visted his hysician for an anual phsical examination. He appeared to b in very good heath and hd no coplaints. A genera examinaion revealed nthing abormal. Te physiian then told th patient that he as about to perfom a rectl examination. A first t patient objected, saying that he dd not fel it wa necessay becaus nothing abnormal was foun a year go. The physicia persistd and finally the patient greed t the exmination A small hard nodle was found projcting from the poterior srface of the prosate. No other anormalites were discoveed. The atient ws informed of the indings, and the possibilty that he nodul was malgnant wa explaind. The ptient ws very uset, especially because he ad no abormal urnary symtoms. Addiional laoratory nd radioogic tess were erformed and the prostte-specfic antigen (PS) level n the blod was ound to be well above the normal rnge. No evidence of pelic lymphatic elargement was seen on pevic computed tomography CT) scas and n evidence of bon metastses was seen on bne scan. A diagosis o early ncer of the prosate was made and was latr confired by a needle iopsy of prostatc tisse throug the antrior wal of th rectum This case illustrates how a physician i general practic who has good knwledge o the relevant anomic features of the pelvis can recognize a abnorma prostat when it is palpted thrugh the nterior ectal wll. This patient ater had the prosate removed, and the prognosis was excellen P.338

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Chapter Objectivs  

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The pelic cavit contain the lowr ends f the inestinal an urinary tracts ad the inernal orans of eproducton as wel as ther nerve upply, bood supply, and lmphatic drainage Th organs project up into the perioneal cavty, causng the ritoneum to be daped ove them in folds, roducing importan fossae hat are he sites for the ccumulation of blod ad pus in differet types f pelvi disease Th physican is often confonted with problms involing infetions, ijuries, and proapses of the recum, uters, and vgina. Emerency sitations involvin the badder, te pegnant terus, eopic pregnancy, sptaneous bortion, and acute pelvic inlammatory disease re examps of probems foun in the emale. Th urinary bladder ad the prostate in th male are frequent ites of disease. The purpose o this chaer is to conside the imporant anatomy relatie to commn clinicl conditins involving the elvic orans.

Basi Anatomy The pevic cavit, or cavit of the ue pelvi, can be defined a the area between the pelvic inlet and the pelvc outlet. It is customary to subdivde it by he pelvic diaphragm nto the ain pelic cavity above and he perineu below (Fig. 7-1). his chapr is conerned wit the contnts of th main pelic cavity A detaild descripion of te perineu is given in Chapter 8.

Contents the Pelvic Cavity Sgmoid Coln Lcation an Descripton Th sigmoid lon is 10 to 15 in. (25 to 38 cm) long nd begis as a coinuation of the decending olon in ront of he pelvi brim. Blow, it bcomes cotinuous wth the retum in font of th third acral vertbra. The sigmoid clon is mobile nd hangs down int the pevic cavity in the frm of a lop. Te sigmoi colon is attached o the poserior pevic wall by the fan-haped sigmid mesoolon.

Reations  

nteriorl: I the mal, the urary bladdr; in th female, he posteror surface of the uterus a the uppr part of the vagin Posterorly: he rectu and the acrum. Th sigmoid olon is aso relate to the wer coil of the erminal art of the ileum.

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Arteries igmoid brnches of he inferir mesentric arter

Veis The vins drain into the nferior msenteric ein, whic s th portal vnous systm.

Lymph Dranage Te lymph drains ino nodes long the ourse of he sigmod arterie; from thse nodes, the lymp travels o the infrior mesnteric ndes.

Nerve Suply Th sympathtic and prasympathtic nerve from the nferior hpogastric plexuses .339

Clinical Notes Variatin in Lenth and Location of the Sgmoid Coln The simoid colo shows grat variaion in legth an may meure as uch as 36 in. (91 c). In the young chid, becaus the peis is smll, this egment of the colo may lie ainly in he abdomn.

Cancer o the Sigmid Colon The igmoid clon is a common ite for ncer of he large bowel. Because the lmphatic vssels of his segmnt of the olon drin ultimaely into the inferir mesentric nodes, it follow that an extensiv resection of the gu and its ssociated lymphati field is necessar to extirate the rowth and its local lymphati metastass. The clon is reoved from the left colic fleure to th distal ed of the sigmoid colon, ad the trasverse coon is anasomosed to the recum.

Vovulus Bcause of ts extreme mobility, the sigid colon sometimes rotates ound its esentery This may correct iself spotaneously, or the rtation my contiue until he blood supply of the gut s cut off completel. The rottion commnly occus in a conterclockise direcion and s referred to as olvulus.

Diverticula

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snell Divertcula of te mucou membrane along th course f the artries suppying the igmoid olon is a common clnical conition an is descried on pae 236. In atients wth divertculitis o ulceratve colit, the simoid col may becme adhernt to th bladde, rectum, ileum, o ureter ad produce an internl fistula.

Sigmodoscopy Because he sigmoi colon les only short ditance frm the anu (6.5 in. [17 cm]) it is posible to xamine th mucous membrane nder diret vision or patholgic conditions. A lexible ube fited with lenses an illuminted inteally is itroduced through te anus ad carefuly ed u through he anal cnal, rectum, sigmod colon, and desceing colon This exaination, alled sigoidoscop, can be carried ot withou an anesthetic in a outpatint clinic Biopsy pecimens o the mucos membran can be otained thugh this instrumet.

Anatoic Facts elevant t Sigmoidocopy  

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T patient is place in the left laterl position with the eft knee lexed and the righ knee extnded (Fig. 72). Aernativey, the patent is paced kneeing in te kneeâ€chest psition. The sgmoidose is gely inserted into the anus nd anal cnal in th directio of the umbilicus t ensure hat the istrument asses alog the lon axis of te canal. Gentle bu firm prssure is pplied t overcome he resisance of th anal spincters (Fig. 7-3) Aftr a distace of abot 1.5 in (4 cm), the instrument entrs the ampulla of he rectu. At this point, th tip of he sigmoioscope shuld be diected poseriorly i the midlne to folow the scral cure of the ectum (Fig. -2). Sow advanement is made unde direct ision. Sme slight side-to-side moveent may b necessar to bypas the transvese rectal folds. At pproximaely 6.5 i. (16.25 m) from he anal argin, th rectosimoid unction wll be reched. The sigmoid olon her bends foward and to the let, and th lumen apears to d in a lind cul-e-sac. To negotiat this anglation, te tip of he sigmodoscope mst be dircted anterorly and o the patent's lef side. Ts maneuve can caus some disomfort in he anal cnal from distortio of the nal sphinters by he shaft of the sgmoidoscoe. Anothr possibility is tht the poit of the nstrument ay stretc the wal of the clon, givig rise to colicky pan in the ower abdoen. Once te instrumnt has enered the sigmoid olon, it hould be ossible t it smoothly along its full extent nd, using the full ength of he sigmodoscope, enter he desceding colo. Te sigmoioscope my now be lowly wthdrawn, arefully nspecting the mucos membran. The noral rectal and coloic mucous membrane is smooth and glistning and ale pink ith an oange ting, and blood vessels in the sbmucosa c be clealy seen. The mucou membran is suppl and movs easil over th end of the sigmoioscope.

Anaomy of Coplications of Sigmodoscopy Perfoation of he bowel a the recosigmoid unction can ocur. This s almost nvariably caused by the opertor failig to negtiate carfully th curve beween the ectum an the sigoid colo. In soe patient, the cure is in te form of an acute ngulation which may frustrat the overzealous advncement o the sigidoscope. Perforaton of the sigmoid clon resuls in the escape of colonic contents ito the peitoneal avity.

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Colonoscopy Dirct inspetion of the linng of th entire clon incuding the cecum has become an important weapon in the early diagnosi of mucosl polyps ad large bwel cancer in recen years. Nt only n the coon be obsrved and uspiciou areas potographed for uture reerence, bt also bipsy speciens can b removed or pathoogic examnation. For the dagnosis o early cacer, phyicians peviously relied lmost enirely on rectal examination, sigmoidoscoy, and te detecion of ocult blood in te feces. Te disadvntage of olonoscop is the igh cost see Fig. -37). Folowing a rgime in wich the large bowe is thorughly wahed out, te patien is relaxd under light nestheti. The fexible enoscopic tbe is intoduced though the nus into te anal cnal, recm, and con. Colonscopy can also be ued in the diagnosi and treament of ulerative olitis an Crohn's isease.

Colostmy The sigmoid clon is oten seleced as a ste for prforming a colostmy in paients wih carcina of the ectum. Is mobiliy allows he surgen to brin out a lop of colo, with i blood upply intct, throuh a smal incision in the lft iliac egion the antrior abdminal wal. Its moblity also makes it uitable or implatation o the uretrs after urgical removal of he bladde. P.340

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Figur 7-1 Coronal setion thrugh the torax, abdmen, and elvis shwing the thoracic, abdominal and pelvc cavitie and the perineum.

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Figure -2 Sigoidoscopy. A. Patiet in the eft latera position with the eft knee flexed an the righ knee extnded. B. Sgittal setion of te male pevis showig the postions (1, 2, and 3) of the ube of te sigmoioscope relative to the patint as it ascends the anal canal an rectum. The area of discofort or ain expeienced y the patient as te tube i negotiaed aroun the ben into th sigmoi colon i referre to the kin of t anterio abdominl wall elow the umbilicu.

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Figur 7-3 Cronal setion thrugh the elvis shwing the rectum ad the pevic floo.

Retum Lcation ad Descrition The rectm is abot 5 in. 13 cm) long and egins in front of the thir sacral ertebra s a continuation f the simoid coon. It psses dowward, folowing te curve of the sacrum and occyx, ad ends i front o the tip of the cccyx by iercing he pelvc diaphrgm and beoming cotinuous ith the nal cana. The loer part of the rectum is lated to form the rctal amplla. The retum devites to te left, ut it quckly retrns to te median plane (Fig. 7-3). On laterl view, he rectu follows the anteior concavity of the sacum befor bending downward and backard at its junctin with te anal anal (Fig. -4). The uborectalis portin of the levator ni muscls forms sling (ee page 318) at th junctio of the ectum wih the anl canal nd pulls this par of the owel forward, producing the anorecta angle.

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snell The peritonum cors the anterior and lateral surfacs of the first thrd of th rectum nd only the anteior surfce of th middle hird, leving the lower thrd devoi of peritoneum (Figs. 7-4 and 7-5). The mucular cot of he rectum is arrnged in he usual uter lonitudinal and inne circula layers of smoot muscle. The three teniae cli of th sigmoid colon, however, me togeter so tht the logitudina fibers orm a brod band n the anerior an posterir surface of the ectum. The mucous membrane of the rectum together with th circula muscle ayer, forms two or three sicircula permanet folds alled th tansverse folds of the rect (Fig. 73); thy vary i positio.

Relatins  

Poteriorly The rectum is in contat with te sacrum and coccx; the piformis, coccygeus, and lvatores ni muscls; the sacral ples; and te sympahetic trnks (see Fig. 6-18. Anterirly: In te male, the uper two hirds of the rectm, which is coverd by pertoneum, is relat to the sigmoid colon and oils of leum that occupy te rectoesical puch. The lower thid of the rectum, hich is devoid of peritonem, is reated to he posteror surface of the bladder, to the erminatin of the vas deferns and te semina vesicles on each ide, an to the rostate Fi. 7-4).

In te female, the pper two thirds f the retum, whih is covred by pritoneum is relaed to th sigmoi colon ad coils o ileum tat occup th retoutrine pouch (pouh of Douas). The lower thrd of th rectum, hich is evoid of peritoneum, is lated to the postrior surace of the vagina Fg. 7-5. P.34

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Figure 7-4 Sagttal secion of te male plvis.

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Figue 7-5 agittal ection o the femle pelvi.

.343

Bloo Supply Arteres The superior, middle, nd inferor recta arterie (ig. 7-6) supply the rectum. Th sperior rctal artry is a direct continuaion of te inferir mesentric arter and is he chie artery upplying the mucos membrane. It entrs the plvis by descending in the rot of the sigmoid mesocolo and divdes into right ad left banches, hich piece the mscular cat and spply the mucous embrane. They anatomose with one anther and with the middle ad inferor recta arterie.

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Figre 7-6 A. Blood supply t the recum. B. Te transvrse fold of the rctum as een throgh a sigoidoscop.

635

snell Te iddle retal artey is small branch of the intenal ilia artery nd is ditributed mainly to the muscular coat The inferio rectal rtery is a brach of th interna pudenda artery n the perneum. It anastomses with the midde rectal artery at the anorctal juntion.

Veins The vei of the ectum corespond o the areries. Te uperior ectal ven is a tributary of the portal ciculation and drais into te inferi mesenteic vein. The middle and inferior recta veins drain ito the iternal iiac and iternal pdendal vins, resectively. The unio between P.34

the rctal veis forms n importnt portalâ€systemic anastomois (se Capter 5).

Lymph Draina The ymph vesels of te rectum drain fist into the pararectl nodes and thn into iferior msenteric nodes. Lmph vesss from te lower part of he rectu follow te middle rectal atery to he interal ilia nodes.

Nerve Spply he nerve supply i from th sympathtic and parasympahetic neves from the inferor hypostric plexuses. Te rectu is senstive only to streh.

Clinica Notes Rectal Curves and Mucosal Folds The ateropostrior flexre of th rectum, as it folows th curvatue of the acrum an coccyx, and the ateral fexures mst be rmembered when one is in a sigmodoscope o avoid ausing te patiet unnecesary disomfort. The crscentic ransvers mucosal folds of the rectum must so be bone in mid when pssing an instrumet into te rectum. It is tought tht these olds sere to supprt the wight of he feces and to revent ecessive distention of the rctal amplla.

lood Suply and Iternal Heorrhoids Te chief rterial spply to he rectu is from the suprior recal artery a contiuation o the infrior mesnteric rtery. In front of the thid sacral vertebra the arty divide into rght and eft branhes. Halway down he rectu, the riht branc divides into an nterior nd a posrior brach. The ributaris of the superior rectal vin are aranged in a simila manner, so that t is not surprisig to fin that

636

snell interal hemorhoids are arraned in thee group (see Chaptr 8): wo on th right sde of the lower retum and nal canal and one n the let.

Partia and Comlete Prolpse of te Rectu Partial nd complee prolapes of th rectum hrough te anus are relatiely commn clinicl conditons. In artial plapse, he recta mucous embrane nd submucous coat rotrude or a shot distace outsie the ans (Fig. 7-7). In omplete rolapse, the whol thickness of the ectal wal protrues throgh the aus. In both conditons, man causatie factors may be nvolved. However, damage t the levatores ani muscles s the reult of hildbirt and poo muscle one in th aged ar importat contributing ftors. A omplete ectal prlapse may be rearded a a slidig herni throug the pevic diaphragm.

Cacer of te Rectum Cancr (carcioma) of he rectum is a comon clinical findng that emains lcalized o the retal wall for a cosiderabl time. t first, it tends to sprea locally in the lmphatics round th circumerence o the bowel. Later, it spreds upwar and latrally aong the ymph vesels, folowing te superir rectal and midde recta arterie. Venous spread ocurs lat, and bcause th superior rectal ein is a ributary f the poral vein, he liver s a commo site fr seconry deposts. One the malgnant tumr has exended beond the confine of the rctal wall knowlede of th anatomic relation of the rctum will enable a ysician o assess te structres and ogans likly to be nvolved. In both sees, a poterior penetration nvolves he sacra plexus ad can caus severe intractabe pain dwn the le in the distributon of the sciatic neve. A latral penetation ma involv the ureer. An aterior pnetratio in the ale may ivolve the prostate seminal esicles, r bladder in the feale, the agina an uterus may be ivaded.

Figue 7-7 Coronal section of he rectum nd anal canal. A. Icomplete ectal (muosal) proapse. B.

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mplete rctal prolpse.

It is clear from the anatomic eatures of the rctum and its lymp drainag that a wde resecton of the rectum wih its lyphatic fild offer the best hance of cure. When the tumor has spred to coniguous orans and i of a low grade of alignanc, some frm of pelvic evisceation may be justifible. It is mos importan for a meical studnt to reember tht the interior of he lower part of the recum can b examine by a goved inde finger itroduced hrough th anal caal. The aal canal is about 1.5 in. (4 cm) long so that the pulp o the inde finger cn easily feel the ucous membane lining the low end of he rectum Most cacers of te rectum an be dianosed by his means This exmination an be exended in oth sexe by placin the oth hand on the lowe part of the anterior abdominal wall. With th bladder empty, he anterir rectal wall can e examine bimanualy. In th female, he placig of one inger in he vagina and anoter in the ectum may enable te physicin to make a thoroug examinaton of the lower pat of th anterio rectal wall.

Rectal njuries The manaement of enetratig rectal njuries wll be deermined b the site of penettion relative to th peritonel coverin. The uppr third f the rectm is coved on th anterio and lateral surfces by pritoneum the midle third s covered only on is anterir surface and the wer third is devoi of a peroneal coering (Figs. 7-3, 7-4, and 7-5. The trtment of enetratio of the itraperitoeal portin of the rectum is identica to that f the coln, becaue the petoneal caity has been violted. In te case of enetratio of the etraperitneal potion, the rectum s treate by diveting the feces though a tmporary abdominal colostomy iistering antibiotcs, and epairin and draning th tissue n front f the crum.

Pelvic Appendx If n inflaed appenix is haging own int the pelvis, abdoinal tendrness in the rigt iliac region ay not b felt but deep tendeness may be experenced above the smphysis ubis. Rectal examnation (o vaginal xaminatio in the fmale) may reveal enderness of the pitoneum n the pelis on the right sid. If suc an inflmed appenix perfoates, a localized plvic pertonitis my result P.45

mbryologc Notes Develpment of he Dista Part of he Large owel

638

snell The lft colic flexure, descendig colon, sgmoid coon, rectm, and uper half of the anl canal ae developed from th hindgut Distally this terinates as a blind sac of entoderm, whih is in wih a shallw ectoderal depression called the prctodeum. The pposed lyers of ctoderm nd entoderm form te loacal mebrane, which seprates the cavity o the hindut from th surface Fi. 7-8). The hindut sends off a dierticulum the allantos, tha es ito the umilical cod. Dista to the alantois, te hindgu dilates o form th ntoderm cloaca (ig. 7-8). In th interval between he allanois and the hindgu, a wedg of mesnchyme ivaginate the entderm. Wit continue proliferion of e mesencyme, a sepum is fored that gows inferorly and ivides e cloaca into antrior and osterior rts. The septum is alled th urrectal sptum, he anterir part o the cloaa become the primitve bladder and th uogenital sinus, nd the psterior art of the cloac forms te norectal canal. On reachig the clcal membane, the rorectal septum fues with i and fors the futre perinea body Fi. 7-8). The fates of the pimitive bldder and the urogeital sinus in bot sexes are considerd in deta on page 57. Te anorect canal frms the rectm and he superir half of the anal caal. Th lining f the infeior half of the anl canal s formed om the etoderm of the proctdeum (Fig. 79). Th posteri part of the cloacl membran breaks own so tht the gut opens onto the surace of te embry.

indgut Atery he hindut, whic extends rom the lft colic flexure t halfway wn the al canal, is suppled by the inerior mesnteric arery (s Fg. 5-46. Here, a number of ventral banches of the aorta fuse to frm a singe artery.

Meconium At full term, the large intstine is illed wih a mixure of inestinal land secetions, ile, and amniotic fluid. Tis substace is dak green i color an is calle meconiu. It start to accumlate at 4 months ad reaches he rectum at the ffth month

Primary Macolon (Hrschsprung Disease) irschsprug disease shows a fmilial tedency and is more ommon in males tha in femals. Symptos usuall appear uring te first ew days fter birh. The cild fail to meconium, and the bdomen beomes enormously disended. T sigmoid olon is geatly ditended an hypertrohied, whie the recum and al canal re consticted (Fig. -10). t is the constriced segmnt of th bowe that caues the obtruction, and histlogic examination reveals a complete failure o developent of th parasypathetic anglion clls in ths region The treament is perative xcision o the aganlionic sement of the bowel. P.46

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Fiure 7-8 Progressve stages 1â“4) i the foration of the uroretal septu, which divides the cloaca ino an anrior par (the priitive blader and te urogenial sinus) and a poerior pa (the anrectal caal).

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Figure 7-9 Stucture of the anal anal and ts embryoogic orign.

P.47

Figure 7-10 Min charateristics f primar megacolo (Hirschprung diease).

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Pevic Viscea in the ale he rectum sigmoid olon, and terminal coils of ileum ocy the psterior part of he pelvi cavity n both sxes, as describe above. The contens of the anterior part of he pelvi cavity in the mle are dscribed the folowing setions.

Ureters Ech ureter is a musular tub that exends fro the kiney to te posteror surface of the bladder. ts abdomnal coure is decribed on page 266

Figre 7-11 Right alf of te pelvis showing elations of the uter and as deferns.

Th ureter nters th pelvis y crossing the bifrcation of the cmmon ilic artery in front of the scroiliac oint. Eah urete then run down th lateral wall of he pelvis in front of the nternal liac artry to th region f the iscial spin and turs forwrd to ener the ateral agle of te bladdr (Fig. 7-1). Nar its trminatin, it is crossed by the vas deferens. The reter asses obiquely hrough th wall o the blader for bout 0.7 in. (19 cm) beore openng into he bladdr.

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Cnstrictins Th ureter ossesses three costrictios: where the rena pelvis jins the reter in the abdoen, wher it is kiked as .348

i crosses the pelvc brim t enter the pelvis, nd where it piercs the bldder wal. The blood supply, lmph draiage, and nerve suply of te ureter are descibed on pge 266.

rinary Badder Locatio and Desription The uinary blader is stuated imediatel behind he pubic bones (Fig. 7-4) ithin th pelvis. It store urine ad in the adult ha a maximum capacty of abut 500 mL The blader has strong uscular all. Its shape ad relatins vary acording o the amunt of urine that it conins. The empty bldder in he adult lies entiely withn the plvis; as the blader fills, its suprior wall rises up into the hypogasric regin (Fig. 7-1). In the youn child, the empt bladder projects above th pelvic nlet; latr, when the pelvc cavity enlarges the blader sink into the pelvis t take u the adult positio.

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Figure 7-12 A. Lateal view the bldder. Noe that te superio wall ries as th viscus fills wih urine. Note also that the peritonem coverig the suerior suface of he bladdr is peeed off fom the anerior adominal all as te bladder fills. B Interio of the ladder i the mal as seen from in font.

644

snell The empy bladder is pyramdal (Fig. 713), aving an apex, a base, and a superio and two inferoleral suraces; it also has a neck. he apex f the bldder poits anterorly and ies beind the pper marin of th symphysis pubis (Fis. 74 and 7-12. It is onnected to the ubilicus y the media umbilicl ligamet (remains of uachus). The base or posterir surface of te bladde, faces osteriory and is triangula. The suerolaterl angle are joied by th ureters, and the nferior ngle givs rise t the urthra (Fig. -13). he two vsa defeentia li side by side on e posterior surfae of the bladder nd sepaate the seminal vicles frm each oher (Fig. 7-13) The uppr part o the P.349

posterior surface f the bldder is overed b peritonum, which forms te anterir wall o the recovesical pouch. Te lower art of the posterior surfce is searated from the retum by te vasa dferentia the seinal vescles, an the recovesical ascia (Fig. 7-4).

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Figur 7-13 A. Latera view of the blader, prosate, and left semnal vesile. B. Posterior iew of te bladder, prostat, vasa dferentia and semnal vesiles.

646

snell he superio surface of the bladder s covere with peitoneum nd is reated to oils of leum or igmoid clon (Fig. 74). Alng the lteral magins of his surfce, the peritoneu es the lateral pelvic walls. As the bladder ills, it becomes void, an the suprior suface buls upward into the abdomina cavity. The perioneal covering i peeled off the loer part f the anerior abominal wall so tat the badder coes into irect cotact with the anteior abdoinal wal. The infeolateral surfaces are reated in ront to he retropubc pad of fat nd the pbic bone. More psteriorl, they lie in with he obturator internus muscle above and the evator ai muscle below. he neck of the bldder lie inferirly and ests on the uppe surfac of the rostate (Fig. 7-3). ere, th smooth muscle fibers of th bladder wall are continuos with hose of the prostate. The neck of he bladdr is held in positon P.350

by the puoprostatc ligamets in he male; these ar called he pubovesial ligamnts i the femle. Thes ligaments are thickenings f the pevic fasca. When the ladder flls, the posterio surface and neck remain ore or less unchaned in poition, bt the suerior suface ries into he abdomn, as described in the previous parraphs. The muous membane o the grater par of the epty blader is thown into folds tht disappar when the bladdr is ful. The are of mucos membrae coverig the iternal srface of the bas of the ladder s called the trigon. Here the mucus membrne is alays smoo, even wen the vscus is mpty (Fig. -12), ecause te mucou membran is firmy adheren to the nderlyin muscula coat. Te superi angles f the trgone corespond t the opnings of the uretes, and te inferir angle o the inernal uethral orfice (Fig. -12). The uretrs pierce the blader wall obliquel, and ths provids a valvlike acton, whic prevent a rverse fl of urin toward he kidnes as th bladder ills. The tigone is limited ove by a muscular ridge, wich runs from the openng of one ureter to that of the oter and i known s the interureteric ridge. The uvula vesicae is a mall eleation siuated imediately behind th urethra orifice which produce by the nderlyin median lobe of th prostat. The musculr coat o the blader is composed of smoot muscle nd is aranged as hree lars of interlacing bundles nown as he detrusor muscle At the neck of he bladde, the cicular coponent o the mcle coa is thickned to frm the sphicter vescae.

Blood Suply rteries The suprior and inferior vesical rteries, branches f the inernal ilac arteres.

Vein 647

snell The veins form he vesical venous pexus wich drais into te internl iliac vein.

Lymph Drinage Internal and extenal iliac nodes.

Nerve Suply Te inferior hypoastric pexuses. The sympthetic ostganglonic fibrs originate in the first nd second lumbar gnglia ad descen to the ladder vi the hypgastric lexuses. he paraympathetc preganlionic fbers arie as the pelvic spanchnic nerves fom the scond, thid, and furth sacal nerve; they ps throuh the inerior hyogastric lexuses o reach he bladde wall, here the synapse with posganglioni neurons Most aferent sesory fiers arising in th bladder each the central ervous system via he pelvc splancnic nerve. Some aferent fbers travel with te sympthetic nerves via he hypogstric plxuses an enter te first nd secod lumbar segments of the spnal cord The sypathetic erves* ihibit contraction of the dtrusor mscle of he bladdr wall ad stimulte closure of the sphincte vesicae The parsympathetic nerves stimulat contration of he detruor muscl of the ladder wal and inibit the action the sphncter veicae.

Micurition Micturition is a reflex action tat, in te toilet-trained ndividua, is controlled by higher nters in the bran. The rflex is nitiated hen the olume of urine rehes abou 300 mL stretch receptor in the ladder wall are stmulated nd tranmit impulses to th central nervous system, an the indvidual hs a conscious desre to miturate. Most affernt impules p the plvic splnchnic neves and nter the second, hird, an fourth sacral sements of the spinl cord (Fig 7-14 Some aferent ipulses tavel with the sympthetic nrves via the hypgastric lexuses nd enter the first and secod lumbar segments of the pinal cod. Effrent parsympatheic impules leave the cord from the second, hird, an fourth acral sements an vi the parsympatheic preganglionic nrve fibes throug the pelic splachnic neres and te inferir hypogatric pleuses to he bladde wall, here the synapse with postganglioni neurons By mean of this nervous pathway, he smoot muscle f the blder wall (the detrusor muscle) is ad to , and the spincter vsicae is made to relax. fferent impulses also pa to the urethral sphincte via the pudendl nerve S2, 3, ad 4), an this unergoes rlaxation Once uine entes the urhra, adtional afferent impulses to th spinal cord fro the urehra and einforce the reflx action Micturtion can be assised by cotraction of the adominal uscles to raise the intraabdomina and pelic pressures and exert external pressure on he bladdr. In oung chidren, miturition is a simle refle act an takes pace whenver the ladder bcomes ditended. n the adult, this simple sretch relex is ihibited y the acivity of the cereral corex until the time and plac for micurition re favorable. The inhibitoy fibers dowward wit the coricospina tracts to the seond, thid, and furth sacal segmets of th cord. Vluntary control f micturtion is ccomplised by cotracting the sphicter urthrae, wich closs the urthra; ths is assisted by the sphincter vescae, whi compresses the bladder neck.

648

snell Vluntary ontrol o micturion is nrmally developed during the second o third yar of lie. P.31

Clinical Notes Ureteri Calculi Ureteri calculi are iscussed on page 66. The reter is narrowed anatomiclly where it bens down ito the plvis at the pelvic brim and where it es hrough te bladder wall. t is at these sits that uinary stnes may be arresed. When a clculus eters the lower pevic part of the ureter, th pain is often reerred to the testis and th tip of he peni in the ale and he labiu majus i the female.

Paation o the Urinary Bladdr he full ladder i the adut projecs up int the abomen and may be papated though the anterior abdomina wall abve the ymphysis pubis. Bimnual palation of he emty blader with r withot a general anesthtic is a important methd of exaining th bladder. In the male, one and is paced on the anteior abdoinal wal above te symphyis pubis and the gloved idex finer of th other hnd is inserted ino the retum. Fro their nowledge of anatomy, studens can se that th bladder wall can be palpted betwen the eamining ingers. n the feale, an abdominvaginal xaminatin can be similarl made. I the chid, the ladder i in a hiher position than n the adlt becaue of the relatiely smaler size f the pevis.

Bladde Distenton Th normal dult blader has capacit of abou 500 mL. In the pesence o urinary obstructon in maes, the ladder ma become greatly istended without rmanent amage to the blader wall; in such cases, i is routnely posible to drain 1000 to 1200 L of urie throuh a catheter.

Urinry Retenion I adult mles, uriary retetion is ommonly caused b obstrution to te urethr by a beign or mlignant nlargemet of the prostat. An acue urethriis or prstatitis can also be resposible. cute retntion ocurs much less freqently in females. The only anatomi cause of urinary etention in femals is acue inflamation arund the rethra (.g., fro herpes).

Suprapubc Aspiraion s the bldder fils, the sperior wll rises out of te pelvis and peel the pertoneum of the poterior srface of the anteior abdminal wal. In cases of acue retenton of urne, when catheteization as

649

snell failed, it is possible t a eedle ino the badder though the anterior bdominal wall aboe the syphysis pbis, without enteing the eritonea cavity. This is simple thod of draining off the rine in n emergecy.

Cystocopy Te mucous membrane of the badder, te two urteric oifices, and the urthral metus can asily be observed by means of a cytoscope. With the bladder dstended ith flud, an ilminated tube fited with enses is introducd into te bladde through he urethra. Over the trigne, the ucous mebrane is pink and mooth. If the bldder is artially emptied, the mucou membran over th trigone remains smooth, ut it is thrown ito folds elsewher The ureeric orifices ar slitlik and ejet a drop f urine t intervls of abut 1 miute. The interuretric ridg and the uvula veicae can easily b recognized.

Bladder njuries The badder ma rupture ntraperitoneally or extrperitonelly. Intrperitonel ruptur usually involves the suprior wal of the ladder ad occurs most comonly whe the blader is full and hs extendd up int the abdmen. Urie and blod escap freely into the peritonel cavity. Extrapertoneal rpture inolves th anterir part o the blader wall below the level of the perioneal rflection it most commonly occurs i fracturs of the pelvis wen bony fragment pierce he bladdr wall. ower abdminal pa and blod in the urine (hematuria are foud in mos patiens. In oung chidren, th bladder is an abominal rgan, so abdomina trauma an injur the empy bladde.

Difficulty wih Micturtion Aftr Spinal Cord Injry After injuries to the sinal cor, the nevous control of miturition is disruted. he normal bladder is innerated as ollows: 





Sypathetic outflow is frm the fist and scond lumar segmets of the spinal ord. The sympathtic nervs (see te footnoe on pag 350) inibit contraction of the detrusor mucle of te bladde wall an stimulae closur of the sphincte vesicae Parasympthetic otflow is from the secod, third and fouth sacral segments of the sinal cord. The parasympathetic neres stimuate the ontractin of the detruso muscle f the bladder wall and inhibit the ation of he sphicter vescae. Sensoy nerve ibers enter the spinal crd at th above gments. The norma process of mictuition is describe on page 350.

Disrution of he proces of micurition y spinal cord injries may produce he following type of blader. The atoni bladder occurs during the phase of spina shock, mmediatey after he injur, and ma last fr a few ays to sveral weeks. The badder wal muscle is relaed, the phincter vesicae ightly cntracted and the phincter urethra relaxed The blader becoes greaty distened and fally

650

snell overflows. epending on the evel of he cord injury, t patient either s or is ot aware that the bladder is full. Te utomatic reflex badder (Fg. 7-15) occus after he patie has recovered frm spinal shock, povided tat the ord lesin lies aove the evel of the parasypathetic outflow (S2, 3, nd 4). I is the ype of badder nomally fond in infancy. Th bladder fills an empties reflexly Stretch receptor in the bladder all are timulate as the ladder flls, and he affernt impuses to the spina cord (segments S, 3, and 4). Effeent implses pas down to he bladdr muscle which cntracts; the sphincter vescae and he urethal sphinter both relax. Tis simple reflex ccurs evry 1 to hours. The autonomus bladdr (Fig. -15) s the codition tat occur if the sacral seents of he spina cord ae destroed. The sacral segents of he spina cord ar situated in the pper part of the lubar regio of the ertebral olumn (se pae 871). The badder is ithout an external reflex cotrol. The bladder wll is flccid, and he capacit of the ladder is reatly icreased. t merely fills to acity an overflow; continul dribblig is the result. Te bladde may be partially emptied manual ompressin of th lower part of the anterior bdominal all, but infection of the uine an back-prssure effects on the ureters nd kidney are invitable. P.35

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Figure 714 Nevous conrol of te bladder. Sympattic fibes have ben omittd for siplificaton.

Male enital Ogans The testes and epidiymides are desribed on page 169

Vas Defrens 652

snell e vas dferens is a thick-alled tue about 8 in. (4 cm) log that cnveys maure sper from th epididymis to the ejculator duct an the urthra. It arises rom the ower en or tail of the epididyis and psses thrugh the nguinal anal. I emerges from te deep iguinal ring and es aroud the laeral marin of th inferir epigasric artey (Fig. 7-11) It then es ownward nd backwrd on th lateral wall of the pelv and cosses th ureter in the region of the ischial spine. e vas deerens then runs medially and downwrd on th posterir surfac of the ladder Fi. 7-11). The trminal prt of th vas defens is dilated o form the ampulla of the vas defere. The inferior end of te ampull narrows down and s th duct of the semial vesice to for the ejacultory duc.

eminal Vsicles The seminal vesicles are wo lobulated orgas about in. (5 m) long ying on he posteior surfce of th bladder (Fg. 7-13). On he media side of each vesile lies he termial part f the va deferens. Posteriorly, te semina vesicle are relted to te rectum (Fg. 7-4). Inferirly, eac seminal vesicle arrows ad s he vas dferens o the same side to orm the ejculatory duct. Each semina vesicle consists of a muc-coiled ube embedded in connective tissue.

Bloo Supply Arteris The nferior esicle ad middle rectal ateries. P.353

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Figue 7-15 A. Nervus contrl of the bladder fter secion of te spinal cord in he uppe thoraci region. Destructon of th sacral egments of the spal cord . The fferent ensory fbers fro the bldder entring the central ervous sstem and the parasympathetic effert fibers ing o the

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bldder are shown; te sympatetic fiers have been omited for larity.

eins T veins rain into the intenal iliac veins.

Lymph rainage The internal ilic nodes.

Functio The fnction o the semnal vesiles is t produce a secreion that is added to the sminal flid. The ecretion nourish the spermatozoa. uring ejculation the seminal vesicles contrct and xpel ther contens into te ejacultory ducs, thus ashing te spermtozoa ou of the urethra.

Ejaclatory Dcts The two ejaculatory ducts are each ls than 1 in. (2. cm long an are formed by the union o the vas deferens nd the dct of te semina vesicle (Fg. 7-16). The ejaculatry ducts pierce te posteror surfae of the prostate and open into th prostatc part o the urehra, close to the argins o the prstatic uricle; teir funcion is t drain te seminal fluid ino the postatic rethra.

Prostte Loctio and Desription The prostate is a fibomuscula glandulr organ hat surrunds the prostatic urethra Fis. 7-4 and 716). It is about 1.25 in. (3 cm) long nd lies etween te neck o the blader abov and the urogenitl diaphrgm below (Fg. 7-16). The prostte is suounded by a fibrous capsul (ig. 7-16). The somewhat conical rostate as a base, which lies P.35

againt the bladder neck above, d an apex, whih lies aainst the urogental diahragm beow. The wo ejacuatory dcts pierce the upper part of the poerior suface of he prosate to open into he prosttic uretra at th lateral margins f the prostatic uricle (Fig. 7-16)

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Figure 7-16 Prostat in coroal sectin A), sgittal sction (B) and horzontal sction (C). In the coronal ection, ote the penings f the ejculatory ducts on the margin of th prostatc utricl.

Relatons 

Sueriorly: The ase of te prostate is contnuous wih the nek of the bladder, the smoh muscle ing ithout iterruptin from oe organ o the oher. The urethra nters th center f the bae of the prostate (F. 7-4.

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

Inferiorl: The apex of he prostte lies n the uper surface of the rogenita diaphrgm. The rethra laves the prostate just aboe the apx on the anterio surace (Fig. 7-16) Anterioly: Te prostate is relted to te symphyis pubis separated from it by the extaperitonal fat in the retropubic space (cav of Retzus). Te prostae is conected to the postrior aspct of th pubic bnes by te fascia pboprostaic ligamnts (Fig. 7-4). Posterorly: The prostate (Figs. 74 and 7-6) is losely rlated to the anteior surfce of te recta ampulla and is P.355

sparated rom it by the rectovsical setum (fasia of Deonvillies). This septu is formd in fetl life b the fuson of th walls o the loer end o the rectovesical pouch of peritone, which originally extendd down t the perneal bod. 

Lateraly: Th prostat is embrced by te anterir fibers of the lvator ani as they run posteiorly frm the puis (Fig. 7-6).

Sructure f the Prstate The nuerous glnds of the prostae are emedded in a mixtue of smoth muscl and conective tssue, an their dcts open into th prostatc urethra. The rostate s incompetely diided int five lobes (Fig. 7-6). Th anterior lbe lis in frot of the urethra nd is deoid of gandular issue. Te edian, or middle, lobe s the wege of glnd situaed betwen the urthra and the ejaclatory ucts. Its upper surface is related t the tigone of the blader; it s rich i glands. The posteror lobe is situted behid the urthra and below th ejaculaory ducts and als contain glandulr tissue The right and left ateral lbes le on eiter side f the urthra and are sepaated fro one anoher by shallow vertical groove o the poserior surface of he prostte. The lateral obes contain many glands.

Function of the Prostate The postate poduces a thin, miky fluid containig citric acid an acid phsphatase that is added to te semina fluid a the tie of ejaulation. The smooh muscle which surrounds te glands squeezs the seretion ito the postatic rethra. he prosttic secetion is alkaline and help neutralize the acidity in he vagin.

Blod Suppl Arteries Brnches of the infeior vesical and middle rectal arteris.

Veins

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snell The veins form the prstatic nous plxus, wich lies outside he capsue of the prostate (Fg. 7-16). The prostatic plexus rceives te deep drsal vei of the enis and numerou vesical veins an drains nto the nternal liac veins.

Lymph Dainage Interna iliac ndes.

Nere Supply Inferor hypogstric plxuses. Te sympatetic neres stimuate the smooth muscle of te prostae during ejaculaton.

Cinical Ntes rostate xaminatin Th prostat can be xamined clinicall by palption by erforming a rectal examination (see pae 397) The exainer's goved finer can fel the psterior surface of the proate through the nterior ectal wal.

Prostat Activit and Disase It is no generaly believd that te normal glandular activiy of the rostate s controled by te androgns and etrogens circulatng in th bloodsteam. The secretios of the prostate re pourd into he uretha during ejaculaton and ae added o the seinal flid. Acid phosphatse is an important enzyme pesent in the secrtion in large amunts. Whn the glndular clls prodcing thi enzyme annot dscharge teir secetion ino the duts, as i carcinoa of the prostate, the serum acid phosphatse level of the bood rise. t has ben shown hat trac amounts of protens prodced specically by prostatc epithelial cells are foud in peipheral lood. In certain rostatic disease, notably cancer of e prosate, this protei appears in the lood in ncreased amounts. The spcific prtein level can be measured by a simle labortory tes called the PSA (prostte-speciic antigen) test.

Benign Enlargemnt of th Prostat Bnign enlrgement f the prstate is common i men oler than 0 years. The caus is possbly an ibalance in the hormonal cotrol of he gland The medan lobe f the glnd enlares upward and enroaches ithin th sphinter vesiae, locaed at the neck of he blader. The eakage o urine ito the postatic rethra causes an intense rflex desre to miturate. he enlarement of the medin and lteral loes of the gland poduces eongation and lateal comprssion nd distotion of he uretha so tha the patent expeiences ifficult in ng urine and the tream is weak. Bak-pressue effecs on th ureters and both kidneys re a comon complcation. he enlagement o the uvua vesica (owing o the enarged meian lobe result in the ormation of a pouh of stanant urine behnd the urethral

658

snell oriice wthin th bladder (Fig. 717). he stagnnt urine frequenly becomes infected, and the inflamed bladder (cystiti) ads to the patient's symptoms. In all peration on the rostate, the surgon regars the postatic enous plxus with respect. The vein have thn walls, are valeless, ad are drined by everal large truks direcly into the intenal ilia veins. amage to these vens can rsult in severe hemorrhae.

Prostae Cancer and the rostati Venous lexus Man connectons betwen the postatic enous plxus and the vertbral veis exist. During cughing ad sneezig or abdminal sraining, it is possible fo prostat venous lood to low in a reverse directio and entr the vetebral vins. Thi explain the frquent ocurrence of skeletl metastes in the lower vertebral column ad pelvi bones o patient with cacinoma o the protate. Cncer cels enter the skull via this route by floating up the alveles prostatc and vertebral vens. P.36

Fiure 7-17 Sagital section of a rostate that had udergone enign enargement of the median lobe. Note he bladdr pouch illed wih stagnat urine behind te prostae.

Protatic Urthra The prosatic urehra is aout 1.25 in. (3 c) long ad begin at the eck of te bladde. It pases throuh the prstate frm the bse to the apex, where it beomes coninuous wth the mmbranous part of the uretra (Fig. 7-6).

659

snell The prostaic uretha is the widest ad most dlatable ortion o the entre urethra. On the postrior wal is a longitudinal ridge caled the urehral crt (Fig. 7-16). On each ide of tis ridge is a grove calle the prosttic sinus the rostatic glands oen into hese groves. On he summit of the urethral cest is a depressin, the protatic uticle, which is an analo of the terus an vagina n female. On the edge of the mout of the tricle ae the opnings of the two ejaculatory ducts (Fi. 7-16).

Viscral Pelvc Fascia The isceral lvic fascia is a layer of connective tissue that covers and s t pelvic viscera Fi. 7-16.

Peritoneum The pertoneum i best unerstood y tracin it aroud the pevis in a sagittal plane (Fig. 7-4). The eritoneu es own from the anteior abdoinal wal onto te upper urface o the uriary blader. It ten runs own on he posteior surface of the bladder or a shot distance until t reaches the uper ends f the seinal vescles. Hee it sweps backwrd to rach the nterior spect of the rect, forming the shallow rectovsical poch. Te peritoeum then es u on the ront of he middl third o the retum and he front and lateal surfaes of th upper tird of te rectu. It the becomes continuos with te parietl peritoneum on th posteror abdomnal wall It is tus seen hat the owest pat of the abdominpelvic pritoneal cavity, hen the atient i in the erect poition, i the recovesical pouch (Fig. 7-4). The eritoneu covering the superior surace of te bladdr es ateraly to the lateral elvic wals and des not cver the lateral urfaces f the bladder. It is important to rember that as te bladder fills, he superior wall rises up ito the adomen an peels ff the pritoneum from the anterior abdomina wall so that the bladder becomes irectly n contac with the abdomin wall.

Pelvic Viscera n the Feale The rectm, sigmod colon, and termnal coil of ileu occupy he posteior part of the elvic caity (Fig. -5), as described previously. T content of the nterior art of the pelvic cavity i the femle are dscribed n the folowing setions.

Ureers Te urete crosses over the pelvic nlet in ront of the bifurcation of the commo iliac atery (Fig. 718). It runs downward and backard in font of te internl iliac rtery and behind the ovary until i reaches the regi of the ischial sine. It then turs forwar and medally benath the ase of te broad igament where t is crosed by te uterin artery Fis. 7-18 and 7-19). The ueter the runs foward, laeral to the laterl fornix of the vgina, to enter th bladder

Uinary Bldder

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snell s in the male, th urinary bladder s situatd immeditely behind the pbic bone (ig. 7-5). Becase of th absence of the postate, he bladdr lies a a lower level tan in th male pelvis, and the neck rests diectly on the uppe surfac of the ogenital diaphragm The cloe relatin of the bladder to the uerus and the vagia is of onsiderale clinical importance (Fi. 7-5. Te pex o the blader lies behind te symphyis pubis (Fg. 7-5). The base, or postrior surace, i separatd by the vagina fom the rctum. Th superior surface is relatd to the uterovescal pouc of perioneum an to the ody of te uterus The inferoateral srfaces are relaed in frnt to th rtropubic pad of fat and th pubic bnes. Mor posterirly, the lie in ontact wth the obturator internus uscle abve and the levatr ani mucle belo. The neck of the ladder sts on the upper urface o the uroenital daphragm. Th general shape an structue of the bladder; its blod supply lymph dainage, nd nerve supply; nd the pocess of micturiion are dentical to those in the mle. P.57

Clinica Notes Stress Incontinnce he bladdr is normally ed by the viscral pelvc fasci which in certain areas is condensd to form ligaments. Howev, the mst imporant supprt for te bladde is the one of te levatoes ani uscles. n the feale, a difficult labor, especially e in whih forces is use, excessvely strtches th of the adder neck, and the norma angle btween th urethra and the osterior wall of the blader is lst. This injury causes stress inconinence, conditon of prtial urinar incontience ocurring wen the patient oughs or strains r laughs excessivly.

Embrologic Notes Developmnt of the Bladder in Both exes The dvision of the cloaca into nterior nd posteior parts by the development of the urrectal sptum s descried on pae 345. The posterir portio forms te norectal canal (Fg. 7-20). The entrance of the dstal eds of th mesonepric duct into th anterir part o the cloa on eac side pemits one for puroses of descripton, to dvide the anterior part of he cloac into an area abve the dct entraces calld the primiive blader an another area below called he urogenial sinus The caudal eds of th mesonepric duct now becme absobed into the lowe part of the blader so tht the urters and ducts hve indivdual opeings in the dorsa wall (Fig. 7-20). With diferentil growth of the drsal blader wal, the urters com to opn throug the laeral anges of th bladder and the mesonephic ducs open cose togeher in wat will e the urthra. Tht part o the dosal

661

snell blader wall arked of by the penings f these our duct forms he trigone of the bladder Fig. 7-21. Thus, it is sen that i the earest stags the liing of te bladde over te trigon is mesoermal in origin; ater, this mesodermal tissue is thoght to b replace by epitelium of entoderml origin The smoth musce of the bladder all is drived frm the spanchnopleuric mesoderm. The prmitive bladder may now be ivided ito an uper dilatd portion, the bladdr, an a lower arrow portion, the rethra (Fg. 7-20). The pex of te bladde is contnuous wih the allanois, wich now ecomes bliterated and forms a fibrus core, the urachus. The rachus prsists troughout life as ligament that rus from t apex o the bladder to te umbilius and s called the median umbilical ligament

Cogenital nomalies of the Badder Exstophy of te Bladde (Ectopi Vesica xstrophy of the badder ocurs thre times mre commnly in mles than in females. The psterior ladder wll protres through a defect in th anterio abdominl wall blow the mbilicus (Fg. 7-22). The conditio is causd by a failure of the embronic mesnchyme to invade the embryonic disc caudal the clcal embrane Fi. 7-22). The absence of interveing mesenchyme between the ectoderm and entoerm prouces an nstable tate, whch is folowed by breakdow of this area. Beause of he urinay incontnence an almost ertain ccurrenc of asceding uriary infetion, sugical reonstructon of te bladde is attempted.

Fate of the Mesonephric ct in Bth Sexes I both sees, the esonephric (or olffian) duct givs origin on each ide to te reteric bud, wich form the ureter, the pelis of th ureter, the majo and minr calyce, and he collectg tubuls of the kidney (see page 27). Is inferir end is absorbed into the developig bladde and fors the trgone and part of he uretha. In the male, it upper o cranial end is jined to he deveoping teis by te efferet ductuls of the testis, nd so it becomes the duc of the pididymi, the va deferen, and the ejaculaory duct. From the lattr, a smal divertculum arises that forms th sminal veicle (ee Fig. 4-2). In the fmale, th mesonepric duct largely isappears Only smll remnats persit—as te uct of te epoophron an the duct o the parophoron. The cudal end may persst and etend from the epophoron the hymn as Gartne's duct.

evelopmet of the Urethra In te male, he prostati urethra is formed from two soues. The roximal part, as ar as th opening of the ejaculatry ducts is deried from he mesonphric ducts. The distal part of th prostatc urethr is formed from the urogenial sinu (ig. 7-21). The mebranous rethra and the reater prt of th pnile urehra aso are frmed fro the uroenital snus. The distal ed of the penile rethra i derived from an ngrowth f ectodemal cell on the lans peis.

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snell In the female, he upper two thirs of the urethra re deried from he mesonphric duts. The ower end of the uethra is formed rom the rogenital sinus (Fig 7-21) P.358

Figure -18 Rght half of the plvis shoing the vary, th uterine tube, an the vaina.

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igure 7-9 A. oronal sction of the pelvs showin the uteus, broa ligamens, and ight ovay on poserior viw. The left ovary and part f the left uterine tube have been removed fr clarity. B. Utrus on lteral viw. Note he strucures tha lie witin the boad ligment. Noe that the uterus has been etrovertd into te plane f the vginal luen in boh diagras.

P.359

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Figure 720 Fomation o the uriary blader from he anterior part o the cloca and he termial parts of the msonephri ducts i both sees. The esonephrc ducts nd the ueteric bds are dawn into the deveoping badder.

P.36

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Figure -21 Prts of the blader and uethra deived fro the mesonephric dcts in bth sexes (atch mars). Te lower nd of th urethra in the fmale and the lowe part of the protatic urthra in he male re forme from the urogenil sinus.

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igure 7-2 A. Estrophy of the bladder. B. Dorsal vew of th embryonc disc. he norma path taen by th growing embryonic mesenchme in th region f the claca is sown. C. Fetus as seen fro the sid. The hed and tal folds ave deveoped, but the mesenchyme hs failed to enter the vental body all betwen the cloaca and the umbiical cor.

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Female Genital rgans

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Ovary Locatio and Desription Each ovary is oval shaed, measring 1.5 by 0.75 n. (4 by cm), an is attahed to te back o the brod ligamet by the msovarium (Fig. 7-9). hat part of the boad ligaent exteding beteen the attachment of the esovariu and the lateral all of te pelvis is calld the suspesory ligment of he ovary (Fig. 7-1). The roun ligamen of the vary, hich repesents te remain of the pper par of the ubernacuum, conncts the ateral magin of the uterus to the oary (Figs. -18 ad 19). The ovary usally lie against the lateal wall f the pevis in a deression alled te ovaria fossa, bounded by the external liac vesels above and by te internl iliac essels bhind (Fig. -18). The postion of he ovary is, howevr, extreely varible, and it is oten foun hanging down in he rectoterine puch (pou of Douglas). Duing pregancy, th enlargig uterus pulls th ovary u into th abdomial cavit. After hildbirt, when te broad igament s lax, te ovary takes up a variabe positin in the pelvis. Th ovaries are surrunded by a thin fibrous csule, th unica aluginea This casule is overed eternally by a modfied are of perioneum caled the gerinal epihelium. The tem erminal pitheliu is a isnomer ecause te layer oes not ive rise to ova. ogonia deelop befoe birth om primorial germ ells. Before puberty, the ovary is smooth but aftr puberty, the ovay becomes progressely scarrd as succssive corpra lutea degenerae. After enopause, the ovary becomes srunken ad its surace is pitted wit scars.

Fnction The ovaries are th organs responsibl for the poduction f the feale germ ells, th oa, and the femal sex hornes, estroge and progsterone, in the exually mture femae.

Blod Supply Arteres The ovaian arter arises from the bdominal aorta at the leve of the irst lumar vertera.

Veis The ovrian vei drains ito the inerior ven cava on he right ide and ito the let renal ein on th left sid.

Lymph Drinage

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snell The lymph vessels of the ovar follow e ovarian artery nd drain nto the pra-aortic nodes at he level f the fist lumba verteba.

Nerve Suply Th nerve suply to th ovary is erived fom the aortic plexu and accopanies te ovaria artery Th blood suply, lymp drainage, and nerv supply of the vary pss over he pelvi inlet and cross the extrnal ilic vessls (Fig. 7-19) They rach the ovary by ing through te lateral end of te broad igament, the part known as the suspnsory liament o the ovay. The vssels and nerves finally enter th hilum o the ovay via th mesovarum. (Compare the blood suply and e lymph drainage of the ovary with those of the tesis.)

Clinial Notes Postion of he Ovary The vary is ept in psition b the broad ligament and te mesovaium. Aftr pregnacy, the road ligment is ax, and he ovares may polapse into the rectouterie pouch pouch of Douglas). In thee circumtances, he ovary may be tder and cause discomfort o sexual intercouse (dysparunia). An ovary situated in the rctouterie pouch ay be papated though the posterio fornix f the vaina.

Cysts of the Ovar Follicuar cysts are cmmon and originat in unrutured graafian follicles; they rarly excee 0.6 in. (1.5 cm) in diameer. Luteal ysts are forme in the orpus lueum. Flud is retined, an the corus lutem cannot become fbrosed. uteal cyts rarel exceed .2 in. ( cm) in diameter

mbryologc Notes Develpment of the Ovar The female sx chromoome causs the genial ridge on th posterir abdomial wall o secret estroges. The pesence o estrogn and th absence of testosterone iuce the evelopmet of the ovary nd the oter femal genital organs. The sex cords ontained within he genitl ridges contain roups of primordil germ clls. Thse becom broken p into irregular cell clusters by t prolifrating msenchyme (Fg. 7-23). The germ cells differeiate into ogonia and by he third month, tey start to undero a numbr of mittic diviions witin the cortex of the ovary o form priary oocyes. Thse primay oocyte become urrounde by a sigle laye of cell derived from the sex cord, called the granuloa cells. Thus, prmordial ollicles have een formd, but lter, many degenerae. The msenchyme that surounds te follicles provides the ovarian strma. The elationsip of te ovary o the devloping uerine tue is shon in Figure 7-24. 669

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Ovaria Dysgeneis Complete filure of both ovares to deelop is ound in Turner's syndrome. The clasic featres of tis syndrme are wbbed nek, short stocky bild, inceased carying ange of the elbows, ack of secondary sex characteristics, and amenorrhea

Imperfect Descent of he Ovary The ovary ma fail to descend nto the elvis or very raely may e drawn downward wth the rund ligaent of te uterus into th inguina canal o even ino the laum majus .362

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Figure 7-2 Formation of e ovary nd its rlationshp to the mesonephic and pramesonehric ducs.

igure 7-24 The descent f the ovry and is relatinship to the deveoping uteine tub and uteus.

P.63

Uterin Tube Locatio and Desription The wo uteri tube are each about 4 in. (10 m) long and lie in the upp border of the boad ligaent (Figs. -18 an 719). Each conects the peritoneal cavity in the region of the ovary with the cavity f the utrus. The terine tbe is diided int four pats: 

  

Th ifundibulm is he funne-shaped lateral ed that ojects byond the broad ligament and overles the ovary. The free edg of the unnel has several fingerlike proceses, know as fimbri, whih are drped over the ovar (Figs. 7-9 and 7-5). he ampulla is the widest prt of th tube (Fig. 7-25) The ishmus s the narowest prt of th tube an lies jut latera to the terus (Fig. 7-25). The intramral part is the segment that pieces the terine wll (Fig. 7-5).

Function Th uterine tube reives the ovum frm the ovary and provides a site whee fertilzation the ovm can tae place usually n the amulla). I provide nourishent for he fertiized ovu and trnsports t to

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snell the cavity o the uteus. The ube serve as a coduit alng which the speratozoa tavel to each the ovum.

Figue 7-25 A. Diffeent part of the terine tbe and te uterus B. Exteral os of the cervx: (above) nulliprous; (belo) parus. C. Aneverted osition f the utrus. D. Ateverte and antflexed psition o the uteus.

Blood Supply 672

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Arteri The terine atery from the internal iliac artery nd the ovarian artery from the abdoinal aora (Fig. 7-2).

Veins Te veins orrespon to the rteries.

ymph Dranage he interal iliac and paraaortic ndes.

erve Suply Symathetic nd parasmpatheti nerves from the inferior hypogastic plexues. P.364

Figure 726 A ectopic pregnanc located where the ampulla of the uterine tu narros down t the isthmus. Note the thin tubl wall cmpared t the thck decida that lnes the ody of te uterus

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Clinial Notes The Uterine Tue as a Cnduit fo Infection The uterne tube lies in the upper free borer of th broad igament nd is a direct rote of comunicatin from te vulva through the vagina and uterne cavit to the eritonea cavity.

Pelvc Inflamatory Diease The pathogenic oranism(s) enter te body through sexual contat and asend throgh the uerus and enter th uterine tubes. Salpngitis may folow, wit leakage of pus ito the pritoneal cavity, ausing elvic peitonitis A pelvi abscess usually follows, o the infction sreads father, casing genral perionitis.

Ectopic Pregnancy Implantaion and owth of a fertilzed ovum may occur outside he uterie cavity in the wll of th uterine tube (Fig. -26). This is variety of ectopic regnancy. Ther being n decidua formatio in the ube, the eroding ction of the trohoblast uickly dstroys t wall of the tube Tubal aortion o ruptur of the ube, wit the effsion of large qantity of blood into the peritonea cavity, s the cmmon result. The blood pors down nto the rectouterine pouch (pouch f Dougla) or into the uterovesical pouch. Te blood ay quicky ascen into the general eritonea cavity, giving rse to seere abdminal pan, tendeness, an guardin. Irritaion of te subdiphragmatc peritoneum (supplied by prenic neves C3, 4 and 5) may give rise to eferred pin to th shoulde skin (suraclaviclar neres C3 and 4).

Tual Ligaton Liation an division of the terine tubes is a method f obtainng permaent birth control and is usually resricted t women ho alreay have cildren. The ova tht are dicharged rom the varian ollicles degenerate in the ube proxmal to te obstrution. If later, the woma wishes o have a additioal child restoraon of the continuity of te uterin tubes cn be attmpted, ad, in abut 20% of women, fertilizaion occurs.

Embrylogic Noes Dvelopmet of the Uterine Tube Early o in deveopment, he paramesoephric dcts ppear on the posteior abdoinal wal on the lateral sde of th mesonehros. The uterine ube on ech side s formed from the ranial ertical nd middl horizonal parts of the pramesonehric duc (ig. 7-27). The ube elonates and becomes oiled; dfferentition of the muscle and mucos membrae takes lace; th fmbriae develop and the inundibulu, ampulla, and istmus ae identiiable.

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Uerus ocation and Desciption The utrus is a hollow, ear-shaed organ with thik muscuar walls. In the ung nulliparous dult, it measures in. (8 cm) long 2 in. ( cm) wid, and 1 n. (2.5 m) thick It is divided ino the fundus, boy, and crvix (Fig. -25). The fudus is the part of the uerus tha lies abve the etrance o the uteine tube. Th ody i the par of the terus tht lies blow the entrance of the urine tues. The ervix s the narow part of the uterus. It pierces he anteror wall f the vaina and s divide into th spravaginl and vainal pars of the cervix. P.365

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Figure -27 Te relatinship of the mesoephric ad parameonephric ducts to the deveoping ovry. A. Coss section of a developing ovary. B. Anteri view of ovaries and duct. and D Mesonepric and aramesonphric duts in a ross secion of te pelvis Note th developing broad ligament

The caviy of te uterin body is triangulr in cornal secton, but t is merly a clet in the sagittal plane (Fig. 7-25). The caviy of the cervix, he cervical canal communiates wit the cavty of th body though the inernal os and with that of the vagina through the extenal os Before th birth o the firt child, the extenal os i circula. In a arous woan, the aginal prt of th cervix s larger and the externa os becoes a trasverse sit so that it posesses an nterior lip and a posterir lip (Fig. 725).

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Aneriorly: The bdy of th uterus s related anteriory to the uterovescal pouc and the superior surface f the bladder (Fig. 75). he supraaginal crvix is elated to te superir surface of the bladder The vagnal cervx is relted to te anterir fornix of the agina. Posterorly: The bod of the terus is related posteriorl to the ectouterne pouch (pouch f Dougla) with cils of ilum or simoid coln within it (Fig. 7-). Laterlly: Te body o the uteus is reated latrally to the broa ligament and the uterine rtery and vein (Fig. -19). The supavaginal cervix is related o the urter as i es orward to enter the blader. The vginal cevix is rlated to the lateal fornix of the agina. Te uterin tubes ener the sperolateal angle of the uterus, and the rond ligamnts of te ovary nd of th uterus are attahed to the uterin wall just below is level

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Functio The uerus seres as a ite for he recepion, retntion, ad nutrition of the fertilized ovum.

Positios of th Uterus In mot women, the long axis of he uteru is bent forward n the lon axis of the vagina. This position s referrd to as antversion f the utrus (Fig 7-25) Furthemore, th long axs of the body of he uteru is bent forward t the level of th interna os with the long axis of he cervi. This position i termed anflexion of the utrus (Fig 7-25) Thus, i the eret positin and wih the bladder empty, the utrus lies in an alost horiontal plane. In som women, the fundus and body of the uerus are bent bakward on the vagina so tha they lie in the rctouterie pouch (pouch o Douglas. In thi situatin, the uterus is said to b rtroverte. If he body o the uteus is, i additio, bent bkward on the cervx, it is said to be retroflxed.

Structure of the Utes 676

snell The uterus is covere with peitoneum xcept aneriorly, below te level f the inernal os where te peritoneum forward onto the bladder Lateraly, there is also space btween th attachment of te layers of the boad ligaent. The musculr wall, or myometium, s thick nd made u of smooh muscle e by connctive tisue. The mucou membran lini the body of the terus is known as the endometium. It is cotinuous bove with the mucos membrae lining the uterie tubes and below with th mucous embrane ining th cervix. The endmetrium i applied directly to the mscle, there being o submuosa. Fro puberty to menopuse, the endometrium underges extesive chages durig the mestrual ccle in rsponse t the ovaian horones.

gure 7-8 Cornal secton of th pelvis howing rlation o the levaores ani muscles and tranverse cevical liaments to the uters and vaina. Noe that te transvrse cervical ligamnts are ormed frm a conensation of visceal pelvi fascia.

The upravagial part f the cevix is srrounded by visceal pelvic fascia, hich is eferred o as the prametriu. It i in this fascia tat the uterine arry crosss the urter on ech side f the cevix.

Blod Supply Arteries

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snell The arterial supply t the uteus is manly from the uteine arter, a branh of the internal iliac arery. It eaches te uteru by runnng medialy in the base of he broad ligament (Fg. 7-19). It cosses aboe the urter at rght angls and reches th cervix a the levl of th interna os (Fig. 7-25) The arery then ascends long the ateral mrgin of he uteru within the broa ligamen and end by anasomosing ith the varian atery, wich also assists n supplyig the utrus. The uterine rtery gies off small decending ranch tht supplis the cevix and the vagina

Veins The uteine vein follows the arter and dras into te internal iliac vin.

Lymp Drainag The ymph vesels from the funds of the uterus ccompany the ovarin artery and drai into t paraaortic node at the level of the firs lumbar vertebra. he vesses from te body ad cervi drain ito the internal and extern iliac lmph node. A few lymph vesels folow the rond ligamnt of th uterus hrough te inguinl canal nd drain into the superfical inguil lymph nodes. P.36

Nerve Spply ympathetc and paasympathtic nervs from banches o the inferior hypoastric pexuses

Spports o the Uteus Te uterus is suppoted mainy by the tone of he levaores ani muscles ad the codensatios of pelic fasci, which form thre important ligamets.

Te Levatoes Ani Mscles an the Perneal Bod he origi and the insertion of the evatores ani muscles are decribed i Capter 6. They orm a brad muscuar sheet stretchig across the pelvi cavity, and, tether wih the pevic fasca on ther upper urface, hey effctively pport th pelvic iscera ad resist the intraabdomina pressue transmtted dowward through the plvis. Th medial dges of the anteor parts of the lvatores ni muscls are attched to he cerx of the uterus b the pelic fasci (ig. 7-28).

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Fiure 7-29 Ligamntous s of uterus. A As seen from belw. B. Laeral view. Thes ligamens are fomed from visceral elvic facia.

Som of the ibers of evator ai are inerted ino a fibromuscular tructure called te erineal ody (Fig. 7-5). This stucture i importat in maintaining te integrty of th pelvic floor; i the perneal bod is damagd during childbirh, prolapse of t pelvic iscera my occur. The perieal body ies in te perinem betwen the vaina and te anal cnal. It s slung up to the elvic wlls by te levatoes ani ad thus spports te vagina and, inirectly the uterus.

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The Tranverse Cervical, Puocervica, and Sarocervicl Ligamets Thes three lgaments re subpeitoneal ondensations of plvic fasia on th upper srface of the levaores ani muscles. They are attached to the crvix and the vaul of the vgina and play an importan part in i the uteus and keping th cervix in its correct postion (Figs. 7-28 nd 729). P.368

Tnsverse Cervical (Cardinl) Ligaments Transerse cerical liaments a fibromscular ondensatons of pevic fasca that pss to th cervix nd the uper end of the vgina from the lateal walls of the plvis.

ubocervial Ligaments Te pubocevical liaments cnsist of two firm bands of connectie tissue that pas to the ervix frm the poterior suface of the pubi. They ar positioed on eiher side of the neck of the bladder to whic they gie some (pubovesical ligament).

Sacrocevical Liaments The sarocervicl ligamets consist of two firm fibomuscula bands o pelvic fscia that t the cerix and the upper nd of th vagina rom the ower end of the sacrum. The form tw ridges one on ither si of the rectouterne pouch (pouch o Douglas) The broa ligament and the round liaments o the utrus are ax structres, and the uters can be pulled u or push down fr a consderable dstance efore the become aut. Cliically, they are considere to play a minor ole in spporting the uters. The round igament f the utrus, hich repesents te remain of the wer half of the gubernaculm, exteds betwen the superolatera angle o the uteus, throgh the deep inguial ring nd inguial canal to the ubcutaneus tissu of the labium mjus (Fig. 7-18). I helps kep the terus antverted (ilted foward) and anteflexd (bent orward) ut is cnsideraby stretched during pregnanc.

Uterus in the Cild Te fundu and body of the uerus remin small until pberty, wen they elarge gratly in esponse o the esrogens ecreted b the ovaies.

Uteus After Menopause After menopaue, the uerus atrphies an becomes smaller nd less ascular. These chnges occr because the ovares no lnger prouce estrogens and rogesterne.

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Uters in Prenancy During pegnancy, the uters become greatly nlarged s a reslt of th increasig produion of estrogens nd progeterone, first by the corps luteum of the ory and lter by te placena. At frst it rmains as pelvic rgan, bu by the hird monh the funus rise out of he pelvi, and by he ninth month it has reaced the xiphoid prcess. Th increas in size is largel a resul of hyprtrophy of the smoth muscl fibers f the mymetrium, although some hyerplasia akes plae.

Role of the Uerus in Lbor Labor, o parturiion, is te series of proceses by hich the baby, th fetal mbranes, and the placenta ae expelld from he genita tract o the moter. Normlly this process tkes plac at the end of te 10th lnar mont, at whic time th pregnany is said to be a erm. Te cause f the onet of laor is no definitly known. By the nd of prgnancy, he contrctility f the utrus has ben fully developd in resonse to trogen, nd it is particulrly sensitive to the actins of oxtocin at his time It is pssible tat the onet of lbor is tiggered the sudden withdawal of rogesterne. Once he presnting pat (usualy the fetal head) starts t stretch the cervi, it is thought hat a nervous refex mechaism is iitiated nd incrases the force of the ions of the uteine body The uterine muscular activity is largey indepedent of he extrisic innevation. n women n labor, spinal aesthesia oes not interfer with the normal utrine conractions. Severe emtional dsturbanc, however can caus prematur parturitin.

Clnical Nots Bimnual Pelvi Examination of th Uterus A grat deal of useful cinical inormation cn be obtined abot the stae of the uterus, uterine ubes, an ovaries from a imanual eamination The examnation is easiest i parous woen who ae able to relax while the exaination i in progrss. In patients in whom it cases distess, the xamination may be pformed uder an nesthetic. With the ladder epty, the vaginal portion of te cervix is first alpated with the indx finger f the rigt hand. Te extern os is crcular in the nullparous wman but as anteror and psterior lips in the multiprous woman The cerix normal has the consistenc of the end of the nose, bt in the pregnan uterus it is sof and vascular and has the consistency of the lis. The let hand is then plaed gently on the anerior abominal wal above he sympsis pubs, and te fundus nd body o the uters may be alpated tween th abdomial and vainal finges situate in the nterior frnix. Th size, hape, nd mobiliy of the uterus ca then be scertaind. In mot women, he uterus s anteveted and aneflexed. A retrovrted, retoflexed uerus can e palpatd through the postrior vagnal forni.

Varicoed Veins and Hemorhoids in Pregnacy

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snell Varicosd veins d hemorhoids re common cnditions in pregnncy. The ollowing factors probably contribue to teir cause: presure of the gravid terus on h inferior vena cava and the inferior mesenteri vein, ipairing venous retrn, and increased progesteone level in the bood, leaing to reaxation f the smoth muscl in the walls of he veins and venou dilatation.

The Aatmy of Emrgency Cesarean ection An emrgency csarean sction is raely performed. Hwever, a physicin may ned to peform thi surgery in cases in which he mothe may die after sufering a severe taumatic incident Followng materal death, placenal circuation ceses, and the chid must e deliveed withi 10 minues; afte a delay of more than 20 minutes, neonatal survival s rare.

The Anaomy of the Technique  

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The bladder is emptied, and an indwlling catheer is let in postion. Ths allow the empy bladdr to sik dwn away rom the operating field. A midlie skin icision s made tat extnds from just belw the umilicus to just above the ymphysis pubis. The folloing strtures ae then icised: sperficia fascia, fatty lyer, an the memranous lyer; dee fascia thin layr); liner alba; fascia tansversais; extrperitonel fatty ayer; an parieta peritoeum. To void daaging lops of th small itestine r the geater oentum, wich migh be lyin beneat the paretal peitoneum, a fold of peritneum is raised etween to hemostats; an icision i then de between the hmostats. The bldder is dentifie, and a cut is ade in the floor f the utrovesicl pouch. The blader is ten seprated frm the loer part f the boy of th uterus nd deprssed donward ito the plvis. The uterus is palpaed to idntify the preseting par of the etus. A transverse incision about 1 n. (2.5 cm) lon is ade into the exposed lowe segment of the ody of te uteru. Care i taken tat the uerine wal is not immediaely pentrated and the ftus injured. When he uterie cavity is entered, the amniotic cavity i opened and amnotic flid spurt. The uerine icision i then enarged suficientl to delver the ead and trunk of the fets. When ossible the lare tributaries an branche of the uterine vessels n the myometrial wall ar avoided. Great are has o be taen to aoid the arge uteine arteies that course long th latera margin f the utrus. Once the fetus is delvered, te umbilcal cord is clamed and dvided. Te contracting uterus will cause th placena to bule throug the uteine inciion. Th placent and fetl membrnes are hen deliered. Te uterin incisio is closd with full-tickness ontinuou suture. The pertoneum oer the badder an lower art of te uterie body is then reired to estore he interity of he uteroesical ouch. Fially, t abdomial wall incision is closd in layrs.

Prolapse of he Uteru The great importance of the tne of the levatores ani uscles i ng the uerus ha already been empasized. he imprtance o the trasverse crvical, ubocervial, and sacrocerical ligamets in psitionig the cervix withn the pelvic cavty has ben conidered. amage to these stuctures uring chldbirth r genera poor body musclar tone may reslt in donward dsplacemet of the uterus called uterne prolase. It most commonl reveals itself after menopause, wen the vsceral plvic ascia tnds to arophy alng with the pelvc organs In advnced caes, the ervix dscends te length of the agina a may prtrude trough th orifice

682

snell Becase of te attachent of he cervi to the aginal ault, it follows hat prolapse of the uteus is alays accopanied some prolapse of the vgina.

Hystrectomy nd Damag to the reter During the urgical procedur of hystrectomy, great cre must e exercied to not damage the urters. Whn the sugeon is looking for the uterine artery o each sie at the base o the brod ligaent, it s essenial that he or s first dentifie the ureer befoe clampig and tyng off te artery The uteine artey es forward from the internal iliac arery and rosses te ureter at right angles o reach he cervix at the level o the intenal os.

Sonograhy of th Female elvis A songram of he femal pelvis an be usd to visalize th uterus nd the dveloping fetus a the vaina (Figs. 7-30, 7-1, and 732). P.369

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Figre 7-30 Longiudinal sonogram f the female pelis showig the utrus, the vagina, and the bladder. (Courtey of M.C. Hill.)

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Figure 7-3 Trasverse snogram o the pevis in a woman afer an auomobile accident, in whch the lver was acerated and blod escape into the peritneal cavty. The bladder B), th body o the uteus (U), nd the boad ligaents (white arrows) are identifie. Note te presee of blod (dark reas) in the uerovesicl pouch (UP) an the pouh of Doglas (PD). (Couresy of . Scoutt)

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Figre 7-32 Longitdinal soogram of a prgnant utrus at 1 weeks sowing th intrautrine gesational ac (black arowheads) and he amnioic cavit (C) filed with mniotic luid; th fetus i seen in longitudial sectin with te head (H) and cocyx (C) wll displyed. The myometri (MY) of the uters can be identifid. (Couresy of L. Scoutt.

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Ebryologi Notes Develoment of he Uteru Th uterus s derived from the fused caudal verical pars of the paramesonephric ducts (Fig. 733), ad the sie of ther angula junctio becomes a convex dome and forms th fndus of the utrus. The fusion between th ducts i incomplte at fist, a sptum peristing between the lumina. ater, th septum isappear so tha a singl cavity remains. The upper art of te cavity forms th lumen f the body and cervi of the uterus. The myomtrium is formed from the surounding esenchym.

Agenesis f the Utrus 686

snell arely the uterus will be absent as the result o a failure of the aramesonphric duts to deelop.

Infantie Uterus Som adults ay have an infantie uterus a condtion in which t uterus is much smaller than normal and resebles tha present before berty. Aenorrhea is preset, but te vagina and ovaries may e normal

Filure of Fusion o the Parmesonephic Ducts ailure o the parmesonephic ducts to fuse my cause variet of uterne defecs: (a) Te uterus may be dplicated ith two bodies ad two cevices. () There ay be a cmplete sptum thrugh the uterus, aking tw uterine cavities and two cervices. c) There may be wo separte uterie bodies with one cervix. d) One pramesonephric duc may fai to deveop, leavng one uterine tub and hal of the ody of he uteru. Cliniclly, the main prolems wit a double uterus my be sen when pegnancy ccurs. Aortion i frequen, and the nonpreant half of the uerus may cause obtruction at labor P.32

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Fiure 7-33 Formaton of th uterine tubes, the uterus, nd the vgina.

Embryologic Notes Bref Summay of the Implantation of te Fertilized Ovum n the Utrus Th blastocyst enters the uterne cavit between the fouth and nnth days after ovlation. ormal imlantatio takes pce in the endomerium of he body f the utrus, most frequenty on the upper art of th posterir wall nar the mdline (Fig. 7-34). As the esult of the enzyatic digstion of the uterie epitheium by he trophoblast of the embro, the bastocyst sinks beeath the surface epithelim and becomes embedded in he strom by the 1th or 1th ay.

Ebryologi Notes

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A Summary of th Formatio of the lacenta Th placent is the rgan tha carries out respration, xcretion and nutition fo the embyo, and is full formed uring te fourth month. Th formatin of the placenta is compliated and is essetially te develoment of n organ y mother and chil in symbosis and consists of fetal and mateal parts. Th fetal prt develps as folows. Th trophobast becmes a highly deveped struture, wih villi hat contnue to erode and enetrate deeper ito the edometrium. Large iregular paces known as lacuae apar, which become illed wth materal blood At the center of ach villus is conective tssue cotaining ftal bloo vessels that wil eventually anastoose with one anoher and cnverge t form th umbilicl cord (ig. 7-35). The matenal part develops as follos. Under the infuence of progesterne, secrted firs by the orpus lueum and later by the placenta itsel, the enometrium becomes reatly thickened nd is knwn as th dcidua Large aeas of te decidua become excavated by the inading trphoblastc villi o form te intervilous space. Th materna blood vssels open into the spaces o that te outer surfaces of the vlli of te fetal art of te placent become athed i oxygenaed blood (Fg. 7-35). B the fouth month of pregnncy, the placenta is a wel- develped orga. As the pregnanc continus, the placenta creases in area ad thicknss. The lacental attachment occupie one trd of the internal surface of the uterus. At birh, a few minutes ater the delivery of the cld, the placenta separate from th uterine wall and is expeled from e uterine cavit as the esult of the ions of the utine musculature The line of sepaation ocurs throgh the songy lay of the decidua Fi. 7-35).

Goss Apperance of the Placta at Bth At full term, th placent has a songelike consistecy. It s flattened and cicular, wth a diaeter of bout 8 i. (20 cm and a hickness of about in. (2. cm), an weighs bout 1 l (500 g) It this out at the edge, where it is continuous wh the feal membanes (Fig. -36). The ouer, or mternal, urface o a freshy shed lacenta is rough on palpatin, is dak red, ad oozes lood fro the ton maternl blood essels. The inner, or fetal, surfce is smooth and hiny and is raisd in rides by th umbilicl blood essels, hich radate from he attahment of the umbiical cor near it center. The fetal membranes (see Fig. 4-6), wich surrund and nclose te amniotc fluid, are contnuous wih the ege of th placent. They are the amnon, the horion, nd a smal amout of the adheren materna decidu.

The Placnta and leeding n Late Pegnancy Th common auses of substantal vaginl bleedig in the third trmester ae placena previa and placntal abrption.

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Plcenta Prvia Pacenta pevia occrs in abut 1 of very 200 pregnanies. It more common in multiparos women nd in those who have had rgery on the lowe part of the uters. Normaly, the placenta is situaed in the upper half of th uterus. Should mplantaton occur in the lwer half of the bdy of th uterus, the conition is called pacenta pevia. Thee types of placeta previa may be ecognized: a central placenta previa, in which the enire internal os is covered y placenal tissu; arginal lacenta revia, when the edge of the placeta is enroaching on the iternal o; and a lowlying plcenta prvia, when the placenta lies low own in te uterus lateral to the iternal s. evere, painless hemorrhag occurrig from te 28th wek onwar is the clinical sign of lacenta revia an is causd by expnsion of the lowr half of the uteine wall t this time and b its teaing away from th placent.

Plcental Aruption Placetal abrution is he premaure sepaation of the plaenta in hich noral implatation hs occurrd. It ocurs in aout 1% of pregnaies. It s more cmmon in ultiparos women nd in woen with hypertnsion in pregnanc. As the placenta separate, hemorrage occrs; the lood clo dissect the fetal membranes away from the terine ll. The lood usully escaes throuh the cevix or rptures nto the niotic cavity. Te blood rritates the myomtrium, an uteri muscle one is icreased, which reults in ontractions. The lacental circulaton is copromised by the pacental eparation and th increasd pressure on the lacenta y the inreased uerine tone.

Vagina Location and Descriptio The vagina s a muscular tube hat extends upwa and bacward fro the vula to the uterus (Fig. 75) It meaures abot 3 in. (8 cm) long and has anterior and postrior wals, whic are norally in ppositio. At its upper en, the anerior wll is pirced by he cervix, which pojects dwnward ad backwad into he vagin. It is mportant to that te upper alf of he vagia lies aove the elvic flor and th lower half lies within th perineum (Figs. 7-5 and 7-28). The area of he vaginal lumen, which surrounds the cervix is divided into four regions, or fornces: aterior, osterior right lteral, ad left laeral. Th vaginal orifice n a virgn posseses a thi mucosal fold called the hyme, whic is perfrated at its centr. After childbirh the hymn usuall consist only of tags. .373

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Figure -34 Sagittal ction o the uteus showin the devloping cnceptus expandin into th uterine cavity. The three ifferent regions f the deidua can be recogized. By the 16th week, the uterine cavity is obliterted by te fusion of the decidua sularis with the decidua parietais.

Relation  

Anteiorly: The vagna is cosely reated to he bladde above ad to the urethra elow (Fig. 7-5). Psteriorl: The upper thrd of th vagina s relate to the rectouterie pouch (pouch o Douglas and its middle tird to the ampull of the rctum. Te lower hird is elated to the perieal body which sparates t from he anal anal (Fig. -5). 691

snell 

Laerally: In its upper pt, the gina is elated t the ureer; its iddle part is related to e anterior fibers of the lvator an, as the run backward t reach te prineal bdy and hook aroud the anrectal jction (Figs. 719 an 728). ontraction of the ibers of levator ni comprsses the walls of he vagia togethr. In it lower part, the vgina is elated to the uroenital daphragm see Chapter 8) and the bul of the estibule

Function The vgina not nly is te female genital canal, bt it alo serves as the exretory dct for te menstral flow nd forms part of the birth canal.

Blood Supply Arteies Th vaginal artery, a branch o the intrnal ilic artery and the vaginal ranch of the uterine artery supply te vagina

Vens The vaginal eins for a plexus around he vagina that drans into he interal iliac vein.

Lymph Drainage The uper third of the vgina drains to te exterl and nternal liac nods, the mddle thid drains to the iternal iac node, and th lower tird drain to the uperficial inguina nodes.

Nerv Supply The inferior hypgastric lexuses.

s of the agina The uppr part o the vagna is ed b the leatores an muscles and the ransvers cervica, pubocevical, an sacrocrvical lgaments. These strctures ae attachd to the vaginal wall by elvic facia (Figs. 7-28 an 729). The mddle par of the vagina is upported by the uogenital diaphragm (see Chaptr 8). The lower part of the vgina, esecially he posteior wall is suppoted by te perinel body (Fig 7-5).

Clinicl Notes Vaginl Examintion he anatoic relatons of te vagina are of geat clinical impotance. Mny pathoogic conitions ocurring n the femle pelvs may be diagnose using a simple vaginal exaination.

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snell The ollowing structurs can be palpated through e vaginal walls from above downward   

Antriorly: The bldder and the uretha Posterorly: Loops o ileum and the sigmoid coln in the rectouteine peritoneal puch (pouh of Douglas), the rectal pulla, ad the peineal boy Laterally: The urters, th pelvic ascia an the anterior fibrs of the levatores ani mucles, and the urognital diphragm

Proapse of he Vagin The vaginal ault is upported by the sme strucures tht the uterne cervi. Prolape of the uterus i necessaily assciated wth some egree of sagging f the vaginal wal. Howeve, if the of the ladder, rethra, r anterir rectal all are damaged n childbrth, proapse of the vagina walls ocurs, wih the uerus remaining in ts corret positin.

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Figure 7-35 section through he placeta showing the maternal (top) and feal (bottom part. Note tat the mternal prt is diided int the basal layer, he spony layer, and the ompact layer. The heavy soid line n the spngy layer indicates where separati occurs etween te maternl and feal parts of the placenta during th third stage of laor.

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Fiure 7-36 The maure placnta as sen from he fetal surface (A) and fom the mternal srface (B).

Sagging of th bladder results n the buging of the anterir wall o the vagna, a codition kown as a cytocele. When the ampulla of the ctum sags against the postrior vagnal wall the bule is caled a rectocele.

uldocentsis Te closeness of the peritonel cavity to the psterior vaginal ornix enbles the physicia to drai a pelvi abscess through the vagia without performng a majr operatn. It is also posible to identify blood or pus in te peritoeal caviy by the age f a needle throug the poserior fonix.

Anatomic Structurs Throug Which te Needle es 695

snell Th needle asses through the ucous mebrane of the vagna, musclar coat of the vgina, conective issue cot of the vagina, visceral layer of elvic facia, and visceral layer of peritonum.

natomic eatures f the Coplicatios of Culocentesis Complicatons are s follos: (a) The loops of ileum and th sigmoid colon, structure that ae normaly present within the pouh of Doglas, cold be ialed by the needle. However, the presence f blood r pus wihin the ouch tens to defect the iscera uperiorly. (b) Ocsionally when th uterus s somewht retrofexed, te needle may ente the poserior wall of the ody of te uterus

Vaginal rauma Coital ijury, piket fenc–type f impalemet injury and vainal peroration aused by water uner pressre, as ocurs in water skng, are common injuries. Lceration of the aginal wll invoving the posterio fornix ay violae the poch of Douglas of e peritneal cavty and cuse prolpse of te small itestine nto the vagina.

mbryologc Notes Develpment of the Vagna Te vagina is develped from the wall of the urognital sius (Fig. 7-33). The fusd lower nds of te parameonephric ducts fom the boy and crvix of he uteru, and once the sold end of the fuse ducts raches te posteror wall o the uroenital snus, two outgrowts occur fom the inus, caled the sinvaginal ulbs. he cells of the siovaginal ulbs prolferate raidly and orm the vagnal plate. The aginal plte thickens and elongates an extends ound the solid end of the fued parameonephric ucts. Laer, the pate is cmpletely canalize and the aginal fonices are ormed.

Vaginl Ageness If the paraesonephr ducts fil to devlop, the wall of he urogeital sinus will fail to form he vagina plate. In these paients, tere is a absence f the vgina, uters, and uerine tubs. Plastic surgicl constrtion of a vagina sould be atempted.

Duble Vagia A duble vagia is causd by incmplete caalizatio of the vginal plae.

Imperfoate Vagin and Impeforate Hyen Imperfoate vagia is caued by a failure f the cels to dgenerate in the ceter of th vaginal lates. Imprforate ymen is used by failure o the cell of the lwer part o the vagial plate and wall of the urgenital sinus to deenerate. hese conditions led to retentio of the mnstrual fow, a cliical condtion caled hematocolpos Surgicl incision of th obstrucion, follwed by dlatation relieves the condtion. 696

snell P.374

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P.376

isceral Plvic Fasca Te visceral pelvic ascia is a layer f connecive tisue, whch, as in the male, covers nd suppors the pelic viscer. It is cndensed o form the pubocervical, transverse ceical, and sacrocerical ligments of he uterus (Fig. 7-29).

Clinica Notes Viseral Pelvic Fasca and Inection Clincally, th pelvic fscia in he regio of the terine cevix is ofen referrd to as te arametri. It is a commn site fo the spred of acut infectins from te uterus and vagin, and her the infetion ofte becomes hronic (plvic inammatory isease).

Peitoneum The perioneum in he femal, as in he male, s best unerstood b tracing it around the pelvi in a sagttal plan (g. 7-5. The peitoneum psses down from the anterior adominal all onto he upper surface o the urinary bladde. It the runs dirctly onto the anteror surface of the uterus, at the level of the nternal s. The pritoneu now pases upwar over the anterior surface f the bod and funds of the terus an then downard over the postrior surfce. It cntinues ownward and coers the upper par of th posterir surfac of the agina, were it frms the anterior wall of the rectuterine ouch (poch of Doglas). Te peritoeum then es nto the ront of the rectum as in te male. In th female, the lowet part o the abdminopelvc peritoeal caviy in the erect poition is the rectuterine ouch.

Clinica Notes The Retouterin Pouch and Diseas 697

snell Snce the ectoutere pouch pouch of Douglas) is the ost depedent par of the ntire peitoneal avity (wen the ptient i in the tanding osition) it frequently becmes the ite for he accuulation f blood from a rptured etopic prgnancy) r pus (fom a rutured peic appenicitis o in gonooccal peitonitis. Because he pouch lies diretly behid the poterior ornix of the vagia, it is commonly violated by misguded nonserile istrument, which ierce the wall of the posteior fornx in a filed atempt at n illega abortio. Pelvic peritoniis, ofte with faal consquences, is the alost certin resul. A eedle ma be d into te pouch hrough te posteror forni in the procedure known as cudocentess (se pge 375. Surgiclly, the pouch ma be enteed in posteior colptomy. Te interir of the female pelvic pertoneal caity may be viewed for evience of isease trough an endoscop; the intrument is introuced thrugh a small colpotmy incison. P.77

Broad Ligament The road ligments ar two-layred fold of perioneum tat exten across he pelvi cavity rom the ateral mrgins of the uterus to the lateral elvic wals (Fig. 7-19). uperiorl, the tw layers re contiuous and form the upper fr edge. nferiorl, at the base of he ligamnt, the ayers searate to cover the pelvic floor. Th ovary i attache to the osterior layer by the mesovarum. The part o the brod ligamet that les laterl to the attachmet of the mesovariu forms te suspensoy ligament of the ovary The par of the broad ligaent betwen the uerine tue and the mesovarim is caled the mesoalpinx. At the se of t broad lgament, he uterie artery crosses he urete (igs. 7-1 and 7-2). Each brad ligamnt contans the fllowing:     

The uteine tube in its uper free border The roud ligamet of the ovary an the roud ligamet of the uterus. They reprsent the remains f the gbernaculm. Th uterine and ovaran blood vessels, lymph vesels, an nerves The epoophoro, a vestgial strcture tat lies n the brad ligamnt above the attahment of the mesoarium. t represnts the remains of the mesoephros (Fig 7-19. The proophoron, also a vestigial structre that ies in the broad lgament jst laterl to the uterus. It is a esonephrc remnan (ig. 7-19).

Cross-Secional Antomy of he Pelvi o assist in the iterpretaion of C scans o the pevis, stuents should study the labled cros section of the elvis sown in Figres 7-37 and 7-38.

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Fiure 7-37 A. Cross sectio of the ale pelvs as see from abve. B. Crss sectin of the female plvis as een from below.

adiogrphic Anaomy 699

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Radioraphic Appearances of the Bony Pelv A routin anteropsterior iew of te pelvis s taken with the patient n the suine posiion and ith the assette underneah the taletop. A somewhat istorted view of he lower part of he sacrm and cocyx is otained, nd these bones may be partlly obsured by he symphsis pubi. A bettr view of the sacrm and cocyx can be obtaied b slightl tilting the x-ry tube. An antroposteror radioraph shold be sstematicaly examied (Figs. 7-39 hrough 742). The lower lubar vertbrae, sarum, and coccyx my be looked at fist, follwed by te sacroiiac s, the dfferent arts of the hip bones, and finally he hip jints and the uppe ends of the femurs. Gas and fecal aterial ay be sen in the large boel, and oft tisue shadows of the skin and subcutanus tissues may also be vsualized. To demonsrate the sacrum a sacroiiac ts more clarly, laeral and oblique iews of he pelvi are oftn taken.

Riographc Appearances of te Sigmoid Colon and Rectum Barium nema he pelvi colon ad rectum can be dmonstratd by the istration of 2 to 3 pnts (1 L of barim sulfat emulsio slowly through he anus. The apperances o the pelic colon are similar to those seen in the mre proxil parts f the coon, but distened sigmid colon usually hows no acculatins. The rctum is een to hve a wier calibr than te colon. P378

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Figure 7-38 Computed tomgraphy san of th pelvis fter a barium meal and intravenous pyelograhy. Note the presnce of te radiopaque material in the small ntestine and the ight ureer. The ection i viewed rom belw.

P.379

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igure 7-9 Anteoposterir radiogaph of te male plvis.

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Figre 7-40 Representation of the raiograph of the pelvis seen n igure 739.

P.380

Figure 7-1 Antroposteror radioraph of he adult female pevis.

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Fiure 7-42 Repreentation of the radiograph f the pevis seen in Figure 7-41.

A cotrast enma is sometims useful for examning the mucous mmbrane o the sigmoid coln. The barium enema is partly evacuaed and ar is injcted int the coon. By tis means the walls of the olon bece outlined (see Fig. 5-90) P.81

Radioraphic Apearances of the Female Genital Tact The instillaion of vscous ioine prearation through the external os of the terus alows the lumen of the cervcal cana, the terine cvity, an the diffrent pars of the uterine ubes to e visualized (Fig. 7-43) This prcedure is known as hysterosalpingography. The patency f these tructures is demontrated b th entranc into th peritoneal cavity of some f the opaque mediu.

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Figur 7-43 Anteropsterior adiograp of the emale pevis afte injectin of raiopaque ompound nto the terine cvity (hyterosalpngogram)

A songram of he femal pelvis hows the uterus and the vagna (Figs. 730, 7-31, and 7-32).

Surface Anatomy The surface anaomy of te pelvi viscera is consiered on age 330. P.82

Clinical Probl Solving Study he folloing case historie and selct the bst answes to the question followig them. A 30-yar-old mn involvd in a brroom brwl was sen in th emergeny department. He was foun to have a blood-ained tear on the seat of his trouers and aceratios of the anal marin. Durig the fiht he ws knocke down an fell in the sittng positon on th leg of n uptured bar sool. While under servatio he deveoped the signs an symptos of pertonitis. 1. Th signs ad symptos displaed by ths patient could be explained by the followin anatomi statemets except which? 705

snell () The paient had impaled his rectu on the leg of the upturne bar stol. (b) At operaton, a laeration f the anterior wall of the middle o the recum was fund. (c) The leg of he bar sool had entered the rectvesical ouch. () The rctal cotents ha contamiated the peritonel cavity and were responsile for te develoment of eritonitis. (e) Th anterio surface of the mddle thid of the rectum hs no pertoneal covering. Viw Answer 1. E. The uper thir of the ectum ha peritonum on it anterio and lateral surfces; the middle tird has eritoneu on its nterior surfac; and th lower tird has no peritonal coverng. A 46-yar-old man had been treating himsel for hemorhoids fr the pat 3 yeas. He ha noticed that his feces wa often slightly blood staied. For he past 2 months, he had ticed tht when he had his bowels open, he lways fet that mre was t come. Smetimes he went to the toiet severl times day but was only able to ass flatu and blod-staind mucus. Recently, pain had develope down th outside of his ight leg Digital examinaton of th rectum revealed large, hard-basd ulcer n the posterior wl of the rectum wth extenive indration of the paraectal tisues. A iagnosis of advaned carcinma of te rectum was made 2. Th following statements about this patient are robably orrect ecept which? (a) Some of he bleedng was fom the crcinomatus ulcer of the rectum as ll as frm the hemorrhoid. (b The lyhatic drainage of the rectum takes lace fist into te parartal lymp nodes. (c) Crcinoma f the retum neve metastaizes to he liver (d) Examnation o the rigt leg reealed soe weaknes of the muscles upplied y the scatic nere. () The cacinoma hd extendd posterorly to nvolve te sacral plexus. (f) The atient idicated tat the lg pain ws felt in skin aras suppled by brnches of the sciaic nerve View Anwer 2. C. Avanced carcinoma of the rctum not only extnds to th pararecal and nferior esenteri nodes, ut may also spread via the uperior rectal, nferior esenteric splenic and poral veins to the lver. An nebriate 40-yearold man as involed in a ight ove a woman The woan's husand gave the man severe low on te lower art of t anterior abdominal wall, whereupo he doubed up wih pain ad collased on te floor. On ission to the emergeny departent of te local hospital the man as in a sate of sock and omplainig of seere pain in the lwer abdoinal region. He wa unable o uine sine the fiht. A dignosis o rupture urinary bladder as made.

706

snell . The folowing satements concernig this ptient are correct except wich? () Rectal examinaton reveaed a buling backard of te rectovsical fossa. (b) Although the patint had cnsumed a considable volme of liuor, dulness was not presnt on pecussion of the aterior adominal all abov the symhysis pubis. c) The uine accuulated i the recovesical pouch. (d A full ladder i more liely to b rupture by a blw on the anterior bdominal wall tha an empt bladder () In the adult as the norml bladde fills, its supeior wall extends uward int the abmen, leaing the covering of parieal peritneum behid. View Answer 3. E. I the adu as the normal bladder fils, its sperior wall bulges upwad into te abdome, peelin off the peritonem from the posterir surfae of the anterior abdomina wall. A 56-yar-old wman was een by hr obstetician an gynecolgist complaining f a “baringdon― feeing in th pelvis nd of a ow backche. On vaginal exmination the extrnal os f the cevix was ound to e locate just wihin the aginal ifice. diagnoss of utrine proapse was made. 4. The following anatomic satements concerning uterne prolaps are corect ext which (a) Te most iportant o the uerus is he tone of the lvator an muscles. (b The trasverse crvical, ubocervial, and crocervical ligamnts play an imporant role in suppoting the uterus. (c Damage o the leator ani and the ervical igaments during cildbirth can be responsibl for propse of the uterus. d) Prolse most commonly eveals iself befre menopuse. (e Prolaps of the terus is always acompanie by some prolapse f the vaina. View nswer 4. D. rolapse f the utrus most often reeals itslf after menopaus, when te pelvic fascia tnds to arophy. A 25-year-ld woman was seen in the eergency epartmen complaiing of evere pain in the right ilac regio. Just bore ision she had fanted. On physical examinaton, her bdominal wall was extremel tende on palption in te lower ight quarant, an some riidity an guardig of the lower abominal mscles we noticed. A vaginal examiation reealed a ather sot cervix with a crcular eternal o. A tener “doghlike mss― cold be fet throug the poserior fonix. Th patient had missed her lat period 5. The following statements cocerning his patint are correct exept whic?

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snell (a) A diagnois of rutured ecopic prenancy wa made. (b Tubal regnancis commony occur here the ampulla narrows t th isthmus (c) Ech uterie tube i situate in the ase of te broad ligament. (d) An etopic tubal pregnacy almost invarialy resuls in rupure of te tube wth sever intrapeitoneal emorrhag. (e) Tuba rupture occurs a a resul of the roding ation of he trophblast. f) Once a tubal pegnancy ies te decidal linin of the uterus begins to e shed because of lack of hormonal , and this causes vaginal bleding. (g) The douglike mas is produced by t accumultion of lood in he pouch f Dougla. View Anwer 5. C. Eah uterin tube is situated in the upper free argin of the broa ligament. A 39-yar-old wman was itted o the lol hospital after xperiencng a gushot woud to the lower part of er back. adiograpic examiation rvealed tht the bulet was odged in the vertbral canl at the evel of the thir lumbar ertebra. A comprehensive nerologic xamination iicated tat a comlete leson of th cauda eqina had ccurred. 6. The followin statemets concening thi patient re likel to be tue excep which? (a) Th cauda euina, whch consits of aterior ad posterir nerve oots belw the leel of th first lmbar sement, wa sectiond at the level of the thir lumbar ertebra. (b) The prenglionic sympatheic nerve fibers o the veical sphncter that descen in the nterior oots of he fourt and fifh lumbar nerves wre sectioed. c) The peganglioic parasmpatheti fibers to the derusor mucle that descend n the anerior rots of th second third, and fourth sacral nrves wer sectiond. () The paient woud have a autonomus bladdr. (e) The bladder ould fil to capaity and hen overlow. (f) icturition could be activated by powerful cotraction of the adominal uscles and manual pressure n the aterior adominal all in te suprapubic regio. View Anser 6. B. T pregangionic sypathetic nerve fiers to te vesical sphincte descen in the nterior oots of e first and secon lumbar erves an were left intact. A 5-year-od man wih a histry of prstatic dsease wa found o radiolgic examnation o his skeeton to ave extenive carcnomatous metastases in th skull and lumbar ertebrae The PSA level in his blod was fond to be xcessively high.

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snell 7. Te following stateents conerning tis patiet are correct exct which? (a) Te patient has advaced carcnoma of he prostte that as spread some disance fro the priary site () The prstate is surrounde by the prostatic venous pexus, whch drain into the interna ilia veins. (c) arge veis with vlves connect the prostatic enous plxus to te vertebral veins (d) Cughing, neezing, or straing at stool can frce the lood fro the protatic plexus into he verteral vein. (e) Disldged caner cells an be crried with the blod to the vertebra column and skull Vew Answe 7. C. The lrge vein that conect the prostati venous pexus to he valveess vertbral veis are also devoid of valve. A 72-year-old woman was suspcted of aving a umor of he sigmod colon. The physician deided to onfirm t diagnoss by perorming a sigmoidscopy. 8. The fllowing anatomic satements are corrct concening the procedur of sigmoidoscopy except whch? (a) Aftr insertig the intrument nto the anus, th lighted end entes the amulla of the rectum after a distance of about 1.5 in. 4 cm). () Some sde-to-sie movemnt may e necessay to avod the trnsverse ectal fols. (c The recosigmoid junction will be eached aproximatey 6.5 in (16.25 m) from he anal argin. (d) To negotiat the recosigmoid junctio, the ti of the igmoidoscope shoul be direted anteiorly ad to the patient' left. (e) Stretchg of the colonic all may give ris to coliky pain n the uppr part o the abdmen in te regio of the iphoid prcess. View Anwer 8. E. Coicky pai from th colon i referre to the lower part of the aterior adominal all abov the symhysis pubis. P.83

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Review Questio Multipe-Choice Question Selct the bst answe for eac questio. 1. The follwing staements cncerning the uters are coect excet which? (a) The fundus i part of the uterus above the openigs of the uterine ubes. (b) The long axis of he uterus is usuall bent anteriorly on he long is of the vagina (ateversion. ( The nere supply o the uteus is fro the inferor hypogatric plexses. (d) The anteror surface of the cervix is completel covere with peitoneum. (e) The uterine eins dran into he interal iliac veins. View Anwer 1. D. Te anterir surface of the cervix les in drect conact wit the posterior surface of the urina bladder nd there is no peroneum searating te two structures. . The folowing staements conerning the ductus (as) deferns are corect ext which? (a) It emerges om the dep inguinal ring and es around the lteral magin of t inferio epigastrc artery () It croses the reter in the regin of the ischial spine. (c) he termina part is dilated to form the mpulla. (d) It lis on the posterior urface o the prosate but i separate from it by the peritoneum. (e) It s the duct of te seminal vesicle t form th ejaculatoy duct. View nswer 2. D The ducus (vas) deferens lies in irect with the posteior surfce of the bladder. he inferio end of te ampulla narrows own and oins the uct of th seminal esicle to form the jaculato duct. 3. Th followin statements concernng the pevic part f the ureter are orrect exept which (a) It enters the pelvis in frot of the bifurcaton of the common iiac arter. (b) The uretr enters the blader by pssing diectly though its wll, ther being no valvulr mechansm at it entrnce. (c It has close rlationshi to the ischial pine before it turs medialy toward the blader. (d) Th blood spply of he dista part of the ureter is from the supeior vesial arter.

710

snell (e) It nters te bladde at the upper lateral anle of th trigone. View Anwer 3. B. he uretes pierce the blader wall bliquely and thi provides a valvlike mecanism tht prevens urine rom reenering th ureter rom the ladder avity. 4 The folowing sttements oncernin the semnal vesile are crect exept whic? (a) he seminl vesicls are reated poseriorly o the retum and can be plpated trough th rectal all. (b) Th seminal vesicles are two obulated organs that store permatoza. (c) The uppe ends of the semial vesices are cvered by peritonem. (d) Te functin of the seminal esicles s to prouce a secretion that is add to th seminal fluid. (e) Th seminal vesicles are related anteriorly to the bladdr, and n peritonum separtes these structures. Vie Answer 4. . The seinal vescles do ot stor spermatzoa; the produce a secreton that ourishes the speratozoa. 5. The following statemets concening the ovary ar correct except which? (a The lymh drainae is into the par-aortic lumbar) ymph nods at the level of the firs lumbar ertebra. (b) The round ligament of the ovary extends fro the ovay to the upper en of the lateral wll of the body of the uter. (c) The varian fossa is ounded aove by te external iliac vessels and behind by the iternal iiac vessls. (d) The eft ovaran arter is a brnch of te left iternal iiac artey. (e) he obturtor nerv lies laeral to he ovary View nswer 5. D. he right and the eft ovaran arteres are banches o the abdominal aoa at th level of the firt lumbar vertebra. 6. The follwing staements cncerning the nerv supply o the urnary blader are orrect ecept whih? a) The smpatheti postganlionic fbers oriinate in the firs and secnd lumba ganglia (b) he parasmpatheti postganlionic fbers oriinate in the infeior hypoastric pexuses.

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snell (c) Te afferet sensor fibers rising n the bladder wal reach t spinal ord via he pelvic splanchnic nervs and alo travel with the sympatheic nerve. (d) The parsympathetic preganglionic fibers arise from the secon, third, and fourh sacral segments of the sinal cor. (e) The parasympthetic pstganglinic fibes are reonsible for closing the veical sphincter during ejaculation. View Anwer 6. E. Th sympathtic nervs are reponsible for the ontractin of the sphincte vesicae during eaculatio. 7. The follwing staements cncerning the vagia are corect ext which (a) Th area of the vagial lumen around te cervix is dividd into fur fornies. (b The uppr part o the vagna is ed b the levtor ani uscles ad the trnsverse ervical igaments () The peineal body lies pterior o and s the lower part of the vagina. (d) The upper part of the vagina is not covered wit peritonum. (e) Te vagina wall reeives a ranch of the uterne arter. Vie Answer 7. D. The uper third of the posterior wall of the agina is covered with peitoneum nd is reated to he rectoterine puch (pouh of Doulas). 8 The folowing sttements oncernig the viceral laer of pelvic fascia in the female ae correc except hich? (a) I the regon of th cervix f the utrus, it s called the parametrium. (b) It i consideed to fom the puocervica, transvrse cerval, and sacrocervical ligments of the uterus. (c) It cvers th obturatr interns muscle d) It dos not beome contnuous abve with he fasci transvesalis. () On the lateral all of te pelvis it fuse with th parieta layer o pelvic ascia. Vie Answer 8. C. The oturator ternus mscle is overed wth the prietal lyer of elvic facia and s called the obtuator intrnus fasia.

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snell . The folowing satements concernig the lyphatic dainage of pelvic structures are corect ext which (a Lymph fom the crvix of he uteru drains nto the nternal nd external iliac lymph noes. b) Lymph from the prostate drains ito the eternal iliac lymph nodes. c) Lymph from the posterio fornix f the vaina drais into te internl and exernal ilac lymph nodes. (d) Lmph from the trigne of th bladder drains ito the iernal and external iliac lymph nods. () Lymph rom the undus of the uteus drain into th para-atic lymph nodes at the level of the first lumbar vertebra. iew Answr 9 B. The ymph fro the proate drais into te internl iliac odes. 10. The following staements cncerning the main venous drainage of pelvic tructure are corect exct which? (a The venus blood from the left ovay drains into the inferior vena cav. (b) he venou blood fom the postate dains int the intrnal ilac veins (c) Th venous lood fro the uriary blader drain into th interna iliac vins. () The veous bloo from th mucous embrane f the retum drais into te superior rectal vein. (e) The venous dainage o the semnal vesiles drais into te internl iliac eins. View Answer 10. A The venus blood from the left ovay drains into the left renal vein. Red the cae histores and select th best anwer to te questin followng them. A 3-wee-old boy was take to a peiatrician because f repeatd vomitig and rluctance to feed. On questioning, te mother said the child ha starte to vomi on the irst day of life and had vomited at least one a day since thn. Early on, the other ha been ressured ad told tat the aby was aking his feedings too quicly and tat the vmiting ventuall would case. Whie initialy accepting this reassurace, the mother nw notice that th child dd not sem hungry at feedig time; moreover she coud see tht the abomen was becoming distended. She added that the child definitey was cstipated very ocasionall, hard econium as e. After thoroug physical examination of the child, the peditrician made the agnosis f primar megacoln (Hirshsprung dsease). 11. Th examinaion of te child rvealed te followi possibl signs exept whic? (a) The abdomn was fond to b distendd.

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snell (b) A rectal exmination ith the loved litle fingr resultd in the age of a lare amoun of flaus and he abdomnal distntion beame visily less. (c) A low barim enema ollowed by a radigraphic amination showed a normal rectum. (d) On he radioraph, abve the rectum, a nrrowed pat of the olon led o a funnl-shaped xpansion which in turn led to a grealy dilate descendig colon ad transvese colon. (e) On placng a stetoscope on the abdomnal wall, the physcian coul not hear sounds of eristalss. View Aswer 11. E. In patiets with rimary mgacolon, the musce of the colon imediately proximal to the ostructio is hypetrophied as the rsult of attemptig to fore the meonium and feces onward. Usually very active peristalss is head on lisening to the abdomen with a stethosope. Afte the bih of a bby boy, a oist, re, protrudig area wa noted o the loer part o his anteior abdomnal wall bove the smphysis pbis. The pediatrian made he diagnois of exsrophy of the bladdr. 12. O further linical exmination, the folloing physial signs ight have been noted except wich? (a) Th abdominl skin ws seen t be contnuous wih the main of t red are. (b) The child had epiadias an bilaterl undescnded teses. (c) adiograpic examiation of the lowe abdominal area showed a nrmal symhysis pbis. (d) On coser exmination, jets o urine could be seen discarging trough th upper ateral orners o the red protrudig area. (e) The scrotum as wide nd shallw. View Answer 12. . Exstrohy of th bladder is belieed to reult from a failure of the embryoni mesenchme to inade the mbryonic disc caudl to the cloacal membrane This prduces an unstable state, wich is fllowed b a breadown of this area of the adominal all with exposur of the ed mucos membrae of the rigone o the blader. Thi results in the eparatio of the ubes and anomalie in the development of the external genitala. P.38

Footntes *Th sympathtic nervs to th detruso muscle re now tought to have litle or no action o the smoth musce of the bladder all and re distrbuted manly to te blood vessels. The sympahetic 714

snell nrves to he sphinter vesiae are hought t play ony a minor role in causing ntractio of the sphincte in maintaining urinary continence However in males, the smpatheti innervaion of te sphincer cause active ontracton of the bladder neck durng ejaculation (brought aout by spathetic action), thus preventing eminal fuid from entering the bladder. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

9. 8. The Perineum A 51-ear-old man was en by he physicia for comlaints of breathlesness, which she noiced was worse on limbing sairs. On questionig, she sad that the problm started about 3 ears ag and wa getting worse. n examintion, th patient was found to have a healthy ppearanc, althoug the connctivae and lips wre paler than noral, suggsting anmia. The cadiovascuar and espiratoy systems were nrmal. On further questionng, the patient said that she freqently pased bloostained stools ad was ofen constipated. Dgital eamination of the aal canal revealed nothing abnormal apart frm the prsence of some blod-staind mucus n the gove. Protoscopic examinaton reveaed that the mucous membrane of the anal can had thee congested swellngs that bulged ito the lmen at he 3-, 7, and 11o'clock ositions (the patint was i the lihotomy psition). Laboratoy examintion of he blood showed te red bod cells to be smller than normal, and the ed blood cell cout was vry low; he hemogobin levl was alo low. Te diagnois was icrocyti hypochromic anemia, secondary to prolonged beeding fom intenal hemorhoids. he sever anemia xplained the patint's brathlessnss. The emorrhois were diatations of the ibutaries of the superior rectal vin in th wall of the anal canal. Rpeated brasion f the heorrhoids by hard tools cased the leeding nd loss of blood Without knowledg of the natomic osition the veis in th anal caal, the hysician would not have be able to make a iagnosis P.88

Chapte Objecties   

Infectons, injries, an prolapss involing the nal cana, the urethra, an the femle external genialia are common problems faing the hysician Urethra obstruction, tramatic ruture of the penie urethra, and infections of the epdidymis nd testi are fruently sen in th male. The urpose o this chpter is o cover the signficant aatomy reative to these clnical prlems. Beause th descent of the tstes and the struture of he scrotm are itimately related o the deelopment of the nguinal anal, thy are dealt with in detai in Chapter 4.

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Definitin of Perneum The caviy of the pelvis i divided by the plvic diahragm ino the man pelvic cavity aove and he perinum below (Fg. 8-1. When een from below wih the thghs abduted, the perineum is diamod shape and is ounded ateriorly by the smphysis ubis, poteriorly by the ip of th coccyx, and laterally by the ischal tuberosities (Fig 8-2).

Pelvic Diaphragm The elvic diphragm i formed y the imortant evatores ani musces and the small ccygeus muscles nd their coverin fasciae (Fig. 8-1. It is ncomplet anterirly to alow ge of th urethra in males and the rethra ad the vgina in emales (for detail see page 8).

Content of Anal Triangle The nal triagle is bunded beind by he tip o the cocyx and n each side by the ischial tuberosiy and th sacrotuerous ligament, oerlapped by the brder of he glutes maximu muscle Fig. 8-3) The anus, or loer openig of the anal canl, lies n the miline, an on each side is the ischorectal fossa. The skin around the aus is splied by the infrior recal (hemorhoidal) nerve. Te lymph essels o the ski drain nto the edial grup of the superficial ingunal node.

Anal Cnal Location nd Descrption The ana canal i about 15 in. (4 cm) long and s downwad and bakward frm the retal ampula to th anus (Fig. 8-4). xcept duing defeation, is latera walls ae kept i appositon by th levators ani muscles and the anal sphinctes.

Relation   

Postriorly: The anococygeal bdy, wich is a mass of ibrous tssue lyig between the ana canal ad the cocyx (Fig. 8-4) Lterally: The ft-filled ischioretal fosse (Fig. 8-5) Anteriorly: In the male, th perinea body, te urogental diapragm, th membranus part f the urthra, an P.389

he bulb f the peis (Fig. 8-). In the female, the pineal boy, the uogenital diaphrag, and th lower prt of th vagina Fi. 8-4)

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Figure 8-1 ight hal of the elvis shwing the mucles foming the pelvic loor. Note that the levaor ani ad coccygus muscls and thir coverng fasca form te pelvic diaphrag. Note aso that he regio of the ain pelic cavit lies abve the pelvic diahragm an the region of the perineum lies beow the daphragm.

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Figue 8-2 iamond-saped perneum divded by a broken lne into he urogeital tringle and the anal triangle

Structur The mucus membane of te upper alf of e anal anal s derive from hndgut enoderm (Fig. 8-6). It has te followng imporant anatomic features:  

 



It is ined by olumnar pitheliu. It i thrown nto vertcal fold called ana columns, whic are joied togeter at thir lower ends by mall semlunar fods called aal valve (remans of prctodeal embrane) (Fgs. 8-5 and 8-7. The nerv supply i the sam as that for the rectal mcosa and is derivd from te autonoic hypogstric pexuses. t is senitive ony to strtch (Fig. 86). The arteria supply s that of the hingut—naely, the superior rectal atery, a banch of the inferior meseeric artry (Fig. 8-6). Th venous rainage s mainly by the sperior rctal vei, a tribtary of he inferor meseneric vei, and th portal ein (Fig. 85). The lymphatic drainage s mainly upward long the superior rectal artery to the pararctal nodes and then evenally to he inferor meseneric nods (Fig. 8-6).

P.390

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Figure -3 Anal triangle and urogenital triangle in the ma as seen from belw.

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Fiure 8-4 Sagittl sectios of the male (A) pelvis. agittal ections f the feale (B) elvis.

P.391

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Figure 85 Coronal section of the pelvis ad the peineum shwing venus drainge of th anal caal.

P.39

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Figure 86 Uppr and loer halve of the nal canal showing their embyologic rigin an lining

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pithelium (A), thei arteria supply B), thei venous rainage (C), and teir lymp drainag (). E. rrangemet of the muscle fbers of he puborctalis mscle and differen parts of the external anal sphinct.

P.393

Figure -7 Conal secion of the anal cnal showng the dtailed aatomy of the mucus membrne and te arrangment of he interal and external anal spncters. Note that the term pectinae line (he line t the leel of te anal vlves) an pecten the tranitional one betwen the sn and te mucous membrane are somtimes usd by cliicians.

he mucous embrane f the loer half f the anl canal is derved from ectoderm of the poctodeum It has the followng imporant featres:

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

It is lned by sratified squamous epithelium, which radually merges a the anu with th perianal epidermis (Fig. 8-). There ar n anal columns Fig. 8-7) The nrve suppy is fro the somtic infeior rectl nerve; it is ths sensitve to pan, tempeature, tuch, and pressure (Fgs. 8-3 and 8-6. he arteral suppl is the nferior ectal arery, a banch of he internal pudendl artery (Fg. 83). The enous drnage is by the inerior retal vein a tribuary of te interal pudenal vein, which drins into the intenal ilia vein (Fig 8-5 nd 8-6). The lyph drainge is donward to the medil group f superfcial inginal nods (Fig. 8-6).

Te pectinate line ndicates the leve where te upper alf of te anal cnal the lowr half (Fig 8-7)

Muscle Coat A in the upper pats of th intestial tract it is dvided ino an outr longitdinal an an inne circula layer o smooth muscle (Fig 8-5).

Anal Sphncters The ana canal hs an invluntary nternal phincter and a vountary external spincter. The intrnal sphncter s forme from a hickenin of the mooth mucle of te circulr coat a the uper end of the anal canal. he interal sphincter is enclosed by a sheath of striped musce that frms the oluntary external sphincte (igs. 8-5, 8-6, and 8-7). Th xternal phincter can be divided nto three parts:   

A subcutneous pat, whh encires the lwer end f the anl canal nd has n bony atachments A superficial part, which is attaced to th coccyx ehind an the perneal bod in fron A deep part, whic encircls the uper end o the ana canal ad has no bony attachments

The puboretalis ibers of the two evatores ani musces blend with the deep par of the xternal phincter (Fgs. 8-5, -6, ad -7). The puboectalis ibers of the two ides for a sling which i attachd in frot to the pubic bos and psses around the juction of the recum and te anal cnal, puling the wo forwad at an cute angle (Fig. 8-). Th longituinal smoth muscl of the nal cana is coninuous above with that of e rectu. It forms a contiuous coa around the anal canal an descend in the nterval P.4

betwee the inernal an externa anal spincters Some of the longtudinal fibers ae attachd to the mucous mmbrane o the ana canal, hereas thers pas laterally into te ischioectal fosa or ar attached to the perianal skin (Fig. 8-5). At the juncion of t rectum nd anal canal (Fig. 8-6), the intenal sphicter, th deep pat of the external sphincte, and te puborectalis mucles for a distint ring, alled th aorectal ing, hich can be felt n rectal examinaton.

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lood Suply Ateries The supeior artey supplis the uper half nd the iferior aery supplies the lower half (Fig. 8-6).

Vens The upper haf is drained by te superir rectal vein ino the inferior mesenteric vin and e lower alf is dained by the infrior recal vein into the iternal pdendal vein.

Lymph Drainage The uper half of the aal canal drains ito the ararecta nodes and then th inferio mesenteic nodes The loer half drains ito the mdial group of superficial inguinal des (Fig. -6).

Nerve upply The mucos membrae of the upper haf is senitive to stretch and is innervated y sensor fibers hat asced through the hyogastric plexuses The lowr half i sensitie to pai, temperture, tuch, and pressure and is inervated by the iferior rctal neres. The involuntry internal sphincter is splied by sympatheic fiber from te inferir hypogatric plexuses. Th voluntary externa sphincer is spplied by the nferior rectal nrve, a banch of he pudedal nerv (Fig. 8-), an the perineal branch of the fourth scral nee.

efecatio The tme, plac, and frquency o defecaton are a matter of habit. Some aduts defecate once day, soe defecae several times a day, an some pefectly normal people defecae once i several days. Te desire to defecte is intiated b stimultion of the strech recepors in te wall o the recum by th presenc of fecs in the lumen. Te act of defecatio involve a coordnated relex tha results in the eptying o the desending clon, sigoid colo, rectum, and ana canal. t is asssted by rise in intraabominal ressure rought aout by cntractio of the scles of the anteior abdminal wal. The tnic ion o the intrnal and external anal spincters, includin the pubrectalis muscles, is now vluntaril inhibied, and he feces are evacated thrugh the nal cana. Depending on te laxity of the sbmucous oat, the mucous mmbrane o the loer part f the anl canal s extrudd throug the anu ahead of the fecal mass. At the end of the act, the mucosa i returned to the anal canal by the tone of e longitdinal fibers of the anal wlls and the conraction nd upwar pull of the puboretalis mscle. Te empty lumen o the ana canal i now cloed by th tonic cntractio of the nal sphincters.

Ischorectal Fssa he ischorectal ossa (ischioanal fossa) s a wedg-shaped sace locaed on eah side f the anl canal Fg. 8-5). The ase of t wedge is superfical and fomed by te skin. Te edge o the wedg is forme by the unction of the media and lateal walls. The medal wall is formed by the sloping levato ani

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snell musce and the anal caal. The lteral wal is forme by the lwer part the obturator inernus musle, coveed with lvic fasca.

Contents f Fossa The ihiorectal fossa i filled wh dense at, which s the anal anal and llows it o distend uring defcation. he pudenal nerve nd internl pudendl vessels are embeded in a fscial canal, the puendal caal, on the latral wall f the ichiorectl fossa, on the edial side of th ischial tuberosiy (Figs. 8- and 8-8). The nferior ectal vesels and nerve crss the fssa to rch the anal canal.

Pudendal Nerve The puddal nerve is a branch of he sacral plexus ad leaves the main pelvic cvity thrugh the reater siatic foamen (Fig. -8). fter a brief course in the gluteal egion of the lowe limb, i enters the perineum through the lesser sciatic foramen. The nerve th es forward n the puendal caal and, y means f its brnches, spplies he exteral anal phincter and the mscles an skin of the perieum.

Braches 

 

nferior rectal nve: This run medially across the ischioectal fosa and spplies the external anal sphincte, the mucous membrane of t lower hlf of th anal cnal, and the perinal skin (Fg. 8-3). Doral nerv of the pnis (or litoris): This is distrbuted to the peni (or clioris) (Fig. 8-8). Perineal erve: his supplies the muscles in the uroenital tiangle (Fig. 8-8) and the kin on te posteror surfae of the scrotum or labia majora).

Inernal Puendal Arery he interal pudenal arter is a brnch of te internl iliac artery ad es from the pelvis trough th greater sciatic foramen nd enter the perneum thrugh the esser scatic foramen.

Braches  

Iferior rctal artry: Tis supples the lwer half of the aal canal (Fg. 8-3). Branches to the pes in he male nd to the lbia and litoris in the female

Interna Pudenda Vein The intrnal pudndal vei receive tributaies that correspod to the branches f the internal pudendal arery. P.395

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igure 8- Coure and brnches of the pudendal nerve in the male.

Cinical Ntes ortal–ystemic nastomoss Te rectal veins fom an imprtant potal–sytemic aastomosi because the supeior rectl vein dains ultmately ito the ortal ven and th inferio rectal ein drais into the systemic syste.

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Iternal Hmorrhoid (Piles) Intrnal hemrrhoids re varicosities o the triutaries of the superior retal (hemrrhoidal vein an are covred by mcous mebrane (Fig. 8-9). The tribtaries o the ven, which lie in te anal clumns at the 3-, 7, and 11o'clock position when th patient is viewe in the ithotomy poition,* are paricularly liable t become aricosed Anatomially, a emorrhoi is theefore a fold of mucous memane and submucos containng a vaicosed tibutary f the suerior retal vein and a teminal brnch of the superior rectal artery. nternal hemorrhods are initially contained within te anal cnal (firt degree. As the enlarge they etrude frm the caal on deecation t return at the end of the act (seond degre). With further longatio, they polapse o defecaton and emain ouside the anus (thrd degre). Because nternal hemorrhoids occur in the uper half of the anal cana, where he mucou membran is innevated by autonomic affere nerves they are painless and are sensitive only to tretch. This ma explain why large internal hemorrhoids give ise to a aching sensatio rather han acut pain. The cuses of nternal emorrhois are may. They frequenty occur n member of the ame famiy, which suggests a congeital weaness of he vein alls. Vaicose vens of the legs and hemorrids oftn go together. The superior rectal vin is th most dpendent art of te portal circulaton and i valvele. The weght of he colum of venos blood s thus geatest i the veis in the upper hlf of th anal caal. Here, the looe connecive tissue of the submucoa gives ittle to the walls of the veins. Morver, the venous return is interruped by th contracion of te musculr coat o the retal wall during dfecation Chronic constipaon, assiated with prologed straining at tool, is a common predispoing factr. Pregancy hemrrhoids re common owing to pressure on the perior ectal vens by th gravid terus. Prtal hypertension as a rest of cirrhosis f the lier can aso cause hemorrhods. The ossibiliy that ancerous tumors of the rectum are bocking e superir rectal vein mut never e overloked.

Externl Hemorroids External hemorrhods are vricosites of th tributaries of the inferir rectal (hemorrhidal) vn as they run latrally frm the aal margi. They ae covered by skin Fg. 8-9 and are commonly associated with wll-estabished inernal heorrhoids xternal hemorrhoids are covered by the mucous membrane of th lower hf of the anal canal or the skin, an they ar innervted by te inferir rectal nerves. Tey are snsitive o pain, temperatre, touc, and prssure, wich explains why eternal emorrhois tend t be painul. Throbosis of an exteral hemorhoid is common. ts cause s unknown, althouh coughig or strining ma produc distenton of th hemorrhid folloed by stsis. The presence of a smll, acutly tende swellin at the nal margn is immediately recognize by the atient.

Peranal Hemtoma periana hematom is a smll colletion of lood benath the erianal kin (Fig. 89). It is cause by a ruture of small sbcutaneos vein, ossibly n externl hemorrhoid, and is extreely painul.

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Anal Fissure The loer ends of the anal columns are conected by small fods called aal valve (Fig. 80). n people sufferin from chonic contipation, the anal valves ay be trn down o the anus as the result o the edge of the cal mass catchig on the fold of mucous memrane. Th elongatd ulcer o formed known s an anal fssure Fi. 8-10), is etremely ainful. he fissue occurs most comonly in he midlie posteiorly or, less cmmonly, nteriorl, and tis may b caused y the lck of proided by he superficial part of the xternal sphincter in these areas. The supeficial prt of th externa sphincer does ot encirle the aal canal, but sweeps past s latera sides. he site f the anl fissur in the ensitive lower haf of th anal canal, which is innevated by the infeior rectl nerve, results in reflex spasm o the extenal anal sphincte, aggravting the conditin. Becaue of the intense pain, anl fissurs may hae to be examined under local anestsia.

Prianal Ascesses Periaal abscesses are roduced y fecal rauma to the anal mucosa (Fig 8-10). Infecion may in entrance to the submucoa throug a small mucosal lesion, r the abcess may complicae an ana fissure or the ifection of an anl mucosa gland. he abscess may be ocalized to the sbmucosa (submucos absces), may ocur beneth the prianal sin (subcaneous bscess), or may ocupy the ischioretal fosa (ischirectal bscess) Large ischioretal abscsses sometimes etend poteriorly around te side of the anl canal o invade the ischorectal ossa of he opposte side (horseshoe abscess. An absess may e found n the spce betwen the apulla of the rectm and th upper srface of he levator ani (pelvirectl absces). Anatoically, hese absesses ar closely related to the dfferent arts of the exteral sphiner and levator ani muscle, as see in Figure 8-10. nal fisulae evelop s the rsult of pread or inadequate treatment of an absceses. The istula pens at ne end a the lumn of the anal canl or lowr rectum and at he other end on the skin srface clse to th anus (Fig. 8-10) If the bscess oens onto only one surface, it is knwn as a sins, no a fistua. The hgh-level fistulae are rare and run rom the ectum t the peranal ski. They ae locate above te anorecal ring; as a result, feal materl constntly sois the clthes. Th low-levl fistulae occur elow th level of the anorectal rin, as shon in Figure 8-10. The most important part of the sphinctric mechnism of he anal anal is the anorecta ring It conists of he deep art of the external sphincter, the iternal phincter and the puborectlis par of the levator an. Surgicl operaions on he anal anal tha result n damage to the aorectal ring wil produce fecal inontinenc.

Removal o Anorectl Foreign Bodies Norally, th anal caal is ket closed by the tne of te internl and exernal anl sphincers and he tone of the pborectals part o the levaor ani mscles. Te rectal contents are ed by the levaor ani mscles, pssibly asisted b the trnsverse ectal muosal folds. For these reasons, the rmoval of a large foreign body, suc as a vae or eletric ligt bulb, rom the rectum my be a frmidable problem.

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snell The folowing prcedure i usually successfl:  

The foreign ody must first be fixed so that th sphinctric tone togethe with exernal atempts to grab the object, do not dsplace te object farther up the reum. Lage, irreular, or fragile oreign bodies ma not be emoved s easily, and it my be necssary to paralyz the ana sphinctr by givng the ptient a eneral asthetic or by peforming n anal shincter erve blok.

Anal phincter Nerve Blk and Aesthetizng the Perianal Skin By blcking th branche of the nferior ectal neve and the perineal branc of the ourth saral nerv, the anl sphincters will be relad and te perianal skin ansthetize. he proceure is a follows   

An intraermal whal is prduced by injectin a small amount o anestheic soluton behin the anu in the idline. A glovd index inger is inserted into the anal canl to serve a a guide A long needle atached t a syrine fille with anesthetic solution i inserte through the cutaeous whel into he sphinter musces along the postrior and lateral urfaces the anl canal. The procdure is epeated n the oposite sie. The urpose o the finer in th anal canal is to guide th needle nd to prvent pentration f the anl mucous membrane

Inontinenc Associaed with ectal Prlapse Feca inconinence cn accompny sever rectal rolapse of long uration. It is thught tha the proonged and excessie streting of the anal shincters is the cuse of te conditon. The conditio can be reated b restorig the anrectal agle by tghtening the pubrectalis part of the levato ani musles and he exteral anal sphinctes behind the anorctal junction.

Incontince After Trauma Traua, such s childbrth, or amage to the sphicters dring surgery or perianal abscesses r fistule can be responsile for incontinence after rauma.

Icontinene After pinal Cod Injury Afer sever spinal ord injuies, the patient is not are of rectal distention. Mreover, he parasmpatheti influene on th peristatic activty of th descendng colon sigmoid colon, an rectum is lost. In additon, contol over he abdomial muscuature an sphincers of te anal cnal may e severely impaire. The retum, now an isolted struture, reponds by contracting when e pressue within its luen rises. This loal reflex response is much ore efficient if the sacrl segmens of the spinal cord are spred. At est, howver, th force o the contractions f the retal wall is small and costipatio and impaction of eces are the usua outcome

Rectal Examinaton Th followig structres can e palpatd by the gloved ndex finer insered into he anal anal and rectum i the normal patit. 730

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Anteiorly In the mle:   

Oposite te terminl phalan are the contnts of te rectovsical poch, the osterior surface f the badder, the semina vesicles, and the vasa defrentia (Fig 8-11. Opposit the midle phalax are he rectorostatic fascia ad the prstate. Opposite the proximal phalanx re the prineal bdy, the rogenita diaphram, and te bulb o the pens.

In he femal:   

Oposite the terinl phalan ar the rectouterine pouch, te vagina and the cervix. Oposite th middle halanx are the urogenitl diaphrgm and te vagina. Oppsite the proximal phalanx are the perineal body and the lowe part o the vagina.

Posteorly he sacru, coccyx and anooccygeal body can be felt.

Latrally he ischirectal fsae and ischial pines can be palpated.

ancer an the Lymph Drainage of the Anal Canl The uppe half of the mucos membrae of the anal canl is drined upwrd to lyph nodes along th course f the suerior rctal artry. The ower half of the mucous memrane is rained ownward o the medial group of superficial inguinal ndes. Man patiens have tought thy had an inguinal hernia, nd the pysician has foun a cance of the lower half of the aal canal with seondary eposits n the inuinal lyph nodes

The Ichiorectl Fossa nd Infecion The isciorectal fossae (schioana fossae) are filld with at that s poorly vascularzed. The close proximity t the ana canal akes the particularly vulerable t infection. Infection commnly tracks laterally from the anal mucosa trough th externa anal sphincter. Infection of the rianal hir folliles or seat glads may aso be th cause o infectin in the fossae. arely, a perirectal abscess bursts ownward through he levatr ani mucle. An ischioretal abscss may inolve the opposit fossa b the sprad of ifection across the midline behind te anal cnal.

Footote * Th patient is in th supine position with bot hip joits flexe and abdcted; th feet ar held i position by stirups. The position is commonly used for pelvic examinaions of he femal. P.396

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397

Embryoogic Nots Deelopment of the Aal Canal The distal ed of the hindgut erminate as a blnd sac o entoder called he cloaca (see Fig. -8). Te cloaca lies in ontact wth a shalow ectoermal deression alled th poctodeum. The pposed lyers of ctoderm and entoderm form he cloacal embrane, which eparates the caviy of the hindgut rom the urface (ee Fig. 7-8). The loaca beomes divded into anterior and postrior pars by the urrectal sptum; the postrior par of the loaca is called te norectal canal. The anorectal canal forms the rectm and th upper hlf of th anal cnal. The lining o the suprior hal of the nal cana is formd from entoderm, and that of the inferior haf of the anal canl is fored from the ectoerm of te proctoeum (see Fig 7-8) The spincters f the anl canal re forme from th surrouning mesnchyme. he posterior part of the coacal membrane brks down o that he gut pens ont the surace of te embryo

Imperorate Ans Abot 1 chil in 4000 is born ith impeforate aus cause by an iperfect usion of the entodermal claca with the procodeum. P.98

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Figur 8-9 A Normal ributary of the superior rctal vei within he anal olumn. B Varicoed tribuary of te superir rectal vein foring the nternal hemorrhid. Dottd lins indicae degrees of sevrity of conditio. . Postions of three inernal hemorrhoid as seen through proctosope with the patient in the lithotom positio.

P.99

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Figue 8-10 A. Tearig downwad of the anal vale to for an anal fissure. B. Common locatios of perianal abscesses. C. Common psitions f perianl fistulae.

P.400

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Figure 811 A. ectal exmination in a prenant womn showin how it s possibe to palate the ervix though the anterior rectal wll. B. Rctal exaination n the mae showin how it s possibe to palate the prostate and the seminal vesicles tough the anterior rectal wll. C. osition f the epsiotomy icision i a woma during he secon stage o labor. he baby' head is presentng at te vagina orifice

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Urogenial Trianle The urogental triagle is bounded in front by the pubic arch and laterall by the schial uberosites (Fig. 8-).

Supeficial Fscia he supericial facia of te urogenital triagle can e divide into a atty layer and a embranou layer. The fatty layer (fascia of Campe) is coninuous wth the fat of the ischioreal fossa (ig. 8-12) and te superfcial fascia of the thighs. In the scotum, th fat is eplaced y smooth muscle, he dartos uscle. The darts muscle contract in response to cd and reuces the surface rea of te scrota skin (se tsticular temperatre and frtility, page 169). he membranus laye (Coles' ascia) is attached posteriory to th posterior borde of the rogenitl diaphagm (ig. 8-12) and lateraly to the margins f the pbic arch anterirly it is contiuous with the membranous lyer of superficil fasci of the anterior abdominl wall (Scarpa's fascia). The fasia is cotinued ver the penis (r clitors) as a tubular heath (Fig 8-13. In the scrotum (or labi majora) it form a disinct laer (Fig. 8-12). P.401

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Figure 8-12 Arangemen of the superfical fasca in the urogenial trianle. Note the suerficial and deep perinea pouches

Suprficial Perineal Pouch The superficil perinel pouch is boundd below y the embranou layer of superfical fascia and abve by th urogental diahragm (Fig 8-12. It is closed behnd by te fusion of its uper and lower walls. Laerally, it is clsed by the attahment of the memranous lyer of sperficia fasia and te urogeital diahragm t the marins of te pubic rch (Figs. 8-1 and 8-15). nteriory, the sace commnicates freely wth the otential space ying beteen the uperficil fasci of the nterior bdominal wall and the anerior abominal muscles.

739

snell Th contens of the superficial perieal pou in bot sexes are descrbed on pages 405 and 408

Urogenital Diaphragm The urogenita diaphram is a triangula musculfascial diaphrag situate in the anterior part of the perineum, filing in te gap o the pubc arch (Fis. 8-12, 8-14, and 8-15) It is ormed by the sphicter urehrae and the deep transvere perineal muscls, which are enclsed betwen a suprior and an inferor layer of fascia of te urogenital diaphragm. Th inferior layer o fascia s often referred to as th prineal mbrane. Antriorly, he two lyers of ascia fue, leaving a smal gap beeath the symphysis pubis. osteriorly, the two layers f fasci fuse wih each oher and ith the embranou layer of the suerficial fascia ad the peineal boy (Fig. 8-1). P.42

Lateally, th layers f fascia are attahed to te pubic arch. The closed pace that is conained beween the superfiial and eep layes of facia is kown as te eep perieal pouc (Figs. -12, 8-14, and 8-1).

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Figur 8-13 The peni. and B. The thee bodie of erecile tisse, the to corpor cavernoa, and t corpus spongiosum with the glans. C. The peile uretra slit pen to sow the flds of mcous memrane and glandular orifice in the roof of th urethra

he contets of th deep peineal poch in boh sexes re descrbed in subsequent sections

Conents of he Male rogenita Triangl 741

snell n the mae, the tiangle cntains te penis nd scrotm.

Penis Locatin and Decription The penis ha a fixed root and a body tat hangs free (Figs. 8-4 ad 8-16). P.03

P404

.405

Root of the nis he root f the peis is mae up of hree mases of erctile tissue called the bulb f the peis and the right and left crura of the penis (Figs. 8-3, 8-16, and 8-17). The ulb is stuated i the midine and s attachd to the undersurfce of te urogental diapragm. It is travered by th urethra and is overed o its outr surfac by the bulospongious muscls. Eac crus is attached to the sde of th pubic ach and i covered n its ouer surfae by the ichiocavenosus mucle. The bulb continud forwar into th body of the peni and fors the corpu spongioum (Fig. 8-17). The two rura conerge antriorly ad come t lie sid by side in the drsal part of the body of te penis, forming he corpora avernosa (Figs. 813 and 8-6).

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Figre 8-14 Coonal section of he male elvis shwing the prostate the urogenital iaphragm and the contents of the sperficia perinea pouch.

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Figue 8-15 Coronal section of the fmale pelis showig the vaina, the urogenital diaphagm, and the contents of te superfcial perineal pouch.

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Figure 8-16 Rot and boy of the penis.

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Figre 8-17 Root of penis a perine muscles

Bod of the enis The body of the pnis is essentiall compose of thre cylindes of eretile tissue encloed in a ubular seath of ascia (Bucks fascia. The erectile tissue made up of two dorsally placed corpora cavrnosa ad a single corpus spongiosm applied to their ventral surfac (igs. 8-1 and 8-1). At ts dista extremiy, the crpus spogiosum epands to form the glns penis, whih covers the distl ends o the corora cavenosa. On the tip f the gans peni is the litlike orifice of the urera, called the extenal uretral meatus. The preuce or foeskin is a hodlike fod of ski that coers the lans. It is connected to he glans just below the urthral oriice by a fold caled the frnulum. The body of he penis is suppoted by to condenations f deep fscia tha extend ownward rom the inea alb and symhysis pbis to be attached to the fscia of he penis

Blood Supply 746

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Arteris The orpora cavernosa ae suppld by th dep arteres of th penis (Fg. 8-13); the orpus spngiosum s supplid by the arery of te bulb In addion, there is the drsal artery of the penis All the above artries are branches of the nternal pudendal artery.

Veins The vein drain nto the nternal pudendal veins.

ymph Drinage The ski of the enis is drained nto the medial goup of suprficial nguinal nodes. he deep tructures of the penis ar draine into th internl iliac odes.

Neve Suppl The nerve spply is from the pudenda nerve ad the pevic plexses.

Scrotu Locaion and escriptn he scrotum is an outpouchng of th lower art of te anteror abdomnal wall and conains the testes, he epidiymides, and the lower ens of the spermati cords (ee Fig. 421). Te wall o the scotum has the follwing layrs:      

kin Supericial facia; the dartos mscle, wich is sooth mucle, replaces th fatty lyer of the anteror abdominal wal, and Scrpa's facia (memranous lyer) is ow calle Colles fascia. Extrnal spematic fscia derved from the extenal obliue remasterc fascia derived rom the internal oblique Interal spermatic fascia derived from te fascia transveralis Tunic vaginals, which is a cloed sac at covers the antrior, meial, and lateral urfaces f each testis

Beause th structure of th scrotu, the dscent of the teses, and he formaion of he inguial canal are intrrelated they are fully descibed n haptr 4.

Blod Supply Subctaneous lexuses nd arterovenous nastomoes promte heat oss and hus assit in the environental cotrol of he temprature o the testes.

Arteres

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snell The externa pudenda brances of the femoral and scrotal branches of the inernal pudendal rteries upply th scrotum

Veis The veins acompany te corresonding rteries.

Lymph Draiage he wall f the srotum is drained into the medial roup of superfical inguial lymph nodes. The lymph drainage of the testis ad epididmis asceds in th spermatc cord ad ends i the lubar (praaorti) lymph nodes at the level of the first lumbar vetebra. his is t be expeted, becuse the estis during development as migrted from high up n the posterior bdominal wall, dwn throuh the iguinal canal, an into te scrotm, draggng its lood supply and lymph vessels afer it.

Nerve Spply The nterior surface f the srotum i supplie by the ilioinginal neres and e genial branc of the enitofemoral neves, an the poerior srface is supplid by braches of he perieal neres and he posteior cutneous neves of te thigh.

Cotents of the Supeficial Prineal Puch in te Male he supericial peineal poch contans strucures foming the root of he penis togethe with th muscles that covr themâ”namely, the bulbspongioss muscles and the ischiocavrnosus uscles (Fi. 8-17). The bulbspongioss muscle, sitated one on each ide of te midlin (Fg. 8-17), covr the bulb of he peni and th posterir portio of the orpus songiosum Their fnction i to compess the enile pat of the urethra and empt it of rsidual uine or smen. The anterior fibers lso compess the ep dorsal vein of the peni, thus ipeding te venou drainag of the rectile issue and thereby assisting in the rocess o erectio of the enis.

schiocaernosus uscles The ischiocverosus mucles covr the cus penis on each side (ig. 8-17). Te action of each muscle i to comress th crus peis and asist in the procss of erction o the pens.

uperficil Transvrse Perieal Musles The superficil transvrse perieal musles lie n the poterior part of te superfcial perneal pouch (Fig. 817). Each muscle ariss from te ischia ramus and is iserted nto the perinea body. Th function of thee mucles is to fi the perineal body in te centr of th perineu.

Nerve Spply ll the uscles o the suerficial perinea pouch ae suppled b the erineal ranch of the puendal nerve. P.406 748

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Prineal ody Tis small mass of ibrous tissue is attached to the cnter of te posteror margn of th urogental diapragm (Fgs. 8-12 and 8-17). It serves s a pint o attachent for he folloing musles: eternal anal sphincter, blbosponosus mucle, and superfiial tranverse perineal uscles.

Prineal Banch of the Pudenal Nerv The prineal banch of the pudedal nere on eac side erminate in the uperficil perinal pouch by suppling th muscles and skin (Fig. -8).

Contents of the Dep Perinal Pouc in th Male The deep peineal poch contans the membranus part of the rethra, the sphicter urthrae, the bulborethral lands, he deep transvese perinal muscls, the iternal pdendal essels ad their branche, and te dorsal erves o the peis.

Membranos Part o the Urehra The embranou part of the urehra is bout 0.5 in. (1.3 cm) lon and lis within the uroenital diaphragm surrouned by th sphinter uretrae muscle; it is contiuous above with the prostati uretha and beow with the penile urehra. It s the shrtest an least ilatable part of he urethra (Fig. 8-14).

Sphincter rethre Muscle he sphinter urehrae mucle surrunds the urethra in the eep perieal pouh. It arses fro the pubic arch n the two sides nd e mediall to encicle the urethra (Fg. 8-14).

Neve Suppl The perineal banch o the pudndal neve supples the sphinctr.

Acion Te muscl compreses the mmbranous part of he ureta and elaxes during miturition. It is he mean by whic micturtion can e voluntrily stoped.

Bulbouethral Glands The bubourethal gland are two small glnds that lie beneath the phincter urethrae muscle (Fi. 8-14). Thei ducts pierce th perinea membrae (inferor fascal layer of the uroenital diaphragm)

749

snell an enter te penile portion f the rethra. The secetion is poured nto the rethra a a resut of eroic stimuation.

Deep Transverse Perineal Muscles Te deep tansvers perinea muscles lie posterior to the sphncter uethrae mscle. Ech muscl arises from the ischal ramu and pases medialy to be insered ito the erineal ody. Thee muscles are cinically unimporant.

Internl Pudendl Atery The interna pudenal atery (Fi. 8-14) on eac side eters the deep erineal ouch an es orward, giving rse to th rtery t the bul of the penis; te arteries to the crura o the pens (deep artery of penis; and the dorsal artery o the penis, hich upplies the ski and facia of te penis.

Dorsl Nerve of the Pnis The dorsal nrve of the penis on each ide s forward throug the dee perinel pouch and supples the sin of th penis (Fg. 8-14).

Erectin of th Penis Eretion in he male is gradully buit up as conseqence of arious exual stmuli. Peasurable sight, sound, sell, ad other sychic simuli, fortified later by direct touh sensor stiuli from the geeral body skin ad genita skin, rsult in bombent of the cental nervos system by affernt stimuli. Efferent nervous impulss dwn the sinal cor to the arasympahetic otflow in the second, thir, and furth saral segmnts. The parasypathetic eganglionic fibers ente the inferio hypogasric pleuses and synaps on the postgangionic nerons. Th postganlionic ibers jon the iternal pdendal ateries and are dstributed along their branches, hich ener the eectile tssue at the roo of the penis Vasodiltation f the areries no occurs, producig a grea increae in blod flow trough th blood paces of the eretile tisue. The corpora avernsa and te corpus spongiosm become engorged with bood and xpand, cmpressing thei drainin veins gainst te surronding fascia By thi means, the otflo of lood from te erectile tisse is retrded so that the interal pressre is frther acentuate and mantained. The peni thus icreases n length and dimeter an assumes the eret positin. Once the limax of sexual xcitemet is reahed and ejaculaion take place, or the ecitemet es off or s inhbited the arteries spplying the erecile tisse undergo vasocnstricton. The penis ten returs to it flaccid state.

Ejaculaion Dring th increasng sexua exciteent that occurs durig sex ply, the eternal uinary matus of the glan penis bcomes mist as a result o the secretions of the bubouretral glans.

750

snell riction n the gans peni, reinfoced by oher affrent nervous implses, reults in dischare along the sympthetic nerve fiers to the smooth mscle of he duct of the epididymis and th va deferns on eah side, he semial vescles, ad the postate. he smooh muscle contract, and the spermatozoa, toether wih the secretion of the eminal vsicles ad prostae, are ischarge into he prosttic uretra. The flud now s th secretins of the bulborethral lands an penile urethral glands nd is thn ejecte from te penile urethra as a esult of the rhytmic ions of the ulbosponiosus mucles, whch comprss the uethra. Manwhile, the sphincter o the bladder conracts an prevent a reflx of the sprmatozo into the bladder. The sprmatzoa an the seretions of the everal ory glands constitue the seminl fluid, or semen. At te climax of male sexual ecitemen, a mass dischage of nevous imulses takes place in the entral nrvous sstem. Imulses pss down he spina cord to the sympattic outlow (T1 to L2). he nervous impules that to he genial organ are tought to leave th cord at the firt and seond lumbar segments in the preanglionic ympatetic fiers. Man of thee fibers synaps with ostgangonic nerons in the firt and second lumar gangla. Other fibers may synase in gaglia in he lower lumbar r pelvic parts o the sypathetic trunks. he postganglioic P.07

fibers ar then ditributed to the as deferns, the eminal vsicles, nd the postate ia the iferior hpogastri plexus.

Male retha he male urethra s about in. (2 cm) lng and xtends rom the neck of he bladder to th external meatus on the gans peni (Fig. 8-4). It s dividd into tree parts: prosttic, memranous, nd penie. The postatic rethra is desribed on page 35. It is bout 1.2 in. ( cm) log and es thrugh the rostate rom the ase to the apex Fi. 8-14). It is the widest and mst dilaable porion of he uretha. The membrnous uretra is bout 05 in. (125 cm) long and ies within th urogenital diapragm, surrounde by the sphincte urethre muscle It is the least dilatabl portion of the urethra Fi. 8-14). The peile uretra i about 6 in. (1575 cm) long and is enclosd in the bulb and the corus spongosum of the peni (Figs. 84, 8-14, 8-16, and 8-17. The eternal matus is he narrowest part of the ntire urthra. Te part f the urthra tht lies wthin th glans penis is dlated to form the fossa terminals (nvicular ossa) (Fig. 8-4). The blbourethral gland open ino the penile urethra belo the uroenital iaphragm

Clincal Note Cicumcisio Circmcision is the oeration f remoing the reater part of he prepue, or foeskin. n many nwborn maes, the repuce annot be retractd over te glans. This can result n infecton of te secrtions bneath the pepuce, ladin to nflammatio, swelling and firosis f the pepuce. Repeated

751

snell inflammaton leads to consriction f the oifice of the preuce (himosis) wih obstrction t urinatin. It is now geneally blieved tat chronic nflammaion of the prepue predisoses to carcinom of the glans pnis. Fo these rasons prphylacti circmcisio is commnly praticed. For Jews, it is a eligious rite.

Cateterization of the Male The follong anatmic fats shoud be reembered efore ing a atheter r other nstrumet along the male urethra      

The external oriice at the glans penis is the narrowet part of the entire uethra. Within the glns, the rethra dlates t form th fossa teminalis (naviclar foss). Near he posteior end f the fosa, a fod of mucus membane projects int the lumen from th roof (Fig. 8-1). The mebranous art of te uretra is arrow an fixed. The rostatic part of the uretra is te widest and most dilatabe part o the urehra. B holding the pens uward, th S-shped curve to the urethra s conveted into a J-shaed curv.

If te point of the ctheter psses though the external orifice and is ten directed toward he urethal floor until i has pased the ucosal old, it hould eaily along a noral ureta into the ladder.

Anatoy of the Procedure of Cateterizaon The rocedure is as follows:  

 

The paient lie in a suine posiion. With gntle trction, te penis s held rect at right anles to te anterir abdomial wall The lbricated catheter is pased hrough te narro externa urethra meatus. The cateter shold easily aong the penile uethra. On reaching the embranou part o the urehra, a sligt resistnce s felt bcause of the toe of the urethrl sphinter and the surrunding rgid perieal merane. Th penis s then lwered toard the thighs, nd the cathter is ently ushed trough th sphincer. ag of the atheter trough the prostatic urehra and ladder nck shoul not preent any ifficuly.

Urethal Infecion The most dependent part o the mae urethr is that which lies ithin the ulb. Here, it is subect to cronic inlammation and stricture formatin. The many gland that opn into te urethr—incluing those of the prostat, the bubourethrl glands and may sall penie urethrl glands€”are comonly the site o chronic gonococcal infection. Injries to the penis may occr as th result f blunt trauma, enetratig traum, or strngulatio. Amputtion of the entire penis should b repaire by anasomosis uin microsurgical techniques to restore continuty of te main bood vessels.

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Rpture of the Urera Rupture f the urthra may complicte a sere blow o the perineum. he commo site of rupture is within the bub of the penis, just belw the prineal mmbrane. he urine extravastes into the suerficial perineal pouch and then es frward ovr the srotum bneath the membraous laye of the uperfical fasci, as desribed i Chpter 4. If the membranous part of he urehra is rptured urine scapes ito the dep perneal pouch and cn extravasate uward arond the ostate nd bladdr or downward ito the superfical perieal pouc.

Erectio and Ejaulation fter Spinal Cord Injuries Erectio of the penis is controlld by the parasympathetic nerves tat origiate from the second, thir, and furth sacal segmts of te spinal cord. Biateral dmage to the reticlospinal nerve tracts in the pinal cord wil result in loss of eretion. Lter, whn the efects of pinal sck have disappeared, spntaneous or reflex erection may ocur if th sacral egments f the sinal cor are inact. Ejaculation is contrlled by ympatheic nerve that oiginate in the frst and econd lumbar segents of the spinl cord. s in th case of erection severe bilateral damage to the spial cord results in loss f ejacultion. Later, refex ejacuation my be posible in patints wit spinal cor transectins i the thoacic or cervical regions

Scotum ee page 167. .408

Contents o the Femle Urogenital Tiangle I the femle, the riangle contain the extrnal gentalia ad the orifices of the urethra and the vagina.

Clitois Lcation and Descrption The citoris, hich coresponds t the penis in th male, is situted at te apex o the vstibul anterirly. It as a stucture smilar t the pens. The gans of te clitois is patly hiden by te prepuce.

Root of the Clitoris The oot f the cltoris s made up of tree masss of eectile tssue caled the ulb of he vestiule and he right and left crura f the cltoris (Figs. 8-5 and 8-8).

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snell The blb of th vestibule corresponds to the blb of th penis, ut becae of the presenc of the vagina, it s dvided into two halves Fig. 8-1). It is attched o the unersurfac of the urogenitl diaphrgm and covere by the bulbospongisus musces. The crura of the litoris crrespnd to the crura of the peis and bcome th corpora cavernosa anteriorly. Eac remains separate and is vered b an ischiocavernous muscl (Fig. 818).

Figure -18 Rot and bdy of the litoris and the perineal muscles

Body of the Citoris The ody of te clitors consists of the two corpra caverosa overed b their ischioavernoss musces The copus spongiosum of the mal is reprsented y a smal amount of erecile tisue leadig from he vestbular bubs to th glans.

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Glns of th Clitori Th glans of the cltoris is a small mass of rectile issue tht caps the bdy of the clitoris. I is provded with numerou sensory endigs. The glans is partly idden by the prepuce.

lood Suply, Lymh Drainge, and erve Suply The bood spply, lmph drainage, an nerve spply ar similar to thos of the enis.

Contets of th Superfcial Perneal Pouh in the Female he supeficial perineal puch contins strctures orming he root f the citoris ad the muscles tht cover hem, nmely, th bulbospongosus muscles and he ishiocavernosus mucles (igs. 8-15 and 818.

Blbospongosus Muscle he bulbspongioss muscle surroun the orfice of the vagna and cvers the vestbular bbs. ts fiber extend forward to gain attachmet to the corpora cavernosa of the clitoris The bubospongosus musle reducs the sie of the vaginal orifice nd compesses th deep drsal vei of the P.09

cltoris, tereby asssting in the mehanism of erection in the clioris.

Ishiocavenosus Muscle The ischocavernous musce on eac side cvers the crus o the clioris. Cotraction of this uscle asists in ausing te erecion of te clitors.

Supeficial Tansverse Perineal Muscles he superficial tansvers perinel muscl are idntical in tructure and functon t thoe of he male.

Nerve Suppl All the muscles of th superfiial perieal pouc are supplied by the perieal brah of th pudenda nerve.

Perinel Body The perinea body is larger tan that of the male and s clinially imprtant. I is a wdge-shaed mass f fibrou tissue situated between he lower end of he vagin and the anal canal (Fis. 8-4 and 8-18). It is the pint of atachment of many perineal muscles as in th male), includi the leatores ai muscle; the later assit the prineal bdy in ing he posteior wall of the vagina.

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Perneal Brch of Pdendal Nrve The peineal brnch of te pudenal nerve on each side terinates i the suprficial perinal pouch by suppying the muscles and skin (Fg. 8-8).

Cotents of the Deep Perineal Pouch i the Femle The eep perieal pouh (Fig. -15 contains part of the uethra; part f the vagina; the sphincter urethrae, which is pierced y the urethra and the vagina the deep transverse erinal muscles; the interal pudenda vessels and ther branches; nd the dorsal nerve of the cltoris. The urthra nd te vagina are desribed in te next column. The sphncte uretrae and the deep transerse erineal mucles ar described on page 406. The intrnal pudenal vessels and the dorsal neves of the clitoris have n arrangment simlar to te corresonding structure found i the mal. A summary of the muscles of the peineum, teir nerv supply, and their action is given in Table 81.

Eection f the Cltoris Sexual excitement produces engorement of the eretile tisue witin the citoris n exacty the same manne a in the male.

Orgsm in te Female As n the mle, visin, hearig, smel, touc, and oter psyhic stimuli gradally build up th intensity of seual excitement. During his procss the vginal wals becoe moist because of tranudation of fluid through the conested mucous mebrane. n additon, the greater vestibuar gland at the vaginal orifice ecrete lubricating mucu. The upper prt of te vagina, which esides i the plvic cavty, is upplied y the hpogastrc plexuss and is sensitive onl to strech. The region o the vainal oriice, the labia miora, ad the citoris re extreely senstive to ouch an are suplied by the ilinguinal nerves and the dorsal nrves of he clitris. Apropriat sexual stimulation of tese sensitive area, reinorced by afferent nervous impulses from the breasts and othe regions, esults i a clima of pleaurable snsory imulses rechin the cetral nervous sysem. Ipulses ten own te spinal cord to the sympathetc outflw (T1 to L2). Th nervous impulses that to the genial organ are thught to leave the cord at the rst nd secon lumbar egments n preganglinic sympthetic fbers. May of these fiers synase with postganglionc neuron in the first and secod lumbar ganglia; other fbers may synase in gnglia in the ower lumar or pevic part of the sympthetic tunks. Th postganglionic fiber are then distributed to the sooth muscle of te vainal wal, which hythmicaly s In addtion, nevous impulses travel i the pudndal nere (S2, 3, and 4) to rech the blbospongiosus and

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snell ischocavernsus musces, which alo underg rhythmi contraction. In many omen, a ingle orasm brings aout sexul contentment but othr women equire a seres of ogasms to feel reete.

Fmale Urthra The female uethra is about 1. in. (3.8 cm) long. It extends from he neck f the bladder to the eternal matus, wher it open into te vestible about 1 in (2.5 cm below te clioris (Figs. 8-4 and 81). I traverses the sphinctr urethre and lis immeditely in fron of the vagina. t te sides f the external urthral metus ae the sall opeings of the ucts of the parauethral land The urhra can be dilted relativel easily.

Paraurehral Glads The paaurethra glands, which corespnd to te prostte in the male, oen into he vstibule y small ucts on eithe side o the urehral oriice (Fig. 8-19).

Greaer Vestiular Glands The reater vestiblar glans are a air of sall muus-screting lands that lie uder cover of he posteior part of th bulb of the vestbule and the abia majra (Figs. -15 ad 8-18). Eac drains its secretion ino the vetibule y a small duct, hich opns into the grooe betwee the hymn and the posterior part f the lbium mins (Fig. 8-9). Tse glands secret a lubriating mcus durig sexua intercorse.

Vagina Locaion and Descripion The vagia not oly is th female genital canal bu also srves as the excrtory dut for th menstrual flow rom the uterus an forms part of te birth anal. Ths musculr tube etends upard and backwar betwee the vula and te uterus (Fig. 8-4). It measures about 3 n. (8 cm) long The cerix of the uterus pierces its antrior wal. The vginal orfice in virgin ossesse a thin mucosal old, P.10

called te hymen which is perfrated at its cenr. The pper hal of the agina lis abov the peic floo within the pelvis between the blader anteiorly ad the rtum poseriorly; the lowr half lies within the perneum beween the urethra nteriory and th anal caal posteiorly (Fg. 8-18). Table 8- Musles of Prineum

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Muscle

Origin

Insertio

Nerve upply

Action

Exernal anal sphicter

Subutaneou part

Encicles ana canal, no bony ttachments

Inerior rectal nere and peineal banch of ourth sacral nere

uperfical part

Perineal body

Deep prt

Ecircles nal cana, no bon attachents

Puborectlis (par of levaor ani)

Pubic bons

Togeter with uborectlis musce forms oluntary sphinct of ana canal

Coccx

Sing aroud junction of rectum nd anal anal

Perineal branch of fourt sacral erve an from peineal brnch of pdendal nrve

Together with extrnal anl sphinter form voluntary sphinter for anal canal

Facia of bulb o penis ad corpu

Perineal ranch of pudenda

Compresses rethra ad assist in erecion of

Mal Urogenial Musces

Bubospongisus

Perieal body

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spongioum and cvernosu

nerve

pnis

Ischiocvernosus

Ishial tubrosity

Fasca coverig corpus cavernoum

Perinel branch of pudenal nerve

ssists i erectio of peni

Sphincer urethae

Pubic arh

Srrounds urethra

Perieal branh of pudndal nere

Voluntar sphinctr of urehra

Superficial ransvers perinea muscle

Ichial tuerosity

Perneal bod

Perneal brach of puendal neve

Fixes erineal body

Deep transvere perineal muscl

schial amus

Perinea body

Perinel branch of pudenal nerve

ixes peineal boy

Fascia of corpus cavrnosu

Perieal brnch o pudendal nerve

Sphincer of agina and assist in erection of citoris

Female Uroenital Mscles

ulbopongisus

Perineal body

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schiocvernous

Iscial tubrosity

Sphincter urethrae

ame a in ale

Superfcial transvers perineal uscl

Sae as n mae

Dep trasverse perieal muscle

Same as in male

Fscia covering corps caverosum

Perineal ranch of puendal nerve

Causes erection of clitois

s f the Vagin   

Uper third: Levatore ani muscles and tranverse cervcal, ubocervical, and sacrcervcal ligaments Middle third: Urogenial diapragm Lower third Perieal body

Blood Supply Arteies The vagial arter, a branch of th interna iliac atery, an the vagnal branh of the uterine rtery spply the vagina.

Veins aginal vins drai into th interna iliac vins.

Lmph Draiage   

Upper third: Iternal ad external iliac nodes Middle tird: nternal liac noes Lwer thir: Sperfical inuinal nodes

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Figure 8-19 A. Vulv. Note te differnt appeaances o the hymn in a virgin (B) a woman who has had sexul intercurse (C) and a mltiparou woman (D).

erve Supply 761

snell Te vagin is suplied by erves frm the inferior hpogastric plexuss.

Vulva The ter ulva is the ollectie name for the feale extrnal geitalia ad includs the mos pubis labia mjora and minora, he clitois, the stibule of the vgina, th vestibuar bulb, and the greater estibula glands.

Bood Suppy Braches of he exteral and iternal pdendal ateries n each sde The kin of the vulva s draine into th medial roup of uperficia inguina nodes.

Lymph Dainage Medial group of sperfiial nguinal ndes

Nerv Suply The anterior prts f the vula are supplied by te ilioinuinal nerves and the genital branch of te genitofmora nervs. he psteror prts f the vula ar suppied y the braches of the prinel nerves and the poserior cutneou neres of the thigh. P.412

Clinical Ntes Vulval Infectin In the region of the ulva, the presenc of nmerous glands and ducts opening onto the urface makes this rea prone to infection. The sebaceous glands of the labia ajora, the ducs of the greaer vestibular glands, the vaina with its ndirct communiatio with th pertonel caity) the urethra, and the parurethral land ca all becoe infecte. Th vagina itself has no glands nd is lined wth stratified quamous epithlium Provided that the pH of its inteior s kept lo, it is capable of sisting infection t a remarkable degre.

The Vulva an Prenancy An importnt sgn in the diagnosis of pregnancy is the apparance of a bluish discoloraton o the vulv and vagin as a result of venous congetion. It appears at the th to 12th week nd increases as the pregnancy progresse.

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rethral Ifecton Th shot length f the female uethr predisposes t asceding infetion consequently, cystits is mre common in females than in mles.

Urethra Injries ecause of the sho lengh of the urthra, injuris are rare In fracture of the pelis the urethr may e damaged b sheaing forces as it merge from the ixed urogenital diaphragm.

Caheterizaton Becase te femae urthra is sorter, wider, and more dilatable, catheterzation is much easir than in male. Moeove, th urethra is sraight, and ony minor resistance is felt as the theter asse through he uethral sphinctr.

Vaginal Examnation Digital eaminaion of th vagna may povide the physician with much valuble inforatio concernig th health of the vaginal walls the uterus, and the surrounding structues (Fig. 8-4). Thus, the anatomic reations of te vagna must be nown; they are considere in dtail n Chapter 7.

Ijury to te Peineum Durng Cildbirth The peineal body is a wedg of fibromuscular tissue that lis betwee the lowr part o the vagna and the anal canal. I is held in positon by th insertin of the perinel muscle and by the attahment of the levaor ani scles. n the fmale, it is a muc larger tructure than in he male, and it serves to the postrior wal of the vagin. Damage by lacration dring childbirth can be follwed by prmanent eakness of the pelvic foor. Fw women escape sme injury to the birth cnal durig delivery. In ost, this is litle more than an brasion of the posterio vaginal wall. Spntaneous delivery of the child wih the patient unattende can reult in a severe tear of te lower hird of the poserior wal of th vagina, the perneal body, and oerlying skin. In severe ears, te laceraions may extend backwar into th anal canal nd damag the extrnal sphincter. In these cases, i is imperative that an accurate repair of the walls of the al canal vagina and perineal bod be undertaken as soon as possible. In the anagemen of chilbirth, hen it is obviou to the obstetriian that the perneum will tear before he baby's head merges hrough te vaginl orific, a planed surgcal inciion is ade thrugh the perinea skin in a posterolateral directio to avoid the anal sphicters. Thi procedue is knon as an episotomy (ig. 8-4). Brech delivries and forceps eliverie are usully precded by a episiotomy.

Pudndal Neve Block Area of nesthesa

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snell Th area aesthetizd is the skin of the perieum; thi nerve block dos not, hwever, aolish snsation rom the nterior art of he perieum, whih is inrvated the iloinguina nerve and the enitofemoral nere. Needess to ay, it des not bolish pin from uterine contracions tha ascend o the spnal cord via the ympathetic affeent nervs.

ndicatios Durng the econd stge of a ifficult labor, wen the resentin part of the fetu, usualy the head, is descending though th vulva, orceps delivery ad episioomy may e necessry.

Tranvaginal rocedure The bony lanmark use is the schial sine (Fig. -20). The indx finger is insered throuh the vaina to plpate th ischial spine. he needl of the yringe i then pased throgh the vginal ucous mebrane toward the ischial sine. On assing trough th sacrosinous liament, te anesthetic soltion is njected around te pudedal nerv (Fig. 8-2).

Peineal Prcedure The boy landmak is the ischial uberosit (Fig. 8-2). Th tuberosty is papated sucutaneouly throuh the butock, an the nedle is itroduced into the pudendal canal alng the mdial sid of the tuberosiy. The cnal lies about 1 n. (2.5 cm) deep the fre surface of the schial tberosity The locl anesthtic is ten infitrated around the pudendal nerve. P.413

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Figure 8-20 Pudendal nerve block. 1, Transvagnal method. The eedle is ed hrough he vaginl mucous membrae toward the iscial spin. After the neede is pased throgh the acrospinus ligant, the anesthetic solution is injected aroud the udendal erve. 2, Perineal method. The iscial tubrosity i palpatd subcutneously hrough te buttok. The needle i inserte on the edial side of the ischial tuberosiy to depth o about 1 in. (2. cm) from the fee surfae of the tuberosty. The nestheti is injeted aroud the pudendal nerve.

mbryologc Notes Developent of te External Genialia arly in developmnt, the mbryoni mesencyme grow around the clacal memrane an causes he overying ectderm to e raisd up to orm three swelligs. One welling ccurs btween th cloaca membrae and te umbilial cord in he midlne and i called the enital tbercle (Fig. 8-2). On each sid of the embrane, another swelling, called te genital old, appears. At the seventh eek, the genital tubercle elongats to fom the gans. The anterio part of the clocal membane, th uogenita membran, no rupture so tha the uroenital snus opens nto the surface. The entodermal ells of he urognital sius proliferate ad grow into the rot of th phallus formin a urethral plate. Meanwhile, a second par of latral swelings, clled the geital swellings, appear lateal to th genita folds. At this tage of developmnt, the genitali of the two sexe are identical

Mal Genitala

765

snell In the male the phalus now rapidly elongats and puls the genital folds aneriorly nto its ventral urface o that tey form the latral edgs of a goove, the urethal grooe (Fig. -22). The flor of the groove is forme by the entodermal urethral plate The pnile urthra deelops a the reslt of th two gental fols fusin togethr progresively along the shft of the phalus to the root f the gans peni. Durin the fouth mont, the rmainder of the rethra i the glas is deloped fom a bu of ectoermal clls from the tip of the lans. Ths cord f cells later beomes caalized s that he penile urethr opens t the tp of the glans. he prepuc or forekin is formed rom a fld of sin at te base o the glns (Figs. 8-21 nd 8-22) The fold of kin remins tethred to he vental aspet of the root of he glans to form the frenlum. he erectile tissue—the orpus songiosum and th corpora avernosa—deveops within the msenchymal core of the peis.

Femle Genitlia The chages in te femal are les extensve than those i the mal. The phllus becmes bet and frms the clitoris (Fig. 8-2). Th genita folds o not fse to frm the uethra, as in he male but deelop ino the labia minora. The laia majo are ormed by the enargement of the gnital sellings

Matal Stnosis The extrnal urinary meaus normlly is he narroest par of the ale uretra, but occasioally the opening is excessively mall an may case back pressur effect n the enire urinry system. In severe caes, diltation o the orifice by incision i necessay.

Hypospadias Hypospdias is he most ommon cogenital nomaly affecting the male urethra. The extenal meats is sitated on he ventral or undersurfac of the enis anywere betwen the gans and h perinem. Five egrees o severit may occur, the frst of wich is he most common: 1) glandlar, (2) coronal, (3) penile, (4) peoscrotal and (5 perinea (Fig. 8-23). In ll excep the firt type, he penis is curved in a dowward or ventral irection a condiion refered to as cordee. Types 1 and 2 re cause by a falure of he bud o ectodemal cell from the tip of te glans to grow nto the substance of the gans and oin the ntoderma cells lning the penile uethra. Types 3, , and 5 re cause by a falure of he genitl folds to unite n the unersurfac of the evelopin penis ad so conert the rethral groove ito the pile urethra. In the penoscotal varety, the genital swelling fail to fuse comletel, so tha the meaal orifie occurs in the dline of the scroum. Type 1 requires no treament; fo the reainder, lastic srgery is ecessary

Epspadias Epispaias is a relatively rare cndition nd is moe commonly found n the mae. In th male, te externl meatus is situted on te dorsal or upper surface o the pens betwee the glas and te anterir abdomial wall Fi. 8-24). The mst sever type is associatd with etrophy o the bladder (se age 361). In he female the urehra is slit dorsally and associaed with double clitoris It is thought

766

snell that epispaias is csed by failure of the embyonic meenchyme to develop in te lower part of the antrior abominal wll, so tat when te cloaca membran breaks own the urogenital sinus oens onto the surfce of the cranial spect of the peis. Plasic surgey is the required treatmen P.414

Figure 8-21 The devlopment f the eernal geitalia i the femle and male.

P.415

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igure 8-2 The developmnt of the penile prtion of the male urethra

P.16

Figur 8-23 ypes of ypospadis: (1) gandular, (2) coroal, (3) pnile, (4 penoscrtal, and (5) perieal. Venral flexin (chorde) of th penis aso is prsent.

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Figure -24 Tpes of eispadias

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Fiure 8-25 Cystouethrogra after itravenou injectin of conrast medum (28-year-old mn).

P.417

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igure 8-6 The main feaures see in the ystourethogram shwn in Figur 8-25

Radioraphic Aatomy The raiographic anatomy of the bones formig the bondaries f the peineum is shown in Fiures 7-39, 7-41, and 7-43. A cysturethrogam of the male urthra is hown in Figres 8-25 and 8-26.

Surface Anatomy The peineum wh seen from below with the highs abucted (Fig. 8-2) s diamon shaped nd is bonded aneriorly y the symphysis pub, poseriorly y the ti of the cocyx, an lateraly by the ichial tuerosities.

ymphysis Pubis The sympysis pubs is the cartilagnous joit that les in the midline between te bodie of the ubic bones (Figs. 8-3, 8-27, and 8-28. It is elt as a solid structure beneath the skin in he midle at the lower extremity of the antrior abdminal wal.

Cccyx Te infeior surfce and ip of t coccyx can be alpated n the ceft betwen the bttocks bout 1 in. (2.5 cm) behind he anus Fig. 8-). P.18

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Figre 8-27 Anterir view o the pelis of a 7-year-od man.

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Figure -28 Aerior viw of the pelvis o a 29-yer-old woan.

P.49

Ischial Tuberosiy Th ischial tuberosiy can be alpated in the lwer part f the butock (Fig. -3). In the sanding psition, he tuberosity is cvered by the glutus maxius. In te sittin position the ischial tubrosity eerges fro beneat the lowr border of the guteus maimus and s the weigt of th body. It is ustomar to divde the prineum ito two riangles by ing the isial tubeosities ith an iaginary ine (Fig. 82). Th posterir triangle, which contains the anus is calld the anal riangle the aterior tiangle, hich conains the urogenitl orifics, is caled the uroenital tiangle.

Anl Triange Ans The aus is th lower oening of the anal canal an lies in the midlne. In te living the anal margin i reddish brown an is pucered by the contrction of the externa anal spincter. Around the anal margin ae coarse hairs (Fig. 8-29).

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Mle Urogeital Tringle The male urogenitl triange contais the peis and te scrotu.

Penis The peis consits of a oot, a bdy, and glans (Fig. 8-13 816, ad 8-27). he root of he penis consits of thee masse of erectile tiss called he bulb of the peni and te ight nd left crra of th penis The bul can be elt on dep palpaion in te midlin of the erineum, posterior to the srotum. The bod of the enis the free portion of the enis, whch is supended fom the smphysis pubis. Note that he dorsa surface (anterio surface of the faccid oran) usully posssses a supeficial drsal vei in te midlin (igs. 8-1). The glans enis orms the extremit of the ody of t penis (Figs. 8-13, 8-16, nd 8-27) At the ummit of the glan is the extrnal urehral meas. Exending fom the lwer margn of the external meatus i a fold onnectin the glas to the prepuce alled the fenulum The edg of the ase of te glans s called the corona (Fig. 8-1). The pepuce r oreskin is foed by a old of skin attached to the neck of the peni. The repuce cvers the glans for a variabe extent and it should be possible to retrat it ove the glas.

crotum The scroum is a ac of skn and facia (Figs. -12 an 827) ontainin the testes and te epididymides. Th skin of the scroum is rgose and is coverd with sprse hair. The biateral oigin of the scroum is inicated b the preence of dark lie in the midline, called te scrotal raphe, long the line of usion.

Testes The tetes shoud be palated. Ty are ovl shaped and have a firm cnsistenc. They ie free ithin th tunica aginalis (see Fig. 421) an are not tethered to the sbcutaneous tissue or skin.

Epiddymides Each eididymis can be plpated o the poserolaterl surfae of the testis. he epidiymis is long, nrrow, fim structre havig an expanded upper end or hed, a bod, and pointed tal inferiorly (ee Fig. 4-2). The cordlike vas deferens emeres from he tail nd ascends medial o the epdidymis o enter he spermtic cord at the uper end f the scotum.

Female Urogenital Triangle Vulva Vulva is the term applied o the feale extenal genialia (Figs. 8-19, 8-2, and 8-9).

Mons Puis 775

snell Th mons puis is th rounded hair-bering eleation of skin found anteri to the pubis (Figs 8-19 nd 8-28). Te pubic air in te female has an arupt horzontal sperior mrgin, wereas in the male it extens upward to the ubilicus.

Labia Majora The laba majora are promnent, har-bearin folds o skin eending osteriorly from te mons pbis to unite posteriorly i the midline (Figs. 8-19 ad -29).

Labia Miora Te labia inora ar two smaler, hailess fols of sof skin that lie beteen the abia maora (Fi. 8-19). Their posterio ends ar united o form a sharp fod, the fourhette Anteriorly, they split to enclose he clitois, formng an anterior prepue and posterir renulum (Figs. 8-9 and 8-2).

Vetibule The vesibule is a smooth triangulr area bunded lterally the laba minora with th clitori at its pex and he fourhette at its base (Fgs. 8-19 and 8-29).

Vagnal Oriice Te vagina orifice is proteted in vrgins by a thin mcosal fod called the hymen, which is perfoated at ts centr (Fig. 8-1). A the firt coitus the hymn tears, usually osteriory or posterolateally, an after cildbirth only a f tags of the hymen remain (Fig. 8-19).

Oifices o the Ducs of the Greater Vestibular Glands mall oriices, on on each side, ar found i the grove betwen the hyen and te posteror part f the labium mnus (Fig. 8-19)

Clitors This is situted at the apex of the vesibule anteriorly (Fig 8-19. The glans of the citoris is party hidden by the prepce (Fig. 8-29). P420

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Fiure 8-29 The prineum i a 25-yer-old woan, infeior view. A. With labia tother. B. With laba separaed.

P.421

Cinical Poblem Soving Red the folowing se histoies and select the best anwer to te questin followng them. A 53-ear-old an complined tha for the past 4 yars he hd frequently ed blood-stained tools. Rcently, e had noticed that his “bwel― rotruded from his anus aftr defecaion, and this caued him onsiderale discofort. 1. The followin symptom and signs in thi patient were cosistent with a iagnosis of thirdegree nternal emorrhods excep which (a) The patint suffeed from ntense prianal iritation caused b the mucus secreions fro the proapsed muous membane. (b) roctoscoic examiation reealed thee pink wellings of mucou membran at the evel of he anal vlves. (c) Te swelligs were ituated t 1, 4, nd 9 o'cock with the patint in th lithotomy positin. (d The swelings buged downard when the patint was aked to srain. (e) Larg, congesed veins were see in the wellings f) The sellings emained utside te anus ater defeation. () Abrasin of the mucous mmbrane ws responible for the bleeng. View Answer 1. C. T swellings of internal hemorrhoids are situated at 3, 7, and 1 o'cloc with the patien in the lithotomy osition. These swllings ae cause by a diatation of the hree mai tributaies of te superir recta vein. A 42-yearold woma visited her physcian becuse she xperiencd an agonizing pan in the rectum, which occurred on efecation. She had first noticed te pain a week befre when he tried to defecate. The pain lasted for about an hur, then ed f, only o return with the next boel movemnt. She aid that she suffred from constipaion and itted that someimes her stools wre streaed with lood. Afer a caeful examination, a diagnois of nal fisure was ade. 2. Th followig statemnts concrning ths case ae correc except which?

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snell () Examintion of he anal anal was difficult because any attempt to inert a gled finger into the canal caused sevre pain. (b) The nus was ept tighly close by the pasm of he external anal sphincter. (c) Getle everion of te anal mrgin uner local anesthesa reveal the loer edge of a linear tear n the osterior wall of he anal anal; a mall tag of skin rojected from the lower end of the tear. (d The forard edge of a har fecal mss may hve caugh one of he anal valves an torn it downward as it decended. (e) Anal fisures ten to occu on the anterior and postrior wals of the anal canl becaus the mucus membane is porly supprted in his regin by the superfical exteral sphicter musce. (f) Th mucous embrane of the loer half of the nal cana is innervated by autonomic afferen nerves ad is sensitive oly to stetch. View Anwer 2. F. Te mucous membrane of the lwer half of the aal canal is innevated by the infeior rectl nerve nd is vey sensitve to pan, temprature, touch, an pressure A 16-ear-old oy was tking par in a biycle race when, on approaching a sep hill he stoo up on the pedals to increase the sped. His right fot slippe off the pedal an he fel violenty, his prineum itting te bar of the bicyce. Severl hours ater he was itd to th hospita unable o micturae. On exmination he was fund to hve extesive sweling of the penis nd scrotm. A diagosis of uptured urethra as made. 3. The followin statemets concering this case are correct xcept whh? (a) upture o the bulous part of the urethra had taken place. (b) he urine had escaped from te urethr and extavasated into the superfiial perieal pouh. () The uine had assed forward ovr the scotum and penis t enter th anterio abdominl wall. (d) Te urine ad extened posteiorly ino the ishiorecta fossae. (e) The rine was located beneath the membraus layer of supericial facia. View Aswer 3. D. The superficial peineal poch is clsed off osteriory by the attachmnt of th membranus layer of supericial facia to th posteror margin of the urogenitl diaphrgm. Becase of ths attacment the xtravasated urine cannot eter the schiorecal fossa. A 34-year-ld man ws sufferng from postopertive retntion of rine ater an appendectoy. The ptient's inary trct was oherwise normal. ecause te patient was in cnsiderabe discomort, the residen decided to cathete.

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snell 4. The follwing staements concerning the cathterization of a male patien are corect excet which? (a Because the extenal urethral orifce is the narrowet part o the urehra, once the tip of the cheter ha ed this poit, the frther pasage should be eas. (b Near th posterir end of the foss terminlis, a fld of mucous membrne projets from he roof nd may atch the end of te catheter. (c) Te membraous part of the urthra is arrow an fixed ad may prduce som resistace to th age of the catheter. (d The protatic pat of the urethra s the wdest and most easly dilatd part of the urethra and should case no dfficulty o the pasage of he catheter. () The bldder neck is surronded by the sphiter vesiae and aways strngly resists the assage of the tip of the cheter. View Anwer 4. E. Te bladde neck dos not case obstrction to he ae of the cathete. In thi patient the sphncter ma provide some minr resistance that is easil overcom. A 41-year-ld woman was seen in the eergency epartmen complaiing of a painful swelling in the rgion of he anus. On examintion, a ot, red, tender welling as found on the rght side of the aal margin A diagosis of schiorecal absces was mae. 5. The llowing tatement concernng this ase are robably correct eept whic? (a) An ischirectal ascess is common complication of anl fissur. (b) Te fat in the ischiorectal fossa is pone to infection hat migh extend aterally through he base of the ana fissure (c) The at in the ischioretal foss has a pofuse blod suppl. (d) A srgical icision o the absess shoud provide adequate drainage of the ps. (e) The surgon shoul avoid th inferi rectal nerve an vessels that cros the ishiorecta fossa fom the ateral t the medial side. View Answer 5. C The fat in the ischiorecta fossa hs a poor blood upply A 35-yearold woman was seen by her bstetrician and gecologist complaning of swellin in the enital rgion. On examinatn, a tense cysti swellin was foud beneat the posterior tw thirds f the rght labim majus nd minus. A diagnosis of a yst of te right greater estibula gland (artholins cyst) as made. 6 The folowing sttements oncernin this case are proably corect excet which?

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snell (a) he cyst f the grater vetibular land is roduced y the reention o secretin caused by the bockage o the duc. (b) Inction of the duct by the gnococcu is a common cause of the blockage. (c) Inection o the cys may occr, formig a painul absces. (d) Th lymphatc drainae of this area is into the lateral roup of uperficil inguinl nodes. (e) small tender sweing was etected elow and meial to te inguinl ligament. View Answer 6. . The lyphatic dainage o this ara is into the medil group f supericial inguinal noes situated below the inguial ligamnt. The spread o infectin can result in an enlargemnt of on of the odes, a in this case, whch becoms tender to palpaion. P.422

Review Qestions MultipleChoice Qustions Selet the bet answer for each questio. 1. The follwing staements cncerning the femae urethr are corect except which? (a) It lies immdiately nterior to the vagina. (b) It externa orifice lies abot 2 in. 5 cm) frm the cltoris. () It is bout 1.5 in. (3.7 cm) lon. d) It pierces the rogenita diaphram. (e) It i straigh, and ony minor esistance is felt s a catheter is pssed trough th urethra sphinctr. View nswer 1. B. The femae urethr opens ito the vtibule a the extrnal meaus about 1 in. (25 cm) beow the citoris. 2. The following structures can b palpated by a vanal examnation ecept whih? (a) Sigmoid olon (b) Uretes (c) rineal bdy

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snell (d Ischial spines (e) Ilipectinea line View Answer 2. E The ilipectineal line lies at the brim of te bony plvis and is far byond the reach of a vagina examinaion. 3. The following statements concernig the ishiorecta fossa ae correct except wich? a) The pdendal nrve lies in its lteral wal. (b) The floor is formed b the suprficial ascia an skin. (c The latral wall is forme by the bturator internus muscle ad its fascia. (d The medal wall s formed in part y the leator ani muscles. (e) The oof is formed by e urogeital diapragm. iew Answr 3 E. The roof of he ischirectal fssa is frmed by he juncton of the medial and lateral walls. The medil wall i formed y the slping leator ani muscle, nd the aal canal nd the lteral wall are formed by the lower part of he obturtor intenus musce, coverd with pelvic fasia. 4. Th followig statemnts concrning th penis ae correc except hich? () Its rot is fored in th midline by the blb of the penis, ich continues anteriorly s the copus spongiosum. (b) ts roots laterall are fored by th crura, hich coninue antriorly a the corpra cavernosa. (c) The penile uethra lis within the corps spongisum. (d) he glans penis is a distal xpansion of the fused corpra caverosa. (e The pens is susended from the lor part o the antrior abdminal wal by two condensaions of eep fascia. View Answer 4. D. The glan penis is a dista expansin of the corpus spongiosum. 5. The follwing staements concerning erineal tructure are corect excet which? (a) Th anorectl ring i formed y the sucutaneou, superficial, and deep fiers of te externl anal shincter. (b The uroenital daphragm s attachd lateraly to the inferio ramus of the pubi and the ischial ramus.

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snell (c) Te bulbouethral gands are situated in the dep perinal pouch (d) The anococcyeal body is rarel damaged in childbirth. (e) The lymp drainage of the skin around the anus is into the medial group f superfcial inguinal nodes. View Answer 5. A At the unction f the retum and nal cana the internal spincter, he deep art of te externl sphincer, and he puboectalis uscles frm a distinct ring, caled the norectal ring. 6. The urogenital diapragm is ormed by the follwing strctures ecept which? (a) eep tranverse peineal mucle (b) Perieal membane () Sphincer urethae (d Colles' fascia (embranou layer o superfiial fasci) (e) Paietal pevic fascia coverig the upper surfac of the phincter urethrae muscle View Answer 6. D. Colle' fascia (membranous layer of supercial fascia) take no par in the ormation of the uogenital diaphrag it is oo superficial an lies jut beneat the ski. 7. In the male the folowing stuctures an be papated on ectal exmination except wich? a) Bulb f the peis (b Urogenial diaphagm () Anorecal ring (d) Th anterio surface of the scrum (e) Ureer View Anwer 7. E. Te ureter cannot e felt o rectal xaminatin in bot sexes. A abnorml ureter thickend by disase, can be felt n vagina examintion. 8. The following statemets concening the anal canl are coect excet which? (a) It is about .5 in. (3.8 cm) ong. (b) It ierces te urogental diapragm. (c) It is relatd lateraly to th externa anal spincter.

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snell () It is he site of an imprtant potal–sytemic anstomosis (e) The mucous mmbrane of the lowr half receives it arteria supply rom the nferior rectal artery. View Answer 8. B. The anal canal lis posteror to th urogenial diaphrgm and, herefore does no pierce t. 9. The followi statemets concening the subcutanous part of the eternal al sphincer are correct exept whic? (a) It ecircles he anal cnal. (b) I is not tached to the anococcygeal body. (c) t is comosed of triated uscle fiers. (d) It is not rsponsibl for cauing the nal canal and rectm to joi at an aute angl. (e) It is inervated the midle recta nerve. View Anwer 9. E. Te subcutaneous par of the external nal sphicter is nnervate by the inferior ectal neve, whic is a brnch of t pudenda nerve. 10 The followin statements concerning defecation re corret excep which? (a) he act i often peceded b the entance of eces into the rectm, which gives rie to the desire t defecat. (b) The uscles o the antrior abdminal wal contrat. (c) Th externa anal spincters nd the pborectals relax. d) The iternal shincter ontracts and causs the evcuation f the fees. (e) The mucos membrae of the lower pat of the anal canl is extuded thrugh the nus ahea of the ecal mas. View nswer 10. D. The intenal anal sphinctr is relaxed durin defecaton. 11. The process f ejacultion depnds on te followngproceses except which? (a) The phincter of the badder cotracts. (b) The sympthetic peganglioic nerve fibers rising fom the first and second luar segments of th spinal cord mus be intat.

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snell (c) Te smooth muscle of the epididymis, ductus (v) deferens, seminl vesicls, and postate cntracts. (d) The bulburethral glands an the urthral glands are ative. () The bubospongisus musces relax View Aswer 11. E. During eaculatio, the bubospongisus muscs rhythmically cntract ad compres the urthra, focing the seminal luid out of the eternal matus. 12. he folloing strutures reeive innrvation om brances of th pudenda nerve ecept whih? () Labia inora (b) Urehral sphncter (c) The osterior fornix o the vagna d) Ischicavernoss muscle (e) Skin of he penis or clitois View nswer 12. C. The postrior fornx of the vagina i innervaed by th inferio hypogasric plexses. Read the cae history and selet the bt answer to the qestions ollowing it. Whil bathin her 5-mnth-old boy, a moher noticed that hs penis ended to curve dwnward. he decidd to see advice rom a peiatricia. 13. Te pediatician exmined th child ad made te following possibe correc observaions and statemens except which? (a) The pen had a definite dwnward curvature chordee) (b) Both testes wre in th scrotum (c The extrnal urehral meaus opene halfway along th udersurfce of th penis. (d) he fusio of the enital flds on he ventral or undsurface f the shft of th penis ws incompete so that the ethra opned on te ventra surface (e) he condition is a rare conenital aomaly. iew Answr 1. E. The clinical conditio is one f the comonest cngenital anomalie affecting the mae urethr. 14. Th pediatcian made the following pssible crrect sttements to the mher regading the diagnosis and tretment exept whic?

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snell (a) Th child hs hypospdias assciated wth chorde. (b) The proximal portion f the pile urethra had developed ormally ut was icomplete (c) he bud o cells (ctoderma) on the tip of he glans penis ha failed o grow ito the sustance o the glns and jin up wih the cels (entoermal cels) of te penile urethra (d The tretment s the sugical orrectio of the hordee, which is folloed by th plasti reconsruction f the peile urehra. (e) In view of the elicate issues ivolved, he treatent shoul be delaed until the chil is at last 10 yars old. View Anwer 14. E. The surgcal treament shold start at about the age f 2 year and be complete before the child goes to school. Little boys ike to look the same as oher litte boys. Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

10. 9. The Upper Limb A 6-year-ol woman fell down the stair and was itted to the eergency epartment with seere left shoulder ain. While she ws sittin up her eft arm was by her side and her left elbow ws flexed and supprted by er right hand. Inection o the let shouldr showed oss of te normal rounded curvature nd evidece of a slight selling below the lft clavile. The hysician then sytematically teste the cutaneous snsibilit of the eft upper limb ad found evere sensory defiits invoving the skin of he back f the am down a far as he elbow, the lower lateral surface f the ar down t the elbw, the mddle of he posterior surfe of the forearm as far a the writ, the lteral haf of the dorsal srface of the hand and th dorsal urface of the lateal three and a half finger proxima to the nail bed. diagnosis of suboracoid isloation of the lef shouldr t as made, complicaed by dmage to he axillry and adial neves. The ead of te humeru was dislaced downward to elow th coracoi process of the sapula by the initl trauma and was displace further y the pul of the muscles subscapuaris, pecoralis ajor). Te loss o shoulde curvatur was caued by th displaceent of he humers (greatr tuberoity) medally so hat it no longer ushed th overlyig muscle (deltoid lateraly. The extensive lss of sin sensaion to te left uer limb was the rsult of amage to the axilary and radial nrves. For physicin to be ble to mke a dianosis in this cas and to e able t interprt the clnical fidings, h or she mst have considerble knowldge of te anatom of the houlder oint. Furthermor, the phyician mut know te relatinship of the axillary and adial neves to te t and the ditributio of thes nerves o the parts of th upper lmb. P.426

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Chapter bjective 

 

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ain, fratures, dslocatios, and nrve injuries of te upper imb are ommonly een by te physician. Wrist and han injurie deserve particular attentin becaus the goa is to preserve a much fuction as possible The piner actio of the humb an index fger and he uniqu ability of the tumb to be drawn acoss the palm to he other fingers ust be peserved at all coss. A phsician must be faliar with the nerves, bons, s, tendos, and blod and lmphatic essels ad their anatomic relationsips. The basic anatoy of the breast i of coniderable clinical importane because of the frequent dvelopmen of caner in th glands nd the sbsequent isseminaion of te malignnt cells along th lymph vessels to the lymp nodes i the armit. The primary oncern o this chpter is o preset to the student the basic natomy o the uppr limb s that as a practcing medical profesional h or she ill be able to make an accuate diagosis and initiate prompt teatment.

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Basic natomy The uppr limb i a multiointed lver that is freel movabl on the runk at the shouler t. At the dstal end of the pper lim is the rehensile organ, te hand. uch of te importace of te hand depends on the pincrlike acion of te thumb, hich enales one to grasp objects between th thumb ad index inger. The upper limb is divied into he shouer (juncion of te trunk ith the rm), arm elbow, orearm, rist, an hand.

Th Pectora Region nd the Ailla The Beasts Location and Description The beasts ar specialized ry glads of th skin tht secrete milk (Fig. 9-1). They ar present in both exes. In males and immature females, they are similar n structre. The niples ae small nd surronded by colored area of kin called the areol. The breast tssue conists of system f ducts ebedded i connectve tisse that des not etend beyond the magin of the areola.

Puberty

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snell At pubety in feales, th breasts graduall enlarge and assme their hemispheical shae under he influece of th ovarian hormone (ig. 9-1). The ducts elngate, bt the icreased ize of he gland is mainy from te depositon of fa. The bse of th breast xtends from the seond to te sixth ib and rom the teral magin of te sternu to the idaxillary line. Te greatr part o the glad lies i the suprficial ascia. A small pat, calld the axillry tail (Fig. 9-1), extnds upwad and laerally, ierces te deep fascia at the lower border o the pecoralis mjor musce, and eters the axilla. Eac breast onsists f 15 to 0 obes, which rdiate ou from th nipple. The main duct fro each lobe opens eparatel on the ummit of the nippe and posesses a dilated amplla jut before its termnation. he base f the niple is srrounded by the areoa (Fig. 91). Tny tubercles on th areola re produed by th underlyng areolar lands. The lobs of the gland are separat by fibrus septa that sere as suspensory ligaents Fi. 9-1. Behind the breass is a sace filld by looe connecive tisse called the retromamary spae (Fig. 91).

Yong Women In yong women the breass tend t protrud forward from a crcular bse.

Pregnacy Ealy In he early months o pregnany, there is a rap increase in length and brnching i the duc system F. 9-2. The scretory lveoli dvelop at he ends f the smller ducs and th connective tisse becomes filled with expaning and udding ecretory alveoli The vascularity o the conective tssue als increass to prvide adeuate nourishment for the deeloping land. Th nipple enlarges and the areola bcomes darker and ore extesive as result of increaed deposts of meanin pigent in te epideris. The areolar gands enlrge and ecome more active

Lte Durng the scond half of pegnncy, the growth pocess sows. The breasts, however, continue to nlarge, mostly bcause of the diention f the seretory aveoli wih the flid secreion cald colosrum.

Postweaning Once the bab has bee weaned, the breats return to thei inactiv state. he remaiing milk is absorbed, the ecretory alveoli shrink, nd most f them dsappear. The interobular cnnective tissue hickens. The breats and te nipple shrink nd return nearly o their riginal ize. The pigmentaion of the areola ades, bu the ara never ightens o its orginal coor.

Postmenpause After th menopaue, the beast atrphies (Fig. 9-2). Most of he secrtory alveoli disapear, leving behid the duts. The amount o adipose tissue my increae or decease. Th breasts tend to shrink i

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snell size an become ore pendlous. Th atrophy after meopause s caused by an abence of oarian esrogens ad progeserone.

Blod Supply Arteies T branchs to the reasts iclude th perforaing braches of he interal thoraic arter and the intercosal arteres. The axillary artery aso supples the gand via its latera thoraci and thracoacroial branhes.

Vein The vins corrspond to the arteries.

Lymph Drainage The lmph draiage of te mamary gland is of great clinicl importnce becase of th frequen developent of cncer in the glan and the subsequet disseminaion of te malignnt cells along te lymph essels t the lymh nodes. The latera quadrants of the breast dain into the anteior axilary or pctoral group of ndes (Fig. 93) (tuated just posterior to the lower order of the pectralis maor musce). The edial qudrants dain by mans of vssels tht pierce the intrcostal paces an enter te internl thoracc group nodes situated within te thoracc cavity along th course f the inernal toracic atery). A few lymph vessels follow the poserir intercstal areries an drain psteriory into te posteior intecostal odes (stuated long the course o the poerior iercostal arteries); some vessels communicate with te lymph essels o the oppsite breast and with those of the aterior dominal all.

Clinical Notes Witch's Milk in t Newborn Whie the feus is in the uters, the mternal ad placetal hormnes cros the plcental brrier an cause poliferaton of te duct eithelium and the urroundig connective tiss. This roliferation may cause sweling of he mammay glands in both exes duing the irst wee of life in some cases a ilky flud, calle witch' milk, may be exprssed fro the niples. The conditio is reslved spotaneousl as the aternal ormone lvels in he child fall. P428

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Fiure 9-1 Mature breast n the feale. A Aerior view with kin partially removed to sow internal structure. B Sagittal section. C he axillry tail, which pirces the deep fasia and etends ino the axlla.

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Figure 9- Exten of the evelopmet of the ducts an secretoy alveol in the reasts i both sees at diferent sages of ctivity.

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Figure 9-3 Lymh drainae of the breast.

Cinical Ntes reast Exmination The beast is ne of th common ites of ancer in women. t is als the sit of diffrent typs of bengn tumor and may be subjct to ace inflamation and abscess formatio. For thse reasns, the linical ersonnel must be amiliar ith the evelopmet, strutur and lyph drainage of this organ. With the ptient undressed to the waist and siing uprght, the breasts re first inspecte for symetry. Soe degree of asymetry is ommon an is the result of unequal beast devlopment. Any swelling shold be noed. A swlling ca be causd by an nderlyin tumor, a cyst, r absces formatin. The niples shold be caefully xamined or evidece of retraction. A carcinoa within the breat substnce can ause retaction o the niple by puling on he lactferous dcts. The patien is then asked to lie down so that he breats can be palpated against the underying thoacic wal. Finall, the ptient is asked to sit up aain and aise bot arms abve her ead. Wit this maeuver, a carcinom 792

snell tethere to the in, the suspensory ligamets, or te lactifrous ducs producs dimplig of the skin or retractin of the nipple.

Mmmograph Mammgraphy i a radioraphic eaminatio of the reast (Fig 9-4). This technique i extensively used for screning the breasts or benig and maignant tmors and cysts. Etremely w doses f x-ray are use so that the dangers are minimal and the exaination an be repeated oten. Its success s based n the fat that a lesion masuring nly a fw millimters in diameter can be detcted lon before t is fel by cliical exaination.

Spernumerry and Rtracted ipples Supenumerary nipples ccasionaly occur along a line extnding frm the axlla to te groin; they may or may nt be asociated ith breat tissue (see page 42). This minor congenital anomaly may reult in a mistaken diagnosi of wars or mols. A lon-standin retracted nipple is a conenital eformity caused by a failur in the omplete evelopmet of the nipple. A retraced nippl of recet occurrnce is uually cased by a underling carcnoma puling on te lactifrous ducs.

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Figure 9-4 Mdiolateal mammoram shoing the landula tissue e by the onnective tissue septa.

The Iportance of Fibros Septa The nterior f the brast is dvided ino 15 to 0 compatments tat radiae from te nipple by fibros septa hat exted from he deep urface o the ski. Each cmpartmen contain a lobe of the gand. Norally, the skin fels compltely moble over he breas substace. However, should the fious septa become involved in a scirhos carcioma or i a disese such s a breast abscess, which results in

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snell the pruction of contrating fibous tisse, the spta will be pulld on, casing dimling of he skin. The fibrus septa are someimes refrred to as the supensory igaments of the mmmary glnd. An acte infection of the mammary gland may occur dring latation. Pathogeni bacteri gain enrance to the breat tissue through a crack n the niple. Becuse of te presene of the fibrous septa, the infection emains ocalized to one cmpartmen or lobe to begi with. Ascesses ould be drained through a radial incision to avoid sreading f the inection ito neighoring copartment; a radal incison also nimizes the damae to the radially arranged ducts.

Lymh Drainae and Cacinoma o the Brest The imprtance o knowing the lymp drainage of th breast in relaton to th spread of cancer from tha organ cannot be overemphsized. T lymph vessels from the meial quadants of he breat pierce the secod, third and fouth interostal spces and enter th thorax o drain nto the ymph nodes alongside the internal toracic tery. Th lymph vssels frm the laeral quarants of the brest drain into the anterior or pectoal group of axillry nodes It folows, theefore, that a cancer occurrng in th lateral quadrant of the breast tnds to sread to he axillry nodes Thoracic metastas are ifficult or imposible to reat, but the lymph nodes of the axla can be removed surgically. Apprximately 60% of crcinomas of the beast occur in the upper leral quarant. Th lymphatic spread f cancer to the opposite breast, o the abominal cvity, or into lyph nodes in the oot of te neck i caused y obstrution of he norma lymphatc pathwys by maignant cells or destruction of lymp vessels y surger or radotherapy The caner cell are swet along he lymph vessels nd follw the lyph stream The entrance of cancer clls into the bloo vessel for the metastass in disant bone. In patents wit localizd cancer of the beast, mot surgens do a imple mastectomy r a lumpctomy, fllowed by radiotherapy to he axillry lymph nodes an/or hormne theray. In ptients wth localzed cancr of the breast wth early metastass in th axillar lymph ndes, most authorites agree that radcal matectomy ffers th best cance of ure. In atients n whom te diseae has aleady sprad beyond these areas (eg., into the thorx), simle mastectomy, followed by radiotherapy or rmone therapy, is the tretment of choice. Rdical matectomy s designd to remve the pimary tmor and he lymph vessels d nodes that dran the ara. This means that the breast and e associted strutures cotaining he lymph vessels and node must be removed en bloc. The excised mass is therefre made up of th followig: a lare area o skin ovrlying te tumor and inclding the nipple; ll the beast tisue; the pectoralis major and assocted fasca throuh which he lymph vessels to the internal thoraic nodes the pecoralis minor and associated fascia elated t the lymh vessel ing to the ailla; al the fat fascia and lymh nodes n the axlla; and the fasca coverig the upper part of the rtus sheath, the serratus anterior, the subsapularis and the latissimus dorsi uscles. he axillry blood vessels the brahial pleus, and he nervs to the serratus anterior and the latissims dorsi are presrved. Soe degree of postoperative edema of the arm is likel to follw such a radical emoval o the lyph vesses draini the uper limb.

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snell A modifed form f radica mastectmy for ptients wth clincally loalized cncer is lso a comon procdure and consists of a siple mastctomy in which the pectora muscles are left intact. The axilary lymph nodes, fat, and fasca are reoved. Ths procedre remoes the pimary tuor and prmits pahologic xamination of the lymph noes for pssible mtastases P.431

P.432

Embyologic Notes Developmnt of th Breasts In he young embryo a linear tickening of ectodrm appeas called the milk rige, hich extnds from the axila obliquely to the inguinal region In anials, sevral mammry gland are ford along this ridg. In the human, he ridge disappeas except for a small part i the pecoral reion. Thi localizd area tickens, becomes slghtly deressed, nd send off 15 o 20 sold cords, which grow into the underlyng mesechyme. Meanwhile the underlying mesenchyme roliferaes, and he deprssed ectdermal tickening becomes aised to form the niple. t the fith month the areola is recgnized a a circuar pigmeted area of skin round th future ipple.

Polyhelia Supernumerary nippes occasonally ccur along a line correspoding to he positon of th milk rige. They are liabe to be mistaken or moles

Retractd Nipple or Invered Nippl Rtracted ipple is a failur in the evelopmet of the nipple uring it later sages. It is imporant clinically, because nomal sucking of a infant annot tae place, and the ipple is prone t infectin (see aso page 43).

Miromastia An excssively mall brest on one side occasionall occurs, resultin from lak of devlopment.

Macromstia Dffuse hyertrophy of one o both brasts occsionally occurs a puberty in otherise norml girls.

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Gynecomstia Unilatera or bilateral enlargement f the mae breast occasionally occus, usualy at pubrty. The cause is unknown, but the conditio is probably relatd to soe form of hormnal imbaance.

Bones of the Soulder Grdle and Arm The shoulder girle consits of th clavicl and the scapula, which ariculate ith one nother a the acrmioclaviular joit.

Clavicle Th clavicl is a log, slendr bone tat lies horizontlly acros the rot of the neck jus beneath the skin It articulates with the sternum a first costal carilage edially nd wit the acrmion proess of the scapua lateraly (Fig. 9-). Th clavicl acts as a strut hat hold the arm away fro the truk. It aso transits forcs from te upper imb to te axial skeleton and provides attament for muscles. The medial two thirds of te clavice is conex forwad and is latera third i concave forward. The impotant musles and ligament attache to the lavicle re shown in Figure 96. .433

Clinica Notes Fractures of th Clavicl Th clavicl is a stut that olds the arm lateally so that it an move reely on the trun. Unfortnately, ecause o its poition, it is exposd to trama and tansmits orces frm the uper limb to the tunk. It is the most commonly fracture bone in the body. The racture sually occurs as result f a fall on the soulder o outstrtched had. The frce is tansmitte along the clavicl, which breaks a its weaest poit, the jnction f the midle and uter thrds. Aftr the frcture, te lateral fragment is depressed by the weig of the arm, and it is pulled medialy and frward by the strog adducor muscls of the shoulder t, epecially the pectralis mjor. The medial ed is tiled upwar by the sternocleidomastoid muscle The close reationshi of the upraclavcular neves to he clavile may rsult in heir invlvement n callus formatio after fracture of the bon. This my be th cause o persistnt pain ver the side of he neck.

Compresson of th Brachia Plexus, Subclavin Artery and Sublavian Vin by th Clavicl

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snell The interval between he clavile and te first ib in sme patiets may become narrowed and thus is esponsib for copression of nerve and blod vessel. (See discussion of thoracic outlet sndrome o page 52.)

Fiure 9-5 Muscle attachmets to t bones of the thorax, clavicle, scapula, and humerus

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Figue 9-6 mportant muscular and ligamentous attachment to the ight claicle.

Scaula Th scapula is a fla trianguar bone Fi. 9-7 that lis on the posterior chest wall betwen the seond and e seventh ribs. O its poserior suface, th sine of te scapul projects backward. Th lateral end of the spine free ad forms he acromion, which articulaes with he clavile. The uperolatral angl of the capula frms the pear-shap lenoid cvity, r fossa, which ariculates with the head of he humers at the shoulder t. Te oracoid rocess projecs upward and forward above he glenod cavity and provdes attchment fr muscle and ligments. Mdial to the base the coracoid process is the suprasular notch (Fig. -7). The aterior urface o the scaula is oncave ad forms the shalow subscaplar foss. The posterio surface of the sula is ivided b the spie into te upraspinus fossa above and an infrspinous ossa elow (Fig. -5). Te nferior ngle of the sapula can be palpaed easil in the iving suject and marks te level f the seenth rib and the pine of he seventh thoracic vertea. The imprtat muscles and ligament attache to the capula ae shown n Figure 9-7.

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ractures of the Sapula Fractues of th scapula are usualy the rsult of severe tauma, suh as occrs in ru-over acident vitims or n occupnts of atomobile involve in crases. Injuies are ually asociated with frctured ribs. Most fracture of the capula rquire lttle tretment because the muscles the anterior and posterior surfaces adequtely splnt the fagments.

Dropped houlder nd Winge Scapula Th positio of the capula o the poserior wal of the thorax s maintaned by te tone ad balanc of the uscles attached to it. If one of tese musces is paralyzed, the balance is upse, as in dropped houlder, which occurs with paralysi of the rapezius or wined scapua (Fig. 9-8), caued by paralysis of the serratus antior. Such imbalance can be detected by carefl physicl examintion. P.435

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Figue 9-7 Importnt muscuar and lgamentou attachmnts to e right scapula.

Humerus The humeus articlates wih the sula at he shouler and with the radius and una at th elbow jint. The upper en of the humerus as a head (ig. 9-9), whih forms bout one third of a spher and artculates ith the glenoid avity of the scapla. Immeiately blow the ead is te natomic eck. elow the neck are the greater and lessr tuberoities, separate from eah other y the bicipital groove. Whre the uper end f the huerus jois the shft is a arrow surgial neck. About halfway wn the lteral aspect of te shaft s a rougened eleation caled the deloid tubeosity Behind nd below the tubeosity is a piral grove, wich accomodates he radia nerve (Fig 9-9) The lower end of the hmerus posesses te edial and lateral epicondyes fo the attchment o muscles and ligaments, the rounded caitulum for artiulation ith the ead of te radius and the pulley-shaped trochea for articulaion with the troclear noth of the ulna (Fig. -9). Aove the apitulum is the radal fossa, which receives the head of the rdius whe the elbw is fleed. Abov the trohlea antriorly s the corooid fosa, whih during the same movement receives the corooid procss of th ulna. Aove the rochlea posteriorly P.436

is the olecranon fossa, wich receves the lecranon process f the ula when te elbow oint is xtended Fi. 9-9.

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Figue 9-8 inging f the right scapua.

Figure -9 Imortant mscular ad ligamentous attahments t the rigt humeru.

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Clinical otes ractures of the Poximal Ed of the Humerus

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Hmeral Hed Fractues Factures f the hueral hea (ig. 9-10) can occur duing the rocess o anterio and poserior dilocations of the houlder oint. Th fibrocatilaginos glenoi labrum f the sapula prduces th fractur, and th labrum an becom jammed n the dfect, maing redution of he shouler t difficult.

Greater Tuberosity Fractres The greater tuberosity of the humeus can be fractur by dirct trauma, displaced by the glenoid labrum during disocation f the shoulder jint, or vulsed b violent contractons of te suprapinatus uscle. Te bone fagment wll have the attachents of the supraspinatus teres mnor, and infraspiatus musles, whoe tendo form part of th rotator cuff. Whn associated with shoulde disloction, seere tearng of th cuff wih the frcture ca result n the geater tuerosity emaining displace posterioly afte the sholder joit has ben reduce. In thi situation, open reduction of the racture is necessary to attach the rtator cuf back ito place

Lesse Tuberosty Fractes ccasionally, a leser tubeosity frcture acompanies posterir disloction of he shouler . The boe fragmet receivs the isertion f the suscapularis tendon F. 9-10), a par of the otator cff.

Surgial Neck ractures The urgical eck of te humeru (ig. 9-10), which lies immediate distal to the lsser tubrosity, an be fractured by a dire blow on the lateral aspec of the houlder r in an indirect manner falling on the outstretched hand.

Frctures o the Shat of the Humerus Frcturs o the humral shft are ommon; dsplacemet of th fragmens depend on the elation f the sie of frature to he insetion of he deltod muscle (Fig. 9-1). Wen the facture lne is prximal to the deltid inserion, the proxima fragmen is adduted by te pectorlis major, latissmus dori, and teres major muscles; the distl fragmet is puled proxmally by the deltid, bices, and ticeps. Wen the fracture i distal to the dltoid inertion, he proxial fragmnt is abucted b the detoid, an the disal fragmnt is puled proxmally by he bicep and trceps. Th radial erve can be damagd where t lies i the spral grooe on the posterio surface of the humerus unr cover f the triceps mucle.

ractures of the Dstal End of the Hmerus Supacondyla fracturs (Fig. 9-1) are common i childre and occr when te child alls on he outsretched and with the elbo partialy flexed Injurie to the median, adial, ad ulnar erves ar not uncmmon, alhough fution usally quikly retuns after reductio of the racture. Damage to or presure on te brachil artery can occu at the ime of te fractue or frm swelli of the urroundig tissue; the ciculation to the orearm my be intrfered wth, leadng to Vokmann's schemic contractre (see pag 483). 804

snell Th medial picondyl (ig. 9-10) can e avulsd by the medial collateral ligament of the ebow if the forearm s forciby abduced. The lnar nere can be injured at the ime of he fractre, can ecome involved lter in e repair proces of the fracture (in the callus), o can undrgo irriation on the irrgular boy surfac after te bone fagments re reunid. he imporant musces and lgaments ttached o the huerus are shown in Fiure 9-9.

The Axila The xilla, or armpit, is a pyramid-shaped space between he uppe part of the arm ad the sde of the chest (Fig 9-11) It fors an imprtant pasage for nerves, lood, an lymph vssels as they trvel from the root of the nck to th upper lmb. The pper end of the xilla, o aex, is directed into th root of the neck and is bunded in front by the clavcle, behnd by te upper order of the scapla, and edially y the ouer borde of the first ri (ig. 9-11). The lower en, or base is bouded in font by te anterir axillay fold (ormed by the lowe border f the pctoralis major mscle), bhind by the posterior axillary fold (formed y the tendon of latissimus dorsi and the teres major muscle) and medlly by the chest all (Fig. 9-11).

alls of he Axill The alls of he axill are mad up as fllows:    

Anerior wal: By the pecoralis mjor, sublavius, nd pectolis minor muscles (Figs. 9-12, 913 and 9-14) Posterior wall: By the subscapuaris, laissimus orsi, an teres mjor musces from bove dow (igs. 9-1, 9-14 915, an 916) Medial wll: B the uppr four o five ris and th intercotal spacs covere by the erratus nterior uscle (Figs 9-14, 9-15, an 916) Lateral wall: By te coracorachiali and bis muscles in the bicipita groove the hurus (Figs. 9-14, 9-15, and 9-6)

The base is formd by the skin strtching btween th anterio and poserior wals (Fig. 9-4). The ailla conains the principa vessels and nervs to the upper lib and may lymph nodes. The oriins, insrtions, erve suply, and ctions o the musles forming the walls of te axilla are descibed in Tabes 9-1 92, and 93. P.438

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Figur 9-10 A Common ractures of the hmerus. B Common ractures of the rdius and ulna. Th displacment of he bony fragment on the ite of te fractue line ad the pul of the muscles. S, suprspinatus D, deltid; PM, ectorali major; F, pull f common flexure muscles; TR, tris; SUB, subscapularis.

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Figur 9-11 Inlet, walls, and outlet o the rigt axilla

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Figure 912 Petoral reion and xilla.

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Figur 9-13 ectoral egion an axilla; the pectralis maor muscl has bee removed to disply the unerlying tructure.

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Figre 9-14 Structures that orm the alls of he axill. The laeral wal is indiated by he arrow able 9-1 Muscls Connecing the pper Lim to the horacic Wall

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Muscle

Oigin

Insertion

Nerve Supply

Neve Rootsa Action

Petoralis ajor

Clavicl, sternum, and uppr six ctal cartlages

Lateral lip of bicipital grooe of hurus

Media and latral pectral nervs from bachial pexus

C5 6, , 8; T

Adcts arm and rotates it medally; clavicular ibers alo flex am

ectorali minor

Third fourth, and fifth ribs

Coracod proces of scapla

Medial pctoral nrve from brachial plexus

C6 7, 8

epresses point of shoulder; if the capula i fixed, it elevate the rib of orign

Subclavis

Fist costa cartilage

Cavicle

Nerve to subclavus from pper truk of brahial pleus

5, 6

Depresss the clvicle an steadie this boe during ovements of the soulder grdle

Seratus anerior

Uppe eight rbs

Medial order an inferio angle f scapul

Long horacic erve

C5, 6, 7

Daws the capula frward arund the horacic all; rottes scapula

a

The prdominant nerve roo supply s indicaed by bodface tye.

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able 9-2 Muscls Connecting the pper Lim to the Vrtebral olumn

Musce

Origin

Inertion

Nere Supply

erve Roosa

Action

Traezius

Occipital bone, lgamentum nuchae, pine of eventh crvical vrtebra, pines of all thorcic vertbrae

Upper fibers ito laterl third f clavice; middl and lowr fibers into acrion and spine of scapula

Spinal part of ry nerv (motor) and C3 ad 4 (sensory)

XI craial nerv (spinl part)

Uppr fibers elevate he scapua; middle fibers pull scaula medally; loer fiber pull medial boder of sapula doward

Latisimus dosi

Iliac crest, lumbar fascia, pines of lower si thoraci vertebre, lower three or four rib, and inerior anle of sula

Floor of bicipital grove of hmerus

Thoracodorsal nerve

C6, 7, 8

Extends, adducts, and edially otates te arm

Levator scapulae

Transverse processes of first four cevical

Mdial borer of

C3 and 4 and dosal scaplar nerv

3, 4, 5

Raises medial brder of

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vertebrae

sula

Romboid mnor

igamentu nuchae nd spine of seveth cervicl and fist thoraic verterae

edial boder of sapula

Dorsa scapula nerve

C, 5

Raises mdial borer of sula upwrd and mdially

Rhomoid majo

econd to fift thoraci spines

Media border of scapua

Dorsal scapular nerve

C4, 5

Rises medal borde of scapla upward and medially

a

scapula

The pedominant nerve rot supply is indited by boldface tpe.

Tale 9-3 Muscles Connecting the Scapula to the Humerus

Muscle Deltoi

Orgin Latral thir of clavicle, acromion, spne of sula

Inserton

Nerve Spply

Midle of laeral surace of saft of hmerus

814

Axillary nerve

Nerv Rootsa C5,

Acion Abducts arm; anterior fibers flex and mdially rate arm; posterio r fibers xtend an

snell

laterally rotate arm

Spraspinau s

Spraspinos fossa f scapul

reater tberosity of humers; capsue of sholder joit

Supracapula r erve

C4, 5, 6

Abduct arm and stabilize s shouldr t

Infraspnatu s

Infraspnou s fosa of scaula

Greate tuberost y of huerus; casule of houlder t

Supascapula nerve

(C4) ,56

Laerally rtates ar and stailizes soulder jint

Teres maor

Lwer thir of lateal borde of scapla

Media lip of bicipital groove o humerus

wer subcapular nerve

C6, 7

Mdially tates and adducts arm and stabilize s shoulde t

Teres minor

Upper to thirds of laterl border of scapua

Greater tuberosi y of humrus; capsule of

Axilary nere

(C), C, 6

Lateraly rotate arm and stabilizs shouldr

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soulder jint

Subsapulari s

a

Sbscapula fossa

Lesser tubrosity o humerus

t

pper and lower suscapular nerves

The redominat nerve oot suppy is indcated by boldface type.

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C5, 6, 7

Medialy rotate arm and stabilize s shouldr t

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Figure 9-15 Pectorl region and axilla; the pectoralis major an minor mscles an the cavipectoral fasci have ben remove to dispay the uderlying structues.

Ky Muscle in the xilla Pectorlis Mino The pectorals minor is a thin triangulr muscle that lie beneath the pectralis major (Fig. 9-3). arises from the third, fourth, and fifth ris and rus upward and laerally t be inseted by its apex ito the cracoid pocess of the scaula. It rosses te axillay artery and the rachial lexus of nerves. It is usd when dscribing the axilary artery to divde it ito three parts (see page 445).

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Clinica Notes Absent Pectorals Major Occasionally, parts of the pectralis maor muscle may be absent. Te sternoostal orgin is te most cmmonly mssing pat, and his causs weaknes in addction an medial otation of the shoulder jint. .444

Figur 9-16 Dissection of the right ailla. The pectoras major and mino muscles and the

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clavipecoral fasia have been remoed to diplay the underlyng structures.

Clvipectorl Fascia The lavipectral fasca is a srong shet of connective tsue that is attaced above to the clavicle (Figs. 9-13 and 9-14). Below it splis to encose the ectorali minor mscle and hen continues donward as the sspensory ligament of the ailla nd s the fascal floor of the armpit.

Contents of the Ailla The axila contais the axllary arery and ts branhes, whih supply lood to he upper limb; th axillar vein an its trbutaries which drain blood from the upper lib; and lmph vesels and ymph nods, which drain lyph from he upper limb and the brest and fom the sin of the trunk, down as f as the level of he umbiicus. Lyng among these stuctures n the illa is an imporant nere plexus, the bracial plexus, whic innervats the uper limb. These sructures are embeded in ft.

Axllary Arery Te axillay artery (Fgs. 9-12, 9-13, 9-5, an 9-16) beins at te latera border f the fist rib as a continuation o the subavian (Fig. 9-17) and end at the ower border of th teres mjor musce, where it continues as he brachial artery. Througut its course, th artery s closly related to the ords of he brachal plexu and ther branchs and i enclose with them in a cnective issue shath calld the axillary sheat. If his sheah is traed upwar into th root P445

of the neck it is seen to be continuou with th prevertbral fasia.

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Figure 9-17 Pats of th axillar artery nd its banches. ote formtion of the axilary vein at the lwer bordr of the teres major muscle.

The pctoralis minor mucle croses in frnt of th axillar artery nd divides it into three parts (Figs. 13, 9-15, and 9-1).

Firt Part o the Axilary Artery This extnds from he laterl border of the frst rib o the uper borde of the ectorali minor (Fig 9-17)

elations    

Anterorly: he pectalis major and te skin. The cephalc vein rosses th artery Fis. 9-13 and 9-15). Posteiorly: The long thoracic nerve (nrve to te serrats anteri) (Fig. 9-15) Lateraly: Th three crds of te brachial plexus (Fig. 9-15) Medally: he axillary vein Fi. 9-15 and 9-16)

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cond Pat of the Axillary rtery This ies behid the petoralis inor musle (Fig. 9-7).

Relations    

Anterioly: Te pectorlis mino, the petoralis ajor, an the skin (Fgs. 9-1 and 9-17) Posterirly: e posterior cord of the brachial plexus, the subscapuaris musle, and he shouler t (Fg. 9-15) Laterlly: Te latera cord of the bracial plexs (Figs. 9-3, 9-15, and 9-16) Mdially: The meial cord of the bachial pexus and the axilary vein (Figs. 9-15, 9-16, ad 9-20)

hird Part of the Axillary Artery Thi extends from the lower boder of te pectorlis mino to the ower borer of th teres mjor (Fig. 9-17).

Reations    

Anterioly: Te pectorlis majo for a sort distnce; lowr down the artery it is crssed by he media root of the medin nerve (Fig. 9-13. Poteriorly The sbscapulais, the latissimu dorsi, and the eres majo. The axllary an radial erves alo lie beind the rtery (Figs. 9-15 and 9-16 Lterally: The cracobracialis, te biceps and the humerus. The lateal root f the mdian and the musclocutaneus nerve also li on the ateral sde (Figs. -13 an 916). edially: The ular nerve the axilary vei, and th medial utaneous nerve of the arm Fig. 913

Branches of the Aillary Atery From th first prt: 

The highst thoraic artery is smll and rns along the uppe border f the petoralis inor.

Frm the second part:  

The thoracocromial rtery immediatly divides into terminal branches. The lateral thracic artery rus along he lower border o the pecoralis mnor (Fig. 917).

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Figu 9-18 The formtion of he main arts of he brachal plexu. Note t locations of th differet parts.

From the thir part:  

The suscapular artery runs alng the lwer bordr of the subscapuris musce. The anteror and psterior ircumfle humeral arteries wind round th front ad the bak of the surgical neck of he humers, respetively (Fig 9-17)

Clinial Notes The xillary heath an a Brachal Plexu Nerve Bock Becase the aillary seath encoses the axillary vessels and the brachial pexus, a rachial plexus neve block can easly be obained. Te distal part of he sheath is close with figer presure, an a syrine needle is inserted into the proximal part of the seath. Th anestheic soluton is thn injectd into te sheath and the solutio is massed along the sheah to prouce the erve blck. The osition f the shath can e veriied by feling th pulsatons of te third rt of the axillar artery.

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Axillary Vein he axillry vein (Fi. 9-12) is fomed at the lower border of he teres major mucle by te union f the vnae comiantes of the brachial artery and th basilic vein (Fig. -17). It runs pward on the medil side o the axilary artry and eds at te latera border o the firt rib by becoming the subcavian ven. The vein receives tributares, whic correspd to the branches of the aillary atery, an the cepalic vei.

Clinial Notes Sponaneous Trombosis of the Aillary Vin Spontanous throbosis of the axilary vein occasionlly occs after excessive and unacustomed movements of the am at the shoulde t.

Brahial Pleus Th nerves ntering he upper limb proide the ollowing importat functins: sensry inneration to the skin and deep structues, such s the jonts; motr innervtion to he muscls; influence ove the diameters of the bloo vessels by the smpatheti vasomotor nerves and symathetic ecretomoor suppl to the weat glnds. At the root of the neck the nerves form complicted plexs called the brachia plexus. This llows th nerve fbers derved from different segments of the sinal cor to P.447

be arranged ad distriuted effciently n differnt nerve trunks to the vaous part of the upper limb. The brchial plxus is frmed in the postrior tringle of he neck y the unon of the anterio rami of the fif, sixth, seventh, and eighh cervicl and th first toracic pinal neves (Figs. -18 and 9-19). The plexus ca be divied into roots, trunks, divisins, ad ords Fi. 9-18). The roots of C and 6 unte to fom the uppe trunk the roo of C7 continue as the midle trun, and the root of C8 and T1 unte to fom the lower trunk Each tunk then ivides ito anteror and psterior ivisions The anerior diisions o the uppr and middle trunks unite form th ateral crd, th anterio divisio of the ower truk contines as th mdial cor, and the posterior diviions of ll three trunks jin to fom the posterior cord The rots, truns, and dvisions f the brchial plxus resde in th lower prt of th posterir triange of the neck and are ful deidoub on pag 771. Th cords bcome arraged aroud the aillary atery in he axill (ig. 9-15). Her, the brachial plus and the axillary artery and vein are enclsed in te axillay sheath

Cords of the Bracial Plexs

823

snell Al three ords of he brachal plexu lie aboe and laeral to the first art of te axillay artery (Fgs. 915 and 9-20). The edial cod crosse behind he arter to reac the meial side of the scond par of the rtery (Fig. 9-20). The poserior cod lies bhind the second prt of th artery, and the ateral crd lies n the laeral sid of the second par of the rtery (Fig. 9-20) Thus, he cords of the plexus have the reltionship to the second par of the xillary artery tht is indcated by their naes.

Figure 9-19 oots, trunks, divisions, crds, and terminal ranches of te brachial plexu.

ost branhes of te cords hat form the main nerve tunks of he upper limb coninue thi relatioship to he arter in its third pat (Fig. 9-2). Te ranches of the differen parts o the brahial pleus (Figs. 919 an 9-21) ar as follws: 

Roots Dorsal scapular nerve (C) Log thoracc nerve C5, 6, ad 7)



Uppe trunk

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snell Nerve to subcavius (5 and 6) Supascapula nerve (upplies he suprapinatus nd infrainatus muscles) 

Lateral cord Laterl pectorl nerve Muscuocutaneos nerve Laterl root o median nerve P448



Media cord Medial pectoral nerve Medial utaneous nerve of arm and edial cuaneous nrve of frearm Ular nerve Media root of median nrve



Posteror cord Upper and lowe subscaplar neres Thoracodorsal nrve xillary nerve Radial nerve

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Figure 9-20 A Reltions of the brhial plus and its brances to th axillay artery and vei. B Section throgh the ailla at he level of the tres major muscl

The branhes of te brachil plexu and their distribution are ummarize in Table 9-4.

Brances of te Brachil Plexus Found i the Axila The nerve to te subclaius (C5 and 6) supplies the sublavius mscle (Figs. 9-15 9-19, nd 9-20) It is mportant clinically becaue it may give a cntributin (C5) o the prenic neve; this branch, when prsent, is referred to as the ccessory phrenic nerve.

826

snell The lon thoraci nerve (C5, 6, and 7) arises rom the oots of the brahial pleus in te neck ad enter the axlla by pssing dwn over he laterl border of the frst rib behind the axillary vesses and brchial plxus (Figs. 9-15 ad P.449

9-9). It descends over th lateral surface f the seratus aterior mscle, which it spplies.

Figue 9-21 Distribtion of he main branches of the bachial pexus to differen fascia compartents of the arm nd foream.

The lateral ectoral nerve arises fom the ateral crd of the brachil plexus and suppies the ectoral major muscle (Figs. 9-13 and 9-2). The muscuocutaneous nerve arise from th lateral cord of he brachal plexu, supplies the coracobrachialis muscle, and eaves th axilla y piercig that mscle (Figs. 9-13 nd -20). A sumary of the compete distribution o the musulocutanous nerv is given in Figure -22.

827

snell The lateral root of he media nerve is the irect cotinuatio of the ateral cord of th brachia plexus Figs. 9-13 and 9-19. It is ed the medal root o form te median nerve trnk, and this pases downwrd on th lateral side of the axillay artery The meian nerv gives of no braches in the axilla The medial pectoral nerve arises from the medial crd of th brachia plexus, supplies and pieces the ectorali minor muscle, and supplies the pectralis maor musce (Fig. 9-1). The medil cutaneus nerve of the am (T1) arises fom the mdial cor of the rachial lexus (Figs 912 and 9-20) and is oined by the intecostobrahial nere (laterl cutaneus branch of the econd itercostal nerve). t supplis the skn on the medial ide of te arm. Te edial cuaneous erve of the forearm arises from the media cord of he brachal plexu and desends in ront of he axillary arter (Fig. 9-20). Th unar nerv (C8 nd T1) rises frm the meial cord of the bachial pxus and escends n the iterval btween th axillar artery nd vein Fis. 9-13 and 9-20). The unar nerve gives of no braches in he axill. A summry of th complete distribion of te ulnar erve is iven in Figre 9-23. Th mdial rot of the median nrve rises from the medal cord f the brchial plxus and rosses i front f the third part f the axilary artry to jon the laeral roo of the median nrve (Figs. -13 and 20). summary diagram f the coplete ditributio of the median neve is gien in Figur 9-22. The uper and lwer subsapular nrves rise fro the poserior cod of the brachial plexus ad supply the uppr and lor parts f the suscapulars muscle In addition, the lower suscapular nrve supplies the eres musle (Figs. 915 and 9-19). P.450

Table -4 Sumary of he Brances of th Brachial Plexus ad Their istributn Branhes

Distriution

oots

Doral scapuar nerve (C5)

Rhombid minor rhomboid major, lvator sulae mucles

Long thoacic nere (C5, 6,

Serratu anterio muscle

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7)

Uppe Trunk

Sprascapuar nerve (C5, 6)

Supraspinatus and infrspinatus muscles

Nerve t subclavus (C5, )

ubclaviu

Laterl Cord

Lateral peoral nerve (C5, 6 7)

Pectorlis majo muscle

Musculoctaneous erve (C5 6, 7)

Corcobrachilis, bis brachii, brachialis musles; suplies ski along lateral borer of frearm whn it becmes the ateral ctaneous nerve of forearm

Laeral roo of median nerve (5, 6, 7)

See media root of median neve

osterior Cord

Uppr subscaular nere (C5, 6

Sbscapulais muscl

Thoracodrsal ner (C6, 7, 8)

Latissius dorsi uscle

Loer subsular neve

ubscapulris and eres majr muscle

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(C5, )

Axillry nerve (C5, 6)

Deloid and eres minr muscle; upper ateral ctaneous erve of rm supples skin ver lowe half of deltoid uscle

Radial nrve (C5, 6, 7, 8; T1)

Triceps anconeu, part o brachilis, extnsor cari radials longus; via deepradial nrve branch supples extensor muscle of forerm: supiator, extnsorcarp radiali brevis extensor carpi ulnaris, etensor dgitorum, xtensor digitimiimi, extsor indiis, abdutor polliis longu, extensor pollics longus extenso pollicis brevis; kin, lowr lateral cutaneos nerve f arm, psteriorctaneous nrve of am, and psterior cutaneou nerve o forearm skin onateral sde of dorum of had and drsal surace of leral thre and a alffinges; articular brances to ebow, writ, and hnd

Medial ord

Medial pectora nerve (8; T1)

Petoralis major an minor mscles

Mdial cutneous nere of arm ed b intercotal bracial nerve from send intercostal nerve (C8; 1, 2)

Ski of medil side of arm

Medal cutanous nerv of forerm (C8; 1)

Skin o medial ide of frearm

Ular nerve (C8; T1)

Fleor carpi ulnaris nd medial half o flexor dgitorum rofundus flexor gitiminii, oppoens digii minimi abductor digiti mnimi, aductor policis, hird and

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fourth lmbricals, introssei, palmaris brevis, skin of medial alf ofdosum of hnd and plm, ski of palmar and doral surfces of mdial onend a ha finger

Medial rot of meian nerv (with lteral rot) forms median nve (C5, 6, 7, 8; T1)

ronator teres, flxor carpi radials, palmais longus, flexor digitorum superficalis, aductor ollicis revis, fexor pollicis brevis, opponens pollis, firs twolumricals (y way of anterior interossous branh), flexr pollicis longs, flexo digitorm profunus (lateal half) pronator quadratu; palma cutaneosbranch o lateral half of alm and igital banches t palmar surface f lateralhree and a half fngers; aticular branches to elbow wrist, nd carpa ts

The thorcodorsal nerve arises fom the psterior cord of the brachil plexus and runs downward to suppl the latssimus drsi muscle (Figs. 9-5 and 9-1). The axilary nerv is on of the erminal ranches f the poterior crd of th brachial plexus Figs. 9-15 and 9-19). It tus backward and es through the qadrangulr space see page 45). Haing give off a banch to te shouldr t, it divids into aterior ad posteror branches (see page 458). A summar of the omplete istributon of th axillary nerve is given i Figure 9-24. The radial nerve s the lagest brach of th brachia plexus nd lies ehind th axillar artery (Figs. 9-15, -19, nd 9-20. It givs off branches to the long and media heads the trieps musce and th posterir cutaneus nerve of the am (Fig. 9-1). Th latter ranch is distribued to th skin on the midde of the back of the arm. A summar of the complete stributin of the radial nerve is iven in Figre 9-25. Lesis of the brachial plexus ad its branches ar described on pag 536.

Lymph Nodes of the Axila Th axillary lymph nodes (20 o 30 in number) rain lymh vessels from the lateral uadrants of the east, the superficial P.51

lymh vessel from th thoracobdominal walls above the lel of te umbilicus, and te vessels from the upper limb.

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Fgure 9-22 Summry of th main brnches of the musulocutaneous and mdian neres.

The lymph nodes are rranged n six grups (Fig. 926). 

 

nterior pectoral group: Lying long the lower boder of te pectorlis minor behind he pectralis maor, thes nodes receive lymph vessel from th lateral quadrans of the breast ad superfcial vesels from the anteolateral abdominl wall aove the evel of the umbilicus. Posterio (subscaular) grup: Lying in front of te subscapulari muscle, these ndes receve supeficial lmph vessls from he back, down as ar as th level o the ilac crest. Lateral group: Lyng along the medl side of the axillary vei, these odes recive mos of the ymph vesels of te upper imb (ext those superfical vessls drainng the lteral sie see infralavicula nodes below). 832

snell  



Cetral grop: Lyng in th center f the axlla in te axillay fat, tese nodes receive lymph from the above three groups. Infrclaviculr (deltoectoral) group: These odes are not stritly axilary node because they are located outside he axill. They le in the groove btween th deltoid and pectoralis mor musces and rceive superficial lymph vesels from the laral side of the hand, forerm, and rm. pical grup: ying at he apex f the axla at the lateral border o the firt rib, hese nods receiv the effrent lymh vessels from all the othe axillary nodes.

The aical node drain ito the sublavian lmph trun. On the left ide, thi trunk dains int the thoacic duc; on the right sde, it dains int the rig lymph tunk. Alternativel, the lymph truks may drain direcly into ne of the large vins at te root f the nek. P.452

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Fgure 9-23 Summry of th main brnches of the ulna nerve.

Figure 9-4 Summry of th main branches of the axilary nerv.

P.43

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Figure 9-25 ummary o the mai branche of the adial neve.

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Figure 9-26 ifferent groups o lymph ndes in te axilla

P.54

Clnical Notes Examinatio of the Axillary Lymph Nodes ith the atient sanding o sitting he or se is askd to plce the hd of the side to be examied on th hip and ush hard mediall. This ation of dduction of the soulder jint causs the pctoralis major mucle to cntract mximally o that i becomes hard lie a boar The examiner then palpates the axilary nods (Fig. 9-2) as ollows: 

The antrior (petoral) odes may be alpated y pressng forwad against the poterior urface o the petoralis major muscle on the anterior wall of he axill.

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snell  

 

The posterir (subsular) ndes ay be papated by pressing backward against he anteror surfae of th subscaplaris mucle on te posteror wall f the axlla. The laeral nods ma be palpated agaist the medial side of the axillary ein. The examine's finges are pressed laterally agains the sublavian ein and the pulsting axilary artry. Te central nodes ay be papated in the centr of the axilla tween the pectoralis majr (anteror wall) and the subscapulris (posterior wall). For the apcal nodes, th patient is asked to relax the shoulder muscs and let the upper limb hang down at the sde. The xaminer hen genty places the tips of the fingers of the exmining hnd high up in the axilla t the outr borde of the irst rib. If the ndes are nlarged hey can e felt.

The examination o the axilary lymh nodes lways foms part f the clnical exmination of the beast.

Te Supercial Pat of the Back and the Scaular Reion Skn The sensory nrve suppy to he skin f the bak is frm the poterior rami of the spina nerves see Fig. 1-4). e first nd eight cervica nerves o not suply the kin, and the poserior rai of the upper thee lumba nerves un downwrd to suply the skin ove the buttock. Te lood suply t the ski is fro the poserior brnches of the postrior intrcostal rteries and the lumbar aeries. Te veins orrespon to the rteries nd drain into th azygos ins and the infeior vena cava. The lymph dainage of the kin of te back aove the evel of he iliac crests i upward nto the osterior group of axillary ymph nos.

Bones the Bac The underlyig bones o the bac are shon in Figure 9-27 nd are dscribed n detail in Chapter 2.

Muscles The muses on te back conecting he upper limb to he thoraic wall nd the vrtebral olumn ar shown i Fgure 9-2 and ae descried in Table 9-1 ad -2, ad the muscles concting the scapul to the umerus are shown in Fgure 9- and re descrbed in Tabl 9-3.

Rotator Cuff The roator cuf is the ame give to the endons o the suscapularis, suprainatus, infraspiatus, an teres minor musces, which are fusd to the underlying capsule of the houlder oint (Fig. -34). The cuf plays a very imprtant roe in stabilizing te shouldr t. The ton of thes muscles assists n holdin the hea of the merus in the gleoid caviy of the scapula uring moements at the shoder t. The uff lies on the aterior, uperior, and postrior aspcts of he t The cuf is deficient inferiorly, ad this i a site f potenial weakess.

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Clinica Notes Rotatr Cuff Tndinitis The otator cff, conssting of the tendns of th subscaularis, upraspinaus, infrspinatus, and teres minor uscles, which are fused to the undrlying sule of the shouder , plays an imporant role in stabiizing th shoulder t. esions o the cuf are a cmmon caue of pai in the houlder egion. Ecessive overhead activity of the upper limb ay be th cause o tendiniis, altough man cases apear spotaneousy. Durin abductin of the shoulde t, he suprapinatus tendon is exposed frictio against the acrmion (Fig. -30). Under nomal conitions, he amoun of friction is reuced to minimum by the lrge subcromial ursa, whch extens lateraly beneah the detoid. Dgeneratie change in the ursa are followed by degenerative changes i the undrlying supraspinatus tendon, and thee may exend into the othr tendon of the otator cff. Cliically, he condiion is kown as subacromial bursitis, supraspinatus tedinitis, or pericapsulitis. It s characerized b the preence of spasm o pain in the midde range f abducton (Fig. 9-0), whn the dieased ara impings on the acromion

Rupture f the Suraspinats Tendon I advance cases of rotator cuff teninitis, the necrotic suprpinatus endon ca become calcified or ruptue. Ruptue of th tendon eriously interfers with te normal abductio movemen of the shoulder t. I will be d that te main fnction of the suaspinatus muscle s to hol the hea of the umerus i the glnoid fosa at the commenceent of abduction. The patiet with a rupture supraspnatus tedon is uable to nitiate abduction of the rm. Howeer, if the arm is ively assisted for the irst 15Â of abdction, te deltoi can the take over and comlete the movement to a riht angle P455

838

snell

Figre 9-27 Bones f the bak.

P.456

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igure 9-28 Suprficial nd deep uscles of the back

P.45

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snell

Figure -29 Mscles, nrves, and blood vessels of he scapuar regio. Note te close elation f the axllary neve to th shoulder t.

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igure 9-0 Subcromial ursitis, supraspiatus teninitis, r pericasulitis showing he painfl arc in the midde range of abductin, when he disesed area impinges on the lteral ede of the acromion

P.48

Quadragular Spce Te quadragular spce is an intermusular spae, locaed immediately belw the sulder t. It s bounde above b the suscapulars and casule of te shouldr t nd below by the eres majr muscle It is bunded meially by the long head of he tris and laterally by the suical neck of the humerus. The axillary nerve and the posterior circumflex humeral vesels pas backwar through this spae (Fig. 9-2).

Nerves Spinal art of te Accessry Nerve (Cranial Nerve XI

842

snell The spinl part o the accssory neve runs ownward n the psterior riangle f the nek on the levator capulae uscle. I is accmpanied y branches from th anterio rami of the thir and forth cervcal nervs. The ory erve runs beneath he anteror bordr of the trapeziu muscle Fi. 9-28 at the unction f its midle and ower thids and, ogether ith the cervical nrves, splies the trapezis muscle

Clnical Noes ory Nrve Injuy Th accessoy nerve an be injured as the result of stab wounds t the nec.

uprascaplar Nerve The uprascaplar nerv arises rom the pper tru of the brachial plexus (5 and 6) in the psterior riangle n the nek. It rns downwrd and lterally and es beneath he suprasular liament which bridges the suprascaular noh, to rech the spraspinos fossa Fi. 9-29). It supplies the supraspiatus and infraspiatus musles and he shouler t.

Axillar Nerve The axilary nere arises from the posterio cord of the bracial plexus (C5 and 6) in th axilla see page 45). It es bckward an enters he quadrngular sace with the postrior cirumflex hmeral artery (Fig. 9-9). s the neve e through the spac, it coms into close relationship with the inferior aspect of the capsle of th shoulde t ad with he media side of the surgcal neck f the huerus. It terminats by diiding ino anterir and poterior banches (Fig 9-29)

Branches he axillry nerv has the followin branche:   

An artiular brach to the shouder An antrior terinal brach, which wins around the surgal neck f the huerus benath the eltoid uscle; i supplie the deloid and he skin that cover its lowr part. A posterir terminl branch, which gives o a branch o the teres minor muscle and a fe branchs to the deltoid, then emeges from the posterior border of the deltoid s the uppe lateral cutaneou nerve o the arm (Fig. 9-9)

It s thus sen that he axillry nerve supplies the sholder t, two mucles, an the ski coverin the lowr half o the detoid muscle.

Clinica Notes Axillay Nerve njury The axilary nere can be injured n disloctions of the shoulder t.

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Arterial Anastomois Aroun the Sholder Joit The extme mobility of the shoulder t may result in kinkng of th axillar artery and a temorary oclusion of ts lumen. To compensat for thi, an imprtant arerial anstomosis exists etween te branchs of the subclavin artery and the xillary rtery, hus ensuing that an adequate blood flow take place ito the upper limb irrespetive of he positon of th arm (Fig 9-31.

Branches from the Subclavin Artery  

The suprasapular artery, hich is istributd to the supraspious and nfraspinus fossa of the capula The superfiial cervcal artey, whch gives off a dep branch that runs down the medial brder of he scapua

Branche from th Axillar Artery   

he subscapuar arter and ts circuflex scaular brach suppl the subcapular nd infrapinous fossae of he scapula, respectively. The anerior cicumflex umeral atery The posteior circumflex humral artey

Bth the crcumflex arteries form an nastomosng circl around he surgial neck o the humrus (Fig. 931).

Clinica Notes Arteria Anastomsis and igation f the Axllary Arery The eistence f the anstomosis around te shouldr t is vital to preseving the upper lib should it be neessary t ligate the axilary artery. P459

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Figue 9-31 Arterie that tae part i anastomsis around the shulder joit.

ternoclaicular Jint     

Articulaion: his occus betwee the stenal end f the clvicle, te manubrum steri, and the first ostal catilage (Fig. 9-32. Tye: Synovial doule-plane t Capule: his surrunds the t an is attahed to the margins of the aticular urfaces. Lgaments: The sule is reinforcd in frot of and behind the t by the stng sternocavicular ligament. Artcular dic: Thi flat firocartilginous dsc lies ithin th t ad divide the joit's inteior into two comprtments Fi. 9-32). Its ircumfernce is atached to the inteior of te capsule, but i is also strongl attache to the uperior rgin of the articlar surfce of te clavice above nd to th first cstal carilage beow.

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snell 

 

Accessory ligament: The costlavicula ligamen is strong ligament hat runs from the junction of the frst rib with the first cosal cartiage to te inferir surfac of the ternal ed of th clavicl (ig. 9-32). Synovial membrane This ines the capsule nd is atached to the margns of th cartilae coverig the aricular surfaces. Nerve suply: The supralavicula nerve ad the nerve to th subclavus muscl

Movemens Forwrd and bckward mvement of the clavicle takes place in the mdial compartment. Elevatio and depession of the claicle tak place in the latral comprtment.

Muscles roducing Movement The forward vement f the clavicle is produced y the srratus aterior mscle. Th backwar movemen is produced by th trapezus and romboid mscles. Eevation f the clvicle is produced by the trapezius sternocidomastoid, levator scapulae, and romboid uscles. epressio of the lavicle s produced by the pectorali minor nd the sbclavius muscles Fi. 9-33. P.460

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Figure 932 A ternoclavcular t. B Acromiolavicula t.

Importat Relatins  

Ateriorly The kin and some fibers of the ternocledomastoi and pecralis maor muscls Posterioly: he sternhyoid mucle; on the right, the braciocephalc artery on the left, th left brahiocephaic vein nd the left common carotid artery

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Clinial Notes Steroclavicular t njuris Te strong costoclaicular lgament frmly hols the mdial end f the clvicle to the firs costal cartilage Violent forces drected along the lng axis f the clavicle usully resut in frcture of that bon, but dislocation f the strnoclaviular t takes lace occsionally. Anterior dislocaton reslts in he media end of he clavile projeting forwrd beneah the skn; it my also b pulled upward by he sterncleidomasoid musce. Poserior dislocation usually follows direct rauma aplied to he front of the t that drives te clavice backwad. This ype is the more seious becuse the displaced clavicl may pres on the rachea, he esophgus, and major blood vesss in the root of he neck. If the ostoclavcular ligment rupures comletely, t is difficult to maintain the norml positin of the clavicle nce redction ha been accmplished

Acromioclaicular Jint   

Articultion: his occus betwee the acromion of e scapul and the lateral nd of th clavicl (Fg. 9-32). Type Synoial plane t Capsle: Tis surronds the t and is attacd to the margins f the aricular surfaces. P.461





 

Liaments: uperior and inferior acromiclaviculr ligamets renforce te capsule from th capsule a wedgeshaped fibrcartilagious disc projets into he t cavity from abov (Fi. 9-32). Accessory igament The ery strog oracoclvicular ligament extens from he coracid proces to the undersurace of te clavice (Fig. 9-3). It s largel responsble for uspendin the weiht of th scapula and the pper lim from th clavicl. Synoval membrne: Ts lines the capsle and is attached to the mrgins of the cartlage covring the articula surface. Nerve supply: The surascapulr nerve

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Figre 9-33 The wde range of movemnts possible at th sternocavicular and acrmioclaviular joits gives great moility to the clavcle and he uppe limb.

Movemens A glding movment taks place hen the capula rtates or hen the lavicle s elevatd or depessed (Fig. 9-33)

Importan Relatios   

Anteriorly The eltoid mscle Posteriorly: The tapezius uscle Supriorly: The ski

Cliical Nots Acomioclavcular Jont Injuries he plan of the rticular surfaces of the acromioclaicular jint s downwa and meially so that thee is a tndency fr the laeral end of the cavicle t ride up over the upper srface of the acroion. The strength of the jint depeds on the strong coracoclaicular gament, hich binds the coracoid prcess to the undesurface f the laral part of the cavicle. he greatr part o the weiht of th upper

849

snell lmb is trnsmitted to the cavicle through ths ligamet, and rtary movments of the scapla occur at this important ligamen

Acomioclavcular Dilocation A svere blo on the oint of he shouler, as is incurred during locking r tacklig in fooball or ny sever fall, an resul in the cromion eing thrst beneath the lateral end of the clavicl, tering the coracoclavicuar ligamnt. This condition is knwn as shoulde separaton. Te displced oute end of he clavice is easly palpale. As i the cas of the sternoclvicular t, th dislocaion is esily redced, but withdrwal of reslts in imediate edislocaion. P.62

Shulder Jont 

 

Ariculatio: Ths occurs between he roundd head o the humrus and the shallo, pearshaped genoid cavity of t scapula. The articular surfaces are covere by hyalne articlar cartlage, an the gleoid caviy is depened by the presnce of a fibrocarilaginou rim caled the glenid labru (Figs. -34 an 935). ype: Snovial bll-and-scket jot Capsul: This surrouns the t and s attachd medialy to the margin o the glnoid cavty outsie the larum; laterally it is attachd to the anatomi neck of the humeus (Fig. 9-5). Te capsue is thi and lax, allowing a wide rnge of mvement. t is stengthene by fibrus slips from the endons o the subcapulari, suprapinatus, infraspiatus, and teres mor muscles (the rtator cuf muscls).

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Fgure 9-3 Shouder and its relation. Anteior view B Sagital sectin.

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Figre 9-35 Interior of the shoulder t.



Ligaments: The glenohumeral ligaments are thee weak ands of ibrous tssue tha strengten the font of the capsul The transerse humral ligaent stengthens the capsle and bidges th gap beteen the wo tubersities (Fig 9-34) The corachumeral P.463

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ligament strengtens the apsule aove and tretches from the root of he coracid proces to the greater uberosit of the hmerus (Fig. 9-34)  



ory lgaments: The coraoacromia ligament extens betwee the corcoid proess and he acromn. Its fnction i to protct the sperior aspect of te t Fi. 9-34). Synovil membrae: Ths lines he capsue and is attached to the magins of he cartiage coveing the rticular surfaces (Fgs. 9-34 and 9-35). It orms a tbular shath aroun the tenon of th long head of the biceps rachii. t extend through the anteior wall of the sule to form the suscapulars bursa beneat the subcapulari muscle Fi. 9-34. Neve suppl: The xillary nd supracapular erves

Movemnts Th shoulde t hs a wide range of movement and the stabiliy of the t ha been sarificed o permit this. (Cmpare wth the hp t, which is stable bt limite in its ovements) The srength o the joit depend on the one of the short otator cff muscles that cross in front, above, and bhind th t—amely, te subsularis, supraspiatus, inraspinats, and tres mino. When the t is abducted, the ower surace of t head of the humeus is spported y the log head o the trieps, whih bows dwnward beause of its lengh and gies littl actual upport t the humrus. In addition the infrior par of the capsule i the weaest area. P.46

The following movements are possible (Fig. 9-36):  

Flexion: Nrmal fleion is aout 90° and is prformed y the anerior fibrs of te deltoi, pectoralis majo, biceps and corcobrachilis musces. Extensio: Noral extenion is aout 45° and is prformed y the poterior fibers of the deltid, latisimus dosi, and teres majo muscles

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Figure 936 Th movemens possibe at the shoulder t. Pre glenohmeral aduction s possibe only a much as about 12°; furter movemnt of te upper imb above the lev of the shoulder requires rotation of the scapula (see text)



Abductio: Abdution of he upper limb occrs both t the shulder jot and beween the scapula nd the toracic wll (see scaular–hmeral mehanism, page 465). Th middle ibers of the deltid, asssted by the suprasinatus, re invoved. The supraspiatus musle

854

snell initites the ovement f abduction and holds the ead of te humeru against the glenid fossa of the capula; this lattr functi allows the deltoid muscle P.45

to cntract ad abduct the humeus at th shoulde t.    

Adduction: Nrmally, he upper limb can be swung 45° acrss the font of th chest. This is erformed by the pctoralis major, atissimu dorsi, teres mjor, and teres mnor musces. Lateral rotation Noral lateal rotaton is 40° to 45Â. This i performd by the infraspnatus, te teres inor, an the poserior firs of th deltoid muscle. Mdial rotation: Normal edial roation is about 55°. This performd by the subscapularis, the latissmus dors, the tees major and the anterior fibers f the detoid musle. Circmduction Thi is a combination of the aove moveents.

Imprtant Reations    

Anterirly: he subsularis mscle an the axillary vessls and bachial pexus Posterirly: he infrapinatus nd teres minor mucles Speriorly The spraspinaus muscl, subacrmial bura, coracacromial ligament, and delid muscl Inferiory: The long he of the triceps muscle, th axillar nerve, nd the psterior ircumfle humeral vessels

The tndon of he long ead of te biceps muscle pases throgh the jint and merges bneath th transvese ligament.

linical otes tability of the Soulder Jint The shalowness o the gleoid foss of the capula ad the lack of provded by wak ligants make this joit an untable stucture. ts strenth almos entirel depends on the tne of te short uscles tat bind he upper end of te humeru to the scapulaâ”namely, the subsapularis in front the supaspinatu above, and the infraspinaus and tres mino behind. The tendns of thse musces are fused to the underling capsle of th shoulder t. ogether, these tedons for the rottor cuff The least ed prt of th t les in th inferio location, where it is unprtected b muscles

Dislocations of the Shoulder t The sholder t is the ost commnly dislcated lage t

Anteior Infeior Dislcation Sudden violence applied to the humerus with the jont full abducte tilts te humera head donward ono the inerior wek part f the casule, whch tears and the humeral head comes to lie

855

snell inferior to the genoid fosa. Durig this movement, te acromin has ated as a fulcrum. The strog flexor and addctors of the shouder joit now usally pull the humeal head orward ad upward into the subcoraoid posiion.

Posteror Disloations Posteior dislocations ae rare ad are usally caued by drect vioence to he front of the jint. On nspectio of the patient ith shouder dislcation, the rounded appearace of th shouldr is see to be lst because the grater tubrosity o the huerus is o longer bulging aterally beneath he deltod muscle A subgenoid dilacement of the head of th humerus into the quadranular spae can case damag to the xillary erve, as indicate by parlysis of the deltid muscl and los of skin sensation over the lower hlf of th deltoid Downward displaement of the humeus can also streh and dmage the radial neve.

Shoulde Pain he synoval membrne, capsle, and igaments of the houlder oint are innervate by the axillary nerve an the surascapular nerve. The t is sensitive to in, presure, exessive taction, nd distetion. Th muscles surroundng the jint undrgo reflx spasm n response to pain originang in th t, which in turn seres to imobilize he t and thus reduce te pain. Injuy to the shoulder t is followed y pain, limitatn of movment, an muscle trophy oing to dsuse. It is imporant to apreciate that pai in the houlder egion ca be causd by diase elshere and that the shoulder t ma be norml; for xample, iseases f the spnal cord and vertbral colmn and te pressre of a ervical ib (see pag 50) cn cause shoulder pain. Iritation f the diphragmatc pleura or perioneum can produc referre pain vi the phrnic and supraclaicular nerves.

The Scapular–Humeral Mchanism The scapula nd upper limb are suspende from th clavice by the strong cracoclavcular liament asisted by the tone of musces. When the scapla rotates on the chest wal so that the position of the glenoid fossa is alterd, the ais of roation ma be conidered t though the coracoclvicular igament. Abuction o the arm involves rotation of the sapula as well as movement at the soulder jint. For every 3 of abdution of the arm, a 2° abuction ocurs in he shouler t and a 1° abduction occurs by rotaion of te scapula. At about 120° of abductin of the arm, th greater tuberosiy of the humerus omes int with the lateral edge of e acromion. Furthr elevaton of th arm aboe the had is acomplishe by rotaing the scapla. Fiure 9-37 summrizes th movemens of abdction of the arm ad shows he diretion of ull of te muscles responsile for tese movements.

The Upper Arm kin 856

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Sperficia Sensory Nerves The sesory nere supply (Fg. 9-38) to th skin ovr the pont of th shoulde to halfway down the deltoi muscle s from the upraclavcular neves (C and 4). The skin over P466

th lower hlf of th deltoid is supplied by th pper lateral cutanous nerv of the rm, a branch o the axilary nerve (C5 and 6). The kin over the lateal surfae of the rm below the deltid is suplied by the lower lteral cuaneous nrve of te arm a branch of the rdial nere (C5 an 6). The skin of the armpit and the edial sie of the arm is spplied by the medial cutaneous nerve of the arm (T1) ad the interostobracial nervs (T2) The ski of the ack of te arm (Fig. 9-38) is suppled by th psterior utaneous nerve of the arm, a brach of th radial nerve (C8. P.467

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Figure 9-37 Movement of abduction of the shouldr t nd rotaton of the scapula and the muscles poducing hese movments. Noe that fr every 3° of aduction of the arm, a 2° aduction ccurs in the shouder joit, and 1° occurs y rotatin of the scapula. At abo 120° of abducton, the reater tberosity f the huerus hit the latal edge of the aromion. levation of the ar above te head i accomplshed by rotating the scapua. S, suraspinats; D, deloid; T, rapezius SA, seratus antrior.

Clincal Notes Dermtomes an Cutaneos Nerves

858

snell It ay be neessary fr a physcian to est the ntegrity f the spnal cord segments of C3 though T1. The diagams in Figues -23 nd 1-24 show th arrangeent of he dermaomes of the uppe limb. t is see that he dermaomes for the uppr cervical segmets C3 to 6 are loated alng the lateral marin of th upper lmb; the dermatoe is siuated on the midde finger; and the ermatome for C8, T1, and 2 are aong the edial magin of te limb. The nerve ibers frm a paricular sgment of the spinl cord, although tey exit rom the ord in spinal erve of te same sgment, pss to th skin in two or mre different cutaeous neres. he skin ver the oint of he shouler and hlfway down the leral surace of te deltoi muscle s supplid by the supraclaicular nrves (C3 and 4). ain may e referred to this region s a resut of infammatory lesions nvolving the diaphragmatic leura o peritonum. The fferent stimuli rech the sinal cor via the phrenic erves (C, 4, and 5). Pleuisy, pertonitis, ubphreni absces, or galbladder isease my therefre be reponsible for sholder pai.

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Figure 9-38 Ctaneous nnervatin of the upper lib.

P.8

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Figur 9-39 uperficil veins f the uper limb. Note the common vriations seen in he regio of the lbow.

Superfiial Vein The eins of he upper limb can be dividd into wo grops: supericial an deep. Te deep vins compise the enae coitantes, which acompany all the lare arteris, usualy in pai, and the axillary vein. The suprficial eins of he arm (Fig 9-39) lie in te superfcial fascia. Th cephalic vein asends in the supeficial fscia on he laterl side o the bis and, n reachng the ifraclavicular foss, drains into the axillary vein.

861

snell The basili vein scends i the suerficial ascia on the medial side of the biceps (Fig. -39). Halfway up the am, it pirces the deep fasia and a the lowr border of the teres major s the venae comitants of the rachial artery to form th axillar vein.

Nerve Supply of the Vins ike the rteries, the smooh muscle in the wll of th veins s innervted by smpatheti postgailionic neve fiber that povide vaomotor tne. The rigin of these fiers is smilar to those o the artries.

Clinial Notes Venipncture ad Blood ransfusin he supericial vens are cinically importan and are used fo venipuncture, trasfusion and carac catheterizatio. Every clinical professinal, in n emergecy, shoud know were to obtain blod from he arm. When a paient is n a stat of shoc, the superficial veins ar not alwys visibe. The halic vin lies airly cnstantly in the superficial fascia, mmediately posterior to th styloi process of the rdius. In the cubial fossa the medan cubitl vein s separaed from he undering bracial artey by the bicipita aponeuosis. Ths is imprtant beause it rotects the artery from the mistake introdution int its lumn of irrtating dugs that hould hve been njected nto the ein. The cephalic vein, in the deltopectoral triangle frequenly commuicates wth the eternal ugular ven by a sall vein that croses in font of te clavice. Fracure of te clavice can reult in rpture of this comunicatin vein, ith the ormation of a lare hematoa.

Intavenous ransfusin and Hyovolemic Shock In extreme hyovolemic shock, ecessive enous toe may ihibit veous bloo flow an thus delay the iroductio of intavenous lood int the vasular sysem.

Anatomy of Basilic and Cephal Vein Ctheterization The edian basilic or bsilic vns are the veins f choic for cenral venos catheterization because rom the cubital fossa untl the bailic vein reaches th axillay vein, the basiic vei increases in diameter ad is in irect lne with he axilary vein (Fig. 9-39) The vales in th axillar vein my be troblesome, but abducion of te shouldr t ay permi the cateter to ove past the obstuction. The cephlic vein does not increas in size as it asends the arm, and it frequntly divdes into small brnches as t lies ithin th deltopetoral tiangle. ne or moe of thee branchs may ascend ove the claicle and the xternal ugular vin. In is usual ethod of terminaton, the ephalic vin s the axilary vein at a riht angle. It may b difficut to manuver the catheter round tis angle P.469

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snell

Superficia Lymph Vesels The suprficial ymph vesels draiing the uperficil tissue of the upper arm upwrd to th axilla Fi. 9-40. Those from the lateral side of he arm fllow the ephalic ein to te infralavicula group o nodes; hose fro the medal side ollow th basili vein to the lateal group of axillry nodes. Th dep lymphtic vessls drining th muscles and deep structurs of the arm drai into th lateral group of axillary nodes.

Clincal Note Lymphangitis Infecton of th lymph vssels (lmphangits) of th arm is common. d streaks along he cours of the ymph vessls are haracterstic of he condiion. The lymph vesels from the thum and inex finge and the lateral art of te hand folow the ephalic ein to he infralavicula group of axillary nodes; tose from the middl, ring, and litte finger and from the medil part o the han follow he basilc vein t the supatrochler node, hich lie in the superfical fasci just abve the medial epicondyle of the humeus, and thence t the latral grou of axillry nodes

Lymphaenitis Once th infectin reache the lymh nodes, they becme enlared and tnder, a ondition known as lymphadeitis. Mot of the lymph vesels fro the finers and palm o the dosum of te hand efore pa nto the orearm. his explins the requency of inflammatory edema, or even abscess formion, whih may ocur on th dorsum of the hnd after infection of the ingers o palm.

Fascal Compatments o the Uppr Arm Th upper am is encosed in sheath f deep fscia (Fig. -41). Two fascal septa one on he media side an one on he laterl side, xtend frm this seath and are attahed to te medial and lateal suprcondylar ridges o the humerus, respctively. By this eans, the upper am is divded into an anteror and a posterio fascial compartmnt, each having i muscles nerves, and arteies.

Contens of the Anterior Fascial ompartmet of the Upper Ar    

Muscle: Bieps bracii, coraobrachilis, and brachias Bood suply: Bachial atery (Fig. 9-42) erve suply to th muscles Musclocutaneus nerve Structres ng throuh the compartment: Musclocutaneus, medin, and unar nervs; bracial artery and basilic vein. The rial nerv is present in the lower part of the compartent.

Muscles of the Anterior Fascial ompartment The mucles of he anterior fascil comparment are shown in Fiures 9-4 and 9-44 and ae descried in Table 9-5. Note that the biceps brachi is a pwerful spinator nd this action is made use of in 863

snell tisting te corkscew into he cork r driving the screw into wood with screwdriver. The biceps aso is a owerful flexor o the elbw t nd a wea flexor f the shoulder jont.

Clnical Noes Bieps Bracii and Oteoarthitis of he Shouler t The tendn of the long hea of bices is attached to the supralenoid tbercle wthin the shoulder t. Advanced osteoarthitic chages in te t an lead o erosio and fraing of he tendo by ostephytic otgrowths and rupure of te tendon can occur.

Stuctures assing Trough th Anterior Fascial Compartmnt Bracal Artery The brachial artery (Figs. 9-42 and 9-43 begins at the lwer border o the tres maor musle as contiuation of th axillry artry. It provides the main arterial supply to the arm (Fig. -42). It erminaes oppsite te neck of the radius by divding ito the radial and ular arteries.

elatins 



Anteriorly: The vesse is suerficil and s overapped rom the lateral side by te coraobrachalis ad bices. The medial cutaneous nerve of the forearm les in ront o the uper pat; the median nerve rosses its iddle art; ad the icipitl aponurosis crosse its lwer pat (Fig. 943. Posterorly: The artery lies o the triceps, the coracobrachialis inserion, ad the rachiais (Fig. -43. P470

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Figure 9-40 Suerficil lymphatics of the upper imb. Nte the positins of he lymh nods.

P.41

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Figure 9-41 Cros secton of he uppr arm ust below the level of insertion of the deltoi muscl. Note the division of the arm by the humerus ad the medial and laeral itermusular spta ino anteior an posteior compartments.

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Figur 9-42 The main ateries of the upper imb.

P.72

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Figure 9-43 Antrior view of the uper arm. The mddle prtion f the iceps brachi has been remved to show the musculocutaneous erve lying in front of the brachilis.

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snell  

Mdially: Te ulnr nerve and the baslic ven in te uppe part f the rm; in the lower part of the arm, the mdian nrve lis on is medil side (Fig. 9-43). Laerally: he medan nere and the coracobrachialis and bieps mucles aove; te tenon of he biceps lies lateral to he artery in the loer par of is coure (Fi. 9-43).

Branches     

Muscular banches to the anerior ompartent of the uper arm Th nutrient artery to th humerus The profunda artey arises near th begining of the brchial rtery and folows te radil nerv into he spial grove of he humrus (Fig. 945) The suerior ulnar collateral artery arises near the midde of te uppe arm and follws the ulnar erve (Fig. 9-45. The inferior ulna collaeral atery ariss near the teminatin of te artey and akes prt in he anatomosi aroud the elbow t (Fig. 945).

Musulocutaneous Nerve The origin of the musculcutaneus nere from the laeral crd of he brahial pexus P.473

C5, 6, and 7) in the axill is decribed on pag 449. t runs downwad and ateraly, pieces th coracobrachialis muscle (Fig. -15, and hen es downward between the bceps ad brachialis uscles (Fig. 9-43). I appeas at te lateal marin of he bis tenon and pierce the eep facia jut abov the ebow. I runs own th laterl aspet of he forarm as the lateral cutaneous nerve of the foream (Fi. 9-38).

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Figre 9-4 Aterior view of the upper arm showng the inserton of he deloid an the origin and insertion f the rachiais.

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Brnches   

Mucular ranche t the bceps, coracorachialis, ad bracialis Fig. 9-2) Cutneous ranche; he lteral utaneos nerv of th foream upplie the sin of he frnt and latera aspecs of te forerm down as fa as th root f the humb. Articlar brnches to he elbw t

P.474

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Fiure 9-5 ain areries of the upper rm. Noe the rteria anastmosis round he elbw .

edian erve

872

snell The orgin of the median nerve frm the edial nd laeral crds of the brchial plexus in the axilla is described on pag 449. It run downwrd on he latral sie of te bracial arery (Fig. 943). Halfay dow the uper ar, it cosses he brahial atery ad contnues dwnward on its medial side. The nerve, like the artery, is terefor supericial, but a the ebow, i is crssed by the bicipitl aponurosis The urther course of thi nerv is decribed on pag 489. The median nerve has no branches in the upper arm (Fig. 9-2), except for a small asomotr nerv to th brachal artry.

Ulnar Nerve Te origin of he ulnr nerve from the mdial cord of the brachia plexu in th axila is described on age 44. It runs downward on the medial side f the rachia arter as far as te midde of the am (Fig. 9-3. Here, at te insetion f the oracobachialis, th nerve pierces the edial fasial septum, accompnied y the uperio ulnar collateral atery, nd entrs the postrior cmpartmnt of he ar; the erve es behind the mdial picondle o the humerus. The ular nere has o braches in the nterior comprtment of the upper arm (Fig. 9-23).

Raial Nrve n leaving the axilla, the radial erve imediatly eners th posteior copartmet of the arm and eners th anteror copartment jst aboe the latera epicodyle.

Conents of the Posterir Fascial Comartmen of th Upper Arm  

Muscle: The three eads o the ticeps uscle Nerv suppl to th muscl: adial erve .475

 

Blood supply: Prfunda rachii and unar colateral arteres Structures ing through the copartmet: Radial nerve and ulnar nere Table 9-5 Musles of the Ar

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Musce

Origin

Inserton

Neve Supply

Nrve Rotsa

Action

Anterir Comprtment Biceps brachii

Long head

Supragln oid tbercle of scaula

Tberosiy of rdius ad biciital aoneuro is int dee fascia of frearm

Musculcutane us nere

C5, 6

Suinato r of forarm an flexo of elbow t; wek flexr of shoulde r t

Short head

Coraoid prcess o scapua

Coracobrachi alis

Corcoid pocess f scapla

Medil aspect of shaft of humeus

Musclocutaeo us nrve

C5, ,7

Flexes arm and aloproc es of wak addctor

Brahialis

Front of ower half of umerus

oronoid process of lna

Musculocutne ous nerve

C5,

lexor of elbw

Posteror Comartmen Trices

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Lng hea

Infragleoid tuercle f scapla

Laeral ead

Upper half of posteior suface o shaft of humrus

edial head

Loer half of posterior surface of saft of humeru

a

Olecran on process of ulna

Raial nrve

C6, 7,

Extensr of ebow jont

The predoinant erve rot suply is ndicatd by bldface type.

Muscl of th Posteior Facial Cmpartmnt Th trices musce is sen in Figure 9-46 an is decribed in Tale 9-5.

Structures in Throuh the osterir Fascal Comartment Radal Neve The origin of te radil nerv from he poserior ord o the bachial plexus in the axill is decribed on pag 450. he neve wins aroud the ack of the ar in th spira groov on the back of th humers betwen the heads of he trieps (Fig. 9-46. It pierces the lteral fascia septu above the ebow an continues ownwar into he cubital fssa in front of the elbow, betwen the brachialis ad the rachioadialis muscles (Fig. 947. In he spial grove, the nerv is accompanied by he prounda vessels, and t lies direcly in contac with he shaft of he humrus (Fig. -46).

Branches  



In th axila, brances (Fg. 9-5) re gien to he lon and medial heads o the ticeps, and te poterior cutaneus nere of te arm is given ff. In the piral groove (Fig. 9-6), brances are given to the latera and mdial hads of the ticeps nd to he ancneus. he lwer laeral ctaneou nerve of th arm supplies the skin ver th laterl and anterir aspets of the lower par of th arm. The osterior cutaneous nerve of the frearm run down he midle of he bac of th foream as ar as he wrist. In the anterior cmpartment of the ar, after the nerve has piercd the atera fascil septum, it gives branchs to the brahialis the bachioradiali, and he exensor arpi radialis lonus musles (Fig. 9-7). It aso givs articular banches to the elbow oint.

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Ulnar Nerve Havin pierced the medial fascia septu halfwy down the pper am, the ulnar nerve descens behnd the septum, covered poteriory by te medal hea of P.476

te trieps. Te nerve is ccompanied by the superio ulnar collaeral essels At the elbo, it les behind th media epicodyle of the humeru (Fi. 9-46) on the medial ligament of he elbow t. It contines dowward to enter the orearm betwee the to heas of oigin of the lexor arpi lnaris (see page 93).

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Figure 9-46 Posterior iew of the upper ar. The latera head f the riceps has been diided t disply the adial erve and the profunda artry in he spiral goove o the hmerus.

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Brances Th ulna nerve has a articular banch to the lbow jint (Fig. -23).

Profuda Brachii Artery The profuda brahii artery aises from th brachal artery near its origin (Fig. 9-45). t accompanie the rdial erve trough the spral grove, supplies the riceps muscl, and takes art in the anastomosis aound the elbw joit.

Supeior and Inferior Ular Collatera Arteres The superior and infrior unar colateral arteies aise from the brachil artey and take prt in the anastomoss aroud the elbow t.

he Cuital Fssa The ubital fossa is a tiangulr depession that ies in front f the elbow Figs. 9-47 ad 9-48). P.77

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Figur 9-47 Rigt cubtal fosa.

Bundaries  

Laterally: The brachioradiais muscle ediall: The prnator teres uscle

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snell The base of the triange is formed by an maginay line drawn between the wo epiondyles of te humeus. Th flor f the ossa i forme by the supiator mscle ateraly and the brchialis musce medally. he rof is fored by kin and fasca and s reinforced by the bicipial aponeuross.

Cntents The cubita fossa (Fig. 9-47) ontais the ollowing strctures enumrated rom the medil to te lateral side: the medin nerv, the bifurction o the bachial arter into the ular and radia arteies, the tenon of he bis muscle, nd the radial nerve and it deep ranch. The supratrochlar lymh node lies in he suprficial fascia ove the upper prt of he fossa, abve the trochla (Fg. 9-0). It receives afferent lymh vessls frm the hird, fourth, and ifth ingers; the medial part of the hand; and the edial ide of the orearm The eferent lymph essels p to te axila and enter he laeral xillar group of nods (Fg. 9-4).

Bons of he Forarm The foearm cntains two bones: the radus and the una. P.478

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Figure 948 The cbital ossa and antrior surface of the forear i a 27-ear-old man.

Radius The adius s the lateral bone f the forear (Fi. 9-4). Its proximal end ariculaes with the umerus at the elbow t nd with the ulna a the proximal radiolnar jint. Is distl end articulates with the scaphoid ad lunae bone of th hand at the wrist t and wih the ulna a the dstal rdioulnr . At the proximal end of the radius i the mall crcular hea (Fig. 9-49. The upper urfac of th head s conave an articlates with te conex captulum of th humerus. Th circumferene of the head articlates ith the radil notch of te ulna Below the had the bone is contrictd to frm the nck Below the neck is he bicipita tubersity for the insertio of th biceps muscle. The shaft of the radius, in conradistnction to tht of the uln, is wder beow thn abov (Fig. 9-4). It as a sarp interosseus borer medialy fr the ttachent of the interossous mebrane that binds te radis and lna together The pronator tubrcle, for the inertion of the pronaor teres muscle, lis halfay down on is latral sie.

881

snell At the distal end of he radius is the stylod procss; this rojecs distally from its latera margi (Fig. 9-49). On the medial surfac is th ulnar notc, hich aticulates with the round head of he uln. The nferio artiular srface rticultes wih the caphoi and lnate bnes. O the osterir aspet of te distl end s a smll tubrcle, he dosal tbercle, which is grooved on its medial side y the endon f the xtenso polliis lonus (Fg. 9-9). Te impotant mscles nd ligments attached to te radis are hown i Figue 9-49.

lna Te ulna is the medial bone o the orearm (Fig. 9-49). Is proxmal en articlates with te humeus at he elbw and ith th head f the adius t the roxima radiolnar jint. Is disal end articlates ith the rdius a the istal adioular t, bu it is excludd from the wrst joit by te artiular dsc. Te proxmal en of th ulna is lare and s known as the oecrann procss (Fig 9-49); this forms the rominece of he elbw. It as a ntch on its anerior urface the trochlar noth, which rticultes wih the trochlea of he humrus. elow te troclear notch is the triangular cornoid process, whch has on its latera surfae the radia notch fo articlation with te head of the radius he saft of th ulna apers rom abve dow (Fi. 9-49). t has sharp inteosseou borde lterall for te attchment of the interoseous embran. The posterior boder is rounde and sbcutanous an can b easil palpaed throughout its ength. Below he radal noth is te supinator crest that gives origin to the supinaor musle. t the distal end of the ula is the small rounded hed, which as proecting from is medial aspct the styloi process (Fig. 9-4). The important musces and ligaments atached o the lna ar shown in Figure 949. P479

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Figure 9-9 mportat musclar an ligamntous ttachmnts to the radius and the ulna.

linical Notes Fractures of the Rdius ad Ulna

883

snell Fractres of the hed of te radis can ocur fro falls on the outstretched hand. s the orce i tranmitted along he radus, th head f the radius is driven sharply against the captulum, splittng or plinteing th head Fig. 9-10). Fractres of the nek of the radus occur in young children frm fall on th outstetched hand (Fig. 10). Fractures of the shafts f the adius nd uln my or my not ccur tgether (Fig. 9-10). isplacment o the fragment is usally cnsiderble an depens on he pul of th attaced musles The proxima fragmnt of he radus is supinaed by he supnator nd the biceps brachi muscls (Fg. 9-10). The dstal fragment of the radiu is prnated nd puled medally by the ronato quadrtus mucle. Te stregth of the brchioradialis and etensor carpi adiali longu and bevis sortens and anulates the frearm. In fratures f the lna, the ulna angulates poteriory. To restor the nrmal mvemets of ronation and spinatin, the norma anatmic reationship of the raius, ulna, and inteosseous membrane mst be egaind. A frcture f one orearm bone my be associated with a disocatio of th other bone. In Monteggi's frature, for example, the shaft f the lna i fractred by a forc applid from behin. Ther is a bowing forwar of th ulnar shaft nd an nterio dislcation of the radial head wth rupure of the anlar ligament. In Gleazzis fracture, the roxima third of the radius is fratured nd the distal end o the una is islocaed at he disal radoulnar t. Facturs of te olecranon process cn resut from a fall on the flexed elbow or fro a direct blow. Depending on the locatin of te fracure lie, the bony fagment may b displced by the pull of he trieps mucle, wich is insertd on he oleranon rocess (Fig. 9-10). Avlsion fractues of part of the olecranon proces can e prodced by the pul of he trieps mucle. God funtional return after ny of hese ractues depend on th accurte anaomic rductio of th fragmnt. Colles' ractur is a frcture of the distal end of the radius rsultin from fall on the outstetched hand. t commnly ocurs in patients older than 50 years. The force drives the dital frgment osterorly ad supeiorly, and the distal articular urface is incined psterioly (Fg. 9-5). This osterir dispacemen produes a psterio bump, someties reerred o as te “dnner-frk defrmity╠becase the forearm and wrist esemble the sape of that eting uensil. Failur to retore te disal artcular urface to its normal positin wil severly limt the range f flexon of he writ . Smith's fractue is a facture of th dista end o the rdius and occrs fro a fal on the bac of th hand. It is revered Coles' frcture ecause the dital fagment is dislaced nterioly (Fig. 9-0).

Oleranon ursiti A small subcutaneous burs is prsent ver th olecrnon process of the ulna, and reeated trauma often roduce chronic busitis. P.480

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Bones of the Hand Ther are eight arpal bones, made p of two row of four (Figs. 951 and 952. The proxial row consists of (fro laterl to mdial) he saphoid lunat, triqetral, and pisiorm bone. The distal row cosists f (fro laterl to medial) he trpezium, trapezoid, capitate, nd haate bone. Togeher, te bone of th carps presnt on heir aterior surfae a cocavity to th laterl and edial dges o which is atached a strog membanous and caled th flexor retinaculu. I this anner, an osteofascial tunnel, the carpal tunnel, is fored for the pasage o the mdian nerve and the flexor tendons of the finger. The bones o the hnd are cartilaginous at birth. Th capiate beins to ossify during the first year, and the others bein to ossify at intrvals hereafer untl the 2th yer, whe all te bons are ssifie. A detaied knoledge f the bones of the and is unnecssary. The poition, shape, and size of he scahoid bne, hwever, should be stuied, bcause t is commoly fratured. The ridge of the trapeziu and te hook of the hamate should be examined.

Figure 9-50 Frctures of the distal end of the radius. A olles' fractue. B Smih's frcture.

The Metacrpals nd Phaanges Tere ar five etacaral bons, each of wich ha a base, a shaft, and a head (Fgs. 9-1 and 9-2). Th first metacarpal bone of the thub is te shorest ad most mobile It dos not ie in he sam plane as the others but ccupies a mor anteror postion. t is aso rotted meially hrough a riht ange so that its extensor surface is directd lateally ad not backwad.

885

snell The ases o the mtacarpl bone articlate wth the dista row o the crpal bnes; the heads, which form the knuckles, articlate wth the proximl phalnges (Figs. 9-51 and -52). Th shaft of eac metacarpal bone is slighty concave forard an is tiangulr in tansvese section. Its surfaces are postrior, ateral and medial. There are hree palange for ech of he finers bu only wo for the thmb. The important muscles attached to the bones f the and an fingers are shown in Figres 9-1 nd 9-2. P.481

Fgure 951 Important muscular ttachmnts to the anerior urfaces of the bones of th hand.

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Clincal Noes Inuries o the ones o the Hnd Fracture f the caphoi bone is commo in yong aduls; uness treaed effctively, the fragmnts wll not unite, and permanent weakness and pain o the wist wil reslt, wih the subsequent devlopmen of oseoarthitis. he fracture line usually oes though te narrwest prt of the bone, whic, becuse of its location, is bathed in synovial flui. The lood vssels to the scaphod ente its proximl and distal ends, althouh the lood upply s occaionall confied to ts disal end If th latte occus, a facture deprivs the roxima fragmnt of ts artrial upply, and ths fragent unergoes avascuar necosis. eep tedernes in te anatmic snffbox fter a fall o the otstrethed had in youn adult makes ne susicious of a fractured scaphoid. Dislocation of the unate bone occasionally occrs in oung aults wo fall on the outstetched hand n a wa that auses yperextension of the wrist t. Involvment o the edian erve i commo. Frctures of the metacarpal bones can ccur a a reslt of irect iolenc, such as th clenched fist striking a hard object. he frature aways agulate dorsaly. Th “bxer's ractur― comonly roduce an obique facture of th neck f the fifth nd sometimes he fouth metcarpal bones. The dital fagment is comonly dsplace proximally, thus shortenig the inger posterorly. Bnnett's fracture is a fractue of te base of the metacapal of the thumb caused when vioence i applid alon the lng axi of th thumb or the thumb s forcefully abducted. The fracture is oblique and eners th carpmetacapal jont of he thub, cauing jont instability. Factures of te phalnges ae commn and sually follow direct injury P.482

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Figre 9-5 Importan muscuar attchments to te postrior srfaces of the bones f the hand.

Te Forarm Skin Th senory neve supply to the skin of the forear is frm the nterio and psterio branches of the lteral utaneous nerve of he forarm, a contination f the musculcutaneus nere, and from the anterior ad postrior banches of th media cutaneous neve of he forearm (Fig. 938) A narow stip of skin down the middle of the posterior surace of the frearm s suppied by the poterior cutaneus nere of te forarm. Th suprficial vein of the foream lie n the uperfiial facia (Fig. 939. The cephalic vei aises from the laterl side of the dorsal venous arch o the bck of the hand and winds around the latral boder of the forearm; it then asceds int the cbital ossa ad up te fron of th arm o the ateral side 888

snell o the bceps. t termnates n the xillar vein in the deltoectora trianle (se page 30. As the cehalic vein psses up the upper limb, it receives a variable umber of triutarie from he latral an posteior sufaces f the imb (ig. 9-9) The median cubita vein, a branch of the cephalc vein in the cubita fossa runs pward nd meially nd jois the asilic vein. n the ubital fossa, the median cubital vein crosses in front of th brachal artry and the meian nrve, but it is searated from tem by he biital poneursis. The basili vein arises from the edial ide of the dosal veous arch on the back of th hand nd wids arond the medial border of the forear; it then ascends into the cubital foss and u the front o the am on te medil side of the bicep (Fig. 9-39). Is termnation by joning he vene comiantes f the rachia arter to fom the xillar vein, is decribed on pag 446. t receves th media cubitl vein and a variale numer of ributaies frm the edial nd poserior urface of te uppe limb. Th supeficial lymph vessel from the thumb and ateral finger and te lateal ares of the hand and forearm follow the cephalic vein to the infraclavicular group f nods (Fi. 9-40). hose fom the media fingrs and the meial aras of he han and frearm ollow he baslic vin to he cubtal fosa. Hee, som of th vesses drai into he spratrohlear ymph nde, whereas othrs bypss the node and acompany the bailic vin to he axlla, where they drain into the lateral goup of axillay node. The efferet P.48

vessls fro the spratrohlear ode alo drain into the laeral aillary nodes Fig. 9-40).

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Figure 9-53 Cros secton of he forarm at the leel of nsertin of the pronator tres mucle.

Fascial Cmpartments of the Foearm Th forearm is enclosed in a sheath f deep fascia whic is atached o the periosteum of the poterior subcutneous border of the ulna (Fig. -53). This fasial seath, togethr with the inerosseous membrane and fibrous intermusular spta, dvides he forarm into seveal comartmens, eah havig its wn musles, nrves, nd blod suppy.

Clinicl Note Compartment Syndroe of te Forerm The orearm is encosed n a sheath f deep fascia whih is atached to the perioseum of the psterio subcuaneous borde of th ulna Fig 9-53). Tis fasial seath, ogethe with he introsseous membrane and fibrus inermusclar seta, diides te forerm int severl comprtment, eac having its own muscles, nerves, and blood suppy. Thee is vry litle rom withn each comparment, nd any edema an caus secodary vasculr compession of th blood vessel; the eins ae firs affeted, ad late the arteries. Sot tissue injry is commo cause and erly dagnosi is crtical. Early igns iclude altered skin ensatin (cased by ischema of te sensry neres pasing though te comartmen), pai disprportioate o any njury (caused by prssure on neres witin the comparment), pain o ie streching f musles tht throug the cmpartmnt (cased by muscle ischema), tndernes of te skin over te comprtment (a lae sign caused by edema), and absence of capillry refll in he nai beds caused by pressure on the arteris withn the ompartent). nce th diagnsis is made, the dep fascia must be incised srgicaly to dcompress the affeced compartment. A delay of as little as 4 hour can cuse ireversble damage to the mscles.

Vokmann' Ischeic Conractur olkmann's ishemic contracure is a ure of the muscls of the forearm that commnly folows factues of the distl end of the humers or fracturs of the radus and ulna. In this syndrome localzed segment f the brachil artery goe into pasm, reducing the arterial flow to the flexor and th extenor musles so that hey unergo ichemic necrosis. The flexor muscls are larger han te extesor mucles, nd they are herefoe the nes manly affected. The muscles are relaced y fibrus tisue, whch conracts, producing te defomity. he artrial sasm is usuall cause by an overtiht cat, but in some cases the fracture itself may be responible. he deormity can be explaied only by understading te anatmy of he reion. Tree tyes of eformiy exis: 

The long lexor uscles of the carpu and ingers are moe ed han the extensor mucles, nd the wrist t s flexd; the fingers are extended. If the wris t is exended assivey, the fingers become flexed.

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snell 



The long extensor muscles to the ingers whic are iserted into te extesor exansion that s attahed to the poximal phalan, are reatly contrated; te metaarpophlangel joits and the wrst joit are xtende, and the interphalangeal ts of the fingers are flexed. Both th flexo and te extesor mucles f the orearm are contracted. The wrist t i flexe, the metacapophalngeal oints re extnded, nd the interpalangel s are flexed.

P.84

Introsseos Membrane The iterosseous membrane is a srong mmbrane that nites the shafs of te radis and he ulna; it is attached to their interoseous orders (Fig. 9-49 an 9-53). Its fiers ru obliqely donward nd medally s that force applied to the lower end of the radius e.g., alling on the outstrtched hand) is trasmitte from he radus to he uln and fom thee to te humrus an scapua. Its fibers are tat when the frearm s in te midrone psition€”that is, th positon of function. The interosseous membrane provdes atachmen for nighborng musles.

Fleor and Extensr Retinacula The flexor an extenor retnacul are srong bnds of deep ascia hat hod the ong flxor an extensor tendons in position at the wrst.

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igure -54 Cross section of the hand showin the rlation of the tendon, nervs, and arteres to he fleor and extensr retiacul.

Fexor Retinaculum he flexor retinaculum is a thickeing of deep fscia hat hods the long fexor tndons in position at the wrist. I streches aross te fron of th wrist and coverts he conave aterior surfac of th hand nto an osteofscial tunnel, the arpal unnel, fo the pssage f the edian erve ad the lexor endons of th thumb and figers (Fig. -54. It s attahed meially o the isifor bone nd the hook o the amate and laerally to the tubercle of the scahoid and the rapezim bones. The attachent to the trpezium consiss of sperfical and deep prts ad form a synvial-lned tunel fo ae of te tendn of te fleor cari radilis. The uper boder of the rtinaclum correspods to he dital trnsvers skin crease in front of he writ and is continuous with he deep fasca of te forearm. The lowe borde is attached to the palmr aponeurosi (Fig. 9-5). .485

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Figure 9-5 Aterio view of the palm of the and. Te palmar aponeurosi has ben let in positio.

Exensor Retinaulum The xtenso retinculum s a thickenig of deep fasia tht streches aross te back of th wrist and hods the long etensor tendos in psition (Fis. 9-56 ad 9-5). It coverts he groves on the posterio surfae of te distl ends of th radiu and una int six sparate tunnel for te ge of he log extesor tedons. ach tunel is lined ith a ynovia sheat, whih exteds aboe and elow te retiaculum on th

893

snell tendos. The tunnes are eparatd from one anther b fibros sept that ass fom th deep urface of the retinaulum t the bnes. Te retiaculum is attched mdially to the pisiform boe and the hoo of the hamat and lterall to th dista end o the adius. The uper and lower borders of the retinaculum are coninuous with he dee fasci of th forearm and hand, espectvely. The contents of the tunnels benath th extenor retnaculu are dscribe on pae 499.

arpal unnel The bones of the hand and the flxor reinaculm form the capal tunel (Fig. 954) The median nerve lies in restricted space betwen the tendons of the flexr digiorum sperficalis ad the lexor arpi rdialis muscle. For urther details, see page 00

Contnts of the Anerior ascial Compartment of the orearm 



Muscle: superficial group, cosisting of te prontor tees, the flexo carpi radials, the palmaris longus, and the flexor carpi ularis; n intrmediate group consisting of he fleor digtorum uperfiialis; and a dep grou cosistin of th flexo polliis lonus, th flexo digitrum prfundus and te prontor qudratus Blod suppy to the muscles: Ulnar and radial ateries P.46



Nere suppy to te musces: All he musles ar suppled by he medan nerve and its branches, except the lexor arpi unaris nd the medial part of the flexor digitoum proundus, which re suplied b the unar neve.

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Figure -56 Dorsa surfae of the han showig the ong exensor tendons and thir synvial seaths.

Clnical otes bsent almari Longu Te palmris logus mucle ma be absent o one o both sides f the orearm in abot 10% f persns. Others show variation in for, such as cenrally r distlly plced mucle bely in he plae of proximal one. Becase the muscle is reltively weak, ts absnce producs no disbility.

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Mucles o the nterior Fascal Comartment of te Forerm The muscles f the nterior fascial copartmet are een i Figres 9-58 9-59, -60, and 9-61 and are describe in able -6. Note that the superficia group of mscles ossesss a common tendon o oriin, whch is ttache to th medial epicondyle f the umerus.

Arteres of he Antrior Fascial Compatment f the Forear Ulnr Artry he ular artry is he larer of the tw termial branches of the rachia arter (Fis. 9-4 ad 960). It begin in th cubitl foss at th level of the neck of the radius. It descends throug the nterior compartment of the forear and enters the pam in front f he fleor retinaculm in company with te ulna nerve (Fig 9-62). I ends y forming th suprficia palmar arch, often anastomoing wih the uperfcial plmar ranch f the radial artery (Fi. 9-62). P.87

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igure 9-57 Dissction of the dorsal surface of te righ hand howing the long extnsor endons and th extenor retnaculu.

In th upper part o its curse, the ulnar artery lie deep to most of te flexr musces. Below, i becoms supeficial and lies between the tendns of he fleor carpi ulnaris an the tndons of th

897

snell flexo digitorum sperficalis. n fron of the flexr retiaculum, it lies jut lateal to he pisform bne and is coered oly by kin and fasia (sie for taking ulnar pulse).

Branches    

Mucular branchs o neigborin muscls Recurren brances that take pat in te artrial aastomois around th elbow t (Fig 9-61) Branches hat take par in th arterial anstomosis arond the wrist t he common nteroseous rtery, which arises from the pper prt of he ulnr artey and after a brief course divide into the anterior an poserior nteroseous rterie (Fig. 9-61. Th intersseou arteres are distrbuted to the musces lyig in front of and behind the intersseus membrane; they provde nutient arterie to te radis and ulna bne.

Radial Artry The radal artery is the smaller f the terminl braches of the rachia arter. It begins in the cubita foss at th levl of te nec of th radiu (Fgs. 9-8, 9-59, ad 9-60). It es donward and laerally beneath P.488

te bracioradialis muscle ad restng on the dep musces of the frearm. In th middl third of its cours, the superfcial brnch of the radial nerve lies o its ateral side.

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Fgure 9-58 Anteior viw of he forearm. The midle porion o the bachiordialis muscle has been rmoved to dislay th supericial branch of the radial nerv and te radil artery.

P.89

Figure -59 Dissection of the front of the left forearm and had showing th supeficial strucures.

In te disal par of th forearm, th radial artery lies on te anterior urface of th radius and s covred ony by sin an fasci. Here the atery hs the endon f bracioradilis on its lteral side ad the endon f flexr carp radiais on ts medal sid (sit for tking te radil puls).

900

snell The rdial atery laves te forerm by inding around the lateral aspect of the wrist o reac the psterio surfae of te han (se pae 509).

Brances in he Forarm   

Mucular ranche t neighoring muscles Recurrent branch, wich taes par in th arteral anastomosis around the elbow t (ig. 9-0) Superfical palar brach, which arises just above the wrist (Fig 9-60), enters he pal of th hand, and frquentl s the ular artry to orm th suprficia palma arch

Neres of the Anterior Fascial Comparment o the Forearm Medin Nerv The median nerve leaves the cubital fssa by in betwen te two eads o the ponator teres (Fig. 9-60). I contiues donward ehind he fleor digtorum uperfiialis nd rets poseriorl on the flexor digiorum pofundu. At te wris, the median nerve emerge from the lateral border of the flexor digitoru supeficials musce and ies beind th tendo of th palmais lonus (Fgs. 9-8, 9-59, an 9-60). t enters te palm by pasing behind the flexor retinaculum see pges 49 and 500). P.490

901

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902

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igure -60 Anteior viw of te forearm. Most of the superficial musces hav been removd to dsplay he fleor digtorum uperfiialis, median nerve, supericial ranch f the adial nerve, and raial arery. Nte tha the lnar head of the prnator eres sparate the mdian nrve frm the ulnar artery

P.91

903

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904

snell

Figre 9-61 nterio view of the foream showing th deep structres.

P.492

Table 9-6 Muscles of the Anterior Fascial Comprtment of th Foream

uscle

Orign

Insrtion

Nerve Suppl

Nere Roota Action

ronator Teres

umeral head

Medal epiondyle of humrus

Laeral aspect f shaf of raius

Ular head

Mdial order f coronoid process of lna

lexor carpi adiali

Medial epicodyle o humers

Base of second and thir metacrpal bones

Palaris lngus

Medal epiondyle of humerus

Flxor retinacuu m and palmar aponerosi s

905

Mdian nerve

C6 ,7

Prontio n and fleion of forear

Median nerve

C6 7

Flexes and abduct hand at writ t

Median nerv

C, 8

Flexes hand

snell

Flexor Crpi Ularis

Humeral ead

Medil epicndyle of humrus

Piiform one, hook of the hmate, base a fift metacrpal bone

Unar had

edial aspect of oleranon rocess and posterior border of ula

Ulnar nere

8; T1

Flexes and adducts hand at writ t

Flexor Digtorum Superfcialis

Humrouln a head

Medial epicodyle o humerus; meial brder o coronoid process o ulna

Middle phalanx of medial four finers

Radal head

blique line o anteror surface o shaft of radus

Fleor policis longs

Anterior surface of shaft of radis

Disal phalanx of thumb

906

Mdian nrve

Aterior interosseou s branch of medan nere

C7 ,8 T1

Flees midle phaanx of fingers and ssists in fleing prximal halanx and had

C8 ; T1

Flees disal phaanx of thumb

snell

lexor digitoum profundus

Anteromedi al surface of shaft of ulna

Distal phalanes of edial our figers

Ulnar medial half) nd median (lateral alf) nrves

C8 ; T1

lexes distal phalan of figers; hen asists i flexin of mddle ad proxmal phlange s and wrist

Pronatr quadatus

nterior surfce of haft o ulna

Anterior urface of shat of rdius

Anterior iterossous brnch of median nerve

C8 ; T1

ronate foream

a

The preominan nerve root spply i indicted by boldfae type

P.49

907

snell

Figur 9-62 Anerior iew of the pam of te hand The palmar aponeurosis and the reater part o the fexor retinaculum have been removed to display te suprficia palma arch, the meian neve, ad the ong flxor tedons. Segmens of te tendns of he fleor digtorum uperfiialis ave been reoved t show the underlyin tendos of te flexr digiorum rofunds.

Brnches  

Muscular ranche in the ubital fossa o the ronato teres the fexor crpi raialis, the almari longu, and he flexor digtorum uperfiialis Fig. 9-22) Aricular branchs to the lbow jint 908

snell  

Aterior interosseous nerve Palmar cutaneous brnch This arises in the lower art of the foearm ad is dstribued to the skin over the laeral prt of he pal (Fig. 9-38).

Aterior Interosseous Nerve The anerior nteroseous nrve arises fom the median nerve as it merges from btween the tw heads of the pronatr tere. It asses ownwar on th anteror surace of the inerosseus mebrane, between the flexor ollici longu and te flexr digiorum rofunds (Fig. 9-61). t ends on the anterior surface of the carpus.

Branches  

Mucular branches t the flexor ollici longu, the ronato quadrtus, ad the ateral half o the fexor dgitoru profudus Articuar braches to te wris and dstal rdioulnr s. It lso suplies he joits of he han.

Ulnar Nere The ulnar nerve (Fig. -61) pases fro behin the mdial eicondye of the humerus, crosses he medial liament f the lbow jint, ad entes the ront o the frearm by pasing beween te two eads o the fexor crpi ularis. It then runs down the forearm beteen th P.494

P.495

flexor crpi ularis ad the flexor digitrum prfundu muscls. In he distal to thirs of the forearm, the ulnr artey lies on the laterl side of te ulna nerve (Fig. 9-61). At the wrist the unar neve becomes sperfical and lies between the tendons of the flexo carpi ulnaris and lexor igitorum superficilis mscles Figs 9-58 and 9-59). The ulnar nerve eners the palm o the hnd by assing in front of te fleor retnaculu and lteral o the isifor bone; here it has he ulnr artey lateal to t (see page 499).

909

snell

Figure 9-63 Inertions of lng fleor and extensor tenons in the figers. Inserions of the lumbrical an interssei uscles are aso shon. The uppermost fgure ilustraes the action of the lumbrical and inteossei muscls in fexing the meacarpohalangal jints ad exteding the interphalngeal oints.

Brnches

910

snell    

Mscular brances to the flexor carpi ulnaris nd to he medal hal of the flexr digitorum profunus (Fig. 9-23) Aricula brances to the elbow t he palmar utaneous brach is a mall banch that arses in the mddle o the forearm (Fig 9-38) ad suppies the skin over the hypthenar eminence. The dorsal osterir cutaneous ranch i a lare branch tha arise in th distal thir of te forerm. It es medially between te tendn of te flexr carp ulnars and he ula and is disributd on he posterior surfac of the hand and ingers.

Cntents of the Lateral Facial ompartment o the Forearm Th laterl fascial copartmet may be regarded s part of the posteror fasial copartment.   

Mucles: Brachioradialis and extesor capi raialis ongus Blood suppl: Radial nd brachial rteries Nerve supply to the muscles: Radia nerve

uscles of th Laterl Fascal Comartment of te Forerm The musles of the laeral fscial compartment of the forearm are see in Fgures 9-58 and 9-60 and ae descibed i Table 9-7.

Areries of the Latera Compartmen of th Forearm The arerial supply is drived from branchs of te radial and brachil arteies.

Nrve of the Lteral Comparment f the orearm Radil Nerve The rdial nrve pierces he latral inermusular eptum in the lower part of the rm an es forward int the cbital fossa (Fi. 9-47). It then e downwrd in front of the laterl epicondyle of the humers, lyig beteen th brahialis on th medial side and te bracioradilis and extesor crpi radialis longus on the lateral sid (Fig. 9-60). At he levl of the latral epcondyl, it dvides nto superficial and deep branchs (Figs. 9-60 and 9-61). Tble 9-7 Muscles of the Latera Fascial Compartmen of th Foream

911

snell

Muscle

Origin

Insertion

Nerve Supply

Nerve Rootsa Action

Bachioradialis

ateral supracondylar ride of humerus

Base of styoid prcess o radius

Radial nerve

C, 6, 7

lexes orearm atridg of huerus ebow t; rotates forearm to the midproe posiion

Etensor carpi adiali longu

Lteral upracodylar idge o humerus

Posteior suface o base f second metacarpal bone

Rdial nerve

C6 7

Exteds and abducts and at wrist t

a

The redomiant neve roo supply is idicated by bodface ype.

Branche    

Muscula brances to th brachoradiais, to the exensor carpi radialis longus, and smal branc to th laterl part of the brachialis mucle (Fig. 925 Artiular banches to the elbow jont Deep brnch of the raial nerve. This winds round he neck of te radis, witin the supinator muscle (ig. 961), and enters he poserior ompartent of the foearm (Fig. -61). Supericial ranch f the adial nerve

Superfiial Banch o the Radial erve he superficil branh of he radal neve is the diect continuation o the nrve after its main stem has givn off its deep brach in ront of the ateral epicondyle of the hmerus Fig 9-60). It rus down under over f the bachioradiali muscl on the lateral sie of te radial artery. In the distal prt of he forarm, it leavs th arter and psses bckwar under the tedon of the bachiordiali (Fig. -60). I reaces th posterior srface f the rist, where t divides into terminal ranche that upply the skn on te lateral tw third of th posterior urface of the hand Fig. 9-38) and he poserior surfac over he

912

snell proimal phalangs of the lateral thee an a half fingers. Th area f skin supplied by he nere on te dorum of he hand is variable.

Conents f the osterior Fasial Compartmnt of he Forarm 

 

Muscle: he sperfical group includes the extenor cari radilis brevis, xtenso digiorum, extensr digii minimi, exensor carpi lnaris and aconeus These muscles posess a ommon tendon of origin, which is attachd to te lateral epicondye of the humerus. Te eep grup includs the supinaor, abuctor ollici longus, extnsor pllicis brevis extensor policis longus and etensor indicis. Blood supply Psterior and anterior inteosseou arteres Nerve suply to he musles: Dee branc of the radial nerv

Mscles of the Posterior Facial ompartent of the Forearm Te muscles of the poterior fascil comprtment are seen in Figurs 9-64 ad 9-6 ad are descried in Table 9-8. P.49

913

snell

914

snell

Fgure 9-64 Posterior iew of the frearm. Parts of the extnsor digitorm, exensor digiti minim, and extensr carp ulnars hav been emoved to sow the deep branch f the adial nerve nd the posterior iterosseous artery.

P.497

915

snell

Fgure -65 Postrior vew of he forearm. The superficia muscls have been removed to diplay te

916

snell

deep structres.

P.498

Table -8 Muscle of th Posteior Fascial Compartment of the orearm

Musce

Orgin

Insertio

Nerve Suply

Neve Roosa Acton

xtensor carpi radiais breis

Latral epcondyl of huerus

Posterior surface of ase of third etacaral bone

Dep brnch of radial nerve

C7 8

Extens and abducts hand t wris t

Exenso r digitru m

Lateral epcondyl e of hmerus

Middle nd disal phaanges f medil four fingers

Dep branc h of radial nerve

7,

Extnds fingers and hand (see ext fo detais)

Extenor digti minmi

Lateral epicondyl e of umerus

Extensor expansio of little inger

Deep banch o radial nerve

C7 ,

Extnds meacarpa phaangeal t of litle finger

Exenso r carpi ulnaris

Lteral epicondyl e of humeru

Base f fift metacrpal bne

Deep branc of raial neve

C7 ,8

Etends nd addcts hand at wrist jint

917

snell

nconeu s

Lateral picondle of umerus

ateral surfac of olecranon proess of ulna

Radial nerve

C7 , 8; T1

xtends elbow t

upinatr

Lateral epicondyl eo humers, anuar ligament of proxmal raioulna t and lna

Neck ad shaft of rdius

Dep brach of adial erve

C5 ,6

upinaion of forearm

Abduto r policis ongus

Posteror surface f shafs of adius and ula

Base o first metacarp al bne

Deep branh of rdial nrve

C7 8

Abduts an extens thub

Exenso r pollics brevis

Posteior suface o shaft of raius

Base of proxmal phlanx o thumb

Deep branc of raial erve

C7 ,8

Extnds metacarpphalangea l jints of thum

Extenso polliis longus

Poserior urface of shaft of ulna

ase of distal phalanx of tumb

Dep branh of rdial nrve

C7 ,

xtends distal phalan of thmb

918

snell

Extesor indicis

a

Posteror surace of shaft f uln

Extensor expansion of ndex fnger

Deep branc of raial neve

C, 8

Etends metacarpophalange al oint o index finger

The predominant nerve oot suply is indicated by boldface type

Clincal Noes Senosing Synoitis of the Abducor Policis Lngus and Extnsor Pllicis Brevis Tendos As resul of reeated frictin betwen thse tenons ad the styloid process of the radis, they sometimes bcome eematous and swell. Later, ibrosi of th synoval sheth prodces a condition known as steosing enosynvitis in which ovement of te tendns becomes restriced. Adanced cases require surgical incision aong th constrictin sheat.

Arteries f the Posteror Fasial Compartmnt of the Foearm The anerior and posterior nteroseous arterie rise fom the commo intersseous arter, a branc of the ulnar arter (igs. 961 and 9-65). They pas downwrd on he anterior and posterior urfaces of te introsseos membane, respectvely, and suply the ading muscles and bnes. Tey end by taking part in the anastomosis aroun the wist t.

linica Note Rupture of the Exensor ollicis Longs Tendon Rpture f this tendo can ccur after facture of the distl thir of the radis. Roughenin of the dorsal tubecle of the rdius b the fracture line can cause excssive frictin on te tendn, wich can then rupture. Rhematoid arthrtis ca also ause rupture of ths tenon.

“Aatomic Snuffbox― Th anatomic snffbox s a trm commonly sed to descrbe a trianguar ski depresion on the latera side f the rist that i boundd medilly by the tendon of the etensor pollics longs and lateraly by he tenons o the aductor pollicis longus and extenor pollicis revis Fig 9-64). Is cliical importace

919

snell lie in the fact that the caphoid one is most easily palpated her and tat the pulsaions of the radial artery can be felt here (Fig. 9-100). P499

Cliical Ntes ennis lbow Tenni elbow is caused by a partal tearing o degeneration of te orign of he suprficil extesor muscles from th lateal epiondyle of the humers. It s charcterizd by pain and tendrness over the laera epicondye of te hmerus, with ain rdiating down the laeral sde of he foearm; t is cmmon in tenns players, violinits, an housewives.

erve of the osterior Fascial Compartment of he Forearm Deep Branch of th Radia Nerve he deep branh ariss fro the rdial nrve in front of the latera epicondyle f the umerus in th cubitl fossa (Fig. 961). I piercs the supinaor and winds around the lateral spect f the neck of th radiu in the subsance o the muscle to reach the osterir comprtment of the foream. The nerve escend in th inerval etween the suerficil and eep groups of muscls (Fg. 9-6). It evetually reaches the posteior suface o the wist jont.

ranche 



Musclar branches t the etenso carpi radials brevis and the supinator, the xtenso digitorum, the etensr digiti mnimi, he extnsor arpi unaris, the abducto pollicis longs, the exensor policis brevis, the extensor pollicis lonus, and the extnsor idicis Aticular branhes to the wris and carpal oints

The Regio of the Wris efore learnig the anatom of te han, it i essenial that a tudent have sound knowldge of the arangement of the tndons, arteres, an nerve in the regin of te writ . Fro a clnical standpoint, he wrst is commn site for ijury. In a ransverse section trough the wist (Fig. -54), ientify the structurs from media to lateral. At the same ime, xamine your own wrist and dentif as many of he strctures as pssible.

Structues on the Anerior spect of th Wrist The ollowig structures superfiial to the flxor reinaculm from medial to lateral (Fig. -54):

920

snell      

Flexor crpi ularis tndon, eding o the psifor bone. (This tendon does nt actually cross the flexor retnaculu but i included fo the ske of compleeness. Unar nrve lies ateral to the pisifrm bon. Ulnar artery lies latera to th ulnar nerve. Pamar cuaneous branch of the ulnar nerve Palmars longs tenon (if prsent), ing to is insetion ito the flexor retinculum and th palmr aponurosis Palmr cutaneous branch f the media nerve

Te following tructues pas beneah the flexor retinaculum from medial to ateral (Fig 9-54):    

lexor digitoum suprficialis tedons and, posterior to these, the tedons o the fexor digitorm profndus; oth grups of tendons shar a comon synovial sheath. Media nerve Flexor policis lngus tndon surounded by a ynovial sheath Flexor carpi radialis tendn oing trough a spli in th flexo retinaculum The tndon is surrunded y a syovial heath

Sructurs on the Poserior Aspect of the Wrist The following stuctures superficial o the xtensor retiaculum from medial o lateral (Fig. 954):    

orsal (posteior) ctaneous branh of he ulnr nerve Basilic vin Cephalic vin Suerficil branch of he radial neve

The followng strcture eneath the etensor retinculum rom medial t lateral (Fig. 9-54)      

Extensor arpi unaris tendon, hich grooves the poterior aspec of th head of the ulna Extnsr digiti minim tendon is siuated osterior to he disal radoulnar t. Etensor digitorum and extensr indiis tendons share a comon synovial heath and are situaed on he lateral part of he poserior urface of the radius. Extensor polliis lonus tenon winds around the meial sie of the dorsal tubercle o the rdius. Etenso carpi radialis lonus and revis endon sare a ommon ynovia sheat and ae sitated o the lateral part of the osterir surfce of the raius. Abducor policis lngus and the xtenso polliis breis tenons have eparate synoial sheaths but share a common copartmet.

Beneth the extensor retnaculum, ibrous septa ass to the nderlyng radus an ulna and form six compatments that ontain the endons of the extenor musles. Ech compartmet is provide with a synovial heath, which extends abov and blow th retinaculum. The radial atery raches the bak of the han by pssing betwee the lateral collatral lgamen of th wist jont an the endons of the abducor policis longus and xtenso pollcis bevis (Fig. 9-65).

The alm of the Hnd

921

snell

kin Te skin of the palm f the and is thick and hirless It i boun down o the nderling dep fascia by umerous fibrous bads. Th skin shows any flexure reases at the sites of skn movement, which are not necessaril place at th site of t. Swea glads are preset in lrge numbers The palmris brvis (Fig 9-55) is a smal muscl that rises rom th flexo retinculum nd palar apoeurosi P.50

and is inseted ino the kin of the pam. It s suppied by the sperfical brach of the ulnar nerve. Its functin is t corruate th skin at the base o the hypothear emience ad so iprove he gri of te palm in holing a rounded object. Te sesory nerve supply to te skin of th palm (Figs 9-38 and 9-55) is derived from he palmar ctaneou branc of th media nerve, which crosses i front of the flexor retinaculum and supplies te lateal par of th palm, and the palmar cuaneous branc of th ulnar nerve; te later nere also crosses in front of the flxor reinaculm (Fig. 9-5) ad suppies th media part of the palm. he skn over the bae of te thenr eminnce is supplid by the laeral ctaneou nerve f the forear o the superfcial banch o the rdial nrve (Fig 9-38).

Dep Fasca Th deep fascia of the wrist nd pal is thckened to for the flexor retinaulum (desribed n page 484) ad the palma aponerosis.

Th Palma Aponerosis Te palar apoeurosi is tiangular and occupies the centra area of the palm (Fig. 9-55). The aex of the pamar apneurosis is attache to th distal bordr of he fleor retinaculm and receives the inserton of he palmaris longu tendo (Fi. 9-5). The bae of te apneuross divides at the baes of the fingers ito fou slips Each slip ivides into two bans, one ing suprfiially o the kin an the other ig deeply to he roo of th fingr; her each eep band divides ito two which diverge aroud the flexor tendons and finally fuse wth the fibrous flexr sheah and he dee transerse lgament. Th medil and ateral border of the palmr aponurosis are continuous wit the tinner eep fascia cverin the hpothenr and thena muscls. Fro each of thee borders, fbrous epta posterioly into the alm an take part in the frmatio of te palmr fascial saces (ee pge 508). Th funcion of the pamar aponeurois is to give firm attacment t the overlying skin and s improve the grip ad to potect the unerlying tendns.

linicl Notes 922

snell

Dupytren' Contrcture Dupuytren's contractur is a ocalizd thickening nd contracture of he palar apoeurosis. It ommonly stars near the rot of the ring finger and draws hat figer ino the alm, flexing it at the metacarpophalaneal jont. Later, te condtion involves the lttle inger n the same mnner. n longstandig cases, the pull on the fibrous sheaths of hese fngers esults in flexion of the poximal interhalangal joits. The disal intrphalageal jints are not involed and are actually extendd by the pressure o the fngers against the alm.

The Carpal Tnnel The arpus s deeply conave on its anterior surfac and forms bony gutter The gutter s converted nto a unnel by the flexr retiaculum (Fi. 9-54). The log fleor tenons t the inger and tumb pss though te tunnl and re accmpanie by th median nerve. The our sparate tendon of th flexo digitrum suerficilis mucle ar arraged i anterior an posterior rws, those to the middle ad ring fingrs lyig in front of those to th index and little fingers. A the lower ordr of the lexor etinaclum, te four tendos diverge ad becme arrnged on the ame plane (Fig. 9-2) Te tendons of the flxor digitoru profundus muscle ae on the sam plane and lie behid the superfcialis tendos. All eigh tendons of he flexor diitoru supericialis and profunus invaginate a comon synvial heath from te lateral sie (Fig 9-54). This alows the arteial suply to the tedons to enter them from he latral side. The tendo of the flexor polics logus muscle runs thrugh th lateral par of th tunnl in its own synovil sheath. The median nrve pases bneath the fexor rtinaclum in a rstricted space between the flexo digitrum superficialis ad the lexor carpi radalis muscles (Fig. 9-4).

Clincal Notes Carpal unnel yndrome The caral tunel, formed b the oncav anteror suface o the crpal bnes an closed by te flexor retnaculum, is tightly packd with the lng fleor tendons f the finger, with their surronding synoval sheths, and the median nerve (Fig. 9-54). Cliniclly, te syndrome cnsists of a urning pain r “pins an needes― long the distributon of he meian nerve to the laeral three nd a hlf fingers ad weakess f the thenar muscles. It s prouced by compession of the media nerve within the tunnel. The xact cause o the cmpression is difficlt to determne, bu thickening of the synoval sheths of the flexor tendns or arthriic changes n the arpal bones are thught t be reponsible in many cses. A you wuld exect, no parestesia ccurs ver te thenr eminence because this area of kin is supplid by te palmr cutaeous ranch f the edian nerv, whic e supericiall to

923

snell th flexor retnaculu. The conditon is ramatially relieved by deompresing te tunnl by mking a longitdinal incision hrough the fexor etinaclum.

Fibous Flexor Sheaths The anterir surfce of ach figer, fom the head of the metacarpal to the bae of te distl phalanx, is proided with a strong fibrous sheath that is attached to the ides o the palange (Fi. 9-66). The poximal end of the firous seath i open, wherea the dstal ed of he sheth is lsed an is atached to the base f the distal phalax. The sheth and the bones form a blnd tunel in hich te fleor tenons of the fnger le. P.501

924

snell

Figre 9-6 Aterior view of the alm of the had showng the flexor synovil sheahs. Coss setion of finge is alo show.

In te thum, the steofirous tnnel contains the tendon f the lexor ollici longu. In te case of the four mdial ingers the tnnel i occuped by he tenons of the flxor diitorum superficialis and profunds (Fig. 9-6). he fibous shath is thick ver th phalages bu thin nd lax over te s.

Synoval Flexor Shaths In he han, the tendon of the flexr digtorum superficiali and pofundus musces invginat a common syovial heath from the laeral sde (Fig. 954). The medial part o this ommon heath

925

snell xtend distally witout inerrupton on he tedons o the lttle fnger. he latral pat of te sheah stos abrptly on the iddle f the alm, ad the istal nds of the log fleor tenons of the inex, th middl, and he rig fingers acquire digital snovial sheath as the enter the figers. he fleor policis longus tendo has is own synovil sheah that es into te thum. These sheaths allow the long tendons o move smoothy, wit a minimum of frction, beneat the lexor etinaclum an the fbrous lexor heaths The synovial sheth of he fleor policis lngus (ometims refered to as the radial bursa) communicates ith th common synoval sheth of he suprficiais and profunus tenons (smetime refered to s the ulnar burs) a the level f the rist i about 50% of subjecs. The vincula loga and bevia are mall vscular folds f synoial mebrane hat conect te tendns to the anterior suface o the phalangs (Fg. 9-63). They rsemble a mesentery and convey blod vessls to he tenons. P.502

Clnical otes Tenosyovitis of the Synovil Sheaths of the Flxor Tedons Tenoynovits is a infecion of a synovial sheath. t most commoly results frm the ntrodution o bacteria into a sheath through a small penetrting wund, sch as hat mae by te poin of a needl or thrn. Raely, the sheath may become infectd by extension of a pulp-space infection. Infection of a dgital sheath resuls in disention of he sheath wih pus; the fnger s held semiflexed nd is wollen. Any attemp to exend the fingr is acompaned by extrem pain ecause the distended seath is streched. s the inflammatory rocess contines, the presure wthin te sheath riss and ay comress the blod suppy to he tenons tht travel in he vinula loga an brevi (Fi. 9-63). Rupture or lter severe carring of he tenons ma follo. A further increae in ressur can cause he sheth to rupture at is proxmal ed. Anatomicaly, th digitl sheath of he inex finer is relate to th thenar spac, wheras tha of te ring fingr is rlated to the midpalar space. Th sheat for te middle finger is relate to both the thenar and midpalmar space. Thes relationshps expain ho infecion ca exten from he digital synovial sheats and nvolve the plmar fascial spaces. In the case f infetion of the igita sheats of the little finger ad thum, the lnar nd radial busae are quicly inolved. Should such an infection be neglected, ps may urst trough the prximal nds of these bursae and enter the fascia space of the foream betwen the flexor digitoum proundus nterioly and the ponator quadratus and th interosseous membrae postriorly This fascia space in the forearm is ommonl referred to clinically as the spce of arona.

Insertion o the Lng Fleor Tenons 926

snell Eah tendn of te flexr digiorum superficialis enters the fibrous flexor sheath; opposte the proximl phalnx it ivides into wo hales, whch pas aroun the pofundu tendo and met on ts dep or osterior surace, were patial decussaion of the fibers takes pace (Fig. 9-63). Te supeficials tendon, hving uited again, ivides almost at once into two futher slips, which re attached o the orders of the midle phaanx. Each tndon o the fexor igitorm profundus, having ed throug the divisin of the suprficiais tenon, cotinues downward, to be inerted nto th anterior surface o the base of the dital phalanx Fig. 9-63).

Clinical Notes Trigge Finge In trigge finge, ther is a alpabe and ven auible nappin when patiet is aked to flex ad extnd the finger. It i causd by te presnce of a locaized selling of one of the long lexor tendon that atches on a nrrowin of th fibros flexr sheah antrior t the mtacarpphalaneal jont. It may tae plac eithe in fexion r in etensio. A siilar cndition occurring in the tumb is calle triggr thumb. The situaton can be releved srgicaly by ncisin the fbrous lexor heath.

Small Muscle of th Hand The small muscle of th hand nclude the fur lumbrical uscles the eight* introssei muscles, the short muscles of the thumb, and te short muscls of the litte fingr. The muscle are sen in Figurs 9-55, -67 9-68, ad 9-6 and are described in able 99.

Short Muscls of te Thum Te shor muscls of the thumb are he abdctor pllicis brevi, the lexor ollici brevis, the oppones pollcis, and the adducor policis (Figs. 9-59, 962, and -67). The first three f these musces form the thenar eminnce.

Opposiion of the Thmb It shold be noted that the opponns policis mscle ulls te thum medialy and forward across the palm so that te palmr surace of the ti of th thumb may cme int contat with the pamar srface f the ips of the other fingers. It is an important muscle an enabes the thumb o form one clw in te pincrlike ction sed fo pickng up bjects This omplex movemet invoves a lexion of the carpoetacaral and metacrpophaangeal ts and a mall aount f abdction nd medal rottion o the mtacarpl bone at the carpoetacaral joit.

Abdction f the Thumb Abdction of the thumb may be defind as a movemnt foward o the thumb i the ateropsterior plan. It takes place at the crpometacarpa t and th metacarpophlangea t

dducton of he Thumb 927

snell This movemen can be defined as movement backward f the abductd thumb in te anteoposterior pane. I restoes the thumb to it anatoic postion, hich i flush with the pal. The dducto policis i the mscle that, in association with te flexr pollcis longus nd the opponens pollicis mscles, is larely reponsibe for the power of the picers gip of he thub. Addction f the humb ccurs t the arpomeacarpl and t the metaarpophlangea t.

Short Musles of the Litle Finger Th short muscles of te litte finger are the abuctor digit minimi, the flexor digit minim brevs, and the opponens digiti miimi, which tgether frm he hypothenar eminence (Figs 9-59, 9-62 and 9-67). .503

928

snell

Figue 9-67 Aterior view of the alm of the hand. Th long lexor tendons have been emoved from the pal, but heir mthod o insetion ito the finges is sown.

Opposition f the ittle Finger Te opponens dgiti mnimi mscle i only apable of rotating the fith meacarpa bone to a sight dgree. However, i assits the flexor digit minim in fexing he carpmetacapal t o the ittle inger, therey pulling th fift metaarpal one forwrd an cuppng th palm.

Arteries of th Palm

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snell

Ulnar Artery The ulnar artery enter the hand anerior o the flexor retinaculum on the lateral side of th ulnar nerve and the pisiorm bne (Fig. 962) The artey gives off a dee branchand then continues nto the palm as the supericial almar rch. Te superfical palar arc is a diect cotinuaion of the ular artery (ig. 9-62) On enterig the palm, t curves latrally ehind the pamar aponeurosis and in frnt of he lon flexr tendns. The arc is copleted on the latral sie by one of he branches f the adial artery The crve of the arch lies acros the alm, level with the distal border of the fully extended thub. Four digital areries arse fro the convexity of the arch and pas to he finers (Fig. 9-62). Th dee branch of te ulna artery arises in front of he fleor retinaculum, pases beween te abductor igiti minimi and te flexr igiti nimi, and jons the radial arter to complet the deep pamar arch (Figs 9-67 an 9-68). .504

930

snell

Fiure 968 Anterior viw of te pal of th hand howing the dep palar arch and the dep terminal ranch f the ulnar erve. he introssei are also shwn.

adial Artery The radial artery leaves the dorsum o the hnd by turnig forwrd beteen th proxial ens of the firt and econd metacapal bones an the to head of the first dorsa intersseous musce (see pag 509). On enterng the palm, it cuves meially etween the oblique and trnsvers heads of the adductor policis nd coninues as the deep plmar arch (igs. -67 and -68). The deep pamar arh s a direct cntinuaion of the rdial atery Fig. 9-68). I curves medilly beneath the lon flexo tendos and n front of te metcarpal bones and th intersseous muscls. The arch is competed o the medal side by te deep branch of th ulnar artery The crve o the rch lies at a level with te proximal border o the etended thumb.

931

snell The deep palar arc sends branches sueriorl, which take part n the nastomosis aound the writ t, and inferirly, t joi the dgital branches of the suprficia palma arch

Brances of he Radial Arery i the Plm Imediately on entering the plm, th radial artery gives off the areria radialis indics, which supplie the lteral side o the idex figer, nd the arteia princeps pollici, hich dvides into to and supplis the latera and mdial ides o the humb.

Veins of the Palm Superficia and deep pamar arerial arches are accompaied by superficial and dep palar veous arhes, rceivin corrspondig triutarie.

ymph Drainag of the Palm Te lymph vesels of the figers alng ther borders to reach the wes. Fro here he vesels ascend onto the dorsum of th hand. Lymph essels on the palm form a plexus that is draine by vssels that acend i front of the foream or arund the medial and latera bordes to jin vesels on the dorsum of the hand. P.505

932

snell

Figure 9-9 Origin and nsertin of he palar and the dorsal iterossi musces. The actons of these uscles are also shown.

The ymph fom the medial side f the and asends in vessls tha accompany te basiic vein; the drain into the upratrchlea nodes an then scend o drai into he lteral xillary node. he lyph fro the lteral ide of the hand ascnds in vessels that accompny the cephalic vein; they drain nto th infaclaviular ndes, and ome drin int the laterl axilary noes.

Nerve of te Palm Medin Nerv The media nerve enters the plm by ing behnd he flexor retinaculum and through the carpa tunnel. t immeiately divides into latera and mdial banches

933

snell The muscuar brach takes recurrent ourse round he lowr border of the fleor retinaculm and lies bout one fingerbreath disal to the tuercle f the caphoid; it supplis the muscle of the thenr emience (he abdctor pollici brevs, th flexo polliis breis, ad the pponens pollicis) ad the first lumbrial musle. The cutanous brnches spply te palar aspct of the laeral three ad a haf fingrs an the istal half of the dorsal aspect of eah fingr. One of thee braches aso suplies te second lumbrical uscle. Not also that te plmar cutaneos branch of the median nerve given ff in the frnt of the forearm (Fig 9-55) crosss anteior to the flexor retinaculum and suplies he ski over the laeral part of the pam (Fig. 938.

Ulnar Nerve The lnar nrve eners th palm anteior to th flexo retinaculum alongside th lateral border of the pisiform bone (Figs. 9-55 and 9-62). As it crsses the retnaculu it diides nto a uperficial ad a deep teminal ranch.

uperficial Banch o the Ulnar Nrve Te supeficial branch of th ulna nerve descend into the palm, ling in the sucutanous tisue between he pisform bone ad the hook o the hmate (Figs. 9-5 ad 9-6). The unar artery is on is lateal sie. Her, the erve ad artry may lie i a fibo-osseus tunnel, te tunnel of Guyon, reated by fibous tssue drived from te supeficial part f the flexor retinaculum. The nrve may be compressd at tis sit, givng rise to linica signs and syptoms The erve gves of the following branhes: a muscular banch to he palmaris revis nd utaneus braches to te palmr aspct of he medal sie of te litte finer and the adjacent sides of the littl and ring figers (Fig. 9-62). It also upplies the istal alf of the drsal apect o each finger

Deep Branch f th1e Ulnar Nerve Te dee branc of the ulna nerv runs backwad between th abducor digiti miimi and the flexor digiti minimi (Fi. 9-6). It pierces he opponens digiti inimi, winds around the loer borer of the hok of he hamte, an e laterlly wihin th concaity of the dep palar arc. The erve les P.50

P.507

P.508

934

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ehind he lon flexo tendos and in front of the metacarpal bones and nterosseous uscles It gives off musular branche o the three uscles of the hypothenar einence namel, the abductr digti minimi, the flexr digii minimi, an the oponens digit minii. It supplis all he palmar an dorsa interossei, the thrd and fourh lumbical muscles, and both hads of the aductor pollicis mucle. Tabl 9-9 Small Musces of the Han

Musle

Oigin

nsertin

Neve Nerve Supply Rootsa Action

almari brevi

Flexor etinaclum , plmar aponeursi s

Sin of palm

Superfici al branch of ulnr nere

C; T1

Corugates skin to impove grip of alm

Lumbricl s (4)

Tedons of flexor digitorum profundu

Extensor expansio n of medial four fingrs

Frst and second, (i.e., lateral tw) medin nerv; thir and furth dep brach of lnar nerve

C8 ;1

Flex mtacarpphalane al jonts and exend inerphaangeal ts of figers ecept tumb

First arise from ase of first metacapal ; rmainin three

Prximal halangs of tumb an index ring, and litle

Deep branc of ular nere

C8 ; T1

almar nterosei addct fingers tward cnter o third finger

Inteossei 8)

Palma (4)

935

snell

Dorsl (4)

from aterior surface of safts o second, forth, and fifh metaarpal s

fingers nd doral extnsor epansin of each figer (Fig. 969)

Contguou s ides o shaft of meacarpa bones

Proimal phalang es of index, middle, nd rin finges and orsal xtenso expansio n Fig. 969)

Deep ranch f ulna nerve

8; T1

Dosal interossei abductshafts of mtacarpl fingrs fro cente of thrd finer; boh palmar and dorsa flex etacarophalageal jints and extend interpalangel s

Short Musces of humb

Abductr pollicis brevis

Scaphod, trapezium flexo retinaculu m

Base of prximal phalan of thumb

edian erve

C8 ; T1

bduction of thumb

Flxor policis revis

Fexor retinaculu m

Base of proximal phalanx of thum

Median nerve

C; T1

Flexe metacrpophaang eal t f thum

936

snell

Oponen s ollici

lexor etinaclum

Shaf of meacarp a bone f thum

Median nerv

C8 ; T1

Pull thumb medialy and orward across palm

Addutor policis

Oblique head; second ad thir metacrpal bnes; tansvere head third metacarp al bone

Base of proximl phalnx of humb

eep branch of ulnar nerve

C; T1

Adduction of thum

Sort Muscles f Litte Fingr

Abuctor digiti minimi

Pisifor bone

Bas of proximal phalan of litle finger

eep branch o ulnar nerve

C8 ; T1

Abduts litle finer

Flexor digiti minimi

Flexo retinculu m

Base of poximal phalan of litle figer

eep brnch of ulnar nerve

C8 T1

Flexes little finger

Oppone ns digiti minimi

Flexr retiaculu m

Media borde fifth metacap al bne

Deep branch of ulnar nerve

C8 ;T

Pulls fift metacrpal frward s in cupping the palm

937

snell

a

The prdominat nerv root upply is indicated y boldface tye.

938

snell

Figure 9-0 Palmar nd pul fascial spaes.

he plmar ctaneou branc o the unar nerve gien off in the front f the orearm crosses anterio to the fexor rtinacuum (Fg. 9-54) nd suplies te skin over te medil part of the palm (Fig. -38).

Facial Spaces of the Palm

939

snell Normaly, th fascil spacs of he pal are ptentia spaces filled with loos connetive tssue. Their boundaries are important clinicall becaue they may liit the spread of infction n the palm. The triangula palma aponerosis ans ou from he lowr bordr of te flexr retiaculum (Fig 9-55). From its medial border a fibrus sepum pases bacward and is atached to the anterir bordr of the fifth metacarpal bone (ig. 9-70) Medil to tis sepum is fascil comprtment contaiing th three hypotenar muscles; this compartment is unimpotant cinicaly. Fro the ateral border of the palmar aponeurosis, a secod fibrus sepum pases obiquely backwad to te anteior border of the third metacarpal bone (Fig. 9-70). Usally, he setum pases between te long flexor tendon of th index and midle fngers. This scond sptum dvides e palm into he thenar pace, whch lie laterl to te septm (and must nt be cnfused with te fasial copartmet contining he thenar musles), nd the midplmar sace whic lies edial o the eptum Fig. 9-70). Prximaly, the thenar and mdpalma space are cosed of from the frearm by the walls f the arpal unnel. Distaly, the two saces ae coninuous with te apprpriate lmbrica canal (Fi. 9-7). The thear space contains the first lumbrial musle and lies osterir to te long flexo tendons to the inex finer an in frnt of he adductor ollici musce (Fig. 9-70. The idpalar space ontains the secon, thir, and fourth lumbrial musles an lies posteror to the log flexr tendns to the middle, ring, nd little figers. t lies in front of the inerossei and he thid, fouth, an fifth metacarpal bones (Fg. 9-70) The lmbricl cana is a potential space urrouning th tendo of eah lumbical mscle and is normally filled with connecive tisue. Poximaly, it s contnuous with oe of te palmr spacs.

Clnical otes ascial Spaces of the Palm nd Infection The fscial spaces of the palm (Fig. 9-70) ar clinially iportan becaue they can bcome ifected and ditended with us as resul of th sprea of inection in acue supprative tenosnovitis; rarly, thy can ecome nfecte after penetrating wounds such as falling on a dirty ail.

Pup Spac of th Finges The deep fascia of he pulp of eah fingr fuse with the peiosteu of th termial phalanx jst disal to he insrtion f the long fexor tndons nd cloes off a fascal comartmen known as the pulp space Fig. 9-70). Eac pulp pace is subdivided by the presence of numerous septa, which ass frm the eep fscia t the priostem. Thrugh th pulp pace, hich i fille with fat, rns the terminl branh of he digtal atery hat suplies the daphysi of th termial phaanx. Te epipysis o the dstal palanx receivs its lood spply poximal to the pulp sace.

Clinical Notes Pulp-Space Infection (Felon)

940

snell The pulp space f the finger is a closed fascial compartment situaed in front of the erminal phalanx of each fnger (Fi. 9-70). Infecion of such space is comon and serious, occrring ost ofen in the thmb and index inger. Bacteria are usually introuced into the space by pinricks r sewig needes. Beause ech spae is sbdividd int numerus smaler copartmets by ibrous septa, it is asily undersood that he accmulation of inflammatory exudate ithin hese ompartents cuses te presure in the pup spac to quckly rse. If the ifectio is let withut decmpresson, inection of the terminl phaanx can occur. In children, the blood suply to the diphysis of th phalax s throgh the pulp sace, and pressure on the blood vessels ould rsult i necrois of he diahysis. The prximall locaed epihysis f this bone is saved because it eceives its arterial supply just proxial to he pul space. Te clos relatonship of the proxial end of the pulp pace t the dgital ynovia sheath acconts fo the ivolvemnt of the shath in the inectiou proces when the pulp-space infction as ben neglcted.

The Dorsum of the Hand Skin The skn on te dorsm of the han is thn, haiy, and freely mobile on the underying tendons and boes. The sensory nerve supply t the skin on the drsum o the hnd is erive from he superficil brach of he radal nere and he poserior utaneos branh of te ulnr nerv. he superfical brach of he radal nere winds around the radius dep to te bracioradilis tedon, dscends over he extnsor retinaculum, and supplies th laterl two hirds f the dorsum of th hand Fig. 9-38). It ivides into several dorsal digital nervs that supply the tumb, the inde and iddle ingers and te lateal side of the ring finger. The aea of skin o the bck of he han and fngers upplie by th radial nerv is sbject o varition. requenly, a orsal igital nerve, a branh of he ulnr nerve, also supples the latera side f the ing figer. P.509

The postrior cutaneous branh of te ulna nerve wnds arund th ulna eep to the flexor crpi ularis tndon, escend over the exensor etinaclum, ad suppies th media third of the dorsum of te hand (Fig. 9-38). It divide into everal dorsal digita nerve that upply he medal sid of th ring nd the sides f the ittle ingers he dosal diital banches of the radial and ulnar nrves d not etend fr beyod the roxima phalax. The remainder of the drsum o each inger eceive its nrve suply frm palmr digial nerves.

orsal enous rch (o Netwok)

941

snell The dorsal venous arch lies in te subctaneou tissu proxmal to the metacarpophalangeal jints ad drais on te lateal sie into the cehalic ein an, on the medial side, into the basilic vein (Fig. 9100. The greater part f the blood rom th whole hand dains ito the arch, hich rceives digital veins and feely communicates wth the deep veins of the plm thrugh te inteosseou space.

Insertion of the ong Exensor endons The fur tenons of the exensor igitorm emere from under the extensor retinaculum an fan ot over the dosum of the hand (Fgs. 9-6 and 9-7). The tendons are embdded i the dep fasia, an togeter the form he roo of a subfacial sace, whih occuies th whole width f the orsum f the and. Srong bliqu fibros band connect the tendons to the littl, ring, and iddle ingers proxial to he heas of te metacarpal bones. The tndon t the idex figer is ed on its medial side y the tendon of the extensr indiis, an the tndon t the lttle fnger i e on is medil side by the two tedons o the etensor digit minim (Fig 9-55). On the posteror surace of each finger, the exensor endon oins te fascal expnsion alled he etensor expanson (Figs 9-56 and 9-57). Nar the proximl intephalaneal jont, th extenor expnsion plits nto thee parts: a centra part, which is nserte into he bas of th middl phalanx, and two lateral parts, which conerge to be iserted into te base of the distal phalan (Fig. 9-63). The dorsl extesor exansion receives the tendon of inertion of the corresonding interosseous muscle on eac side nd father dstally receivs the endon f the umbricl musce on te latral sie (Fg. 9-6).

Clinical Notes Malle Finge Avulsion of the nsertin of oe of te extesor tedons nto th dista phalages ca occur if the distal phalanx is frcibly flexe when he extnsor tndon is taut. The lat 20° of actve exension is lost, resulting n a codition known s mallt fingr (Fi. 9-7).

Botonnière Deormity Avlsion of the central slip of the extensor tenon proximal o its nsertin into the base of the midle phaanx reults n a chracterstic dformity (Fig 9-71C). he deormity result from lexing of th proxial intrphalageal jint ad hyperextenson of he disal intrphalageal jint. This injry can resul from direct end-n traua to te fingr, dirct trama ove the ack of the prximal nterphlangea t or lceratin of te dorsm of he finer.

The adial rtery on the Dorsum of the Hand he radal artry wins aroud the lateral margi of th wris t beneah the endons of th abducor policis lngus ad extnsor pllicis brevis and les on he latral liament f the oint Fig. 9-65). On reaching the orsum of the hand, he artry desends bneath he tenon of he extnsor pllicis longu

942

snell to rech the intervl betwen the two heds of he firt dorsl introsseos musce; her the atery trns forward to enter the palm of the had (see page 504. Branhes of the radial atery o the drsum o the hnd take prt in he anatomosi aroun the wist jont. Dosal diital ateries to the thumb and index finge (Fig 9-65).

ts o the Uper Lib The sernolavicular jont, th acromioclaicular t and te shouder jont are fully described on ages 49 and 60.

Elbw 

 





Articulation: This occrs beteen th trochea an capitlum of the huerus ad the rochlear noth of te ulna and th head f the adius Fig. 9-72). The articuar suraces ae coveed wit hyalie carilage. Typ: ynovial hinge t sule: Anteriorly it is attahed abve to the humerus along the upper margins of th corooid and radial fossae and to the front of the mdial ad lateal epicondyls and below t the mrgin o the cronoid process of the ulna and t the aular lgament which surrounds th head f the adius. Poteriorly it is ttache above to the margins of the olecranon fossa of the hmerus nd belw to te uppe margi and sdes of the oecrano procss of the uln and to the aular lgament Lgaments: he lteral igamen (Fig. 972 is tiangulr and s attahed by its apx to te lateal epicondyle of the humerus and by its base t the uper magin of the anular ligament. The medial ligamnt s also triangular and conists pincipaly of hree srong bnds: te anteior bad, whih pases fro the mdial eicondyle of te humrus to the mdial mrgin f the coronoid procss; th posteior bad, whih s from the medial epicondyle of the humerus to the medial side of he oleranon; and te tranverse and, wich pases beween te ulna attacments f the two prceding bands. Synovial membrane: This lines the casule and covers fatty ads in the foors o the cronoid, radil, and olecraon P510

fssae; t is cntinuos belo with the synovial membran of the proxial radoulnar t. 

Neve supply: Branches from the median, lnar, usculoutaneos, and radial nerves

943

snell

944

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Figure 9-71 A Poterior view of norml dorsl extesor exansion The etensor expanion ner the proximal interphalangeal t splits int three parts a cenral pat, whih is iserted into he bas of th middl phalnx, an two lateral parts, which onverg to be insertd into the bse of he disal phaanx. B Mallet or baeball finger The inertion of the extenor expnsion into the base of te distl phalnx rupured; someties a fake of bone o the bse o the palanx s pulld off. C Bouonnièe defomity. he insrtion f the xtenso expanion ino the base o the mddle palanx s ruptred. Te arros indiate th diretion o the pll of he musles an the dformit.

Movemets Th elbow t s capale of flexio and etensio. Flexion is limited by the anterio surfaes of he forarm an arm cming into . Exensin is cheked by the tesion o the aterior ligament and the brchialis muscle. Flexion s perfrmed b the bachialis, biceps brahii, rachioadiali, and ronato teres muscle. Extesion i perfomed by the ticeps nd ancneus mscles. It should be noted that the long axi of th extened foearm les at n angl to th long xis of the arm. This angle, which opens lateraly, is called the carryin angle and is about 170° in the male and 16° in he femle. Th angle disappars whn the lbow jint is fully flexed.

Imortant Relations    

Antriorly: The brachialis, the tndon o the bceps, he medan nere, and the brchial artery Poteriorly: The triceps muscle, a sall bursa inervenig edialy: he unar neve pases behind the media epicodyle ad croses the medial ligamet of te t. ateraly: The comon exensor endon nd the supinator.

P511

945

snell

Fgure 9-72 Right elbow t. A Laterl view. B Medil view. C Anteior viw of te interior of the jint. Sgittal sectio.

Clinica Notes Stabiity of Elbow oint The lbow t is stable because of the wrenchshape artiular srface f the lecrann and he puleyshaed trohlea o the umerus it alo has trong edial nd latral liaments When examining th elbow t, the phsician must remembe the nrmal elatios of te bony points In exension the mdial ad lateal epcondyls and he top of the olecraon proess ar in a traigh line in flxion, he bon point form the bondarie of an equilaeral riangle.

Dslocations of the Elbow Jont 946

snell Elbow disloctions re comon, and most are poterior Postrior dslocaton usully folows flling n the utstreched hnd. Psterio dislocations of the t are common in childrn becase the parts of the bones that sabiliz the jint ar incomletely develoed. Aulsion of he epiphysis of the medial epiconyle is also cmmon i chilhood bcause hen th media ligamnt is uch stonger han th bond of unin between the epiphsis an the daphysi.

Arthrocetesis f the lbow Jint The anteror and posteror wals of te capsle are weak, and when the t is disended with fluid, te postrior apect f the oint bcomes wollen Aspirtion o t fluid an easly be perfored thrugh th back of the t n eithr side of the olecranon process.

Damge to the Ulnar Nere With Elbow oint Ijuries The close relatioship o the unar neve to he medal sie of te often result in is becoing damaged n dislocations of he t or in fracure dislocations in this egion. The neve leion ca occur at the time of injury or weeks, months, r year late. The erve cn be ivolved in sca tissu formaion or can beome sretche owing to latral deiation of the forear in a adly rduced supracndylar fracture of he humrus. Dring mvement of th elbow t, the continued friction beween te medil epicndyle and th streched unar neve evetually result in ular paly.

Radiolgy of he Elbw Regin afte Injur In eaminin laterl radigraphs of the elbow region, it is important to remembr that the loer end of the humerus is normally angulted foward 4° on he shaft; whe examining a patien, the physican shold see that the medial epicondyle in th anatomic poition, is dircted mdially and poteriory and aces i the sme diection as the head o the hmerus. P.512

Proximl Radiulnar t    





Articulation: Betwee the crcumference of the head of the raius an the aular lgament and te radil notc on th ulna Figs. 9-72 and 9-73) Type Snovial pivot t Casule: The capsul encloes the t and is continuous wih that of the elbow oint. Ligaent: The anula ligamnt is atached o the nterio and psterio margis of te radial notch on the uln and frms a ollar round the hea of th radiu (Fig. 9-73). It is continuous abov with he capule of the elbow t. It is not attachd to te radis. Synvial mmbrane: his i contnuous bove wth tha of th elbow t. Below t is attached to te infeior magin of the aricular surfac of th radiu and he lowr margn of te radil notc of th ulna. Nere suppy: Branchs of te median, ulnar, musculocutaneous and rdial nerves

947

snell

Fiure 9-73 igamens of the proximal ad distl radioulnar oints, wrist oint, arpal ts, and ts of the fingers.

948

snell .513

Mvement Pronation ad supiation f the orearm (see blow)

Importat Relaions  

Ateriory: Supinaor musle and the radial nerve osteriorly: Supiator muscle and the common extensr tendn

Distl Radiulnar oint     

 

Aticulation: Betwen the rounded head of the ulna ad the lnar ntch on the raius (ig. 973) Tpe: Synovial pivot apsule: Te capsle encoses te t but is deficient superiory. Ligaents: Wea anterior and posteror ligamets strngthen the casule. Articulr disc his is trianglar and composed of fibrocartilage. It i attaced by its apex to the latral sie of he bas of th stylod procss of he ula and y its ase to the loer borer of he ulnr notc of th radis (Figs. 9-3 and 9-74). It shuts off the distal radioulnar t from the wris and srongly unites the raius to the ula. Synoial mebrane: This lines the sule assing from te edge of one articular surface t that f the ther. Nrve suply: Anteior inerosseus nere and he dee branc of th radia nerve

ovemens The movemets of pronation and supinaion of the foearm nvolve a rotay moveent arund a verticl axis at the proximl and distal radiounar jonts. Te axis es throug the head of the radius above ad the attachent of the aex of the triangula articlar disc beow. In the moement f prontion, he hed of te radis rottes wihin th anular ligamnt, whreas te distl end f the radius with the han moves bodily forwar, the lnar ntch of the rdius mving around the circumference of the hea of th ulna Fig. 9-75). In addition, th dista end of the lna moves latrally o that the hnd remins in line wth the upper imb an is no displced meially. This movement of the ulna is imprtant when using an instrument such as a screwriver ecause it preents sde-to-ide moement f the and during the repetitive movements of supinaton and pronaton. The movement of prnation results in te hands rotaing mdially in such a manner that the alm coes to ace poteriory and the thumb lies on the medial side The mvement of supnation is a eversal of this proess so that te hand returns to the anatomic psition and th palm aces ateriory. Prnation is perfored by he proator tres an the ronator quadratus.

949

snell Supinaton s performed by the biceps brachi and te supiator. upinaton is he more poweful o the to moveents bcause f the trengt of th bicep muscl. Becuse suinatio is th more owerful movement, screw threads ad the spiral of corscrews are mae so tat the screw and corkscrews are riven nward by the ovement of suinatio in riht-haned peole.

Imprtant Relations  

Anteriorly: Th tendos of fexor igitorm profundus Postriorly The tendn of etensor digiti minimi

Clinical Noes Radoulnar t Disease Te proimal rdioulnr t commnicate with he elow joit, wheeas th dista radiolnar t does not communcate with th wrist t. In pratical erms, his means tht infetion o the elbow oint ivariably invoves th proximal raioulna t The strengt of th proxial radoulnar t epends on the integrty of the stong anlar ligament. Rupture of this ligament occurs i cases of anerior islocaion of the had of the raius on the caitulum of the humers. In oung cildren in whom the head of the rdius i still small and unevelopd, a sdden jrk on he arm can pul the adial head down through the anulr ligaent.

Wist t (Radiocaral Joit) 

  





Aticulation: Betwen the dista end o the rdius ad the rticulr disc above nd the scaphoid, luate, ad triqetral ones blow (igs. 973 and 974) The poximal articuar surace foms an llipsoid conave suface, hich i adaptd to te distl ellisoid cnvex srface. Type: Syovial llipsoid joit Capsle: The apsule encloss the t and is attached above to the distal ends of the radius and ula and elow t the poximal row of carpal bones. igamens: Antrior and posterior liaments strengthen the capsule. The medial igamen is attaced to he styoid prcess o the una and to the triqueral bone (Fgs. 9-73 nd 9-4) The ateral ligamnt s attahed to the styloid process of the radius and to the shoid one (igs. 973 and 974) ynovia membrne: This lines he capule an is atached o the margins of the articular srfaces The jint caity dos not ommuniate wih that of the dista radiulnar oint o with he joit cavities of the itercaral joits. Nerve suppy: Anterir inteosseou nerve and th deep ranch f the adial erve

Moements The folowin movements ae posible: flexion, extesion, bductin, addction, and circumdution. otatio is not possible because the rticulr surfces ar ellipoid shped. Te lack of roation is comensate for b the mvement of pronation and supinaton of he forarm. Flexin is perfrmed by the lexor arpi rdialis the fexor carpi lnaris, and he palaris ongus. These muscles are assisted by the flexor digitoum suerficilis, te flexr digiorum pofundus, and the flexor pollicis longus.

950

snell P.514

Figue 9-74 Dissection o the orsal urface of the left hand and distal end of the orearm Note he caral bons and he intrcarpa t; note also he wrist (radiocarpal) t.

P.515

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snell

952

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Figure 9-7 Mvement of suinatio (A) and pronaion (B) of the forear that ake plce at the proximal nd distal radoulnar ts C Relatve postions f the adius nd uln when he forearm is fully pronatd.

P.516

Extenson is perormed y the extensr carp radiais lonus, th extenor cari radilis brevis, and th extenor cari ulnaris. These mucles are asssted b the xtenso digitrum, te extesor indicis, the exensor igiti inimi, and te extesor pollicis longus. bduction s perfrmed b the lexor carpi radialis and te extesor capi radalis lngus ad breis. Thse musles ar assised by he abdctor pllicis longus and etensor pollics longs and brevis dduction is peformed by the flexo and etensor carpi ulnari.

Importnt Reltions  

 

nteriorly: The endons of the flexo digitrum prfundus and suerficilis, te fleor pollicis longus, the flexor carpi radialis, he fleor cari ulnris, ad the edian nd ulnr nervs Psteriorly: The tendon of th extenor cari ulnais, th extenor digti minmi, the extnsor dgitoru, the xtensor indics, the extensr carp radilis logus an brevi, the xtenso polliis logus an brevi, and the abuctor pollicis longus Mdially: Te posterior cutaneous branh of te ulna nere Laterlly: The adial rtery

Clnical otes rist t Injuries The wrist t is essentially a synoial jont beteen te distl end f the adius nd the proxial row of caral bons. The head f the lna is separaed fro the crpal bnes by the stong tiangular fibrocartilaginous ligment, hich sparate the wist jont frm the istal adioular joit. The t s stablized y the trong medial and laeral lgament. Because the styloi proces of the radius is longer han tat of he uln, abdution o the wist jont is ess extensive than adduction. In flexio–extnsion ovemens, the hand cn be fexed aout 8° but extened to only about 45°. The range f flexon is ncreasd by ovemen at th midcapal jont. A fal on te outsretche hand can stain th anteror liament f the rist jint, poducin synovial effusion, t pain, and limitation of movment. hese smptoms and sins mus not b confsed wih thos produed by fractred shoid r dislocation of te lunae bone, which are smilar.

Fall on th Outstetched Hand

953

snell In falls n the utstreched hnd, forces are transmitted from the scaphoid t the dstal ed of the radius, from the radius across the inerosseus memrane t the una, an from he uln to te humeus; thnce, trough the glenoid fossa of the sula to the oracocavicular ligaent an the clavicle; and inally to the stenum. I the frces ae excesive, ifferet part of th upper limb ive wa under the stain. The are affeced sees to b relatd to ge. In a youn child for eample, there ay be posteior displacement of the distal radial epiphysi; in te teenger th clavcle miht frature; n the oung ault th scaphid is ommonl fracured; nd in he eldrly th dista end o the rdius s fracured about 1 in. (2.5 cm) proximal to the wris t (Colle' fracure) (Fig 9-50).

ts of the Hand and Finers Intercarpal ts 

   



Articultion: Beween te indiidual bones of the proxima row o the crpus; etween the individual bones of te distl row f the arpus; and fially, he micarpal t, betwee the poximal and distal rows of arpal bones (Figs. -73 and -74) Type: Synoval plae s Capsule: The casule surrounds each t. Ligaments: The bones are unied by trong anteror, poterior, and interosseus ligaments. Synovil membrane: Thi lines the casule ad is atached to the margin of th articlar surface. The oint cvity o the mdcarpa t extend not oly beween te two ows of carpal bones ut aso upwrd beteen th indiidual ones frming he proimal rw and ownwar between the bones of the distal row. Nerve suply: Anteror introsseos nerv, deep branch of the radial nerve, and deep brach of he ulnr nerv

Mvement A small amount of glidin movemnt is ossibl.

Carpmetacapal an Interetacaral Joits The carpoetacaral and intermtacarpl s are synovil plan t possesing aterior, postrior, nd introsseos ligments. They hve a cmmon jint caity. A small mount f glidng moement is possible (Figs. -73 and -74.

Carpomtacarpl of th Thum    

Articulatin: etween the trapeziu and te sadde-shapd base of the first etacaral bone (Fig. 9-73) Typ: Synovia saddl-shape t Capsul: he capule surrounds te . Syovial embran: his lies th capsue and orms a separae cavit.

Movemets Th folloing moements are posible: 

Fleion: Flexr pollcis brvis an opponns policis 954

snell    

Extesion: Extnsor pllicis longus and brvis bductin: Abductr pollcis logus an brevis Aduction: Aductor pollics Rotation (oppositin): The thumb is rotate medialy by he oppnens pllicis

etacarpophalangeal oints    

Articuation: Between te head of the metacarpal bones and the ases of the poximal phalanges (ig. 9-3) Type: Synvial cndyloi t Capsule: he capule surounds the jint. igaments: The almar igamens are strong and contai some ibrocatilage They re firly attched t the palanx ut les so to the meacarpa bone Fig. 9-73). The palmar ligamnts of the seond, tird, fourth, and fifth ts ae united by he eep trnsverse metacarpal ligamets which hold the heas of the metacarpal bones togethr. The collteral igaments re codlike ands pesent n each side o the jints Fig. -73). Each es downard an forwad from the hed of te metaarpal one to the bae of te phalanx. The P517

cllaterl ligaents ae taut when te joit is i flexin and ax whe the t is in extnsion. 

ynovia membrne: This ines the capsule an is atached o the argins of the articuar surfaces.

Moements The ollowig moveents ae possible:    

Flexion: The lumbricls and the inerosse, assisted by the flexor digitoru supericiali and pofundus Extenson: Extenor digtorum, extensr indiis, an extenor digti minmi Abdction: Moement way frm the idline of the third finger is performed y the orsal nterosei. Addction: Mvement towar the midline of the thid fingr is performd by te palar introssei In th case f the etacarophalangeal t of the thumb, flexon is perormed y the lexor pollics longs and revis nd extensio i perfomed by the extensor pollics longus and revis. The moements of abuction and aduction are peformed at the carpometacarpal t.

Interphalangeal Jints Intephalaneal jonts ar synovial hige joits tha have structure similar t that f the etacarpophalangeal ts (Fig. -73).

Th Hand as a Functional Unt The pper lmb is multiointed lever freely movabl on te trun at th shouler t. At the distal end of te upper limb s the importnt preensile organâ”the hnd. Muh of te impotance f the hand 955

snell epends on the pincer action of th thumb which enable one t gras objecs betwen the thumb nd indx fingr. The extrem mobilty of the fist metacarpal bone makes the thumb functionally as imprtant as all the remaining finers combined To compreend fuly the importnt positioning and movemets of he han descrbed in this sction, the reader is stronly adised to closey observe the movemets in is or er own hand.

Postion o the Hnd or the hand to be able to perfom deliate movements, such as those use in th holdig of small instruments in watch repairig, the forear is plced in the seiprone positin and he wrst joit is artialy exteded. I is inerestig to nte tha the forearm bones are most stabe in te midpone poition, when te introsseos membane is taut; n othe positons of the foearm bnes, the interosseous membrane is lax. With the wris partially extended, the lon flexo and etensor tendon of th finges are orking to thir bes mechaical avantag; at te same time, he fleors an extensors of the carpus can exert a baanced ixator action on the wrist t, ensurig a stble bae for the movements of the finger. The position of rest is the osture adoptd by te hand when he finers ar at ret and he han is reaxed (Fig. -76). The forearm is in the smipron positon; th wrist t s sligtly etended; the econd, third, fourth and ffth figers ae partally lexed, although the index finger is not flexed s much as the others and he plae of te thumnail les at right angle o the lane o the ther fingernils. The position of function i the posture adopte by th hand hen it is abot to gasp an objec between the humb ad index finge (Fig 9-76). he forarm is in the semiprne postion, he writ t is partially extended (mre so han in the poition f rest, and he finers ar partally fexed, he indx fingr bein flexd as mch as he oters. he metcarpal bone o the tumb is rotate in suh a maner tht the plane of the thumbnail lies parallel wih that of the index inger, and te pulp of the thumb nd indx fingr are n contct. The ollowig moveents ae descibed wth the hand i the aatomic positin.

Moements of the Thumb Fexion is he movment o the thumb across the pal in such a maner as to mintain the plne of the thumbnai at right anges to he plae of the othe fingenails Fig. 9-76). Te moveent taes plce between th trapeium an the frst meacarpa bone at th metacrpophaangeal and inerphalngeal oints. The mscles roducig the movement are the flxor policis ongus nd brvis an the oponens pollicis. Extenson s the movemet of he thub in a latera or coonal pane awy from the palm in uch a manner as to aintai the pane of the thmbnail at right angles to the plane of the othr fingrnails (Fig. 9-76 and 9-77). The movement takes place etween the trpezium and th first metacapal bne, at the meacarpohalangal and interpalangel s. The muscls prodcing te moveent ar the etensor pollics longs and brevi.

956

snell Abdution is te moveent of the humb i an aneroposerior lane aay fro the plm, th plane of the thumbnail being kept at right anles o the lane of the other nails (Figs. 9-76 and 9-78A). he movment tkes plce maily between the trapezium and the first metacaral bon; a smll amont of ovemen takes place t the metacapophalngeal oint. he musles prducing the moement re the abducor policis lngus and breis. Aduction is the moement of th thub in an anteroposteior plne toward th palm, the plane o the humbnil beig kept at rigt angls to te plan of th other fingenails ig. 9-6 nd 978B). The movement takes place between the trapezum and the fist metcarpal bone. The mucle prducing the moement s the dducto polliis. Oppositio is the mvement of the thumb across the palm in uch a anner hat th anteror surace o the tp come into ontact with the anterior surface of the tip of any of the oter finers (Figs. -76 and -77C). Te moveent is accompished y the edial otatio of th first metacrpal bne and the attached phalanges o the trapezium. The plane of the thumbnil coms to le paralel wih the lane o the nil of the oposed inger. The mucle prducing the moement is the opponens pollicis.

Movments f the ndex, iddle, Ring, and Litle Figers Fleion is the movement forward of the finger in an ateroposterior plane The mvement takes lace a the interphalangeal P.58

P.51

and mtacarpphalaneal ts. The distal phalanx is flexed by the flexo digitrum profundus, the iddle halanx by the flexor digitorum superficialis, and the proximl phalnx by he lumricals and the interossei.

957

snell

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Fiure 9-6 arious positins of the hand and movements of te thum.

Figre 9-77 Lft han with he finers abucted and the thumb extended (A), wth th fingers adducted ad the thumb aducted (B), and with the thmb in he position f oppoition (C.

Exension is the moement backward of he finer in n anteoposterior plne. The movemnts take place at the interphalangeal and metacarpophlangea t. The istal phalanx is etended by the lumbrcals ad inteossei, the midle palanx y the umbricls and interosei, ad the roxima phalax by he extnsor dgitoru (in adition by th extenor indcis fo the ndex fnger ad the xtenso digit minim for te little finer).

959

snell Abduction is the movement of the finers (icludin the mddle finger) away fom the imaginry midine of the middle finger (Figs. -69 and -77A). The movement takes plae at te metaarpophlangea t The mscles producng the movement are the dorsal interosse; the bductor digit minii abduts the little finger Addution is te moveent of the fingers oward he midine of the midle figer (Fig. -77B). Th movemnt taks plac at th metacrpophalangeal t. The muscles roducig the ovemen are te palmar interossei. Abdction nd addction f the fingers are possible only n the xtende positon. In the flxed poition f the inger, the aticular surface of the base of the proxial phaanx lis in cntact with te flatened aterior surface of te hea of the metaarpal one. he two bones re held in close by the cllateral ligaents, which re tau in ths posiion. I the etended positin of te metcarpopalangel , the ase of the phalanx is in with te rouned par of th metacrpal had, an the cllaterl ligaents re slak.

igure -78 Left and wih the humb about to move the pencil away from he pal to deonstrate abduction (A) and wth the thumb bout t move he penil in he dirction f the alm to demonsrate adductin (B).

Cupping the and

960

snell In he cupped position, the pam of te hand is fored ino a dep concvity. o achive this, the thumb s abduted an placd in a partialy oppsed poition nd is lso slghtly lexed. This as the effect of draing the thenr eminnce foward. The fourth and fifth metacrpal bnes ar flexe and lightl rotatd at te carpmetacarpal jints. his ha the efect of draing th hypotenar einence forwar. The almari brevi muscl s and pulls the skin over the ypothear emience mdially it aso pucers th skin, which improves the gripping ability of the palm The index, middle, ring, and litle figers ae parially lexed; the figers ae also rotatd slighly at he meacarpohalangal joits to increae the eneral concaity of the ped hnd.

Making a Fit Making a ist is accompished y flexing th metaarpophlangeal t and te intephalaneal jonts of the fingers and thumb. It is perormed y the ontracion of the log fleor musles of the fingers and thub. For this mvement to be carrie out eficienly a snergic contrction f the xtenso carpi radiais lonus and brevis and th extenor cari ulnais musles mut occr to etend te wris t (Try o make a “trong ist― with te writ flexed—it is very diffiult.) .520

Clinicl Note Diseass of te Hand and Prservaton of Function Frm the linica standoint te hand is on of th most importnt orgns of he bod. Withut a nrmally functioning hand the patient's lvelihod is oten in jeopary. To tudents who dubt ths staement, I woul sugget that they place their right (or left) and in a pocet for 24 hous. The will e astoished t the umber f times they would lke to se it if the could From the purely mechanicl poin of view, the hand can be regardd as a pincerike mehanism betwen the thumb ad fingers, stuated at the end of a multte lever The mst imprtant art of the hand is the thmb, an it is the phsician's responsibility to preserve the thumb, or as uch of it as ossile, so that the pincerlik mechaism can be mantained. The incerlke acton of he thmb larely deends o its uique bility to be rawn aross te palm and opposed to the other ingers This ovemen alone althogh imortant is inufficint for the mehanism to work effectively. The pposing skin urface must ave tatile snsatio—and this eplains why mdian nrve pasy is o much more disabling than ulnar erve plsy. If the hand require immoblizatin for he tretment f disase of any pat of te upper limb, it shuld be immobiized (f posible) n the positon of unctio. This mans tht if lss of ovemet occus at te wris t or at the ts of the hand or finger, the atient will a leas have hand that i in a position of mechanicl advatage, nd one that cn sere a usful pupose.

961

snell Pysicias shoud also remembr that when a finger (excuding he thub) is normall flexe into he palm, it points to the tubercle of te scapoid; idividul fingrs reqiring immobiizatio in flxion, on a splint or within a cas, shoud theefore always be plaed in his poition. Always refr to te patint's fngers y name humb, ndex, iddle, ring, and little figer. Nmberin the fngers s conusing is the thumb finge?) and has led to such disastrous resuls as aputatig the rong fnger.

Embryologic Notes Development of the pper Lmb The limb bud appea durin the sxth week of development as the rsult o a loclized rolifeation f somaopleurc mesnchyme This auses he ovelying ctoder to buge fro the tunk a two pairs of flattened padles (Fig. 9-79. The arm bus deveop befre the leg buds and lie at the level of the lower six cervial and upper wo thoacic sgments The fattene limb buds hve a halic preaial boder and a caudal postaxial border. As the limb buds elongate, the anterior ram of th spina nerve situted oposite he bass of te limb buds sart to grow ito the limbs The msenchye situated along the preaxial border becmes asociatd and nnervaed wit the lwer fie cervcal neves, wereas the meenchym of te postxial brder bcomes associated with the eighth cervicl and irst toracic nerves Later the meenchyml masss divie into anterior and posterior groups, and the erve tunks entering the base of each limb also divid into nterio and psterio divisons. Te mesechyme within the lmbs diferentates ito indvidual muscle that igrate withi each imb. A a conequenc of thse two factor, the nterio rami of the spinal nerves become arraned in omplicted plxuses hat ae foun near he bas of eah limb so tha the brachil plexs s formd.

Amelia Absene of one or mre limbs (amlia) or prtial bsence (ectomelia may occr. A dfectiv limb ay posess a udimenary had at te extemity f the imb or a welldeveloed han may sring fom the shoulder with absence of the intrmediae porton of he lim (phocomelia) (Fig. 9-80.

Congnital bsence of the Radius Occasionally, the radius is congeitally absent and th growt of th ulna ushes he hand lateally (Fig. 981).

Syndactly In syndactyly, there is webbig of te fingrs. It is usully biateral and ofen famlial (Fig. -82). Plastic repair of the figers is caried ot at te age f 5 yers.

Lobter Hand 962

snell Loster hnd is form f syndctyly that i assocated with a entral cleft ividin the hnd into two parts. It is a heredofamilial disoder, fr whic plastc surgry is ndicated wher possble.

Bracydactyy In brachyactyl, there is an absenc of on or moe phaanges n seveal finers. Povided that te thum is functioning normally, surgery is not indicted (ig. 9-83)

Floatin Thumb A flating humb rsults f the etacaral bone of the thumb is absent but the phalangs are resent Plastc surgry is indicaed whee possble to improve the functional capbilities of te han (Fig. 9-8).

olydacyly I polydactyly, one o more xtra dgits dvelop. It tends to un in familis. The additinal diits ar removd surgcally.

Lcal Giantism Macrdactyl affecs one r more digits; these may be of adult siz at bith, bu the sze usally dminishs with age (Fig. 985). Surgical removal may be necessar. P.521

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snell

Figure 9-79 Secion though te lowe cervial regon and the fomation of the uppe limb ud. Noe the resenc of th developing bones and muscles from th mesenhyme.

964

snell

Figure 9-8 Ectromelia. (Cortesy f G. Aery.)

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965

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Figre 9-8 Congenital absence of the radius.

Figue 9-82 Patial sndactyy. (Cortesy f L. Tompson)

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Fgure 983 Brachyactyly due t defecs of te phalnges. Courtey of L Thompon.)

Figure 9-8 Floating thumb. The meacarpa bone f the humb i absen, but he phaanges are prsent. Courtey of R Chas.)

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igure 9-85 Macroactyly affecting th thumb and inex finer. (Curtesy of R. eviaser.)

P.523

Radioraphi Anatoy Rdiograhic Apearancs of te Uppe Limb Radiologic eaminaton of he upper lim concetrates mainly on te bony strucures bcause the mucles, endons and nrves lend ito a hmogeneus mas. The adiogrphic apearanes of he uper lib are shown i Figures 9-86, 9-87, 988, 9-89, 990, 9-91, 992, 9-93. Magetic rsonanc imaging of the uppr limb can be useful to demnstate th soft issue aroun the bones (Fig. -94).

Surface natomy Anterior Surace of the Chst uprasternal Notch

968

snell The sprastenal noch is he superior margin of the manubrum steni and is easly palated btween the prominent medial ends f the lavicls in te midlne (igs. 995 and 9-96.

Figure 9-86 Anteroposterior radiogrph of he sholder rgion i the ault.

Strnal Agle (Agle of Louis) Te sternal angle is the angle betwen the manubrum and the body of the sternum (Fig. 995; at tis levl the econd ostal artilae the lteral argin f the ternum

Xiphisternal t The xiphisernal oint i betwen the xiphoid process of the sterum and the boy of te sterum (Fig. 9-97).

Costal Marin Th costal margin is he lowr boundary of the thorax and is formed by the artilaes of he 7th 8th, th, an 10th ibs an the nds of the 11h and 2th catilage (Figs. 9-9, 9-96, and 9-97).

Clavcle 969

snell The clavcle is situatd at te root of the neck and throughou its etire lngth les jus beneah the kin an can b easily palpate (Fgs. 9-5, 9-96, an 9-97). The poitions of the sternoclaviclar an acromoclaviular jints cn be asily dentifed. Noe that the meial en of th clavile proects bove te margn of te manurium serni. P.52

970

snell

971

snell

igure 9-87 Anteroposterior radiograp of th elbow region in the adult.

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Figure 9-88 Lateal radograph of the elbow egion n the adult.

972

snell

igure -89 Posteoanteror radograph of an dult wist an hand.

P.526

973

snell

Figure 990 Posteroanterior radigraph f the rist wth the forear prnated

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Figur 9-91 Postroanteior raiograph of the wrist and hnd of an 8-yer-old oy.

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Figure -92 Lateral radigraph f an ault wrst and hand.

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Figure 9-9 Lateral radiogrph of n adul wrist and had with the figers a different dgrees f flexon.

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Fgure 9-94 Transerse (xial) agnetc resonance iage of the uper par of th right forearm (as seen frm belo).

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Fiure 9-95 nterio view of the thora and adomen n a 29year-od woma.

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Figure -96 The pctoral region in a 2-year-ld man

Ribs The frst ri lies eep to the clavicle and cannot be palpaed. Th laterl surfces of the remaining ribs an be elt by pressng the finger upwar into he axila and drawin them ownwar over the lateral surface of the chest all (Fig. 997) Each rib can be identified by first papating the strnal agle an the econd ostal artilae (see previos colun) and countig down from here.

Dltopecoral Tiangle This smal, tringular depresion is situated below the outer third of the cavicle and is bounde by th pectoalis mjor an deltid musles (Figs. -95 and 9-96).

Axillay Fold

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snell The anteior axllary old is fomed by the lwer magin of the petorali major muscle and cn be palpated betwee the fnger ad thumb (Fig. 9-95, -96 and 9-97). Ths can e made to stad out y askig the atient to press his or her hand against the ipsilatera hip. he poterior axillary fold i forme by th tendo of laissimus dorsi as it es around the lwer boder of the tees majr musce. It an be asily alpated beteen the finger and thumb (Fg. 9-98).

Axilla The axlla shuld be examind wit the frearm upportd and the petoral uscles relaxed. With the am by te side the nferio part f the head of the humerus can be easily palpated hrough the flor of the axilla. The pusatios of te axillary artery can e felt high up in the axilla, and around the arery ca be papated he cords of the brachial lexus. The medial wall of the axilla s formed by te upper rib coered by the serrats anterior muscle, the erratins of hich cn be sen and felt i a musular sbject Fig. -96). The latera wall s formd by te coacobrahialis an bis brahii mucles and the bicipital groove of the umerus

Posterior urface of the Chest Spinous Processes of Cervical ad Thorcic Vetebrae The spinous proceses ca be papated n the midline posteriorly Fig. 9-98). Te inde finge shoul be plced on the skn in te midlne on he poterior surfac of the neck and drawn downward i the nchal goove. The fist spious prcess t be fet is tat of he sevnth cevical verteba P531

vertebra prominens). Beow this leve are he ovelappin spine of th thoraic verebrae The sines o the irst trough sixth cervical verterae are coverd by te larg ligaent caled th ligmentum nuchae

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Fgure 997 Surfac anatoy of te ches, shouder, ad uppe limb s seen anterirly.

Scapul The ip of he cracoid proces o the sapula Fig. -97) can be fel on dep palption i the lteral part of the deltopectoral triangle; it is coverd by te anteior fiers of the detoid mscle. The cromio forms the lateral extremity o the sine of the sula. t is sbcutanous an easil locatd (Figs. 9-95 ad 9-9). Immediatel below the laeral ege of he acrmion i the sooth, ounded curve f the shoulder prodced by the dltoid muscle, which covers the greaer tubrosity of the humers (Figs. 9-95 and -96). The cres of th spine of the scapul an be alpate and taced mdially to the media border of the scapula, which it s t the evel o the third thracic spine (Fig. 998.

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snell Th suprior agle of the sula can e felt throug the tapeziu muscl and les oppsite te second thoracic spine. Te inferior ngle o the sapula can be palated oposite the seenth toracic spine Figs. 9-98 and 999).

The Beast n chilren an men, the breast antomy i rudimntary and th glandlar tisue is confined to a small area bneath he pimented areola In yong womn (Fi. 9-95) i is uually emisphrical nd slightly pendulos, overlaps te secod to he sixh ribs and thir cosal carilages and etends rom th lateal magin of the sternum to the midaxillary line (Fi. 9-95). The grater prt of he brest lie in th supericial fascia and ca be mved frely in all diection. Its pper lteral dge axillay tail extends around the lower bordr of te pectralis ajor and entes the xilla Fig. -95), where it comes into cloe relaionshi with he axilary vssels. In midle-agd multparous women he brest may be large and pendulus, ad in oder woen the breast may be smalle. P.532

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igure -98 Surfae anatmy of he scaula, soulder and ebow reions a see posteriorly

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Fgure 999 The back in a 27-yea-old mn.

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In the livng subject, te breat is soft because te fat contaied witin it s flui. On creful alpatin with the open hand, the breast has a firm, oerall lobulaed conistenc, produced b its glanduar tissue. The nipple projects frm the ower half of the breast (Fig. 995), but its position n relaion to the chst wall varies gretly an depeds on he devlopmen of the gland. In males an immatre femles, he niples ar small and usually ie ove the furth itercosal spces abut 4 i. (10 m) fro the mdline. The bae of te nippe is urrouned by circuar area of pigmented skin called the arola (Fi. 9-95). Pink i color in the young girl, he arela becmes daker in color n the second month f the irst pegnany and ever rgains ts forer tit. Tin tuberles on the arola ar produed by he undrlying areoar glads.

Th Elbow Region The medil nd laeral epicondyles of th humers (Fis. 9-9 and 9-9) ad the lecranon process of the una can be palated (Fig. 9-98. Whe the ebow jont is xtende, thes bony oints ie on he same stright lne; whn the elbow is flexe, thes three points form te boudaries of an quilatral trangle.

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snell The hea of the radius cn be alpated in a depression on the poterolaeral apect o the extended elbow, distal to the lateral epcondyl. The ead of the radius can be felt to rotate during pronation and supination of the forearm The cubital fossa is skin depresion in front f the lbow (Figs. 9-48 and 9-97), and the oundares can be see and flt; th brachoradiais musle foms the latera boundry and the prnator eres forms the medil boudary. he tendon f the iceps uscle can be palated a it pases donward nto th fossa and te bicipital aponeuosis can e felt as it eaves he tenon to oin th deep ascia n the edial ide of the forearm (Figs. 9-48 and 9-97). The tendon and aoneurosis are most esily flt if he elbow is flxed aginst rsistane. The ulnar nerve can e palpated here i lies ehind he medal epiondyle of the humerus. It feels ike a ounded cord, nd whe it is compresed, a “pin and eedles€• senation s felt along the meial pat of te hand The brchial artery can be fet to pulsate as it es own th arm, verlaped by he medial border o the biceps muscle. In the cubita fossa it lis beneth the biciptal apneuross, and at a evel jst belw the ead of the adius, it divdes ino the adial nd ulnr arteies. Te posterior border of the ulna one is sucutaneus and can be palpatd alon its etire length.

The rist ad Hand At th wrist the styloi proceses of the rdius (Fi. 9-10) nd ula an be alpate. The tyloid proces of th radius lies about 0.75 in (1.9 m) disal to hat of the ula. The dorsal ubercl of th radiu i palpale on he poserior surface o the dstal ed of te radis (Fg. 910) The ead of the ula is most easily felt wth the forear pronaed; th head hen stnds out prominently on the lateal side of the wrist (Fig 9-75). Th rounded head can be distiguishe from he mor dista pointd stylid proess. Th pisiorm bne an be felt o the mdial side of the anerior spect of the wrist etween the two transverse reases (Figs 9-48 and 9-100). The hok of te hamae bone ca be fet on dep palation of the hypothenar eminence, a fingrbreadh distl and ateral to the pisifom bone The transverse creases seen in frnt of he writ are mportat landarks (Fig. 9-100). Th proxial trasverse crease lies a the level of the wrist t. Te distl tranverse rease orrespnds to the prximal order f the flexor retinculum.

mportnt Strctures Lying n Fron of th Wrist Radil Artey Th pulsations of the radial artery an easly be elt anerior o the istal hird o the rdius (Figs. 9-48 and 9-100). Hee it les jus beneah the kin an fasci lateral to the tenon of lexor arpi rdialis muscle

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Tendn of Fexor Crpi Raialis Th tendon of the flexr carpi radialis lies medal to he pulsating radial artery.

Tndon o Palmais Longus (I Preset) The tendon of the palmaris lonus lie media to th tendo of flxor capi radalis ad overies the median nerve (Fig 9-100).

Tendons f Flexr Digiorum Sperficalis Te tendons of the flxor dgitorum supeficialis are grou of for that lie meial to the tendon of palmaris lonus and can b seen oving beneath the skn when the figers ae flexd and extendd.

Tendon of Flexor Carpi Ulnaris The endon f the flexor carpi lnaris is the most ediall placed tendon on the front of th wrist and ca be folowed distaly to is insetion n the pisifom bone (Figs 9-48 and 9-100). The tedon ca be mae promnent b asking the atient to clech the fist the mucle cotracts to assst in ixing nd stailizin the rist jint).

lnar Artery The pulsations of the ulnar arter can b felt ateral to the tendon of fleor cari ulnaris (Fig. 9-100).

Ulnar Nrve The ulnr nerv lies mmediaely meial to the ular artry (Fig. 9-00)

Importnt Strctures Lying on the Latera Side f the rist Anatomc Snufbox The â€anatomc snufbox― is an mportat area It is a ski depresion tat lis distal to th styloid proess of the rdius. It is bounde medialy by the tendn of etensor polliis longus and aterally by he tendons f abdutor pollicis P.534

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longus and extensor pllicis brevis (ig. 9-00) In it floor can be palpaed th styoid prcess o the rdius (proximally) and the bas of th first metacarpal bone of the thumb (distaly); beween tese

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snell boes benath th floor lie th scahoid and te trpezium (felt but not idntifiale). Te radial artery can e palpted wihin th snuffox as he artery winds around the laterl margn of te wris to rech the dorsum of th hand Fig. -100). Te cephalic ein can alo someimes b recogized crossing the snuffbox as it scends the foearm.

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Figur 9-100 Suface aatomy f the rist rgion.

Imporant Stucture Lying on the Back o the Wist Lnate he lunate lies in te proxmal ro of capal boes. It can b palpaed jus dista to th dorsa tubecle of the raius whn the wrist oint i flexe.

Importnt Strctures Lying in the Palm Recrrent ranch f the edian Nerve Te recurrent ranch o the uscles of the thenar eminence cuves arund th lower border of the flexor retinaculum nd lis abou one fngerbreadth dstal to the tbercle of the scaphod (Fg. 9-6).

Sperfiial Pamar Arterial Arch The superficial palmar arterial arch s locaed in he cenral pat of te palm (Fig. 9-100) and lies on a lne dran acros the palm at the leel of he disal borer of he fuly exteded thmb.

Deep Palmar Arteril Arch Th deep almar rteria arch s also located in the central par of the palm Fig 9-10) and lies on a line drawn across the palm a the lvel of the prximal order f the ully etended thumb.

Metcarpophalangeal Joits The meacarpohalangal joits lie approximately at the level of the distal transvrse palmar crease. he inerphalangeal ts lie at the level of the middle and distal figer crases.

Important Structres Lyng on he Dorsum of the Hand Th tendons of extensor digiorum, the extensor indicis, and he etensor digiti minimi can be seen and felt as they ditally o the bases o the fingers (Fig. -100).

Dosal Veous Nework The networ of suerficial veins can e seen on the dorsum of the hand (Fig. -100). Th netwok drais upwad into the laeral halic vein ad a meial bailic vin. The cehalic ein crosss the anatomic snuffbox and winds aroun onto he antrior apect o the orearm It thn asceds int the am and uns alng the latera borde of te bices (Fg. 9-9). It ens by percing the dep fasca in te deltpectorl triagle an enter the aillary vein.

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snell The basilc vein can be traced from the dorsum of the hand around the medial side of th forerm and reache the aterior aspect just blow th elbow (Fig 9-39). It pierces the deep facia at about he midle of he arm The median cubitl vein (or median cephalic and median basili veins links the cehalic nd baslic vens in he cubtal fosa (Fg. 9-3). T identfy thee vein easil, appl firm pressure arond the upper rm and repeatdly clnch an relax the fist. By this means the veins becom disteded wih bloo.

Cinical Notes n the rterie of th Upper Limb Aterial Injury The arteris of te uppe limb an be amaged by penetrating wounds or may require liation n amputation operations. Because of the existece of n adeqate collatera circulation round the shulder, elbow, and wrist ts, ligation of the main ateries of th upper limb i not fllowed by tisue ncrosis or ganrene, providd, of ourse, that te arteies foming te collteral circultion ae not isease and te patient's eneral circultion i satifactor. Nevetheles, it cn take days o weeks for th collteral essels to ope suffiiently to provide the distal part of the limb with th same olume f bloo as prviousl supplied by he man artey.

Palpaton and Compresion o Arteries A clinicin must know were th arteres of he uppr lim can b palpaed or ompresed in an emegency. The suclavia artey, as t croses the first ib to ecome he axilary atery, can b palpated in the rot of te postrior triangle of the neck (Fig. -31). Th arter can b comprssed hre aganst th first rib to stop a catasrophic hemorrage. Te thir part f the axillary artery can be felt in the axill as it lies i front of the teres major uscle Fig. -17). Th brachal artry can be palated i the arm as it lies on the brachialis and is oerlappd from the laeral sde by he bieps bachii Fig. 9-43). he radal artery lies superficialy in font of the dstal ed of te radis, beteen th tendos of te bracioradilis and flexor carpi radialis; it is here that the clnician takes he raial puse (Fig. 9-8). If the pulse cannot be fet, try feelin for the radal arery on the other wrist; ocasionlly a congenially anormal radial artery can be difficlt to feel. he radal artry can be les easil felt as it crosses the aatomic snuffbx (Fig. 9-10). Th ulnar artery can be palpated as t croses antrior o the lexor etinaclum in compan with he ulnar nerve. The artery lies ateral to th pisiform boe, seprated from it by th ulnar nerv. The rtery is comonly damaged here n laceation wounds in front of the wrist.

Alen Test The Allen est is used to determine te patecy of he ular and radial arteris. Wit the patients hand restig in te lap, comprss the radial arteris agaist the anterior surface of each radius and as the ptient to tightly clench th fists The cenchin of te fist close off te supeficial and dep palmr arteial aches. hen th patiet is aked to open te hand, the kin of the plms is at firt whit, and then nrmally the blod quikly flws int the arches throug the unar areries, causin the plms to prompty

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snell tur pink. This etablises tha the unar areries re patnt. Th patecy of he radal artries cn be etablised by epeatig the est bt this time cmpressng the ulnar rterie as thy lie ateral to the pisiform bones.

Aterial Innervation and Raynaud's isease The ateries of the upper imb ar innerated b sympatheic neres. Th preganglioni fiber origiate frm cell bodies in the second to eighth thoracic segmens of te spinl cord. They ascend in the sympathetic trunk ad synase in he midle cerical, inferir cervcal, frst thracic, or stelate gnglia. The pstgangionic ibers oin th nerve that orm th brachal pleus and are dstribued to he artries wthin the branches of the pexus. or exmple, the digtal areries of the fngers re supplied y posganglinic sypathetic fibrs tha run i the digital erves. Vasosastic isease involing diital ateriols, suc as Ranaud's diseae, may requir a cericodoral preanglioic symathectmy to preven necrois of he finers. Te opertion i folloed by rteria vasoilataton, with consequent increaed blod flow to the upper imb. P.536

Clinial Nots on te Nerves of the Uppr Limb Dermatmes an Cutanous Neves The importance of the dermatomes and ctaneou nerve in th upper limb i discused on page 46.

Tendon Relexes nd the Segmenal Innrvatio of Mucles The skeletal muscle receives a sgmenta inneration. Most uscles are inervate by several pinal erves nd theefore y several sements f the pinal ord. A physican shold kno the egmentl innervation of the follwing mscles ecause it is ossibl to test them by eliciting simpl muscl reflexes in he patent: Biceps rachii tendon reflex C and 6 (lexion of the elbow t by tapping the biceps tendon). Trices tendn reflx: C6, 7, and (etensio of th elbow t by taping th tricep tendo). Bracioradilis tedon relex: C5, , and (supiation f the adioular joits by apping the insertion of the brachioradiais tenon).

Brachil Plexs Injuies The roots, trunks, and diisions of the brachil plexs reside in the loer part of th posteior trangle f the eck, wereas the cods and most of the branches of the plxus lie in th axilla. Comlete lsions nvolvig all he roos of te plexs are are. ncomplte injries ae commn and re usully cased by tractin or ressur; indiidual erves an be ivided by sta wound.

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Uper Lesons of the Brchial lexus Erb-Duhenne alsy) Uppe lesios of the brchial lexus are inuries resultng fro excesive diplacemnt of he hea to th opposte sid and epresson of he sholder o the sme sid. This causes excessve trction or even tearing of C and 6 roots f the lexus. It occrs in infants during a difficult delivey or in adult after a blow to or fall o the soulder The sprascaular nrve, te nerv to th subcavius, and th muscuocutaneous ad axilary neves al possess neve fiber derivd from C5 and 6 roos and ill threfore be fuctionlss. Th folloing mucles wll conequenty be pralyze: the suprasinatus (abductor of the shulder) and inraspintus (lteral rotato of th shoulder); the sublavius (depreses th clavicle); te bis brahii (spinato of th foream, fleor of he elbw, wea flexr of te shouder) ad the reater part of the brachialis (flexor o the lbow) nd th coracbrachilis (fexes te shouder); nd the deltid (abuctor f the houlde) and the tees minr (latral roator f the houlde). Thu, the limb wll han limpl by th side, medialy rotated b the uoppose sterncostal part o the pectorais majr; the forerm wil be prnated ecause of loss of te actin of te bices. Th positon of he upper lim in ths condtion has been likend to hat of a porter or waiter hintin for a tip (Fig. -101). In additin, thee will be a loss of sensaton dow the lateral side of the am.

Figre 9-101 Erb-Duhenne palsy waiters tip)

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Loer Lesons of the Brchial lexus (Klumpe Pals) Loer lesons of the brachial plexus are usally ractio injures caued by xcessie abdution o the am, as ccurs in the case of a person falling from a height clutcing at an objct to save hmself r herslf. Th first thoracic nerve is usually torn. The nere fibes from this sgment un in he ulnr and edian erves o suply all the mall mscles f the and. The hand hs a clwed apearanc cause by hyerextension f the metacapophalngeal oints nd fleion of the inerphalngeal oints. The etensor digitoum is nopposd by te lumbicals nd introssei and extnds th metaarpophalangel ts; th flexo digitorum uperficialis and prfundus are uoppose by the lumbricals nd inerosse and fex the middle and teminal halangs, resectivey. In additin, loss of sensation will occur along th media side f the arm. I the eghth crvical nerve s also damaed, th exten of aesthesia wil be grater ad wil invole the edial ide of the frearm, hand, and medial two finges. Lower esions of the brachial pleus can also be produced by the presence of a crvical rib or maligant meastase from the lugs in he lowr deep cervial lymh node.

Long Thoraic Nere Te long thoracc nerv, whic arises from C5, 6, and 7 and suplies he seratus aterior muscle, can be injued by lows t or pessure on the posteror tringle o the nck or uring he sugical procedure of adical mastecomy. Pralysi of th serraus anerior esults in the inabilty to otate he scapla durng the movement of abduction of the arm above right angle. The paient herefoe expeiences difficlty in raising the arm aboe the head. Te verebral order nd infrior agle of the sula wll no onger e kep closey appled to he chet wall and wil protude poteriory, a onditin know as “winged scapula― (Fig. 98).

Axillary Nrve he axilary nrve (ig. 924) which arises from the posterior cord o the bachial plexus (C5 and 6), can be injure by the pressre of badly adjustd crutch presing uward ito the armpit The age of the axillay nerv backward fro the xilla through the qudranguar spae makes it paticularly vulnerable here to downward displacement of the humeral ead in shouler disocatios or facture of th surgial nec of the humeus. Pralysi of th deltod and eres mnor mucles rsults. The cuaneous brances of he axilary nrve, icludin the uper lateral ctaneou nerv of th arm, re funtionless, and conseqently here i a los of sin senation over th lowr half of he detoid mscle. he parlyzed eltoid waste rapidly, and the underlying greter tuerosit can b readiy palpted. Bcause he suraspintus is the ony othe abducor of he sholder, this mvement is much impaired. aralyss of te teres minor is not recogizable clinially.

adial Nerve The adial erve (Fig. -25, whch aries fro the psterio cord f the rachia plexu, chaacteriticall gives off its branches some distance proximal to the part t be inervate.

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snell In the axilla i give off hree banches: the posterir cutaeous nrve of the am, whih supplies the skin on the back f the rm dow to th elow; the nerv to te long head of the triceps; and te nerv to th media head f the tricep. In the siral goove of te humerus it gives off four branhes: te lowe laterl cutaeous nrve of the arm, which suplies the lateal surace of the ar down o the elbow; the poterior cutaneus nerve of the forarm, wich suplies the skn down the midle of the bck of the forearm as far as the wrist; he nere to te lateal hea of th trices; and the neve to he meial hed of te tris and the anoneus. In he antrior cmpartmnt of the arm above the lateal epiondyle it givs off hree banches the nrve to a smal part of the brachialis, the nerve to te bracioradilis, ad the nerve t the xtenso carpi radials longs. In the cuital fssa it gves of the dep brach of he radal nere and ontinus as te superficial radil nerv. The eep brnch suplies he extnsor crpi rdialis brevis and th supintor in the cubital fossa and all the extensor uscles in th posteior copartmet of te forerm. Th supeficial radial nerve is sensory and supplies the skin oer the laterl part of the dorsum of the hand ad the orsal urface of th lateal thre and half ingers proximl to te nail beds (Fig. -102). (Te ulna nerve supplis the medial part o the dorsum o the hnd and the drsal srface f the edial ne and a hal finges; the exact cutaneus ares innevated by the radial and ulnar neves on the had are subjec to vaiation.) The adial erve i commoly damaged in the axilla and in te spirl grooe.

Injuries to he Radal Nere in te Axila In te axila the erve cn be ijured by the pressue of the upper end of a badly fittng crutch pres into the arpit o by a runkar fallig aslep with one ar over he bac of a hair. It can also be badly damagd in te axila by facture and islocaions o the poximal end of the huerus. hen th humers is isplaced downward in dislocations of the shouldr, the radial nerve, which is wrpped around the bac of th shaft of the bone, s pulled downward, stretcing th nerve in the axilla excessvely. The clnical inding in inury to the radial nerve in the axlla ar as folows.

Motor Th trices, the anconeus, an the lng extnsors f the wrist re parlyzed. The ptient s unabe to etend te elbo t the wrist t, and the fingers. Wristdrop, r flexon of he writ (Fi. 9-103), occur as a esult of the action of the unoppoed fleor musles of the wist. Wistdro is vey disaling bcause ne is nable o flex the fngers trongl for te purpse of irmly rippin an obect wih the wrist fully flexed. (Try i on yorself. If th wrist and proximal phalanges are pssivel extened by holding them n position wih the opposie hand the mddle ad distl phalnges o the fngers an be extendd by te actin of te lumbicals nd introssei which are iserted into the extensor expansios. The brachioradiais and supintor muscles re als paralzed, bt supination is stil perormed well b the bceps bachii.

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Sensoy A sall los of sin senation ccurs down te postrior urface of the lower art of the arm and own a arrow trip o the back of the foearm. variale are of sesory lss is resent on the lateral part of the dorsu of the hand and on the drsal srface f the roots of the latera three and a alf figers. he are of toal ansthesi is reativel small becaus of th overlp of snsory innervtion b adjacnt nerves.

igure -102 Senory inervatin of the skn of te vola (palmr) and dorsal aspecs of the hand; the

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arrangement of the dematome is alo show.

Figre 9-13 Wristdrop.

Trophic Changes Tophic changes are sight.

Ijuries to the Radial Nerve in the Spiral Groove In te spirl grooe of te humeus, th radia nerve can be injured at the time of frcture f the haft o the hmerus, or susequenly invlved dring te formtion o the cllus. he presure f the back o the am on te edge of the operatng tabe in a unconsciou patient has also ben known to njure he nere at tis site. The prolonged applicatin of a tourniuet to the ar in a erson with a slende trices musle is often followed by temporary radial palsy The cinical findins in ijury t the rdial nrve in the spral groove are as follows. The injury to the radial nerve ccurs ost comonly n the distal part of the groove, beyond the orgin of the neves to the triceps and the anconus and beyond the orgin of the cuaneous nerves   

Motr: The paient i unabl to etend te wris and te fingrs, an wristrop ocurs (se page 537). Senory: A variable small area o anestesia i preset over the dosal suface o the hand and the dorsal urface of the roots f the ateral three nd a alf figers. Tropic chages: Thes are vry slght or absent

Injuries to the Deep Banch of the adial erve

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snell he deep branh of the radal nerve is motor nerve to the extesor mscles n the osterir comprtment of the forearm. It can be damage in frctures of the proximl end f the adius r durig dislocation of te radil head The nerve supply to the spinato and he extnsor crpi raialis ongus ill be undamaed, an because the latter muscle is poerful, it wil keep he writ extened, an wrisdrop wll not occur No sesory loss occurs bcause his is a motr nerv.

Inuries to the Superfcial Rdial Nrve Diision of the superficial radia nerve which is sesory, s in a stab wund, rsults in a vriable small rea of anestesia oer the dorsum of the hand ad the dorsal surface of the roots of th lateral thre and half fingers.

Muscuocutanous Neve he muculocuaneous nerve Fig. 9-22) is arely njured because of its protected psition beneat the bceps rachii muscle If it is injred hih up in the arm, the biceps and coracobrachials are aralyzd and he brahialis muscle is weakened (the latter mscle i also upplie by th radia nerve. Flexion of the forearm at the elbow t is then poduced by the remainer of he brchiali muscl and te flexrs of the foearm. hen th foream is in the prone ositio, the xtenso carpi radials longus and the bachiordialis muscle assis in flexion f the orearm There is als sensry los along the lteral ide of the foearm. ounds r cuts of the forerm can sever he latral cuaneou nerve of th foream, a ontinution o the msculoctaneous nerve beyon the cbital ossa, resultng in sensor loss long te lateal side of te forerm.

Medan Nerve Th median nerve (Fig 9-22), hich aises fom the media and lteral ords o the brachia plexu, givs off o cutaeous o motor branchs in te axila or i the am. In the prximal hird o the front of the forearm, by unnmed brnches or by ts antrior iterossous brnch, i supples all the mucles o the ront o the frearm xcept he fleor cari ulnais and the meial hlf of he fleor digtorum rofunds, which are supplid by te ulna nerv. In te distl thir of th forearm, t give rise o a pamar ctaneou branc, whic crosss in font of the flxor reinaculm and supplis the kin on the laeral hlf of he pal (Fig. 9-10). In the palm the median nerve supplies th muscls of te thenr emience ad the irst to lumbicals nd givs sensry innrvatio to te skin of the palmar aspect of the lateral three and a half fngers, incluing th nail beds o the drsum. Fom a clinica standoint, he medan nere is ijured occasionally in the elbow region n suprcondylr fracures o the umerus It is most cmmonly injured by stab wounds or broken glass just prximal to the flexor retinaculum; here it lies in the nterva betwen the tendon of th flexo carpi radials and lexor igitorm suprficiais, ovrlappe by th palmais lonus. The clnical inding in inury to the median nerve ar as follows.

Injuies to the Meian Neve at he Elbw Motor 998

snell The pronator muscle of th foream and he long flexor muscles of the wrst and finger, with the eception of th flexo carp ulnars and he medal hal of th flexor digitrum prfundus will be parlyzed. As a result, the foearm i kept n the upine positin; writ flexon is eak an is acompanid by aductio. The latter deviation is caused by the paralyis of he fleor cari radalis ad te strength of he flxor carpi ularis and the medial half of the flexor digitorum prfundus. No fexion s possible a the interpalangel s of te inde and mddle fngers, althouh weak flexion of the metcarpophalangel s of tese figers i attemted b the iterossi. Whe the ptient ries t make fist, the inex and to a esser extent the midle figers tnd to emain traigh, wheras th ring nd litle figers fex (Fig. -104). Th latte two fngers are, owever weakeed by he los of th flexo digitrum superficialis. Flexion of the teminal halanx of th thumb is los becase of aralyss of te flexr pollcis logus. Te musces of he tenar eminence are paralyzed and asted o tha the einence is flttened. The thumb i laterlly roated ad adducted. The hand looks flattned an “aplike.â•

Figur 9-104 Meian nerve palsy.

Sensory Skin sensaton is ost on the laeral hlf or ess of the palm of the hand and the palar aspct of he latral thee and a hal finges. Senory los also occurs on the skin of the distal part o the drsal srfaces of the latera three and a alf figers. The area of total anesthesia is considerbly les becase of he ovelap of adjacnt neres.

Vasomotor hanges

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snell The skin aeas inolved n sensry los are wrmer ad drir than normal becaus of the arteiolar ilataton and absenc of seating resultng fro loss f sympthetic contro.

Trophic Canges In log-staning cases, changes are foud in te hand and fngers. The skn is dy and scaly, the nails crack easly, an atrohy of he pul of th finges is pesent.

Injuris to te Medin Nerv at th Wrist 

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Moor: The uscles of the thenar eminence are paralyed and wasted so that the eminence becoes flatened. The thmb is ateraly rotaed and adduced. Th hand ooks fattene and âœapelie.― pposiion moement of the thumb s impossible. The first two lumbrcals ae parayzed, which an be ecognied cliically when te patint is sked t make fist slowly and te inde and mddle fngers end to lag beind th ring and lttle fngers. Sensory, vaomotor, and rophic change: hese canges re idetical o thos found in the elbow lesion.

Perhaps the most serious dsabiliy of al in mdian erve ijuries is the loss o the ability to oppse the thumb o the other ingers and th loss f senstion oer the latera finges. The delicate pincerlike actio of th hand s no lnger possible.

Carpal Tunnel Synrome The carpal tunnel, formed by the concav anteror suface o the crpal bnes and closed by te flexr retiaculum is tghtly acked ith th long lexor endons of the finger, with their surrounding synovial sheats, and the meian neve. Clnicall, the syndroe conssts of a burnng pai or â€pins ad needes― long te disributin of te medin nerv to th lateral thre and a half fingers and weakness of the thena muscls. It is produced by compression of the median nerve ithin he tunel. Th exact cause f the compresion i diffiult to determne, bu thickning o the ynovia sheats of te flexr tendns or rthritc chanes in he capal boes are though to be responible i many ases. s you ould xpect, no parsthesi occur over he thear emience bcause his aea of kin is supplied by the palmar cutaneous branch of the median nerve which e supericiall to th flexo retinculum. The condition is damaticlly reieved y decopressig the unnel by making a ongituinal icision throug the fexor rtinaculum.

Ulnar Nere Th ulnar nerve (Fig. 9-23), wich arses frm the edial ord of the brachial plexus (C8 an T1), gives ff no utaneos or mtor brnches n the xilla r in te arm. As it enters the foearm from beind th media epicodyle, t suppies te flexr carp ulnars and he medal hal of th flexo digitrum pofundu. In te disal thid of te forerm, it gives ff its palmar and psterio cutanous brnches. The pamar ctaneou branc supples th skin ver th hypotenar einence the psterio branc supples th skin ver th media third of the dorsum of the hand ad the edial one an a hal finges. Not uncommnly, te postrior banch spplies two ad a half instead of one and a half fingers. It oes no suppl the kin ovr the istal art of the drsum o these finger.

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snell Haing enered te palm by pasing in front of the flexor retinaculum, th suprficia branc o the unar neve suplies te skin of the palmar surfac of th media one ad a haf fingrs (Fig. 9-102) incluing their nail beds; it alo suppies the palmris brevis mscle. he deep brach supplis all the small muscles of the hand except the uscles of the thena eminece and the fist two lumbrials, which are supplied by the mdian nrve. he ulnr nerv is mot commnly inured a the ebow, here i lies ehind he medal epicondyle, and t the rist, here i lie with he ulnr artey in font of the flxor reinaculm. The injuries at the elbow are usuall assocated wth fratures f the medial epiconyle. Te supeficial positin of te nerv at th wrist makes it vulerable to damge fro cuts nd sta wound. Th clinial finings i injur to the ulna nerve are as follow.

Injuries to the Ular Nere at the Elbw Motor The flexor carpi unaris and the medil half of the flexo digitorum profundus muscles are aralyzd. The paralysis of the flexor carpi ulnaris cn be oserved by askng the patien to mae a tghtly lenche fist. Normally, th syneristic ction f the flexor carpi ulnari tendo can b obsered as t s to te pisiorm boe; th tightning o the tndon wll be bsent f the uscle s parayzed. The prfundus tendons to te ring and litle figers wll be functionless, and the terminal phalanges of thee fingrs are therefre no capabe of bing makedly lexed. Flexio of th wrist t ill rsult i abducion, oing to paralyis of he fleor cari ulnais. Te medil bordr of the front of te forerm wil show lattening owng to he wasing of the unerlyin ulnars and rofunds musces.

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Figur 9-105 Ulnar nerve palsy.

The small muscle of th hand ill be paralyed, exept te musces of he thear emience ad the first two lumbricals, which are supplied by the median nerve. The paient i unabl to aduct an abduct the finger and cnsequently is unable to gri a piee of pper paced btween he finers. Rmember that te extesor diitorum can aduct te fingers to a small extent, but only when the metacapophalngeal oints re hyprextended. It is impossible to addut the humb bcause he aductor ollici muscl is paalyzed If the patient is asked to grip a piec of paer beteen th thumb and th index finger he or she dos so y strogly cotractig the flexor pollics longs and lexing the trminal phalan (Frment's sign). The metacapophalngeal oints ecome hyperextended becaue of te paralysis o the lmbrica and iterossous mucles, which ormall flex hese jints. ecause the fist and second lumbricals are not paralyed (thy are upplie by th media nerve, the hyperetension of the metacarpophalangeal ts is mot promnent n the ourth nd fifh fingrs. The interhalangal joits are flexed owing agin to the paalysis of the lumbrcal an intersseous muscles, whch norally extend these jints trough he extnsor expansion. The flexin defomity a the iterphaangeal ts of th fourt and ffth fngers s obvious beause te firs and scond lmbrica muscls of the inex and middle fingers are not parlyzed. In lon-standng cases the hand assumes the chracterstic “claw― defrmity main e griff). Wasting of the paralyzed mucles rsults n flatening of th hypohenar minenc and lss of he conex cure to te medil border of the had. Exainatio of th dorsum of the hand will sow holowing betwee the metacarpal bons causd by wasting f the orsal interoseous uscles (Fig. 9105).

Sensry Los of skin sensation will b obsered ove the nterio and psterio surfaes of he medal thid of the hand and the medial one and a half figers.

Vasomotor Changes The skin aeas inolved n sensry los are wrmer ad drir than normal becaue of the artriolar dilatation ad absece of sweatig resuting fom los of sypathetc contol.

njurie to the Ulnar Nerve at the Wrist 

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Motr: The small mucles o the hnd wil be paalyzed and shw wastng, except for the muscle of th thena eminece and the fist two lumbrials, a descibed (ee preiou colum). The clawhad is much moe obvius in wrist esions becaus the fexor digitorum profundus muscle is not aralyzd, and marked flexio of th termial phaanges ccurs. ensory: Te mai ulnar nerve nd its palmar cutaneous brnch are usualy severed; he posterior cutaneous brach, whch aries fro the unar neve trunk abot 2.5 n. (6.5 cm) bove te pisiorm boe, is usually unaffected. The sesory lss will thereore be confind to te

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palmr surfce of the meial thrd of he han and te medil one nd a hlf finers an to te dorsl aspets of he midle and distal phalanes of the sae finers. asomotr and rophic change: These are the same s those descrbed fo injures at he elbw. It s imprtant o remeber tht with ulnar erve ijuries the hgher te leson, th less bvious the clawing deformity of the hand

nlike median nerve injuries, lesins of he ulnr nerv leav a reltively efficint hand. The sensaton ove the lateral part f the and is intact and the pincerlike action of the thumb and indx finer is easonaly goo, althugh there is some wakness owing o los of th adducor pollicis. P.37

P.538

P.39

P.54

P.541

P542

Clinial Problem Solving Stdy th folloing cae histories ad selet the est anwers t the qestion followng them. An 18-yar-old woman omplaiing of sever ain and rednss around the base of the nail of the right index finger visited her hysicin. She state that he had trimme the cticle eponychium) of her ail wih scisors, nd the following day the pain commenced. On examinatio, the skin flds arund th root f the ail were red, swolle, and xtremey tener. Th index finger was swllen, nd red streak were een cursin up th fron of th foream.

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snell 1. Te follwing smptoms and signs in this ptient ere cnsistet with a diagosis o an acte bacterial infection under the nail folds (pronycha) of he rigt inde finge except which (a Some ender ymph ndules ould be palpted in the inraclavcular fossa. (b) The atient's temeratur was aised. c) The infection had spread into he lymh vessls draning te fingr. () The red streaks o the font of the frearm ere cased by the loal vasdilataion of the blood vesels long te coure of te lymp vesses. e) The lymph vessels from the inex finer dran into the suratroclear nde, whch was inflamed and enlargd. Viw Answer 1. E The lmph vesels fom the index finger drain nto th infralavicuar nods. A 20-yer-old an, riing pilion on a snwmobil, was nvolve in an accidnt. The machie was traveling at high speed whe it hi a tre stump buried in snow. The man was thrown 12 f. and anded n his ight houlder and the rigt side of his head. fter 3 weeks f hositaliztion, t was oticed that h kept is rigt arm nternaly roated b his sde wit the frearm ronate. An aea of nestheia wa preset alon the lateral side o the uper pat of te arm. 2. The following statements conerning this ptient are correct except which? (a) A diagosis o damag to th upper part o the bachial plexus (Erb-Duchenn palsy) was mde. () A leion of the fith and sixth cervicl root of th brachal pleus was present. (c) The median radal ulnr nerv was mde funtionles. (d) The suraspintus, ifraspinatus, subclvius, iceps rachii greatr part of the brachialis, coracorachiais, detoid, nd ters mino were aralyzd. (e) Th loss f senstion dwn the lateal side of th right arm wa cause by th lesin invoving te fifh and ixth crvical dermatmes. Viw Answer 2. . The uprasular erve, he nere to te subcavius, the msculoctaneou nerve, and the axilary nrve wee made functinless. A fathe, seeng his 3-yearold son playing in the garden, ra up an picke him p by bth hands an swung him aound in a cicle. Te chil's enoyment suddeny turnd to tars, ad he sid his left elbow hurt. On examiation, the chld hel his lft elbw semifexed ad his forear pronaed. . The ollowing statements concering ths case are cnsistet with the dignosis of dislocatin of the supeior raioulna excep which (a) The ead of the rdius ws puled out of the anular ligamnt. 1004

snell (b) A age 3 years the cild's nular ligament has a large diametr and he head of te radus can easil be plled ot of te ligament b tracton. (c The incidence of his conditio is eqal in oth sees. d) The pain from the t caused reflex contration of the urrouning muscles to protect th t from rther ovemet. (e) The subluxaton of he joit can be trated by pulling dowward o the frearm nd at the same time perfrming he movment o pronation ad supiation Finaly, the elbow t is fleed and held in that position View nswer . B. Under ge 6 yars, te child's hed of te radis is o a reltively small size ad may easily be puled out of the anular igament by ractio on th forearm. A 60-year-od woman fell down te stairs and was aditted to the emergncy deartment with sever right shoulder pain. On eaminaton, te patint was sitting up wth her right rm by er side and her riht elow t ed y the left hnd. Inpectio of th right shoulder shwed los of the noral rouded cuvature and evidence of a light wellin belo the rght cavicle Any atempt at active or iv movemnt of the shoulder t as stopped by severe pain in the shouder. A diagnois of dislocation f the ight soulder t was mde. 4. The folloing sttement concerning his paient are conistent with he dianosis xcept which? () This patient had subcoacoid disloction o the rght shulder oint. (b The head of the humerus as dislocated downwrd thrugh th weakst par of th capsule of he joit. c) The pull of the ectorais major and subscaularis muscles had isplacd the pper end of the humerus ediall. (d) The grater tberosiy of the humrus n longe displaced the deltid musle latrally and te curv of th shoulder ws lost (e) he intgrity of the axillay nere shoud alwas be tested y toucing th skin over the uppr half of the deltoid muscle. View nswer . E. The inegrity of th axillry nerve is ested y touhing te skin over the loer haf of the deloid mucle. The ski of th curve of th shouder, icluding the kin covering the uper half of the deloid mscle, is suplied b the spraclavicula nerves. A 45-year-ld woman havng her yearl physical exmination was found he have a hard, painless lump in the pper lteral uadrant of the left breas. On examination wih her rms at her sides, te lef nippl was een to be hiher thn the ight, nd a small dimple o skin as notd over the ump. O examination of the left ailla, hree small, ard dscrete nodule could be palated blow te lowe

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snell border of te pecorali major muscle. The ight beast was noral. A iagnoss of arcinoa of he lef breast was made, wth secndary deposis in te axilla. 5. The followng statement concerning his paient ae correct except whch? (a The ontracting fibrous issue of the malignant tmor ha pulle on the lactferous ducts of the nipple raising it above he levl of te oppoite npple. (b) The dimplig of te skin was cused b the fbrous tissue pullin on th suspensory igamens of the breast. (c) The uper laeral quadrant of th breast is dained nto te pectral or anteror axllary ymph nodes. (d) he enlarged ectora lymph node could be palpate agaist the surgical nec of th humerus. (e) The malinant tmor ha spread by ay of the lymph vesels to the petoral lymph odes. iew Aswer 5. D. Th enlared petoral ymph nodes cn be palpate againt the osterir surace of the cntracted pecoralis majo muscl. A youn secrtary, runnin from her ofice, hd a glss door swin back n her face. To protect hrself, she held out her left han, whic smashed through te glas. On amissio to the hosptal, she was bleeding profusey from a suprficia lacertion in fron of her left writ. She had snsory loss oer the palmar aspect of th media one ad a haf fingers but norml senstion o the bck of these ingers over te middle and proxmal phlanges She hd difficulty in graping a piece of paper beteen he left ndex ad midde fingrs. Al her lng flexor tndons ere inact. 6. Te follwing statements conerning this patient are corect ecept wich? () The radial artery was cut in font of the flxor retinaculum, and this ccountd for the prfuse beeding () The loss of skin sensatin on the palmar asect of the meial one and half ingers was caused b the everane of the ulnr nerve as it crosed in front f the lexor retinaculum. (c) The nrmal snsatio on th back of th medial one nd a hlf fingers over the proxial phalanges was cused by the fact that the osterior cutneous branch of the ulnar nerve rises about .5 in. (6.25 cm) proximal to the flexo retinculum and was spard. (d) The inbility to hold the iece o paper was aused y the aralysis of he secnd palmar inerosseus muscle, which i suppled by the dep branh of te ulnar nerv. (e) There was no sensory loss on the palm f the and beause he palar cutneous ranch of the ulnar erve was not cut. View Anwer 6. A. Te radial artery doe not enter the palm by pasing i front of th flexr retinaculu; it des so by pasing forward etween the two head of te first dorsl interosseous musces between te first

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snell and econd metacarpal bnes. It was the ulnr artey that was ct with the ulnar nrve i front of the flexr retiaculum. A 50-yea-old woman complaning of sevee “pns and needles― i her right and and lateal fingers vsited er physician She sid that she had experienced dificulty in butoning up her cloths when dressng. O physical eaminaton the patient poined to her thmb and inde, midle, and ring finger as th areas where she fet discmfort. No ojectiv impaiment of senstion ws foun in these aras. Th muscls of the thenar einence appeared to e funtionin normaly, alhough there was soe loss of power compared wth the activity of the musles o the lft thear emience. 7. The folowing statements cncerning this patient ar corect exept wich? (a Altered sin senation as felt in the skin areas supplied by the digtal brnches of the medin nere. (b) he mucles of the thenar minenc showd some evidece of asting as sen by fattenng of he thenar emnence. (c) The mscles of the thenar eminece ar suppled by he recrrent musculr brach of he meian nerve. d) Th median nerv enter the alm though he caral tunnel. (e) The median nerv occupes a lrge space beween te tendons beind th flexo retinaculum (f) This ptient as caral tunnel sydrome. Vew Anser 7. E. The media nerve occupis a small retricte space in the carpa tunne. A 64-year-old an conulted his pysicia because he ad noticed dring he pas 6 moths a thickeing of the sin at the bae of hs left ring finger As he descrbed it “There appears t be a band of tisse that is plling y ring finger into the pal.― O examination of the palms of boh hands, a lcalize thickning of subcutaneous tissue coul be flt at the base of the left ring nd litle ingers. The metacapophaangeal t of the ring inger could ot be ully extended, eiter actvely or ively. 8. Th folloing sttements concrning this ptient are corect ecept wich? (a The deep facia beeath te skin of th palm s thickened o form the plmar aponeursis. b) Th dista end o the poneursis gives rise to fve slis to the fiv finges. (c) Each slp is atached to the base of the proximl phalanx and to th fibrous flexor sheth of each finger. (d Fibrus conraction of te sli to th ring finger resultd in prmanet flexon of te metacarpopalangel t.

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snell (e) Te patint had Dupuytren's ontracure. Vie Answe 8. B The dstal ed of the palar aponeurosis gives rise to four slips, whic o the four medial fingers 15-year-ol girl, while emonsrating to he friens her proficiency a standing o her hands, uddenl went off baance ad put ll her body weight on her left outstreched hnd. A distintive cracking noise was heard, nd she felt a sudden pain n her eft shulder region On eaminaton in the emergency departent, te smooh contour of her let sholder was absent. Te clavcle was obviusly facture, and the eges of the ony frgments could be palated. 9 The followig statements concering this case are crrect xcept hich? () The clavicle is oe of te mos commo bones in th body o be factured. (b) Antomiclly, the weakest pat of he clvicle is the junctin of te medial and middl thirds, and this i wher the ractur commoly occurs. (c) he latral boy fragent is depresed downward by the weight of the arm. (d) The laeral fragmen is puled forward nd medally b the pctora muscls. (e) he medial frgment s elevated b the sernocleidomatoid mscle. (f) The spraclaicular nerves or a communicatin vein etween the cephalic and inernal jugula vein may b damagd by he bon fragments. View Aswer . B. Anatomically the wakest part o the cavicle is the juncton of the midle and lateal thirs, and that is where the fracture occrred n this patient. A 63-year-ld man fell own a flight of stars and sustained a ractur of te lower end f the left radius. n examnation the distal ed of he radius wa displced poteriory. This patint ha sustined a Colles' fracture. 1. The followng staements concening tis cas are crrect except which? () Occaionally the tyloid process of te ulna is alo fracured. (b) The meian nerve may be inured a the time of the fal. (c When the frcture s redced, te styloid pocess f the adius hould ome to lie about 0.5 in. 1.9 c) proximal t that f the ulna. d) The fracture prouces psterior anguation f the distal fragment of he radus. (e) n redution o the facture the distal end of te radis should lie t an agle of 15° ateriorly. f) The hand should lways e splnted i the psition of function.

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snell View nswer 0. C The nrmal ositio of the tip f the tyloid proces of te radius is about 0.75 i. (1.9 cm) dstal t that of the ulna. 22-year-ol medicl student fel off her biycle onto he outstetched hand. She tought she ha spraned he right wrist t nd treted hrself by bining he wrist with an elasic banage. But 3 weks lter, se was till eperiencing pain on oving er writ and o decded to visit the emrgency departent. O examiation f the orsal surfacs of bth hands, with the fingers and thmbs fuly extnded, localized tenderness cold be elt in the anatomic snuffbx of hr rigt hand A dianosis of frature o the right scaphoid bone was mad. 1. The folloing sttement concrning his paient re corect exept whch? (a The facture line on the caphoi bone may derive te proxmal fragment of it arterial suply. (b) A ony fragment deprivd of its blod supply may underg ischeic necrosis. (c Because the scaphod bone articlates with oher boes, th fractre lin may enter a t cavity and beome bthed i synovial fluid, whch woud inhiit repir. (d The saphoid bone s an esy bon to immobilie becase of ts small size. (e) Frctures of the scaphoid bon have high incidece of onunio. Viw Answr 11. D. The scaphoid bon is a ifficut bone to immobiliz becaue of is posiion an smal size. A 6-yer-old oy, rnning long a concrte pat with a glas jam jar in his hand, sliped an fell. The glass frm the roken ar pieced th skin on the front f his eft wrst. On examination a small wound was pesent n the front f the left wist and the palmari longus tendn had been svered. The tumb was latrally otated and adducted and the bo was uabl to oppose his tumb to the other figer. There was loss f skin sensation ovr the latera half of the palm and the palmar aspec of th lateral three and a half ingers 12. Th following facts conerning this atient are crrect xcept which? (a) Snsory oss of the distal prt of the dorsal sufaces f the lateral three and a alf fngers was exeriened. (b) he median neve lie superficial to the palmris logus prximal to the flexor retinaculum and was seered by the piece f glass. () The median nerve ies in the interval betwen the tendon of flexor dgitoru superficials and the flxor crpi raialis muscles just roxima to th wrist t. d) Aductio of the thum was produce by the conractio of the addutor policis uscle, which is suplied y the lnar nrve. (e The almar utaneous brach of the meian neve had been severed

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snell iew Answer 12. B. The median neve lis deep to th palmais logus tedon prximal to the flexor retinculum. P.543

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Rview Qestion Multipl-Choic Questons Select the best answer for each qestion 1. Te following sructurs posteior to the flexor retinaculum except whih? (a) lexor igitorm supeficials tendns (b) edian erve () Flexr pollcis logus tedon (d) Unar neve (e) Anterir inteosseou nerve Vie Answe 1. D. he ulnr nerve es supeficial to the flexor retinaulum jst latral to the pisiform bone. 2 The following tendons are insertd into the bae of te proxmal phlanx o the tumb except which? () Exenso polliis breis b) Abdctor pllicis longus (c) blique head o adducor pollicis (d) Flexor pollics brevs (e) First palmar interosseous

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snell View Aswer 2. B. The abductr pollcis logus is insertd into the base of he first metacarpal bone. 3. The folowing muscle abduc the hnd at he writ except which? () Flexr carp radiais () Abdutor policis ongus (c) Etensor carpi adiali longu (d) Extesor diiti miimi () Extesor policis longus View nswer 3 D. Te extesor diiti miimi exends te metaarpophlangea t of th littl finger and dducts the had at te wris t . The followng bons for the poximal row of carpal bones except which? (a) Lunate (b) Pisifom (c) Saphoid d) Triuetral e) Trapezium Viw Answr 4. E. The trpezium is in he disal row of caral bons. 5. The tendon of th folloing muscles form th rotatr cuff except which? (a) eres minor (b) Suprasinatus (c) Subscaplaris (d) Teres maor (e) Infrasinatus View Anser 5. D The tres maor tenon is inserted into the medial lip of the bicipital goove o the hmerus. 6. The quadragular pace i bounded by the following structures ext whih?

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snell (a) Sugical eck of the humerus (b) ong hed of ticeps (c) Deltoid (d) Tere major e) Teres minor iew Anwer 6. 7. The radial nerve ives of the followng braches in the psterior compatment f the rm except which? () Lateral head of the triceps () Lower lateral cutaneous nerve o the am (c) Meial hed of the triceps (d) Brahioradalis (e) Aconeus View Anser 7. D. The branch rom th radia nerve to the brachiradials musce leaes the nerve after t has eft th posteior copartmet of te arm by piecing te lateal intrmuscuar sepum. 8. All th folloing sttements concrning he brahial pexus ae corrct ext whih? (a) The rots C8 nd T1 oin to form te lowe trunk (b) Te cord are nmed acording to their position relative to the first art of the axllary artery. (c) he nere that innervtes te levaor scapulae s a brnch of the upper trnk. (d) he roos, truks, and diviions ae not locate in th axilla. e) No nerves originte as branchs from the individual diviions o the brachial plexu. View Answe 8. B. The cords ae name accoring to their relatie posiion to the scond prt of the axillry artery as it lie behind the ectorlis mnor mucle. 9. Th anteror fasial copartmet of the forearm contains the following rteries excep which (a) rachia (b) Anterior interoseous

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snell (c) Rdial (d) Ulnar (e) Profunda Viw Answr 9. E. The prfunda rtery uns through the posterior fascial comparment o the am accopanied by the radial nerve. 1. The oundares of he anaomic suffbox include the following except which? a) Abdctor pllicis brevis (b) Extenor policis lngus c) Exensor ollici brevi (d) Abductr pollcis logus Viw Answr 10. A The aductor pollics brevis is a muscle of th thena eminece and is not near the anatomic snuffbox. 1. The following structures are atached to th greater tuberosity of the humeru excep which (a) Supraspinatus uscle (b) Coacohumral liament (c) eres mnor mucle d) Infaspinaus musle (e) Subsapulars musce View nswer 1. E. Te subcapulais musle is insertd into the leser tuerosit of th humers. 12. Th folloing stucture form he boundaries to the superior entrance ito the axilla except which (a) Clavicl (b) Coacoid rocess (c) Uper boder of the sula (d) Outer order f the first rib iew Anwer

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snell 12. B 13. The carpal tunel cotains he folowing mportat strutures xcept hich? (a) Flexor pollics longs tendn (b) Fleor digtorum rofunds tendns (c) Meian neve (d) Fleor carpi radials tendon (e) Flexor digitrum suerficalis tendons Viw Anser 13. D. The flexor carpi radialis tenon entrs the palm trough a spli in th flexr retiaculum in a groove on the rapezim. Completion uestios Select te phrase that best omplets each statement. 14. Hperextnsion f the proximl phalnges o the lttle ad ring finger (i.e, claw hand) can reult frm damae to te _______ neve. (a) ulna b) axillary (c) radial (d) mdian (e anteror introsseos View Answer 4. A. The ular nere suppies the lumbical ad inteossei uscles, which normaly fle the poximal phalanges and extend the middle ad distl phaanges f the little nd ring finges. 15. Wrist rop ca result from damage to the ________ nerve. (a) media (b) ular (c) rdial (d) anteror introsseos (e) axillry View Aswer

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snell 15 C. se page 537 and Fiure 9103. 16 An inability to opose th thumb to the little finger can rsult fom damge to he _______ nerve. (a) anerior nteroseous (b) poterior interosseous (c) radial (d ulnar e) medan iew Answer 16. E. The oponens ollicis musce, whih is responsible fo pullig the thumb medialy and forwad acros the alm so that te palmr surfce of the ti of th thumb may coe into with the pamar suface of the tips of the other figers, s suppied by the median nerve. 17. he senory inervatin of he nai bed o the idex figer is the (a media nerve (b) rdial nrve. () dorsal cutneous ranch f the lnar nrve. (d) supericial ranch f the lnar nrve. (e) palmar cutaneus brach of he ulnar nerve. View Answer 7. A 8. The sensory innervation of the medial side o the plm is he (a radial nerve. (b) palmar utaneos branh of te ulna nerve c) doral cutneous ranch f the lnar nrve. (d) media nerve (e) superfiial brnch of the ulnar neve. iew Answer 18. B 19. The snsory nnervaion of the dosal suface o the rot of he thub is te

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snell a) medan nere. (b) radial nerve. (c) sperficial brach of he ulnr nerv. (d) dorsal ctaneous branc of th ulnar nerve. (e) poserior interoseous erve. View Answer 1. B 20. The ensory innervtion o the medial side of the palmar asect of the rig fingr is te (a) adial erve. b) poserior nteroseous nerve. (c) orsal utaneos branh of te ulnar nerve. (d) meian neve. (e supericial ranch f the lnar nerve. View Answer 2. E 2. The usculoutaneos nerv origiates fom the _______ of the brachial plexus. (a) postrior crd (b laterl cord (c) boh medil and ateral cords (d) upper trunk (e media cord Viw Answr 21. B 22. The suprascapulr nerv origiates fom the _______ of te bracial plxus. (a) medial cord () lower trun (c) poterior cord

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snell () lateral cord (e) uper trnk View nswer 22. E 23 The mdian nrve originats from the _______ f the rachia plexus. () medal and lateral cords (b) medal cor (c) posterior cord d) uppr and ower tunk () lateral cord View Aswer 23. A 24. The toracodrsal nrve orginates from the _______ of the brachial plexus. (a) laeral crd (b) posteror cor (c) mdial crd (d) medial and poterior cords (e) lwer trnk View nswer 24 B 25 The axillary nerve origintes frm the ________ of the brachial plexus. a) poterior cord (b) middle runk c) latral cod (d) lower trunk e) medial cod View Answer

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snell 25. A 26. he lymh from the uper lateral uadran of the breat drais mainly int the (a) lateral axilary ndes b) internal thoracic nodes (c) posterir axilary noes () anteior axllary nodes (e) dltopecoral goup of nodes View Anser 26. D 27. he medal colateral ligament of the elbow t is clsely rlated o the (a) brachil artey (b) radial nerve (c) ulnr nerv (d) basilic ein (e) ulnar artery Vew Anser 27. ultipl-Choic Questions ead the case histores and select the bet answr to te quesion folowing them. patient was seen in the emergeny depatment ith a aceraton of he ski over the middle palanx f the ight idex figer. Ater caefully examinng th patiet, the physician decided t sutur the wund uner a dgital nerve block. 8. The site o the aesthetc injetion depended on the folloing statement excep which (a) Te skin of the right index inger over te midde phalnx is nnervaed antriorly by two digitl braches o the mdian nrve. (b) The skin of the right index figer oer the middle phalan is inervate posteiorly by two digita branhes of the suerficil radil nerv. (c) These nerves can easily be blocke by inecting small olumes of anethetic solutin around the base o the fnger.

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snell (d) The digital nerves to the fingers are difficult to inject ecause they are imbdded i tough deep fscia. (e) Provided that the wound was clean nd di not bcome ifected the haling rocess should take place without any complications an full eturn f skin sensaton shold occur. View Answer 8. D. he digtal neves at the rot of he finers ar relatvely esy to injec and ae not imbedde in tough dep fasca. A 46-yea-old mn was involvd in n autoobile cciden and sstaine a ter of the capule of the carpometacarpal t f his ight tumb. In view of his histor of lug disese, it was deided to repair the laceraion uner a bachial plexus nerve lock. he ortopedic surgeo decided to inject the anesthetic into th brachial plexus belw the clavice. 29. The inection procedre depnded on the following statements xcept hich? (a) The bachial plexus lies i the ailla ad is frmed fom the anterior rami of C5 throug C8 an T1 spnal neves. (b) The aillary sheath is fored of deep fascia ad surrounds te axillary arery an the bachial pleus. (c) The ar is abducted to an angle greater tha 90° o that the axllary rtery ould be palpated high up i the ailla. (d The anestheic bloking nedle i insered int the seath. (e) The cords and ranche of th bracial plxus, icludin the msculoctaneou nerve lie within he shath, ad all the braches ae bloced by he anethetic using his aproach View Answer 9. E. The dsadvanage f the axillay apprach to the brchial lexus nerve lock i the difficulty sometimes xperieced in blockig the musculcutaneus nere. Thi nerve is a banch o the lteral cord of the lexus nd the anesthtic agnt may not rech hig enoug up in the seath t block this nrve. T overcme thi disadvantage, the axillary artery and the sheth are compresed dital to the pont of njectin, so that he sheath may be cloed off below. By using ths maneuver, te anethetic agent ises i the seath t the lvel of the msculoctaneou nerve It is the teminal ranche of th musclocutaeous nrve (lteral utaneos nerv of th foream) tha suppy the kin ovr the arpomeacarpa t of the thumb.

Footnot There are eght interossi, cosisting of our dorsal ad four palmar muscls. Som authors descrie only three palmar interosei an state that te firs palma inteosseou is in realit a second hed to te flexr pollcis brevis: others believe that it is part of he addctor pllicis muscle Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product. 1019

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11. 10. The Lower Limb An 1-year-ol student was doin part-time work eliverin pizzas n his moorcycle. His boss insisted on quick delivery, so the student ended to weave in and out f traffi wheneve there as a holup. On oe occasn, he misjudged te gap beween two vehicle, and th outer srface of his left knee hit a car buper. On examinaton in th emergeny departent, he as found to have extensive paralysi of the uscles o the anerior an lateral compartments of the left leg. As result, the patint was unble to drsiflex he ankl t (hich shoed footdop) and evert the foot. In addition, there was evidee of diminished snsation own the nterior nd lateal sides of the lg and dosum of te foot and toes, icluding he medil side o the big toe. A sries of adiograph of the nee regin showed no evidce of boe fractues. The physicia made th diagnoss of parlysis of the comon peronal nerve secondar to blun trauma o the laeral sid of the left fibul. The radiographic examination ruled out the possibily of facture o the nec of the fibula. To be in a postion to ake such a diagnois, physcians mst be cognizant of the detaled anatmy of th course f the comon perneal nere as it inds arond the oter side of the nk of th fibula. Knowledg of the istributon of th branche of this nerve enables phyicians t eliminae other erve injuies. Morover, thy are ale to asess the egree of nerve daage by tting the strength of the arious mscles suplied by this nere and coducting uitable tests to assess the sensory deficits P.550

Chpter Obectives  

  

Lower limb roblems ae some o the mos common dealt wih by heath professionals, hether wrking in general practice surgery or an eergency epartment. Arthriis, varicose veins vascula deficincies, factures, dislocatons, sprins, laceration, knee effusions leg pain ankle ijuries, nd periperal nerv injurie are jut a few f the coditions hat physcians se. The anatomy of the lower limb is iscussed in relaton to comon clincal condiions. A neral dcription of the bnes, jonts, and actions f muscles is give Emphasis is placed on the functios of the muscles, and only the brieest coverage of thir attahments i provide. The basic aatomy of the vasclar suply, lymptic draiage, and distribuion of te nerves is reviewed.

Baic Anatoy The primary unction f the loer limbs is to th weight f the boy and to provide stable oundatio in staning, waking, and running; they hav become pecializ for locmotion.

rganizaton of th Lower Lib

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snell Te lower imbs are divided nto the luteal rgion, th thigh, the knee the leg, the anke, and te foot. he thigh and the leg are ompartmenalized, ach comprtment hving its own muscles that perform group unctions and its own distnct nrve and lood supply. P.51

The Gluteal Rgion The glueal regin, or butock, i bounded superiorly by te iliac crest an inferioly by the fold f the buttock. The region is larely made up of te glutea muscle and a tick laye of suprficial fascia.

The Skn of the Buttock The ctaneous erves (igs. 101 and 102) ar derived fro posteror and aterior rmi of spnal nervs, as folows:    

The uper media quadran is suppied by te posteror rami f the uper three lumbar nrves and the uppe three scral neres. The uppr latera quadran is suppied by he lateral branch of the iliohypogstric (L1) and 12th thoracc nerve (anterir rami). Th lower lteral qudrant is supplied by brances from the latera cutaneos nerve f the thgh (L2 ad 3, antrior ram). Te lower edial qudrant is supplied by brances from he posteior cutaous nerv of the high (S1 2, and , anterir rami).

Te skin oer the cccyx in he floor of the ceft beteen the uttocks s supplid by smal branchs of the lower sacral and coccygeal nerves.

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Figure 10-1 Ctaneous nrves of the posteior surfce of th right lwer limb

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Figre 10-2 Cutaneos nerves of the aterior srface of the right lower lib.

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The lymh vessel drai into the lateral roup of he supericial inuinal noes (Figs. 1-3 and 104).

Fasci of the uttock The supericial facia i thick, especialy in women, and is impregnated with arge quntities of fat. It contributes to te prominnce of te buttoc. The dep fascia is cotinuous elow wit the deep fscia, or fascia lta, of the thig. In the gluteal egion, i splits t enclose the gluus maxims muscle (Fg. 10-5). Aboe the gluteus maxmus, it ontinues as a sinle layer that covers the oter surfce of th gluteus medius ad is attched to he iliac crest. O the laeral surace of the thigh the fasia is thickened o form strong, wide bad, the iiotibial P.554

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trct (Fig. 10-6) This is attache above to the tubercle of the iliac rest an below t the lateral condle of th tibia. he iliotbial tract forms sheath for the tensor fasiae latae muscle and receves the reater prt of te inserton of the gluteus aximus.

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Figre 10-3 , B. Superfical veins arterie, and lyph nodes over the right feoral trangle. Nte the

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sphenous opening in the deep fascia ad its rlationshp to the femoral heath. Nte also he line f attachent of he membrnous laye of supeficial fscia to he deep fascia, abut a fingerbreadh below he inguial ligamet.

Figue 10-4 Lymph rainage or the sperficial tissues of the riht lower limb and the abdominal wals below the leve of the mbilicus Note th arrangment of he superficial and deep inginal lymph nodes nd thei relationship to he sapheous openng in the deep fasia. Note also tht all

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lyph from hese nods ultimatly drain into th externa iliac odes via the femorl canal.

Figue 10-5 Right guteus maimus muscle.

Bones f the Glteal Regon Hip Bone

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snell The ilum, ischum, and ubis for the hip bone (Figs. 10-7 nd 10-8). They met one anther at he acetaulum. Th hip bons articuate with the sacum at the sacroilac t and for the antrolatera walls o the pevis; the also articulate th one aother aneriorly t the smphysis ubis. The detailed stucture o the inernal asect of te bony pelvis is considerd on pag 308. Th importat featurs found on the ouer surfae of the hip bone in the guteal reion are s follow. he ilium which i the uppr flatteed part f the boe, posseses the ilic crest (ig. 10-8). Thi can be elt throgh the sin along its entie length it ends in front at the anteior supeior ilia spine and behind at the psterior uperior liac spine. Te liac tubrcle ies abou 2 in. ( cm) behnd the aterior superior spne. Belo the antrior suprior ilic spine s a promnence, te nterior nferior liac spie; a similar rominenc, the posteior infeior ilia spine is locaed below the posterio superio iliac sine. Aboe and beind the cetabulu, the ilum possesses a large notch the greate sciatic notch Fis. 107 and 10-8). he ischium is L aped, posessing an upper thicker part, the body, and a lower hinner prt, the rams (Figs. 10-7 ad 0-8). The ischia spine projects from the posterio border f the ishium and intervens between the greate and lesr sciatic notches. The iscial tubeosity forms te posteror aspec of the ower part of the body of the bone. The grear and lesser sciatic notces are converted into greater and lessr sciati foramin by th presenc of the acrospious and sacrotubrous liaments (ee page 318). he pubis can be divided nto a body, a superor ramu, and an inferio ramus (ig. 0-8). Te bodies of the o pubic bones aticulate with eac other i the midine anteriorly a the symphsis pub; th superio ramus jins the ilium an ischium at the aetabulu, and th inferior ramus oins th ischial ramus beow the oburator framen The oburator foramen in life s filled in by te obturato membran (see pge 318). The pubic crest forms the uppe border of the body of the pubis, and it ends laterally as he pubic tubercle (igs. 10-7 and 10-). On the uter surface of the hip boe is a dep depresion, caled the aceabulum, that aticulate with th P.556

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almos spherical head o the femr to for the hip t (Figs 10-8 and 10-9) The infrior marin of the acetabulum is defcient an is markd by the actabular otch Fig. 10-8. The aticular urface o the aceabulum i limited to a horseshoe-shaped are and is cvered wih hyalin cartilae. The foor of he acetaulum is onarticuar and i called he acetabulr fossa (Fig. 10-).

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Figure 10-6 emoral tiangle ad adductr (subsatorial) anal in he right lower lib.

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Fgure 10- Media surface (A) and ateral srface (B) of the rght hip one. Not the lins of fuson betwen the thee bones (the ilim, the ichium, ad the pubis).

Figur 10-8 Muscles nd ligamnts attahed to te external surface of the ght hip one.

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Figure 1-9 Mucles attched to he exteral surfae of the right hip bone and the posterior surface of te femur.

In he anatoic positon, the ront of he symphysis pub and the anterior superior iliac spnes lie n the sae verticl plane This mens that he pelvic surface f the syphysis pbis face upwar and bacward and the anteior surfce of the sacrum is direct forward and dowward. The impotant musles and igaments attached to the oter surfce of th hip bone are shown in Figure 10-8.

emur

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snell Te femur rticulats above ith the cetabulu to form the hip oint and below wih the tiia and te patell to form the knee t. he upper end of te femur as a hea, a neck and greter and esser trchanters (Fgs. 10-1 and 10-1). T ead foms about two thirs of a shere and articulaes with he acetaulum of he hip bne to fom the hip t (Fig 10-9) In the enter of the head is a smal depresion, called the P.560

ovea captis, fr the atachment f the lgament o the hea. Part o the blood supply o the hed of the femur fom the oturator rtery is conveyed along ths ligament and enters the bone at the fovea

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Figue 10-10 Muscles and ligaments atached to he anteror surfae of the right feur.

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Figure 1011 Musles and igaments attached to the psterior surface o the righ femur.

The neck, which onnects te head o the shft, s downwad, backwrd, and terally and makes an angle of abou 125° (lightly ess in te female with th long axi of the shaft. The size of this ngle ca be alteed by disease. The greatr and leser trochnters are larg eminencs situatd at the junction of the nck and th shaft (Fig. 10-10 and 10-11). Conncting th two trohanters re the intetrochantric line anterorly, whre the iliofemora ligament is attached, and prominet ntertrocanteric rest osteriory, on whch is the qadrate tbercle (Fg. 10-11). The haft f the feur is smooth and ounded on its antior surfce but posteriorl has a rdge, the liea asper (Fig. 1-11), to which are attahed musces and itermuscuar septa The marins of he linea aspera dverge above and below. The medial marin contiues belw as the P.561

edial suracondylr ridge to the adductor tubercle n the meial condle (Fig. 1011). Te latera margin ecomes cntinuous below wih the lateal supracondylar ridge. On the posteror surfce of th shaft blow the reater tochante is the luteal tuberosit for the attahment of the glueus maxius muscl. The shft becoms broader toward its dista end an forms a flat, trangular rea on is posteior surfce called the poplital surfae (Fig. 0-11). The lowr end of the femu has laterl and medial codyles, sparated osteriory by the inercondylr notch. The anterior rfaces of the codyles ae ed by an articular srface fo the patlla. The two condyles take part in he formaion of he knee oint. Abve the cndyles are the media and lateal epicodyles (Fg. 10-11). The adductor tubercle s continous with the medial epiconyle. The iportant uscles ad ligamets attaced to th femur ae shown n Figures 10-10 an 1-11.

Clnical Noes Tnderness of the Had o th Femur nd Arthrtis of te Hip Jont Th head of the femu—that s, that art that is not ntra-aceabularâ€can be plpated o the antrior aspct of th thigh ust infeior to te inguinal ligament and jus lateral to the ulsatin femoral artery. enderness over the head of he femu usually indicates the preence of rthritis of the hp t.

Blood upply t the Femoral Head and Neck Fracture Anatomic knowledg of the blood suply to te femora head explains wy avascuar necrois of th head ca occur after fractures of the neck f the femur. In te young, the epipysis of he head is suppled by a mall brach of th obturatr artery which asses to the head along th ligamen of the femoral head. The uper par of the eck of te femur eceives profuse blood suply from the medal femorl circumlex artey. These branches pierce te capsul and asend the eck deep to the snovial 1039

snell membrane. As long as the epiphyseal rtilag remain, no comunicatin occur betwee the two sources o blood. In he adult after the epiphseal catilage isappear, an anstomosis between the two ources f blood upply i establshed. Frctures of the feoral ne interfre with r compltely iterrupt he bloo supply rom the oot of he femorl neck o the fmoral head. Te scant blood flw along the smal artery that acompanies the roud ligamnt may b insufficient to sustain the viaility of the femral head, and ishemic nerosis grdually takes plce.

he Neck of the Femur and xa Valg and Cox Vara The neck of the femur is inclied at an angle wih the saft; the angle is about 160° in th young cild and bout 125° in the adult. An increase in this angle i referred to as cox valga, and i occurs, for examle, in cses of cngenital dislocation of the hip. In this conition, aduction f the hi t i limited A decrase in ths angle is refered to a cxa vara, and i occurs n fractues of th neck of the femr and in slipping of the femoral epiphysis. n this cndition, abductio of the ip t is limied. Shenon's lin is a usul means of assessing the angle of he femoal neck n a radigraph of the hip egion (se igure 1072).

Fractures of the Fmur ractures of the nck of th femur ae common and are f two tyes, subital an trochaneric. Th ubcapital fracture occus in the elderly nd is usally prouced by minor tip or sumble. Sbcapital femoral eck fracures are particularly common in womn after enopause. This geder predspositio is becase of a thinning of the crtical ad trabecular bone aused by estrogen deficiecy. Avasular necosis of he head s a commn compliation. I the frments ar not impacted, cosiderabl displacment occrs. The strong mscles of the thig (ig. 10-1), inluding te rectus femoris, the addutor musces, and he hamstring musles, pul the disal fragment upward, so tha the leg is shortned (as measured from the anterior superior iliac spne to th adducto tubercle or medl malleolus). The gluteus maximus, he pirifrmis, th obturaor interus, the emelli, and the uadratus femoris rotate te dista fragmen lateraly, as sen by the toes poiting latrally. Trohanteric fracture comonly occr in the young an middle-ged as a result o direct trauma. he fractre line s extrasular, nd both ragments have a rofuse bood suppy. If the bone frgments ae not imacted, te pull of the strong muscls will poduce shrtening and lateral rotation of th leg, as previousy explaied. Fractres of te shaft f the feur usualy occur n young nd healty person. In fractues of th upper tird of te shaft of the femur, he proxial fragmnt is flexed by th iliopsos; abduted by te glute medius nd minims; and lterally otated b the glteus maxmus, the piriforms, the oturator nternus, the gemlli, and the quadatus femis (Fig. 1013). The lowe fragmen is adduted by t adductor muscle, pulled upward y the hastrings and quadreps, and laterally rotated by the adductors and the eight of the foot (Fg. 10-13). In fracures of he middl third o the shat of he femur the disal fragmnt is puled upwad by the hamstrins and th quadris (Fig. 103), esulting in consierable sortening The disal fragmnt is alo rotatd backwad by the pull of he two hads of t gastrocemius (Fig. 10-13.

1040

snell In fratures of the distl third f the shft o the femr, the sme displaceent of te distal fragment occurs a seen i fracturs of the middle thrd of the shaft. owever, he dista fragmet is smaler and s rotate backwar by the astrocneius musc (Fig. 1013) to a greate degree nd may eert presure on te poplital arter and intrfere with the blood flow rough the lg and foot. From these acounts it is clear that knoledge of the diferent acions of the muscle of the leg is necessary o understand the displacement of th fragmens of a factured emur. Cosiderabl tractin on the distal fagment i usually required to overcme the owerful muscles and restore the limb to its crrect legth befoe maniplation ad operatve theray to brig the prximal an distal fragments into corect aligment. P.52

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snell

Fiur 10-12 A. Fractures of te neck o the femr. B. Dsplacemet of the lower boe fragmet caused by the pll of th powerfl muscle. Note i particuar the otward roation of he leg o that he foot characteristically oints laerally. M, glutes maximu; PI, priformis OI, obtrator internus; GE, gemell QF, quaratus fmoris; R, rectus femoris; AM, addutor musces; HS, amstring muscles

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snell

Ligaents of he Glutel Region The two impotant ligments in the glutal regio are th sacrotuerous an sacrospnous ligments. Te functin of thee ligamnts is t stabili the sacrum and pevent it rotatio at the sacroilic t y the weght of te vertebal colum.

acrotubeous Ligaent he sacruberous igament onnects he back f the sacrum to te ischia tuberosty (Fig. 1014; se ig. 6-1).

Sacrospinous Ligament Th sacrospnous ligment conects the back of he sacru to the spine of he ischi (Fig. 10-4; see Fi. 6-1).

oramina of the Gluteal egion The two impotant formina in the glueal regin are th greate sciatic foramen nd the esser siatic foamen.

Geater Scatic Foramen The greatr sciati foramen (see Fg. 6-11) is formed by the greater sciaic notch of the ip bone and the acrotubeous and sacrospious ligaents. It provides an exit from the pelvis into th glutea region. The followin structes exit the foraen (Fig. 10-15):        

Pirformis Scatic nere Posterir cutaneus nerve of the tigh Sperior ad inferir glutea nerves Nerve to the bturator internus and quadratus feoris Pudenda nerve Suerior an inferio gluteal arterie and veins Inernal puendal arery and ein

Leser Sciaic Foramn Th lesser sciatic foramen (see Fig. 6-1) is ormed by the lesser sciatc notch of the hi bone an the sacrotuberos and sacospinous ligament. It proides an ntrance nto the perineum from the gluteal region. Is presene enable nerves nd bloo vessels that hav left th pelvis hrough te greate sciatic foramen above th pelvic loor to enter the perineum below the pelvic floor. The ollowing structurs trough th foramen (Fg. 10-14): 

Tendon f obturaor internus muscl

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snell   

Nerve to obturtor inteus Pudedal nerv Internal pudendal artery ad vein

Mscles of the Glutal Regio Te muscle of the gluteal rgion incude the luteus aximus, he glutes medius the glueus minius, the ensor faciae laae, the piriformis, the obtrator inernus, te superir and iferior gmelli, ad the qudratus fmoris. Te muscle are shon in Figure 10-5 10-14, ad 0-15 d descried in Table 10-1. Noe the folowing:  

Th gluteus maximus Fi. 10-5) is th largest muscle i the bod. It lie superfiial in te glutea region and is largely reonsible for the promience of he buttok. The ensor faciae late runs dwnward nd backwrd to its insertion in the iliotibil tract nd thus ssists the gluteu maximus muscle i maintaiing the nee in te extendd positon P.63

1044

snell

Fiure 10- Fracures of he shaft of the fmur. A. pper thrd of th femoral shaft. Nte the

1045

snell

dsplacement caused y the pul of the powerful muscles. B. Middl third o the femral shaft. Note t posteror displacement of the lowe fragmen caused y the gatrocnemis muscle C. Lowr third o the femral shaf. Note te excessive displaement of the lowr fragmet caused by the pll of th gastrocnmius musle, thratening he integity of te poplital arter. IP, ilopsoas; GME, gluteus mediu; GMI, guteus miimus; GM gluteus maximus; PI, pirformis; I, obturtor intenus; GE, gemelli; QF, quadatus femori; AM, aductor uscles; DF, quadiceps feoris; HA, hamstrings; GAST gastronemius.





The pirifors (Fig. 10-15) les partl within he pelvis at its oigin. It emerges hrough te greatr sciati foramen o enter he glutel region Its posiion seres to searate th superior gluteal essels ad nerves from the inferio gluteal essels ad nerves (Fg. 10-15). The obturato internus is a fanshaped uscle tht lies wthin the pelvis a its oriin. It eerges though the lesser siatic foamen to nter the gluteal rgion. Th tendon is ed by the sperior ad inferir gemell and is iserted ito the reater tochanter f the feur. P.564

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snell

Figure 10-14 Dep structres in te right luteal rgion; th gluteus maximus nd glutes medius muscles ave been ompletel remove.



Three bursae are usally assciated wth the luteus mximus: bween the tendon o insertin and th greater trochanter, betwen the tedon of isertion and the vatus latealis, and verlying the ischal tubersity.

Clincal Note Gluteus Medius and Minmus and oliomyeltis The gluteus medus and mnimus mucles may be paralzed when poliomyeitis invlves the lower lumbar and sacral sements of the spial cord. They are supplied by the superior glteal nere (L4

1047

snell an 5 and 1). Paraysis of these musces seriosly inteferes with the ality of he patiet to til the pelis when wlking.

Clnical Noes Gluteus Maxmus and ntramusclar Injetions The luteus mximus is large, hick musle with oarse fsciculi hat can be easil separad without damage. The grea thicknss of ths muscle makes it ideal for intramusular injctions. To avoi injury t the unerlying ciatic nrve, the injectio should be given well forard on the upper oter quadrnt of th buttock

Gluteus aximus and Bursiti Busitis, o inflammtion of bursa, n be caused by aute or cronic truma. An inflamed ursa beces distended with excessie amount of fluid and can e extremly painfl. The brsae assciated wth the guteus maimus are prone to nflammation. P565

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snell

Figure 1-15 Structurs in th right guteal reion. The greater art of the glutes maxims and pat of the gluteus edius hae been rmoved.

Nerves f the Glteal Region Sciatic Nerve Te sciatic nerve a branh of th sacral plexus (4 and 5; S1, , and 3) emerges from te pelvis throuh the loer part f the reater sciatic framen (Figs. 10-14 and 10-15. It is he larget nerve in the bdy and cnsists o the tibal and ommon peoneal nrves boud together with ascia (Fig. 10-16 and 10-

1049

snell 17). Th nerve apears below the iriformi muscle and cures downwrd and laterall, lyig succesively on the rot of the ischial spine, te supeior gemelus, the obturatr interns, the iferior mellus, and the quadrats femoris to reah the back of th adducor magnu muscle (Fi. 10-15). It is relaed postiorly t the poterior ctaneous erve of he thig and th gluteu maximus It leaes the bttock rgion by assing eep to he long head of he bicep femoris to enter the bac of the thigh see page 587). Occasinally, te common peronea nerve eaves th sciati nerve high in te pelvis and appars in he gluteal regio by pasing abov or through the iriformi muscle. The scitic nerv usually gives no branches in the guteal reion.

Postrior Cutneous Neve of th Thigh The posterio cutaneos nerve f the thgh, a brnch of he sacra plexus, enters te glutea region hrough te lower art of he greatr sciatic foramen below th piriforis muscle (Fig. 10-14). t es downward on the psterior urface o the scitic nerv and rus down t back of the thih beneah the dep fascia In the popliteal fossa it supplie the ski. P.566

Table 10-1 uscles o the Glueal Regin

Mscle

Orign

Nerve Nerve Suply ootsa Action

nsertio

Gluteus aximus

Outer urface o ilium, acrum, coccyx, sacrotuberous ligament

Iliotibil tract nd glutel tuberoity of fmur

Inferior glutal nerv

L5; S1 2

Extends nd laterlly rotaes hip jint; thrugh ilioibial tract, it exends kne t

Gluteus mdius

Outer suface of lium

Lateral surface f greate trochaner

Superor glutel nerve

5; S1

Abducs thigh t hip jont; tilt pelvis hen

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snell

walkng to permit opposite leg o clear round

of feur

Glteus minmus

uter surace of iium

Anterio surface of greater trochanter of femur

Superor glutel nerve

L5; S1

Abducs thigh t hip jont; tilt pelvis hen walkng to pemit oppoite leg o clear gound

Tesor fascae latae

Ilic crest

Iliotbial trat

Suerior gluteal nerve

4; 5

ssists guteus maimus in xtending the knee t

Pirifrmis

Anterior surface of sacru

pper boder of greater trchanter of femur

First an second acral nrves

L5; S1, 2

Lteral rtator of thigh a hip t

bturator internus

Iner surface of obturator membrane

pper boer of geater trchanter f femur

Sacral pexus

L5; S1

Lateral otator o thigh a hip jont

Gemellu superir

Sine of ichium

Upper order of

Sacra plexus

L5; 1

Latral roator of

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snell

greater trochanter of feur

high at hip

Gemelus infeior

Ischial uberosiy

Uper bordr of greter trocanter o femur

Saral plexus

L; S1

Lateral otator o thigh t hip jont

uadratu femoris

ateral border o ischial tuberosy

Quarate tubrcle of emur

Saral plexs

L5; S1

Latral rotaor of thigh at hp t

a

The redominat nerve root suply is inicated b boldfac type.

ranches   

Glutal branches t the ski over th lower medial qudrant of the buttck (Fig. 1-1) Perieal brach to the ski of the ack of the scrotm or labum maju Cuaneous banches to the back of the thig and th upper prt of th leg (Fig. 10-1)

perior luteal Nrve he supeior glutal nerve a branh of the sacral plexus, eaves te pelvis through the upp part f the grater sciatic foamen aboe the piiformis Fg. 10-15). It uns forward betwen the guteus mius and inimus, supplies both, an ends by supplyin the tenor fascie latae. .567

Infrior Glueal Nerv Th inferir gluteal nerve, a banch of the sacral pexus, leavs the pelv throug the lowr part of he greatr sciati forame below te pirifomis (Fgs. 10-4 and 1015). t supples the guteus maximus mucle.

erve to the Quadatus Feoris 1052

snell A brnch of he sacra plexus the nere to th quadraus femoris leave the pelvis throgh the ower prt of th greatr sciatic foramen Fig. 1-15). It ends by suppling the quadratu femori and th inferi gemells.

Pudendal Nerve an the Nere to the Obturatr Interus Braches of the sacral lexus, te pudenal nerve and nerve to te obturaor internus leae the pevis hrough te lower part o the greter sciatic foraen, belo the pirformis (Fig. 10-14 and 10-5). hey cross the ischial spie with te internl pudenal arter and imediately re-ente the pelis throgh the lsser scitic foraen; thy then le in the ischioretal foss (see page 394). The puendal neve supples strutures in the perieum. The nerve to the obtrator inernus suplies th obturatr interns muscle on its pelvic srface.

Artries of he Glutel Regio uperior Gluteal Artery The suerior glteal artery is a branch from the internal iliac atery and enters the glutal regio through the uppe part o the grater scitic foramen aboe the priformis (Figs. 1014 n 10-15). It dvides ino braches tha are disributed hroughou the glueal regin.

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snell

Fgure 10-6 Sumary of he origin of the ciatic nerve and the main branches of the common eroneal erve.

Infeior Gluteal Arter Th inferio gluteal rtery is a branc of the iternal liac artry and eters the luteal rgion thugh the ower par of the greatr sciati foramen, below th piriforis (Figs. 0-14 ad 0-15) It divies into merous branches tat are dstributed throughot the glteal regon.

The ochanterc Anastoosis

1054

snell The trohanteric anastomos provis the man blood supply t the head of the fmur. The nutrient arteries alog the fmoral nek beneath the capsle (Fig. 1018). The following arteies take part in he anastmosis: te superi glutea artery, the infeior glutel artery the medal femorl circuflex artry, and te latera femoral circumfle artery.

The Cruciate Anasomosis The cuciate aastomosi is situed at the level o the leser trocanter of he femur and, togther wit the trohanteric anastomsis, provdes a conection etween te internl iliac and the fmoral areries. Te followng arteres take art in th anastomsis: th inferior gluteal rtery, te medial femoral circumflex artery, he lateal femora circumfex arter, and th first prforatin artery, a branh of the profunda artery.

linical otes rterial Anastomoses and Feoral Artry Occluion he impotance of the trocanteric nd crucite anastmoses in femoral atery occusion is discusse on page 658. P.568

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snell

Figue 10-17 Summary of the oigin of he sciatc nerve and the ain branches of te tibia nerve.

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snell

The Front nd Medial Aspect of the Thigh Sin of th Thigh Cutneous Nrves The lateral cutaneou nerve o the thih, a branch o the lumbar plexus (L2 and ), enter the thigh behind the lateral end of the ingunal ligaent (Fig. 1-2). Having dvided ino anterir and poterior branches, t supplis the sin of th lateral aspect of the thig and kne. It als supplie the ski of the ower latral quadant of the buttock (ig. 10-1). The femoral branch of the gnitofemoal nerve, a banch of he lumba plexus (L1 and 2), enters the thigh behind e middle of the nguinal igament nd suplies a sall area of skin (Fig. 10-). Th genital branch splies th cremastr muscle (see page 29). Te lioinguial nerve, a brnch of te lumbar plexus (1), entes the thgh through the suerficial inguinal ring (Fig. 10-2). t is disributed o the skn of the root of the penis .569

and adjacnt part o the scrtum (or oot of te clitors and adacent prt of th labium ajus in he female) and to a small kin area below the medial art of te inguinl ligamet.

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snell

Figure 0-18 Coronal ection f the riht hip jint (A) and articular sufaces of the riht hip jint and rterial upply of the hea of the emur B).

The medial cutanous nere of the thigh a branc of the emoral nrve, suplies the medial apect of he thigh and the patllar pleus (Fig. 102).

1058

snell The intermeiate cutneous neve of th thigh, a brach of th femoral nerve, dvides ito two banches tat supply the antrior aspct of th thigh ad s he patelar plexu (ig. 10-2). Branche from the anterior division of the obtrator neve suply a vaiable ara of skin on the edial asect of te thigh Fi. 10-2). .570

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snell

Figure 0-19 uperficil veins f the riht lower limb. Note the imprtance of the valed perfating vens in te “venus pump―

1060

snell Te patellar plexus lies i front f the kee and i formed rom the terminal branches of the lateral intermediate, ad medial cutaneos nerves of the tigh and he infapatella branch f the sahenous nerve (Fig 10-2

Superficial Veins The supeficial vins of te leg ar the great and smll sapheous vein and ther tribuaries (Fig. 10-1) They ar of grea clinica importace. The great aphenous vein dains th medial ed of th dorsal enous arh of th foot an es upward dirctly in ront of the meial mallolus (Fig. 0-19. It thn ascens in company with the saphnous nerve in th superfiial fasia over he media side of the leg. The vei es ehind th knee ad curves forward round th medial ide of e thigh. It s through the lower part of the saphenou opening in the deep fasca and jins the femoral ein abou 1.5 in. (4 cm) blow and ateral t the puic tubercle (Figs. 1-3 an 10-19). .571

The great sphenous ein posesses nuerous vlves and is conected to the smal saphenos vein by one or two branhes that behind the knee. Seeral perfrating veins conect th great saphenous vein with the deep veins alng the medial si of the calf (Fig. 10-19. At te saphenus openig in the deep facia, the great saphenous vein usully receves thre tributries that are vaiable i size ad arranement (Figs 10-3 and 10-19): the suprficial ircumfle iliac vin, te superfical epigatric vei, and the superfcial exrnal pundal ven. Thee veins orrespon with th three banches o the femral artey found in this egion. An additional vein known a the accssory ven, usally s the min vein about th middle of the thigh or hgher up t the sahenous oening. The small aphenous vein i descrid on pag 615.

Cliical Notes Vens of th Lower Lmb Te veins f the loer limb can be diided into three gups: suprficial, deep, and perforting. Th sperficia veins consis of the great and mall sapenous veins and thir tribuaries, hich are situatd beneat the ski in the uperficil fascia The costant position of the great saphenou vein in front of the medial malleolus should be remmbered fr patiens requirng emergncy bloo transfsion. Th dep veins are the venae comitanes to th anterio and poserior tial arteres, the opliteal vein, ad the feoral vein and ther tributries. Th prforatin veins are comunicating vessel that ru between he supericial an deep vins. Man of thes veins ae found articulaly in th region of the ankle an

1061

snell the medal side f the loer part f the leg. They possess vaves that are arraged to pevent th flow of lood fro the dee to the superfical veins.

Venus Pump f the Loer Limb Withn the clsed fascil compartments of the lower limb, te thin-wlled, vaved vena comitanes are sbjected o intermttent prssure at rest and during eercise. he pulsatons of he adjacnt arteris help mve the bood up the limb However, the cntractios of th large mscles wihin the ompartments during exercis compres these deply plaed veins and forc the blod up the limb. he supericial sahenous veins, exept near their trminatin, lie wthin the superfiial fasca and are not suject to these copression forces. The valves in the perforaing vein prevent the hig-pressur venous blood frm being orced ouward int the lo-pressur superfial veis. Moreoer, as he muscls within the closed fascial comrtments relax, vnous blod is sucke from th superfcial ino the dep veins.

Varcose Veis A aricosed vein is ne that has a larer diameter tha normal and is eongated d tortuus. Variosity of the esophgeal and rectal eins is escribed elsewhere (see pages 129 ad 95). his condtion comonly occrs in th superfiial vein of the lower li and, alhough no life-hreatenig, is reposible fr considerabl discomfort ad pain. Variosed veis have mny causes, including heredary weaness of he vein alls and incompetnt valves elevate intra-bdominal pressure as a resut of muliple prenancies or abdomial tumor; and thombophleitis of the deep vins, whih result in the superficial veins ecoming he main venous patway for he lowe limb. t is eay to undrstand how this conditin can be produce by incmpetenc of a vave in a perforaing vei. Every ime the patient exercies, highpressure venous bood eses from the dee veins into the superfical veins and prodces a vaicosity which mght be ocalized to begi with bt become more eensive ater. Th successul operaive treatment of aricosed veins dpends on the ligation and division of all the main tibutarie of the great or small sahenous veins, to pevent a ollatera venous circulaton from evelopin, and th ligatio and diviion of al the prforatin veins rsponsible for the eakage o high-prssure blod from the deep to the suerficial veins. It is now cmmon pratice to remove o strip te superfcial veis in addtion. Needless to say, it is impertive to ascertain hat the eep vein are patnt before operatie measurs are taen.

Great Sahenous ein Cutdwn Exposure of the geat saphnous vei through a skin icision ( “cutdown―) i usually performe at the nkle (Fig. 0-20). This site has te disadvantage tha phlebits (inflamation of the vein wall) s a poteial compication. The great saphenou vein alo can be entered at the goin in th femoral triangle where phebitis i relatiely rare the larger diametr of the vein at his site ermits he use o large-dameter ctheters nd the rpid infuion of lrge volumes of flids.

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snell

Anatomy f Ankle Vein Cutdon Te proceure is as follows: 





he sensoy nerve upply to the skin immediaely in front of th medial alleolus of the tbia is fom branhes of te saphenous nerve, a branch of the fmoral neve. The saphenous nerve brnches ar blocked with locl anesthtic. A trasverse icision is made though the skin and subcutanous tisse across the long axis of he vein just anteior and superior to the mdial mallolus (Fig. 0-20) Althoug the vein may not be visible through the skin it is consantly ound at this site The vein is asily idntified, and the sapenous neve shld be recognized; the nerv usually lies jus anterio to the vin (Fig. 10-20).

Anaomy of Goin Vein Cutdown 





Te area o thigh skin below nd laterl to th scrotum or labiu majus i supplie by branhes of the ilioinuinal neve and te intermdiate cutneous neve of th thigh. The brances of thse nerve are bloed with local anethetic. A transvrse inciion is mae through the skn and sucutaneou tissue entered n a poin about 1. in. (4 m) belo and latral to te pubic ubercle (Fig 10-20). If te femoral pulse ca be felt (may be bsent in patients with severe shock, the inision is carried edially jst media to the ulse. The great saphenous vin lies n the sbcutaneus fat ad es osteriory throug the sapenous opning in he deep ascia to the femoral ein about 1.5 in. 4 cm), o two figerbreadhs below and laterl to the pubic tuercle. I is impotant to nderstan that the great sahenous vin e through the sapenous opeing to gin entrace to the femoral ein. Howver, th size an shape o the opeing are sbject t variation.

The Geat Saphnous Vein in Coronry Bypa Surgery In patiets with cclusiv coronar diseas caused y atheoscleross, the dseased aterial egment an be byassed by inserting a grat consising of a portion f the geat saphenous ven. The enous sement is eversed so that ts valve do not obstruct the artrial flw. Folloing remoal of th great aphenous vein at the donr site, he supericial vnous blod ascends the loer limb y ig through perforating vens and entering he deep veins. The grea saphenos vein cn also e used o by obstructons of th brachia or femoral arteies. P.52

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snell

Figure 10-20 Great saphenous ein cutdwn. A, B. At the ankle. e great saphenou vein is constantly found in front of the dial maleolus of the tiba. C, D At the groin. Te great saphenou vein drains int the femral vein two finerbreadths below and lateal to the pubic tbercle.

P.573

Inguinl Lymph odes The inginal lymph nodes are divied into uperfical and dep group.

Suprficial nguinal ymph Nods 1064

snell he supeficial odes li in the uperficil fascia below the inguial ligamnt and cn be diided into a horizontal an a vertcal grou (Figs. 103 and 104). The horizontal goup lis just below and parallel to the iguinal lgament (Figs. 10-3 and 10-4). The edial mebers of the group receive superfical lymph vessels rom th anterio abdominl wall elow the level o the umbilicus ad from he perieum (Fig. 0-4). The lymp vessels from te urethr, the exernal geitalia o both sees (but not the testes, and th lower alf of te anal canal are drained b this rute. Th lateral of the grop receie superfcial lyph vessls from the back below te level f the ilac cests (Fig. 10-4. The vertial grou lies along te termial part of the geat saphenous ven and rceives mst of the superfcial lymh vessels of the lower lb (Figs. 1-3 an 1-4). he effeent lymp vessels from th superfiial ingunal nodes hrough the saphenous openng in the deep fascia and he deep nguinal odes.

Deep Inguinal Lymph Nodes The dee nodes are locatd beneah the dep fasci and lie along th medial side of he femoal vein (ig. 10-1); he effernt vesses from tese node enter the abdomn by pasing thrugh the femoral anal to ymph noes along the extenal ilia artery (see Fig. -76).

Cliical Noes Lymphatcs of the Lower Lm The suerficia and dee inguina lymph odes not only drin all the lymph from the lower limb, but aso drai lymph fom the kin and uperficil fascia of the anteior and osterior abdominl walls blow the evel of he umbilcus; lymh from the eternal enitalia and the ucous membran of the ower hal of the nal cana also rains ino these nodes. emember he arge ditances te lymph hs had to travel n some istancs before it reaces the guinal nodes. or examle, a paient ma present with an nlarged, painful inguina lymph ode causd by lymhatic spead of pathogeni organiss that ntered he body hrough a small scatch on the undeurface f the big toe.

Supericial Facia of te Thigh Th membranous laye of the superfiial fasia of the anerior abominal all exteds int the thih and i attache to the deep facia (fascia lata about a fingerbradth below the nguinal igament (Figs. 10- and 1021). he impotance of this fat in conection wth extraasation of urine after a rupture of the uethra is fully decribed i Capter 4. The fatty ayer of he supericial fscia n the aterior adominal all exteds into the thigh and ntinues own over the lowe limb without inerruptio (ig. 10-).

Deep Fascia of the Thigh Fascia Lata)

1065

snell The eep fasca encloss the thgh like tro leg (Fig. 10-22 and at ts upper end is ttached to the plvis an the inginal ligment. On its lteral asect, it is thickned to orm the ilotibial tract (Fgs. 10and 10-22), which is ttached bove to he iliac ubercle ad below o the lteral cndyle of he tibi. The ilotibial ract receives the insertion f the tnsor fasiae lata and the greter par of the luteus mximus muscle (see Figurs 10-5 and 10-6). In th gluteal region, the deep fscia fors sheath, which enclose the tenso fascia latae ad the gluteus maimus musles. The sahenous oening is a gap in the deep fasia in the front f the thgh just elow the inguinal ligamet. It trnsmits te great aphenous vein, soe small branche of the emoral artery, ad lymph vessels Fig. 1-3). The saphnous opning is ituated about 1. in. (4 cm) belo and latral to te pubic tubercle The falciorm margn is he lowe lateral border f the opning, wich lies anterior to the moral vsels (Fig 10-3). The brder of the pening ten curvs upward and medally, an then terally behind he femorl vessel, to be ttached o the pctineal line of he superior ramus of the pubis. The saphenous oening is filled ith looe conneive tisue called the cririform fscia.

Facial Copartment of the Thigh Three fascia septa pss from he inner aspect f the dp fascial sheat of the high to he linea aspera f the fur (Fig. 0-22). By this means, te thigh s divide into thee comprtments, each hving musles, neves, and arterie. The compartmens are anerior, edial, ad posteior in psition

Content of the Anterior Fascial Compartmnt of th Thigh   

Muscle: Satorius, iliacus, psoas, ectineu, and qudriceps femoris Blod supply Femoral artey Nerve supply: Femora nerve

Musles of he Anterior Fascial Compatment of the Thih The mscles are seen in Fgures 1-6, 10-23, an 1-24 ad are decribed i able 10-. Note th followig:

Action o Quadriceps Femoris Muscle (Quadiceps Mchanism) The uadrices femori muscle, consistng of the rectus femoris the vasus interedius, te vastu laterals, and P.574

P575

th vastus edialis, is insered into he patela and, va the liamentum atellae, is attaced to th tibial uberosit (Fig. 10-5). Tgether tey provde a powrful extnsor of he knee oint. Soe of te tendinous 1066

snell fibers of the vstus laralis ad vastus medialis form bads, or retiacula that jon the sule of the knee t ad strenthen it. The lowet muscle fibers f the vstus medalis are almost orizontal and prevent the patella from being pulle lateraly durin contration of the quadiceps mscle. The tone of the quariceps mscle greatly strngthens he knee t.

igure 10-21 ight femral sheah and its contents.

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Fgure 10-2 Trasverse ction troug the midle of te right high as seen fro above.

The ectus femoris mucle also flexes he hip jint.

Femoal Trianle Te femora triangle is a tiangular depresse area ituated n the uper part of the edial aspect of he thig just beow the nguinal igament (ig. 10-). Its boundares are a follow:   

Supeiorly: The iguinal lgament aterally: The sartoriu muscle dially: The aductor lngus musle

Its floor is gutter shape and fored from lateral o medial by the iiopsoas, the pectneus, an the addctor lonus. Its roo is frmed by he skin and fascie of the thigh. The femoral triangle contains the terinal par of the femoral nerve an its braches, th femoral sheath, the femoal artery and its branhes, the femoral ein and its tribtaries, nd the dep inginal lymph nodes

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Adducor (Subsrtorial) Canal The dductor canal is an interuscular cleft siuated on the medial aspet of the middle ird of e thigh beneath he sartrius muscle (Figs. 0-6 ad 0-22) It comences abve at th apex o the femral triagle and ends belo at the opening n the aductor magus. In cross secion it i trianglar, havng an anteromedial wall, a posteror wall, and a lateral all.   

The ateromedal wall is fored by the sartorus muscl and fasia. The posteior wall is fomed by te adductr longus and magus. The laterl wall is forme by the vastus mdialis.

Te adductr canal ontains he termial part of the femoral artery, th femoral vein, te deep lmph vessls, the aphenou nerve, the nere to the vastu mediali, and te terminal part o the oburator nrve. P576

1069

snell

Figur 10-23 Dissecton of th femoral triangle in the left lowe limb

.577

1070

snell

igure 1-24 Rlationship betwen the oburator nrve and the adductor uscles i the right lowe limb.

P578

1071

snell

able 10-2 Musles of te Anteror Fascil Compartment of the Thigh

Musle

Origi

Nere Nerve Spply Rootsa Acion

nsertio

Sartrius

Anterio superio iliac sine

Uper medal surfae of shat of tiia

Femral nerv

L2 3

Flxes, abcts, latrally roates thih at hip t; fexes and medially otates lg at knee t

Iliacs

Iliac fossa f hip boe

Wth psoas into leser trochnter of emur

Femoral nerve

L2,

Flexs thigh n trunk; if thigh is fixed it flexes the truk on the thigh as in sittig up fro lying dwn

Psos

Trasverse pocesses, bodies, ad intervrtebral iscs of the 12th toracic ad five lmbar

With iliacus nto lessr trochater of fmur

Lumba plexus

L, 2,

Flexes thigh on runk; if thigh is fixed, i flexes he trunk on thigh as in

1072

snell

sitting up from lying down

verebrae

ectineus

Supeor ramus of pubis

Upper end of linea asera of saft of fmur

Femorl nerve

L, 3

Flexes ad adduct thigh a hip joit

Quadiceps feoris

Rectus emoris

Straiht head: anterior inferior iliac spine Refleted head ilium aove acetabulum

Quariceps tendon in patella then vi ligamenum patelae into tubercle of tibia

Femral nerve

L2, 3,

Exension o leg at nee ; flexes thigh at hip

Vasts laterais

Uppr end an shaft o femur

Quadiceps tedon into atella, hen via igamentu patella into tubrcle of ibia

Femoral erve

L2, 3, 4

Extensin of leg at knee oint

Vasus mediais

Upper end and shaft of femur

Quaiceps tendon into patell, then va ligametum patellae int

Fmoral nrve

2, 3, 4

Extension of lg at kne t; tabilizs patell

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snell

tubercl of tibi

Vstus inermedius

a

nterior nd lateral surface of shaft of femu

Quariceps tndo into paella, thn via ligamentum ptellae ito tuberle of tiia

Femora nerve

L2, 3,

Extensio of leg at knee jint; artcularis enus retrcts synoial membane

The predominnt nerve root suply is inicated by boldface type.

linical otes Quadrices Femori as a Kne t tabilize he quadrceps femris is a most important eensor muscle for the knee t. Its tone reatly trengthes the jont; theefore, ths muscle mass mus be careully examned when disease f the kee is suspcted. Boh thighs should b examine, and th size, onsisteny, and strength of the quadiceps mucles shold be tsted. Reuction i size cased by mscle atrphy can tested y measuing the ircumfernce of each thigh a fixed distance above th superir border of the ptella. he vast mediali muscle extends farther distally than the vstus latralis. Rmember tat the vstus medalis is he first part of he quadrceps musle to atophy in kee t disease nd the ast to rcover.

Ruture of he Rectu Femoris The rectus fmoris mucle can upture i sudden iolent xtension movement of the kee t. The mucle belly retracts proximaly, leavng a gap that may be palpable on th anterior surface of the thigh. In complete rupture of the mule, surgcal repar is inicated.

Rupture of the Liamentum atellae Ths can ocur when suden flexng force is applid to th knee jont when he quadrceps femris musce is actvely cotracting P.579

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snell

Fgure 10-5 Th quadris femors mechansm. The ateral ad upward pull of the poweful rects femori and the vastus lteralis uscles o the patlla is unteracted by the lowest orizonta muscular fibers of the vtus medialis and the larg lateral condyle f the femur, whic projects forward.

Femoal Sheat The emoral seath (Figs. 10-3, 106, 10-21, and 10-2) is a downward protrusin into te thigh f the facial envlope linng the abdominal wlls (see pae 177 Its anterior wall is coninuous aove with the fasca transvrsalis, nd its posterior all with the fasca iliaca The sheth surronds the femoral

1075

snell essels ad lymphaics for bout 1 i. (2.5 c) below he ingunal ligament. The feoral artry, as it enter the thgh beneah the inguinal ligament, occupies th lateral cmpartmen of th sheath. The femoral vein, s it leaes the tigh, lie on its edial sie and is separate from it by a fibous septm and ocupies th itermediae compartent. he lymph vessels, as they eave the thigh, ae separaed from the vein a fibros septum and occuy the mot edial copartment (Fig. 10-21). Te femoral anal is the smll media compartent for he lymph vessels Fi. 10-21). It is about 0. in. (1. cm) lon, and it upper oening is called te emoral rng. Te emoral sptum, which is a condenation of extrapertoneal tssue, clses the ing. The femoral canal coains faty connecive tisse, all te efferet lymph vessels rom the ep inguinal lymph nodes, ad one of the deep inguina lymph des. T femora sheath s adheren to the alls of he blood vessels and infeorly blends with the tunica adventiia of thse vessls. The art of te femora sheath hat forms the medilly locaed femoal canal is not aherent t the wals of the small lyph vessels; it i this si that forms a potentially weak area in the adomen. A protruson of peitoneum ould be orced don the feoral canl, pushng the fmoral setum befoe it. Suh a condiion is kown as a foral henia an is descibed belw. The femoral ing (Fig. 10-21) has the ollowing important relation: anterirly, the inguinal ligamen; posterorly, th superio ramus o the pubs; medialy, the lacunar ligament; and laterlly, the femoral ein. Te lower nd of th canal i normall closed y the aherence of its medal wall o the tuica advetitia of the femoal vein It lies close to the saphenous opeing in t deep fascia of the thigh (Fig. 10-3). P.580

Clinical Notes Feoral Sheth and Fmoral Hernia The herial sac escends hrough te femora canal wthin the femoral heath. The femoal sheat is a proongatio downward into the thigh of the fascial lining of th abdomen. It surrnds the femoral essels ad lymphaic vessels for abot 1 in. 2.5 cm) elow the inguina ligamen (see Fig. 0-21). The femora artery, as it nters th thigh below th inguina ligamet, occupies the ateral cmpartmet of the sheath. The femora vein which les on its medial side an is separated frm it by a fibrous septum occupie the intermediat compartent. The lmphatics, whic are seprated frm the vein by a ibrous eptum, ocupy th most meial compartment. he femoral canal the cmpartmen for th lymphatc vessel, occupis the meial part of the heath. I is abou 0.5 in (1.3 cm long, ad its uper openig is reerred to as the emoral rng. The femoral septum, which is a conensation of extraeritoneal tissue, plugs th opening of the fmoral rig.

1076

snell A femora hernia is mor commo in wome than i men (posibly because of their wier pelvs and fmoral caal). The hernial ac es down te femora canal, ushing he femoal septu before t. On esaping through the lower ed of the femoral canal, i expands to form a swelling in th upper prt of the thigh deep to he deep ascia (se age 184). With further expansion, the herial sac ay turn pward to cross th anterir surfae of the inguinal ligament. The neck of the c always lies below and latral to te pubic ubercle (see pag 185) This srves to istinguih it fro an ingunal herna, which lies abve and edial to the pubi tuberce. The nck of th sac is arrow an lies a the femral ring. The rig is reated anterioly to th inguial ligamnt, postriorly to the petineal ligament nd the superior ramus of the pubi, medialy to th sharp ree edge of the lacunar ligament and latrally t the femral vein Because of these anatomc structres, the neck of the sac s unabl to expad. Once n abdoinal viscus has assed though the neck int the body of the sac, it may be dificult o push i up and return i to the abdominl cavit (irreduible henia). Furtherore, aftr the patient srains o coughs, a piece f bowel may be frced thrugh the neck, ad its blod vessels may be comprssed by he femoal rig, serously imairing its blood supply (strangulatd hernia. A femoral hernia i a dangerous conition and should always e treate surgiclly. Wen consdering te diffeential dagnosis of a femral hernia, it s imporant to cnsider iseases that may involve ther aatomic sructures close to the inginal ligament. Fr example: 









Inuinal caal: he sweling of n inguinal herni lies abve the edial en of the inguina ligament. Shoul the herial sac emerge through th superfcial inginal ring to stat its decent ino the srotum, te swellng will ie above and medal to the pubic tubercle. The sac f a femra hernia ies belo and latral to the pubic tubercl. Supericial inuinal lmph node: Usually, moe than oe lymph ode is elarged. n patiens with iflammatin of the nodes (lympadenitis, caefully eamine th entire area of the body tht drains its lymph into ese node. A smal, unnotied skin brasion ay be fond. Neve forget he mucou membrane of the ower hal of the nal cana—it ma have a undiscovered carcinoma. Geat saphnous vei: A calized dilatation of the terminal part of the great aphenous vein, a sahenous vrix, can caus confusin, especally becuse a henia and varix icrease n size when the ptient is asked to cough. (levated ntra-abdminal pessure dives the blood donward.) he presece of varicose veins elsewhere in the leg should hel in the diagnosis. Poas sheah: Tberculou infecton of a umbar vetebra can result i the exravasation of pus down th psoas sath into the thig. The prsence o a swellng above and belo the inginal ligment, toether wih clinial signs and sympoms refeed to the vertebral column should make the diagnosi obvious emoral atery: An expasile sweling lyig along he cours of the emoral atery that flucuates in time wit the pulse rate shuld make the diagosis of anerysm of he femorl artery certai.

Blood Supply of he Anteror Fascial Compartment of the Thigh Femora Artery

1077

snell The feoral artry enter the thih from bhind the inguinal ligament as a cotinuatio of the xternal liac artry (Figs. 1-6, 10-23, and 10-6). Hre, it les midwa between the anteior supeior ilia spine ad the smphysis ubis. Th femoral artery i the mai arterial supply the lower limb. It desceds almos verticaly towar the addctor tubrcle of the femur and ends at the pening in the addutor magns muscl by entering the popliteal space as the poplteal artry (Fig. 1024).

Relatios  

 

Antriorly: In the upper prt of it course, it is surficial and is covered by skin and fascia. n the loer part f its cose, it psses behnd the artorius uscle (Fig 10-6. Posterorly: The artery lies n the psas, whic separats it fro the hip t, te pectinus, and he adductor longus (Fig. 10-6). The emoral vin interenes beteen the rtery an the addctor lonus. edially: It is related o the feoral vein in the upper part of its urse (Figs 10-6 nd 10-23). Laterall: The emoral nrve and ts brances (Fig. 106)

Branche     

Te uperficil circumlex ilia artery is a sall branh that rns up to the region of the anterior superior iliac spine (Fig. 10-3). The supeficial epigastric rtery is a smal branch that croes the inguinal ligament and runs to the regon of th umbilics (Fig. 10-). The supericial exernal puendal arery (Fig 10-3) is a smal branch that run mediall to suppy the skn of the scrotum or labiu majus). The eep external pudedal artey (Fig. 10-6) rns medialy and spplies th skin of the scrotum (or lbium majs). The profund femoris artery is a large and portant ranch tht arises from the lateral ide of he femora artery bout 1.5 in. (4 c) below he inguinl ligamet P.581

P.582

(Fgs. 10-6, 10-23 and 10-2). It es mdially bhind the femoral essels ad enters the medil fascia compartent of te thigh Fis. 10-3, 10-24, and 10-2). It ends by becoming the fourth prforatin artery. At its origin, t gives ff the medl and laeral femral circflex artries, and durig its corse it gves off thre perforting arteies (Fig 10-27).

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Figur 10-26 Major arteries of the lowe limb.



The descending geniular artry is a small branch tha arises from th feoral arery near its termnation (Fi. 10-24). It asists in upplying the knee t.

Cinical Ntes Fmoral Atery Catterization long, fne catheer can be inserte into th femoral artery s it desends through the emoral tiangle. e catheter is guded unde fluorosopic vie along the externa and comon iliac arterie into th aorta. he catheer can ten be paed into the infeior meseteric, sperior msenteric, celiac, or rena arterie. Contrast medium can then be injeced into the arter under eamination and a prmanent ecord obained by taking a radiograh. Pressre recods can aso be obained by guiding he catheer throuh the aotic valve into the left ventricle.

Femral Vein The fmoral ven enters the thig by ng throuh the oening in the addutor magns as a cntinuatin of the popliteal vein (Figs 10-23 and 10-24). It scends through te thigh, lying at first o the lateral sid of the artery, then poserior t it, and finally on its mdial sid (Fig. 10-). I leaves the thig in the ntermedite compartment o the femral shth and asses behind the inguina ligamen to becoe the eternal iliac ven.

Tribtaries The tbutarie of the emoral vin are he great sphenous ein ad veins that corespond t the braches of he femorl artery (ig. 10-3). Th superfiial circmflex ilac vein, the supeficial eigastric vein, ad the exernal puendal vins drai into th great sphenous ein.

Cinical Ntes emoral ein Cathterizaton emoral in cathterizatin is usd when rpid acces to a large vei is need. The femoral ein has constat relatinship t the medal side f the feoral arery just below th inguina ligamnt and i easily annulate. Howevr, because of the high incidence f thromsis wit the possibility f fatal ulmonary embolis, the caheter shuld be removed one the patient is tabilize.

Anatom of the rocedure 

The skin of the tigh belw the inuinal igament s supplid by the genitofeoral nerve; this nerve is blocked with a local anesthetic.

1080

snell  

Te femoral pulse is palpated midway between the anteior supeior ilia spine ad the smphysis ubis, and the fmoral ven lies imediatel medial o it. A a site bout two fingerbradths blow the nguinal igament, the neede is inerted into the fmoral ven.

Lymph Nodes of the Antrior Fasial Comartment f the Tigh Th eep inguinal lymph nodes are variable number, but there are comonly three. Thy lie along the medial ide of he termial part f the fmoral vein, and he most superio is usualy located in te femora canal Fg. 10-21). They receie all th lymph fom the uperficil inguinl nodes ia lymp vessels that through he cribrform fasia of th sapheno openig. They lso receie lymph rom the eep strutures o the lower limb tat have scended n lymph vessels alongside te arteris, some having pssed thrugh the popliteal odes. Th efferen lymph vssels fom the dep inguial nodes scend ino the abominal cvity thrugh the femoral anal and drain ino the external iliac nodes.

Nerve Spply of he Anteror Fascal Comprtment o the Thih Femral Nerv The femoral erve is he largest branc of the umbar pexus (L2, 3, and 4). It eerges frm the lteral rder of the psoas muscl within he abdomn (see pag 278) and es downard in he interval beteen the soas and iliacus It lies behind the fasca iliaca and eners the thigh laeral to the femoal artey and te femora sheath, behind te inguinl ligamet (Figs. 1-6, 10-1, ad 10-23) About .5 in. ( cm) belw the inuinal liament, i terminates by diiding ino anterir and poterior dvisions. he femorl nerve supplies all the uscles o the anterior comprtment o the thih (Fig. 10-). Note that the fmoral neve does ot enter the thig within he femora sheath.

Banches Anterir Divisin Th anterio divisio (ig. 10-2) givs off tw cutaneous and two muscular branches The cutneous brnches ar the medial cutaneou nerve o the thigh and he intermedate cutaeous neres tha supply the skin f the meial and nterior surfaces of the thih, respetively (Fig. 10-2 and 10-6). The musular braches suply the srtorius nd the pectineus.

Poterior Dvision The poterior dvision (Fig 10-28 gives of one cuaneous branch, he sapheous nerv, and mucular brnches to the quadceps muscle. The saphenous nerve rns downwrd and mdially ad crosse the femral artey from is latera to its edial si (Fig. 10-). It merges o the medial side of the kn between the tendns of satorius ad gracils (Fig. 10-). It then runs down te medial side of he leg i company with the great sphenous ein. It es in ront of he media malleols and alng the edial border of th foot, were it trminates in the rion of te ball f the bi toe. The musclar branh of the rectus femoris lso suppies the ip t the braches to he three vasti muscles also supply te knee jint.

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snell P.583

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Fire 10-2 Obturtor extenus musce (A) and vertica section of the mdial comartment f the thgh (B). ote the ourses tken by te obturaor nerve and its ivisions and the profunda femoris arery and its branches. Not also th anastomsis beteen the erforatig arteris and the medial femoral cicumflex artery.

Contets of th Medial ascial ompartmnt of th Thigh   

Muscles: Gracils, adducor longu, adductr brevis adducto magnus, and obturtor extrnus Bloo supply: Profuda femors artery and obtuator artry Nere supply Obturtor nerv

Muscles of te Medial Fascial Cmpartme of the high The uscles o the medal fascil comparment are seen in Figres 10-2, 10-23, 0-24, and 10-27 and are escribed in Table 10-3. Note th following: 

The adductor magnus (Figs. 1-24, 10-7, an 1-29) i a large trianguar muscl consistng of aductor an hamstrig P.584

portios. The addutor hiats is gap in he attacment of his musce to the femur, wich permts the emoral vssels to fro the addctor canl downwad into te poplieal spac.

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Figure 10-28 Summary f the man branchs of the femoral erve. Table 103 Muses of the Medial Fascial Cmpartmen of the high

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Musce

Origin

Insrtion

Nere Supply

Nere Rootsa Ation

Gracils

Iferior rmus of pis, ramu of ischum

Upper art of haft of ibia on edial suface

Obtuator nere

L2,

Adduts thigh at hip jint; flexes leg a knee jont

Aductor logus

ody of pbis, medal to puic tuberle

Posteror surfa of shaf of femu (linea spera)

Oturator erve

L2, 3, 4

Adducts thigh at hip and asssts in lteral roation

Adducto brevis

Inferor ramus of pubis

Poterior srface of shaft of femur (linea aspea)

Obtuator nerv

L2 3,

Aducts thgh at hi t and assist in lateral rotatin

Aductor mgnus

Inferior ramus of pubis, rus of ischium, ishial tubrosity

Posterio surface of shaft of femur adducto tubercle of femur

Adductr portio: obturator nerve Hastring portion: iatic neve

L2, 3, 4

Adducts thigh hip t and assists in ateral rtation; amstring portion xtends tigh at hp t

Obturtor extenus

Outer urface o obturatr membrae and puic and ichial

Meial surfce of grter trochanter

Oturator erve

L3, 4

Laterally rotates thigh at hip jint

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snell

rai

a

The predominant nerve root supply i indicatd by bolface type.

P.585

1086

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1087

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Fiure 10-2 Deep structues in te posteror aspect of the right thigh.

Blood upply of the Medil Fascil Comparment of the Thig Profnda Femois Artey Te profuna femoris is a large artey that rises from the ateral sde of te femoral artery in the fmoral tiangle, bout 15 in. (4 cm) belo the inginal liament (Fis. 10-6, 10-24, and 10-26). It descends in the iterval btween th adducto longus nd adducor brevs and thn lies o the addctor magus, wher it ends as the ourth peforatin artery Fi. 10-27).

Brances 



Mdial feoral cirumflex atery: This sses bakward beween the muscles hat form the flor of th femoral triange and gies off muscular ranches n the meial fascal comartment f the tigh (Fig. 1-27). It takes part in the formtion of he crucite anastmosis. Lateral femoal circuflex artry: Tis e lateraly betwee the terinal braches of the femoal nerve (Fig. 10-6). P586

It breaks u into brnches tht supply the muscles of te region and taks part i the fomation o the criate anstomosis 

Fou perforting artries: Three f these rise as ranches f the prfunda feoris artry; the fourth prforatin artery s the teminal art of te profuna artery (ig. 10-2). Th perforaing artries run backward piercing the vaious musle lays as thy go. Thy supply the musces and erminate by anatomosing with on another and with the infrior gluteal artry and he circmflex feoral artries abve and te musclar branhes of te poplieal artey below

Profuda Femors Vein The rofunda emoris in receves triutaries that corespond to he brances of te arter. It drins into the femoral vein

Obtrator Atery The obtrator arery is a branc of the nternal liac artery (see page 328). It asses frward on the lateal wall f the pevis and accompanes the obturato nerve trough th obturar canal (i.e., he upper part of the obtrator foamen) (Fi. 10-27). On ntering he medial fascial compartent of te thigh, it dvides ino media and latral branhes, whih round th margin f the outer surface of he obtuator mebrane. I gives ff muscuar brances and n articuar branh to the hip t.

Obturtor Vein

1088

snell The obturator vein receives tributaries that corespond t the braches of he artery. It drans into he interal iliac vein.

Nerv Supply f the Meial Fascal Compatment of the Thih Obturator Nerve The oburator nrve ariss from te lumbar plexus (L2, 3, an 4) and merges o the medal border of the soas musle withi the abomen (se ge 278). It rus forwar on the ateral wll of th pelvis o reach he upper part of he obturtor foraen (see Fig 6-12) where it divides into antrior and posterio divisios (ig. 10-).

Banches 



The antrior divsion asses downward n front f the oburator eternus and the adctor brvis and bhind the pectineu and addctor lonus (Figs. 1-27 an 1-30). It gives muscular branches to the racilis, adductor brevis, ad adducor longu, and ocasionall to the ectineus It gives articular branchs to the hip and terinates a a small nerve tht supplis the fmoral arery. It ontributs a varible branch to the subsartrial pleus and spplies t skin on the medil side o the thgh. The pterior ivision pierce the oburator eternus ad es downwrd behin the aductor brvis and in front of the ductor agnus (Fig. 10-27). It terminats by desending hrough he openig in the adductor magnus to suppl the kne t. It ives musular brnches to the obtuator externus, o the auctor part of te addutor mgnus, an occasinally t the aductor brvis.

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Figue 10-30 Summary of th main brances of the obtrator nrve.

P.587

Cliical Nots Aductor Mucles and Cerebral Palsy In ptients wth cerebal palsy who have marked spasticity of the aductor goup of mscles, t is comon practce to perform a tnotomy o the addctor lonus tendo and to ivide th anterio division o the obturator nerve. In addition, in some sere cass the poterior dvision o the obtrator neve is crshed. Ths operaion overomes the spasm of the adducor group of muscls and prmits slw recovey of the muscles upplied y the poterior dvision f the oburator nrve.

The Back of the Thigh 1090

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Skin Cutanous Nervs The psterior utaneous nerve of the thig, a ranch of the sacral plexus leaves he glutel region by emergng from beneath he lower border o the glueus maxius muscl (ig. 10-1). It descends on the bck of th thigh, nd in th poplitel fossa t pierces the de fascia and supplies the sin. It gves off umerous branches to the sin on th back of the thig and the upper pat of the leg (Fig. 10-1)

Superfcial Veis May smal veins crve arond the media and latral aspets of th thigh ad ultimaely drai into th great sphenous ein (Fig. 10-1). Suerficial veins frm the lower part of the bac of the thigh jon the smll sapheous vein in the politeal fssa.

Lymph Vessels Lymph rom the kin and uperfical fasci on the ack of he thigh drains uward and forward nto the ertical group of superficl inguinl lymph odes (Fig. 10-4).

Cntents o the Poserior Facial Comartment f the Thgh   

Musces: Bceps femris, semtendinoss, semimembranosus, and a small par of the dductor agnus (hmstring uscles) Blood spply: ranches of the pofunda fmoris artery Nere supply Sciatic nerve

The mscles of the postrior fasial comprtment ae seen i Fgure 10-1 and re descrbed in Tabl 10-4 Nte the fllowing:   

T biceps femoris uscle reeives it nerve upply from the scatic ner, the log head fom the tbial potion and the shor head frm the comon peroeal portion. The amstring part of he adducor magnu muscle receives its nerv supply rom the ibial potion of he sciatic nerve nd the aductor prt from he obturtor nerv. The seimembransus insetion sens a fibous expasion upwrd and lerally, which reinforces the capsu on the back of he knee oint; th expansin is caled the obliue poplieal ligaent.

Blod Suppl of the osterior Compartmnt of th Thigh Th four peforating branches of the pofunda fmoris arery provde a ric blood suply to his compartment (Fig. 10-27. The prfunda feoris vei drains he greatr part o the blood from te comparment.

Nere Supply of the Psterior ompartmet of the Thigh Satic Neve 1091

snell The sciatic nerve, a branch of the sacal plexu (L4 and 5; S1, and 3), leaves te glutea region s it desends in he midlne of th thigh (Fig 10-31). It is overlaped posteiorly by the adjaent margns of th biceps emoris nd semimmbranosus muscles. It lies n the poterior apect of he addutor magns muscle In the ower third of th thigh i ends by dividig into te tibial and comon peronal nervs (Figs. 0-29 nd 10-31. Occasionally, the sciatic nerv divides into it two terinal pats at a higher evel—i the uppr part f the thgh, the luteal egion, o even iside the pelvis.

Branhes  



The tibil nerve, a teminal brnch of e sciat nerve Fis. 10-17, 10-29 and 10-31), enters the popliteal fossa. Its further course s descried on pae 604. The common peroneal nerve, a termnal branh of the sciatic erve (Figs. 10-29 and 1031), enter the popiteal fosa on t latera side of the tibal nerve Its futher couse is decribed o page 604. uscular ranches to te long had of th biceps emoris, the semiendinosu, the smimembrnosus, ad the hastring prt of th adducto magnus. These banches rise fro the tibal compoent of he sciatc nerve nd run edially o supply the muscles (Figs. 10-29 and 10-31.

Hip oint rticulaion Te hip jint is te articuation btween th hemisphrical hed of th femur ad the cu-shaped cetabulm of the hip bone (ig. 10-8). Te articuar surfae of the acetabulum is hoseshoe saped and is defiient infriorly a the acetaular noth. Th cavity f the actabulum s deepend by the presence of a fiocartilginous rm called the acetabuar labru. The labrum bidges acoss the acetabuar notch and is ere called the trnsverse cetabula ligamen (Fig. 1-18). Th articulr surfacs are cvered wih hyalie cartilge.

Typ The hip t s a synoial balland-sockt t

apsule The capule enclses the oint an is atached o the actabular abrum meially (Fi. 10-18). Laterally it is atached P.588

to he intetrochantric line of the femur in ront and halfway long te posteror aspec of the neck of he bone ehind. A its attchment o the itertrochanteric ine in front, soe of it fibers, accompaned by bood vesels, are refleced upwar along he neck as bands called retinaula. hese blod vessel supply he head nd neck f the feur.

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Fgure 10-1 Stuctures n the poterior apect of he right thigh.

Lgaments 1093

snell The iliofmoral liament is a stng, inverted Y-shaped ligaent (Fig. 10-32). Its bas is attached to the anterir inferir ilia spine above; bew, the wo limb of the Y are attached to te upper nd lower parts of the intertrochanteric line of the emur. Ths strong ligament prevents overextension duing staning. The pubofmoral liament is trianular (Fig. 0-32) The base of the ligament is attached to th superio ramus o the pubis, and te apex i attache below t the lowr part o the inertrochateric lie. This igament limits exension a abduction. The ischofemoral ligament is spral shaped and is ttached o the boy of the ischium ear the cetabula margin Fi. 10-32). The ibers pas upward and laterlly and re attaced to th greater trochantr. This igament imits exension. The trnsverse cetabula ligamen is fmed by the acetablar labrm as it ridges te acetablar notc (ig. 10-1). P.89

The ligament converts the notch into a tunnel though whh the blod vessels and neves ente the jont. Table 10-4 Muscles f the Posterior ascial Compartment of the Thigh

Musle Bceps femris

Origin ong hea ischia tuberosiy

Isertion Head of ibula

Shot head: inea aspera, laterl

Nerve Nrve Suppy Rots Actio Long hed: tibia portion of sciatc nerve

hort hea: commo

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L; S, 2

Flxes and aterally rotates eg at kne t; long hea also exends thih at hip oint

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supracndyla r rdge of saft of fmur

n peronea l portion of sciatic nerve

Semitendinosus

Ishial tubrosity

Upper part of edial suface of haft of ibia

Tibil portio of sciaic nerve

L5; S1 2

Flexes nd medialy rotats leg at knee joit; extens thigh t hip jont

Semimemranosu s

Ischil tuberoity

Medial cndyle of tibia

Tibial portion of sciati nerve

L5; S1 ,2

Fexes and mediall y rotates g at kne t; extends thigh at hp t

dductor agnus (hmstring ortion)

Ischial uberosit

dducto r ubercle f femur

Tbial porion of siatic neve

L2, 3, 4

Etends thgh at hip t

a

The redominat nerve oot suppy is indcated by boldface type.

1095

snell he ligament of the had of th femur is flat and triagular (Fig. 10-18). It is ttached by its ax to th pit on the head of the femr (fovea capitis and by ts base o the trnsverse igament nd the mrgins of the aceabular ntch. It ies withn the jont and is ensheathd by syovial mebrane (Fig. 10-18).

Synovil Membrae The synovial membrane lines th capsule and is atached t the marins of te articuar surfaces (Fig. 10-18). t covers the porton of th neck of the femu that lis within the joit capsul. It enseathes te ligamet of the head of te femur nd coves the pa of fat ontained in the aetabular fossa. A pouch of synovial membrane frequenty protrues throuh a gap n the anterior wal of the capsule, between he pubofmoral ad iliofeoral ligments, an forms te soas bura benath the soas tendn (Figs. 1032 an 1-33).

Nerve upply Femoral, obturator and scitic nervs and th nerve t the quaratus feoris suply the aea.

Movments he hip jint has wide rage of moement. The strength of th t dends largely on the shae of the bones takig part i the articulatin and on the strng ligamnts. Whn the kne is flxed, flxion is limited y the anterior srface of the thig coming into cotact wit the antrior abominal wll. When the knee is exteded, flxion is imited y the tesion of the hamsring grup of mucles. Extension which is the mvement o the fleed thih backwad to the anatomi positio, is limted by e tensin of the iliofemoal, puofemoral and ishiofemorl ligamets. Abdution is imited b the tesion of he pubofmoral lgament, nd adduction is limited by with the opposite limb an by the ension in the ligament of the head of the fmur. Latral rottion is imited b the tenion in the iliofemoral and pubofemal ligaents, an medial otation s limited by te ischioemoral lgament. The follwing movments tae place     

Fleion is performd by th iliopsos, rectu femoris and sartorius ad also by te adducor muscls. xtension (a bakward moement of the fled thigh) is perfrmed by he glutes maximu and the hamstrin muscles Abducton is performe by the luteus mdius and minimus, assisted by the sartorius tensor asciae atae, an piriforis. Aduction is prformed by the aductor logus and revis an the aductor fiers of he adducor magnus. These muscles re assiste by the ectineus and the gracilis Latera rotatio is erformed by the iriformi, obturaor interus and eternus, superior and inerior geelli, an quadrats femori, assistd by the gluteu maximus P.90

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Figure 0-32 Anterio aspect A) and osterior aspect B) of th right hip t



Media rotatin is perfrmed by the anterior fibrs of th gluteus medius ad gluteu minimus and th tensor fasciae atae.

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Circumduction is a combination of the pvious moements.

The etensor goup of mscles is more powrful tha the flxor group, and the lateral rotators are more powerful than the medial otators.

Imporant Relaions    

Anterioly: Iiopsoas, pectineu, and retus femois muscls. The iiopsoas ad pectieus sepaate th femoral vessels and nerv from th t (Fig. 10-33. osteriory: Th obturatr interns, the gmelli, a the quadratus feoris musles sepaate the oint from the sciic nerve (Fg. 10-32). Superiory: Pirformis ad gluteu minimus (Fg. 10-33) Ineriorly: Obturaor exterus tendo (ig. 10-3) P.591

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Figue 10-33 Structues surronding th right hi t.

Clinial Notes Refered Pain From the Hip t The femoral nerve not only suplies th hip joit but, ia the itermedia and medal cutanous nervs of the thigh, aso suppies the sin of th front ad medial side of e thigh. It is no surprising, therefore, or pain oiginatin in the ip t to be rferred to the fron and medal side f the thh. The posterior division of the obturator erve suplies bot the hip and knee ts. This woud explai why hip t dsease soetimes gves rise to pain in the kee t

Cngenital Dislocaton of th Hip

1099

snell The stability o the hip t depends o the bal-and-socket arragement o the artcular sufaces an the strng ligaments. In ongenita dislocaion of te hip (se page 643), th upper lp of the acetabulm fails o develo adequately, and te head f the feur, havig no stble platorm unde which it can lodge, rides up out the aceabulum oto the guteal suface of he ilium.

Tramatic Dilocation of the Hp Taumatic islocatin of the hip is rre becaue of its strengt; it is sually cased by otor vehcle accients. However, shuld it ocur, it sually des so whe the joit is fleed and dducted. The head of the fmur is dsplaced psteriorl out of he acetbulum, an it come to rest on the guteal suface of he ilium (posterir disloation). Te close elation f the scatic nere to the posterio surface of the jint mak it prone to injuy in poserior dslocatios.

Hip Joit Stabilty and Trendelenbrg's Sign he stabiity of te hip joit when a person sands on one leg ith the oot of te opposie leg rased abov the ground depens on thre factor:   

he glutes medius and minius must e functining normally. The hed of the femur must be located normlly withn the actabulum. Th neck of the femu must be intact ad must he a noral angle with the haft of he femur

If any one of these fators is efective then th pelvis will sik downward on the opposite uned side. The patent is ten said o exhibi a positve Trendeleburg's sgn (Fig. 10-34) Normally when waking, a erson alernately contracts the glueus medis and miimus, fist on on side an then on the othr. By ths means e or she is able o raise he pelvi first on one sid and the on the ther, alowing th leg to e flexed at the hi t nd moved forwardâ”that is the leg is raised clear of the groud befor it is tust forwrd in taing the orward sep. A paient wit a rightsided cgenital dislocaton of th hip, when asked o stand o the riht leg ad raise he opposte leg cear off te ground will ehibit a ositive rendelenurg's sin, and the uned side of the elvis wil sink blow the orizonta. If the patient is asked to walk, e or she will show the caracteristic “dipping― ait. In patients with bilteral cogenital islocatin of the hip, the gait is typicall “wadding― i nature.

Arthritis of te Hip Jot A patient with an iflamed hp t ill plac the feur in th position that givs minimu discomfrt—tha is, the positio in whic the joit cavity as the geatest acity t contain the increased amont of syovial flid secreted. The ip t is partally fleed, abduced, and xternall rotated Osteoathritis, the mst commn diseas of the ip t in the adlt, causs pain, tiffness and deormity. he pain ay be in the hip oint itself or reerred to the kne (the obtrator neve supples both oints). he stiffess is aused by the pain and reflx spasm of the surounding uscles. he defomity is lexion, adduction, and extenal rotaion and produced initialy by mucle spas and latr by muscle contrcture.

1100

snell P.592

Figure 10-34 rendelenurg's tet.

Bones of th Leg he leg i the par of the ower lim between the knee t an the anke t.

Patela The atella (Fig 10-35) is the largest sesamoid bone (i.., a bon that deelops within the endon of the qadriceps femoris uscle in front of the knee t). It is tringular, nd its aex lies nferiorl; the apx is conected to the tubrosity o the tiba by the ligamentm patellae. The posterior surface ticulates with the condyle of the emur. Th patella is situted in a exposed position in front of the kne t and can easily b palpate through the skin It is separated from the sin by a importat subcutneous bursa (Fig. 1036).

1101

snell Th upper, ateral, nd media margin give atachment o the diferent prts of the quadriceps feoris musle. It is preveted from being dsplaced aterally during te action P.593

o the qadricep muscle by the lwer horiontal fiers of he vastu mediais and b the lage size f the lateral codyle of the femu.

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1103

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Figure 0-35 Muscles and ligaents attached to the anterior surfaces of th right tibia d fibul. Attachments to the patella are also shown.

Tibia The tiba is the large weght-bearng media bone of the leg Figs. 10-3 and 10-37). t articuates wit the conyles of he femu and the head of he fibua above and with the talu and the distal nd of th fibula elow. I has an xpanded pper en, a smaler lower end, and a shaft. At the upper end are th lteral and medial condyles (someimes called lateal and mdial tibial plateas), whch articlate wit the latral and medial cndyles o the femr and th lteral and medial enisci interveing. Seprating te upper rticular surfaces of the ibial codyles ar aterior and posteior intecondylar areas; lying btween thse areas is the intrcondyla eminence (Fig. 1-35). The lteral cndyle posesses o its latral aspet a smal ircular rticular face for the head of the fibua. Te medial condyle as on is posteror aspec the insrtion of the semimembanosus uscle Fg. 10-3). The shaft f the tibia is trianglar in coss secton, presnting three bordrs and hree sufaces. Its anteior and medial brders, with the edial suface beween the, are sbcutaneos. The nterio border s promint and forms P.594

th shin. A the juntion of he anterior border wth the uper end of the tbia is the tuberoity, which receives he attachment of the ligaentum paellae. Te anterir border becomes rounded below, where it becomes connuous wih the mdial maleolus. Th lateral or intersseous brder givs attachent to te interoseous mebrane.

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Figure 10-6 A. he right knee joit as see from th lateral aspect. B The antrior aspect, with the t flexe. , D. he posteior aspet.

Th posterir surfac of the haft shos an oblque line, the soleal line (Fig 10-37), for te attachent of the soleus uscle. The lowr end of the tibi is sligly expanded and o its inerior asect show a saddl-shaped rticular surface or the alus. Th lower ed is prolonged doward medally to orm the medal mallelus. The laterl surfac of the edial maleolus aticulate with th talus. The lowe end of he tibia shows a ide, rouh depression on it latera surface for artiulation ith the ibula.

1105

snell The mportant muscles nd ligamnts attahed to te tibia re shown in Figures 0-35 ad 0-37. P.595

1106

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1107

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Fgure 10-7 Musles and igaments attached to the posterior srfaces o the rigt tibia nd the fbula.

Fibula The fibula i the sleder lateal bone f the le (igs. 10-5 and 1037). t takes o part i the artculation at the kee t but belo it fors the laeral maleolus of the ankl t. It takes n part in the trnsmissio of body weight, t it provides attachment fr muscle. The fbula has an expaned upper end, a saft, and a lower nd. Te pper end, or head, is sumounted y a styloi process. It posesses a aticular surface for ariculatio with th lateral condyle f the tiia. Te haft of he fibul is ong and lender. ypically, it has four borders and fr surfas. The medial or interosseous border gives ttachmen to the nterosseus membane. The lower end of te fibula forms the triagular laeral maleolus, wich is sbcutaneos. On th medial urface of the lateal mallelus is a triangulr rticular facet for artiulation ith the ateral apect of he talus. Below an behind the articlar face is a deression alled th mlleolar ossa. The important muscles ad ligamets attaced to th fibula re shown in Figures 0-35 and 10-37. P.596

Clinica Notes Patellr Disloctions The patlla is a sesamoid bone lyig within the quariceps tndon. The importane of the lower hizontal ibers of the vasus mediais and te large ize of th lateral condyle f the feur in preventin lateral displacement of th patella has been emphasizd. Congnital recrrent dilocation of the atella ae caused by underevelopmet of the lateral femoal condye. Traumtic dislcation of the patlla resuts from irect tauma to the quadrieps attahments f the paella (esecially he vastu medialis), with o without fractur of the atella.

atellar ractures A palla fracured as result f direct violence, as in an autombile accdent, is broken ito severl small agments. Because the bone lies witin the qadriceps femoris endon, lttle searation f the frgments tkes plac. The cloe relatinship of the patlla to te overlyng skin my result in the facture bing open. Fractur of the patella as a result of indirect violnce is cused by the suddn contration of he quadrceps snaping the patella across te front f the femral condles. The knee is n the seiflexed osition, and the racture ine is tansverse. Separation of the fragmens usuall occurs.

1108

snell

Factures f the Tiia and Fbula Fractres of the tibia ad fibul are comon. If oly one one is factured, the othe acts as a splint and dispacement s miniml. Fractures of the shaft o the tiba are ofen open ecause te entir length f the medial surfce is cored only by skin and superficial fscia. Frctures o the disal third of the saft of te tibia are pron to delaed union or nonunon. This can be bcause the nutrient artery is torn t the facture lne, with a conseqnt reduction in blood flw to the distal fragment; i is also possible that th splintlke actio of the ntact fiula prevents the proximal nd dista fragmens from cming int appositon. Fractues of th poximal ed of the tibia at the tibial cndyles (ibial plteau), ae common in the middle-aged and eldrly; the usually result frm direct violence to the lateral se of the knee joit, as whn a persn is hit by the bmper of n automile. The tibial cndyle ma show a split fracure or b broken up, or te fracture line ma beween bot condyles in the rgion of the intecondylar eminence. As a reult of forced abdution of he knee t, te medial ollatera ligamen can also be torn r rupturd. Fracturs of the dital end f the tiia are considerd with te ankle oint (se pge 637).

Intaosseous Infusion of the Tbia in the Ifant The echnique may be ued for te infusin of fluds and lood whe it has een found impossile to obain an intravenous line. Te procedre is eay and raid to perform, as ollows:   

With the distal lg adequaely supprted, th anterio subcutaeous surace of t tibia i palpate. The skin is nesthetized about 1 in. (2.5 cm) dtal to te tibial tuberosty, thus blocking the infapatella branc of the aphenous nerve. Th bone mrrow neele is drected a right angles trough te skin, uperfical fasci, deep fascia, ad tibia perioseum and he corte of the ibia. Oce the nedle ti reache the meulla and bone marow, the operato senses feeling of “give.― he posiion of te needle in the arrow ca be confrmed by aspiraton. The needle sould be irected lightly caudad t avoid njury to the epipyseal plte of th proximl end of the tibi. The tansfusio may thn commenc.

Bones of the Ft The bones of the fot are te tarsal ones, the metatasals, and the phaanges.

Trsal Bons The tarsal bnes are he calcneum, the talus, the navcular, he cuboi, and th three cneiform bones. Oly the tlus artculates ith the ibia and the fibua at the ankle jont.

Calcaneum The calcneum is he larget bone f the fot and foms the pominence of the hel (Figs. 1-38, 10-39, an 1-40). It articulates abve with he talus and in front with the cuboid. It has six surfaces.

1109

snell      

The antrior suace i small ad forms the artiular fact that aticulate with t cuboid bone. The posterior urface forms te promnence of the hee and givs attahment t the teno calcaeus (Achilles tedon). The suerior suface s dominaed by tw articulr facets for the talus, sparated y a rouhened groove, te sulcus alcanei. The inferor surfce has an anterio tuberce in he midlne and a large medil and a smallr ateral tubrcle at the juncion of he inferor and osterior surface The mdial surface ossesses a large, shelflie proces, terme the susteaculum ali, which asists in the suppor of the alus. The laeral surace is almost fat. On is anterir part i a small elevatio called he peroneal tubercle, whic separates the tendons of te perones longus and brevs muscle.

The imprtant mucles and ligament attache to the clcaneum re shown in Figures 10-39 and 1040

Taus The talus ariculates above at the ankl t wth the ibia and fibula, elow wit the calaneum, ad in frot with te naviclar bone. It posseses a hed, a nec, and a dy (Figs. 10-38 and 10-39. The head of th talus i directed distal and has an oval onvex aricular srface fo articuation wi the navcular boe. This rticular surface s continued on it inferio surface where i rests o the susentaculu tali beind and he calcaeonavicuar ligamnt in frnt. P597

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Figue 10-38 Calcanum, talu, navicuar, and uboid boes.

The nck of he talus lies poterior t the hea and is lightly arrowed. Its upper surface is rougened and gives atachment t ligamens, and is lower surface hows a dep groove the sulcu tali. The sulcs tali ad the sucus calcnei in te articulated foot form a tnnel, th snus tarsi, whih is ocied by te strng interossous taloalcaneal ligament

1111

snell The bdy of he talus is cubodal. Its superior surface rticulats with te distal end of te tibia it is cnvex fro before ackward and slighty concav from sie to sie. Its lteral suface preents a tiangular aricular fcet fr articuation wih the latral mallolus of he fibul. Its meial surfce has a small, cmma-shaped rticular facet or articlation wth the mdial maleolus of the tibi. The poterior srface is marked by two smal ubercles, separted by a groove fr the fleor halluis longu tendon. Numrous imprtant liaments ae attachd to the talus, bt no muscles are atached t this boe. Te remaining tarsa bones sould be dentified and the ollowing importan feature noted. .598

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igure 1039 Musle attacments on the dorsl aspect of the boes of th right fot.

P.599

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Fgure 100 Musle attacments on the plantar aspect of the bnes of te right oot.

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Naicular Bne The tuberosity of the naviular bone (igs. 10-8, 10-39, and 10-4) ca be see and fel on the edial border of the foot 1 n. (2.5 m) in font of ad below the medial malleolu; it givs attachent to te main art of th tibiali posterir tendon

Cubod Bone A deep grove on the inferor aspec of the uboid bon (igs. 10-38, 10-39, and 10-4) lodges the tdon of te perones longus muscle.

Cuniform Boes Th three sall, wedg-shaped uneiform bones (Figs 10-39 and 10-40) articulate oximall with the navicula bone an distall with th first tree metaarsal boes. Thei wedge sape contibutes geatly to the fortion and maintenace of th transvere arch o the foo (see page 42). The tarsl bones, unlike tose of te carpus, start to ossify efore bith. Cents of ossification for the alcaneum and the talus, an often fr the cuoid, are present t birth. By the fifth year, ossifiation is taking pace in al the tarsal bones P.600

Mtatarsal Bones an Phalangs he metatrsal bons and phlanges (Fig. 10-39 and 10-40) resemle the mtacarpal and phaanges of the hand and eac possesss a head distally a shaft, and a base proximlly. The five mettarsals re numbeed from he medial to the lteral sie. The first etatarsa bone s large and strog and plys an imortant rle in ing he weigh of the body. The head is grooved n its inerior asect by te medial and latral sesamoi bones in the tendons of the flexr hallucs brevis Th ffth metaarsal has a prminent tubercle n its bae that cn be easly palpated along the latel border of the oot. The tubercle gives atachment o the peoneus brvis tendn. Each to has thre phalanges excep the big toe, which possesses only two.

Clinicl Notes Fractres of te Talus Fractures occu at the ck or bdy of the talus. Nck fracures occr during violent orsiflexon of th ankle jint when the neck is drive against the anteior edge of the dstal end of the ibia. Th body

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snell of the talu can be ractured by jumpin from a eight, lthough he two mlleoli pvent dislacement of the fagments.

Fracures of he Calcaeum Compression fractures of the calcanum result from fas from height. The weigt of the body dries the tlus downard into the calaneum, cushing it in such a way tha it lose vertica height and becoes wider laterall. The poserior potion of he calcaum above the insrtion of the tendo calcaneu can be ractured by postrior dislacement of the talus. The ustentaclum tali can be actured y forced inversio of the oot.

Fractures of the Metaarsal Boes The base of the ffth metaarsal ca be fracured durng forced inversion of the foot, a which tme the tndon of insertion of the perneus breis musce pulls ff the bse of th metatasal. Stress fracture of a mettarsal one is common in joggers and in oldiers after long marche; it can also occr in nures and hikers. It occurs mst frequntly in he dista third o the seond, thid, or forth metaarsal bo. Minima displacment occrs becase of the attachmet of the interossous musces.

Popliteal Fosa Te poplital fossa is a diaond-shapd incular sace situated at th back of the knee (ig. 10-4). Te fossa s most pominent wen the kee t is flexe. It conains th poplitel vessel, the smll sapheous vein, the commn peronel and tbial neres, the osterior cutaneous nerve of the thig, the gnicular ranch of the obtuator nerv, connecive tisse, and lmph nods.

Boundaris  

Laterally: The bis femors above nd te latera head of the gastocnemius and planaris belw (Fig. 10-1) Medially: The seimembransus and emitendinosus abve and te medial head of he gastocnemius below (Fig 10-41)

The anterir wall or floor of the fossa i formed y the politeal srface of the femur, the osterior ligamen of the nee , and th poplites muscle (Figs. 1041 and 1-42). The roof is fomed by kin, suprficial ascia, ad the de fascia f the thgh. Te iceps feoris, the semimembranosus, and te emitendiosus uscles ae descried in th section on the bck of the thigh, n page 57. The gastocnemius and planaris ae descried in th section on the ack of the leg, on page 615.

Popiteus Mucle he popliteus uscle pays a ke role i the movments of the kne t nd will be descried in deail.

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 

Oriin: Fom the ateral srface of the lateal condye of the femur by a rounde tendo and by few fibers from the lateral semilunar cartilge (Figs. -42 ad 0-43) Insertion: The ibers pas downwad and meially an are atthed to he posterior surace of the tibia, above the soleal ne. The muscle arises within the sule of the knee t, ad its tedon seprates th lateral meniscu from th lateral ligament f the jnt. It eerges though the lower prt of th posterir surfac of the apsule of the t to to its insertion. Nerve spply: ibial nerve Action: Medil rotatin of the tibia on the femu or, if he foot s on the ground, lateral otation f the feur on th tibia. he latte action occurs a the comencement of flexion of the extended knee, an its roatory acion slacens the ligamets of th knee jont; this action s someties refered to as “unlocing the nee t.― Because of its attachent to te latera meniscu, it als pulls te cartilge backward at the commencement o flexion f the kee.

Politeal Atery The poplteal artry is deply placd and eners the poplitea fossa trough th opening in the aductor magnus, as contination of the femoal arter (ig. 10-4). It ends at te level of the lwer bordr of the popliteu muscle y dividig into aterior ad posteror tibia arteries.

Relations  

nteriorl: The poplitea surface of the fmur, the knee joit, and te poplitus muscl (ig. 10-4) Posteiorly: The poplteal vei and the tibial nrve, fasia, and kin (Figs. 0-41 ad 0-42)

Branches The popiteal arery has musular braches nd articula branches to th knee. P601

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Figure 10-41 Boudaries ad contens of the right politeal fssa.

P.602

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Fgure 10-2 Dee structures in the right politeal fssa. The proximal end of he soleu muscle s shown in outline only.

P.603

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Fiure 10-4 Deep structurs in the posterio aspect o the rigt leg.

P.604

Clinial Notes Poplieal Aneuysm The pulsations of the wall o the feoral artery agains the tedon of aductor mgnus at he openig of the adductor magnus i thought to contibute to the caus of poplteal aneurysms.

Semimemranosus ursa Sweling Semimemranosus ursa sweling is the most common selling fund in te poplital space It is mde tense by extening the knee joit and becomes flacid when he t is flexed. It should be dstinguished from a Baker' cyst, wich is cetrally lcated an arises as a patologic (steoarthitis) dierticulu of the ynovial membrane through a hole in he back of the casule of he knee oint.

opliteal Vein he poplieal vein is forme by the unction f the vnae comiantes of the anteior and osterior tibial ateries a the loer borde of the popliteus uscle on the medil side of the politeal atery. As it ascens throug the fosa, it crsses behnd the opliteal artery s that it comes to lie on i latera side (Figs. 10-41 and 10-42. It pases throuh the opning in he adducor magnu to becoe the femoral vei.

Tribtaries The trbutaries of the ppliteal ein are s follow:  

Veins that crrespond o branchs given ff by th poplitel artery Smal saphenos vein, which perforats the dep fascia and s betwee the two heads of the gasrocnemiu muscle o end in the poplteal vei. The orgin of his vein is described on page 615.

Arteria Anastomsis Aroud the Kne t To compensae for th narrowig of the poplitea artery, which ocurs durng extree flexio of the nee, arond the kee t is a prfuse anatomosis of small branches the femoral artery with muscular nd articlar branhes of te poplital arter and wit branchs of the anterior and postrior tibal arteres.

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Politeal Lmph Node Abot six lyph nodes are embeded in te fatty onnective tissue of the popiteal fosa (Fig. 1-4). hey receie superfcial lymh vessel from th lateral side of he foot and leg; these acompany te small aphenous vein int the politeal fossa. They also recive lymp from th knee jont and fom deep lymph vesels accmpanying the anteior and osterior tibial arteries.

Tibial Nerve The largr terminl branch of the siatic neve (see pag 587), the tibial nerve arises n the lower third f the thgh. It rns downard throgh the ppliteal ossa, lyng first on the lateral sie of th poplitel artery then poterior to it, and finally dial to t (Figs. 10-41 ad 0-42). The popiteal ven lies btween th nerve ad the arery throghout it course The nere enters the postrior comartment f the le by pasing beneth the sleus musle. Its urther curse is described on page 618.

Branches 

 

Cutaneus: Te ural nere descends beteen the two heads of the gstrocnemus muscl and is sually jined by he sural comunicatig brach of th common peroneal erve (Figs. 10-41 nd 10-17. Numerus small branches arise fro the surl nerve o supply the skin of the alf and he back f the le. The sual nerve accompanes the mall sapenous vein behind the laterl malleous and is distribted to he skin long the lateral border o the foo and the lateral ide of he little toe. uscular branchs supply both heds of th gastrocnemiu and the plantaris, soleu, and pliteus igs. 1041 an 10-42). Articlar brnches suply the nee .

Common Perone Nerve The smaller terminal branch of te sciatic nerve (ee page 587), the common peroneal nerve arises in th lower trd of the thigh. t runs ownward hrough te poplital fossa closely followin the medial bordr of the biceps muscle (Fig. 10-42. It leves the fossa by crossing superficially the teral head of the gastrocemius mucle. It hen s behind the head of the fbula, wnds lateally arond the nck of th bone, erces the peroneu longus muscle, nd divids into to terminl branchs: the sperficia peronel nerve nd the deep peroneal nerve (Fg. 10-44). As he nerve lies on he lateral aspect f the nek of the fibula, t is subcutaneous and can easily be rolled ainst the bone.

Branchs 

 

Cutneous: The sural ommunicaing branh (Figs. 0-16 nd 10-41) runs dowward and s th sural nrve. The laeral cutneous neve of th calf supplies the skin on the lteral sie of the back of he leg (Fig. 10-1 and 10-41). Muscular branc to the short hea of the iceps feoris muscle, which arises high up in the popiteal foa (Fig. 10-2) Aticular brances to the knee jont

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Cliical Nots Common Peroeal Nerve Injury The cmmon perneal nere is extemely vunerable o injur as it wids aroun the nec of the ibula. A this sie, it is exposed to direc trauma o is invoved in factures f the uper part of the fbula. Injry to th common eroneal erve caues footdrop P.65

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Figu 10-44 Deep stuctures n the anerior an lateral aspects f the riht leg and the dosum of the foot.

Poterior Ctaneous rve of e Thigh Th course f the posterior cutaneous erve of he thigh through the gluteal region and the back of e thigh s described on pge 565. t termintes by spplying he skin ver the opliteal fossa (Fig. 101).

Obturato Nerve Te course of the psterior ivision f the oburator nerve in the medial compartmnt of th thigh i deidoub on pag 586. I leaves the subsarorial caal with he femorl artery by ig throuh the opening in he adductor magnu (Fig. 10-2). Th nerve trminates by suppling the nee .

Facial Comartments of the Leg Te deep fscia surounds th leg an is contnuous aove with the deep fascia o the thih. Below the tibil condyls it is attached to the piosteum on the anerior an medial orders o the tiia (Fig. 1045). wo intermuscular spta P.606

fro its dee aspect o be attched to he fibul. These, together with th interoseous memrane, diide the eg into hree comartments€”anterir, laterl, and psteriorâ”each haing its wn musces, bloo supply, and nerv supply.

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igure 1045 Transverse sction though the middle o the rigt leg as seen fro above.

Interoseous Memrane The interosseous membrane inds th tibia an fibula ogether nd provies attacment for neighborng muscls (Figs. 1044 and 10-45).

Reinacula f the Anle Te retinaula are hickenins of the deep fasia that eep the ong tendns aroun the anke t n positin and ac as pulleys.

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Suerior Exensor Retnaculum The uperior extensor retinaculum is atached to the distal ends o the antior borders of te fibula and tibia (igs. 10-46, 10-47, and 10-50).

Infeior Extesor Retiaculum The iferior etensor rtinaculu is a Y-shaped band located in front of the kle (Figs. 1044, 1046, and 10-4). Firous bans separae the tedons into compartments (Figs. 0-48 nd 10-50, each o which i lined by a synovial sheat

Flexr Retinaulum The flexor retinaculum exteds from the medi malleols downwrd and bckward t be attahed to te medial surface f the clcaneum Fi. 10-49). It bids the tndons of the dee muscles of the bck of th leg to he back f the medial maleolus as they forward o enter he sole. The tendns lie i comparments (Fig. 10-48) each of which is lined by a synovil sheath

Superir Peronel Retinaculum The supeior peroeal retiaculum cnnects te latera malleols to the ateral rface of the calcaneum (Fig. 10-49) It bind the tenons of te perones longus and brevs P.607

P.608

P.609

to the back of te latera malleos. The tndons ar provide with a ommon syovial shath.

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Figur 10-46 Dissecton of the front o the rigt leg an dorsum of the foot.

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Figure 10-47 Structres in te anterir and laeral aspcts of te right eg and te dorsum of the fot.

Figure 1-48 Rlations f the riht ankle t.

Inferio Peronea Retinaclum The infeior peroeal retiaculum bnds the endons o the peoneus logus and brevis mucles to he laterl side o the cacaneum (Fig 10-49. The tedons eac possess a synovil sheath which i continuus above with the common seath. The arrangement of the tndons beeath the differen retinacula is described o pages 68 and 61.

The Frot of the Leg

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kin Cuaneous erves The lateral cutaneou nerve o the cal, a branch of the common peronal nerve (see page 64), spplies the skin on the uppe part of the lateal surfae of the leg (Fig. 1-1). The suerficial peroneal nerve, a branch of the common peneal nee (see page 604), supplies the skin of the lwer part of the aterolateal surfae of the leg (Fig. 1-2). The sapenous neve, a branch o the femral nerv (see page 582), spplies te skin o the antromedial surface f the le (ig. 10-2).

Supericial Vens Nuerous sall veins curve arund the medial asect of te leg an ultimatly drain into the great sahenous vin (Fig. 1051).

Lymph Vessels The eater pat of the lymph frm the skn and sperficia fascia n the frnt of the leg drans upwar and medially in vessels at follo the gret saphenus vein, to end i the verical grup of suerficial inguinal lymph noes (Fig. 104). A small amunt of lmph from te upper ateral part of he front of the leg may pas via vesels tha accompay the smll sapheous vein and drain into the popliteal nodes Fg. 10-4).

Cntents o the Antrior Fasial Comprtment o the Leg   

Muscles: The tbialis aterior, xtensor igitorum longus, eroneus trtius, and extenor halluis longus Blood spply: Anterior tibial atery Nerv supply: Deep eroneal nerve

Muscles f the Anerior Facial Comartment of the Leg The musces are sen in Figurs 10-44, 0-45, 1046, 10-47, 10-48 and 10-50 and are describe in Table 1-5. P.610

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igure 1049 Stuctures assing bhind th lateral malleolus (A) and te media malleolus (B). ynovial

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heaths o the tenons are shown i blue. Nte the positions of the rtinacula

P.61

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Figure 10-50 Dissetion of he right ankle reion showng the sructures ing behind he laterl malleos. Note he position of th retinacla.

P.612

Fgure 101 Disection f the riht ankle region sowing th origin f the grat saphnous vei from th dorsal enous arch. Note that the eat sapenous ven ascends in frnt of th medial alleolus of the tbia.

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snell ote the ollowing  



Extension or dorsflexion f the anle, is th movemen of the oot away from the ground. The peroeus tertius muscl extends the foo at the ankle t alng with he other muscles n this compartment and is supplied by the dep peronal nerve The musle also everts te foot a the subalar and transvere tarsal ts aong with the perneus lonus and bevis muscles but ceives n innervaion from the suprficial eroneal erve. The extensor digitoru longus tendons o the dorsl surfac of each toe becoe incorprated into a fascal expanion calld the extenor expaion. The cental part f the exansion i inserte into the base f the mddle phalanx, and the two lteral pats convege to be inserted into th base of the distl phalan. (Compae with te inserton of exensor dgitorum i the han.)

Arery of e Anterir Fascia Compartent of te Leg Aerior Tibial Artery Te anterir tibial artery i the smaler of te termial branches of the poplitea artery. It aris at the level of the lowe border f the politeus mscle (se pge 600) and pases forwrd into he anteror compatment of the leg hrough a opening in the uper part of the interosseo P.63

P.14

memrane (Fig. 0-42) It descends on the anterior surface of the iterosseos membrae, accomanied by the deep peroneal nerve (Fig. 10-44. In th upper prt of it course, it lies eep beneth the mscles of the comartment. In the lwer part of its course, it lies supeficial n front of the loer end o the tiba (Figs. 1-44 ad -47). Having assed beind the uperior xtensor etinaculm, it ha the tedon of te extensr hallucs longus n its meial side and the eep perneal nere and th tendons of extenor digitrum longs on its lateral side. It is here that its ulsation can easly be fet in the living subject. In front of the ankle t the artry becomes the dorsalis pedis arter (see page 625). Tble 10-5 Musces of the Anteior Fasial ompartmet of the Leg

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Mscle

Orig

nsertion

erve Suply

Nerve ootsa Actin

ibialis anterior

Lateal surfae of shat of tiba and interosseous membran

Media cuneifom and bae of firt metatarsal bone

eep perneal nve

L4, 5

Exendsb fot at anke t; inverts oot at subtalar an transvese tarsa ts; holds up medial longitudinall arch f foot

Extesor digiorum lonus

Anterior surface f shaft f fibula

Etensor epansion f latera four tos

Deep peroneal nerve

L; S1

xtends tes; exteds foot t ankle oint

Proneus trtius

Anterir surfac of shaf of fibua

Bse of fith metatrsal bon

Dep peronal nerve

L5; S1

Extends foo at ankl t; everts fot at subtlar and ransvers tarsal jints

Extenor halluis longus

Anerior suface of haft of ibula

Base of dista phalanx f great toe

Deep peoneal neve

5; S1

Extends ig toe; xtends foot at ankle t; inverts foot at ubtalar nd transerse tarsal ts

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Extensor digtorum brvis

a b

Calcaeum

By four tendons nto the roximal halanx o big toe and long extensor endons t second, third, ad fourth toes

Dep peronel nerve

S1 2

Extends oes

The pedominan nerve rot suppl is indiated by boldface tpe. Extensio, or doriflexion of the nkle is he movemnt of the foot awa from t ground.

Figure 10-52 nterior view of he ankle and fee of a 29year-old woman shwing invrsion (A and evesion (B) f the riht foot.

Branchs

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Musular braches t neighboing muses Anasomotic branches that anatomose wth brances of oter arteres aroun the kne and anke ts

Venae cmitantes of th anterio tibial rtery jon those f the poterior tbial artry in th poplitel fossa o form th poplitel vein.

Nere Supply of the Anterior Facial Coartment of the Leg Deep Proneal Nrve he deep eroneal nerve is oe of the terminal branches of the cmmon perneal nere (see page 604). t arises in the sbstance f the peoneus lous muscl on the ateral sde of th neck of the fibua (Fig. 10-4). he nerve enters te anterior compartent by percing te anterir fascia septum. It then escends eep to the extenso digitorm longus muscle, first lyg latera, then aterior, nd finaly latera to the anterior tibial atery (Fig. 10-44). The nerv es behind the extensor retinacua. Its frther corse in th foot is describe on page 629.

Banches  

Muscular branches to th tibiali anterio, the exensor digitorum lngus, th peronus tertis, and te extensr hallucs longus Articuar branc to te ankle oint Tabl 10-6 uscles o the Latral Fascal Compartment of he Leg

Muscle

Origin

Isertion

Neve Suppl

Nerve Rotsa

Action

Peoneus logus

ateral srface of shaft of fibula

Bas of first mtatarsal and the edial cueiform

Superficial peroneal nerve

L; S1,

Platar flexs foot a ankle oint; evrts foot at subtar and tansverse arsal jonts; s laeral lonitudinal nd transverse arces of fot

Peroneus brevis

Lteral suface

Bae of fifh metatasal

uperfical peronal

L5; S1,

Planar flexs foot at ankle

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shaft of fibula

a

of

bone

nerve

2

jont; evers foot a subtala and trasverse tarsal joit; suppots laterl longitdinal arh of foo

Te predomnant nere root spply is ndicated y boldfae type.

Clinical Notes Anterio Compartent of te Leg Sydrome The aterior cmpartmen syndrom is prodced by an increas in the ntracomprtmental pressur that reults fro an inceased prduction f tissue fluid. Soft tissu injury asociated with boe fractues is a ommon case, and arly dianosis is critical. The dee, aching pain in he anteror compatment of he leg that is characteritic of tis syndrme can bcome sevre. Dorsflexion o the fot at the ankle jont increses the everity f the pan. Strething of the musces that throuh the copartment by ie planta flexion of the akle also increase the pai. As the pressure ises, te venous return i diminished, thus roducing a further rise i pressure. In sevee cases, the artrial suply is eentually cut off y comprssion, nd the drsalis edis artrial pule disappars. The tibialis anterior the extnsor diitorum lngus, an the extesor halucis longus musles are aralyzed Loss of sensatio is limied to the area spplied b the dee peronea nerveâ€that is, the skin cleft btween th first ad second toes. Th surgeon can open the anteior comartment the le by makig a longitudinal incision trough th deep fscia and thus decmpress te area ad preven anoxic ecrosis of the muscls.

Cntents o the Latral Fascal Compatment of the Leg   

Muscles: Peronus longu and perneus breis Bloo supply: Brances from the peroeal artey Nerve supply: Superfiial peroeal nerv

Mucles of the Lateral Fascial Compartment of te Leg Th muscles are seen in Figures 0-44, 10-5, 10-46, 10-47 1-48, 10-4, and 1050 and described in Table 1-6. Note the following:

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The eroneus longus an brevis uscles bth flex he foot t the anle t and ever the foo at the ubtalar P.615

and transverse tarsal ts. They aso play n importnt role n holdig up the lateral ongitudial arch n the fot. In adition, te peronus longus tendon srves as tie to he transerse arc of the foot.

Clinical Notes Teosynovits and Dilocation of the Proneus Lngus and Brevis Tndons Tnosynovitis (inflmmation f the snovial sheaths) can affect the tendn sheath of the eroneus ongus and brevis muscles as they ass posterior to the later malleolus. Treatment conssts of mmobiliztion, het, and pysiotherpy. Tendn disloction can occur wen the tendons of peroneus longus a brevis dislocate forward rom behnd the lteral maleolus. or this ondition to occur the suprior peoneal retinaculum must be orn. It sually ocurs in lder children and is caused by traa.

Artery of the Lteral Facial Compartment of the Leg Numerous branche from th peronea artery see page 61), which lies n the poerior cmpartment of the leg, pierc the poserior facial sepum and spply the peroneal muscles.

Nerve of the Lateral Fascial Compartment of the Leg Superfical Peronal Nerve The uperficil peronel nerve s one of the termnal branhes of te common peroneal nerve (se age 604). It arses in te substace of th peroneu longus uscle on the lateal side f the nek of the fibula (Fig. 10-44, 10-46, and 10-50). It decends beween the peroneus longus ad brevis muscles, and in te lower art of te leg it becomes ctaneous Fis. 10-47 and 10-5).

Branches  

Musclar banches t the perneus lonus and bevis (Fig. 0-44) Cutaneus: edial an lateral branches are distibuted t the ski on the ower pat of the front of the leg nd the drsum of he foot. In additon, braches supply the orsal srfaces o the ski of all the toes except he adjacen sides o the fist and scond toe and th lateral side of the litle toe (ee page 627.

The ack of te Leg Skin 1142

snell

Cutaneou Nerves The postrior cutneous nerve of he thigh descends on the bck of th thigh (ee page 587). In he popliteal foss, it suplies the skin over the popliteal fssa and the upper part of he back f the le (ig. 10-1). Te ateral ctaneous erve of the calf, a brach of th common peroneal nerve (see page 604, supplis the skn on the upper pat of the posterolteral suface of the leg (Fig 10-1) The sural neve, a branch of the tibal nerve (see page 60), suplies th skin on the lowe part of the postrolatera surface of the lg (Fig. 10-). he sapenous neve, a branc of the emoral nrve (see pae 582, gives ff brances that upply th skin on the postromedial surface f the le (ig. 10-1).

Suerficial Veins The small saphenous vein aises fro the latral part of the drsal venus arch f the fot (Fig. 10-9). It ascends beind te latera malleols in comany with the sura nerve. t follow the laeral borer of th tendo clcaneus nd then runs up the middl of the back of the leg. he vein pierces the deep fascia ad es between the two eads of the gastocnemiu muscle in the lwer part of the poplitea fossa Figs. 10-1 and 10-40); i ends in the popteal ven (see page 604). The smal saphenus vein as numerus valve along ts cours.

Tibutarie   

Numerous small vein from the bac of the eg Comunicati veins wih the dep veins f the fot Iportant anstomotic branche that run upwad and medially ad te great aphenou vein (Fig. 10-19

Te mode o termination of he smal saphenos vein i subject to varation: I may jon the politeal vin; it my the grea saphenos vein; r it may split in two, on divisio ing the politeal ad the oter ig the grat saphnous vein.

Lymph essels Lymph vessels from the skin and superfiial fasca on te back o the leg drain upard and either pss forwad around the medial side of the lg to end in the vrtical roup of uperfical ingunal node or drain into te poplital nodes (ig. 10-4).

Content of the osterior Fascial Compartmnt of te Leg Te deep trasverse fscia f the lg is a eptum tat divids the mucles of he posterior comartment nto suprficial nd deep groups (Fi. 10-45). 

Superfiial grou of musles: astrocnmius, plntaris, and soles

1143

snell   

Deep group of muscles: Popliteus, flexor dgitorum ongus, fexor halucis logus, and tibiali posterir Blood supply: Posterior tibil arter Nerve upply: Tibial erve

Muscles of te Posterior Fascial Compartment of the eg: Suprficial Group The musces are een in Fiures 10-5 and 1-53 and are described i Tble 10-. Note the ollowing 

ogether, the soleus, gastrocnemius, and pantaris act as pwerful pantar fexors of the anke t. They povide th main frward prpulsive force in walking and runnng by ing the foot as a lever nd raising the hel off te ground.

P616

1144

snell

Figure 10-53 Structures in the posrior asect of the right leg. In B, part o the gatrocnemis has ben removd.

P.617

1145

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Table 10-7 Muscle of the osterio Fascia Compartent of te Leg

Muscle

Origin

Insrtion

Nerve Suppy

Nerve otsa Actin

Suprficial Group

astrocneius

Lateral head fro lateral condyle f femur nd medil head fom above medial cndyle

Via endo calaneus into posteior surfce of cacaneum

Tibial nrve

S1, 2

Pantar fexes foo at ankl t; flexes kee t

Plntaris

Laterl supracndylar ridge of emur

Posterior surface of calcaneu

Tbial nve

S1, 2

Plntar flees foot t ankle t; fexes kne t

Soles

Shfts of tbia and ibula

Via teno calcaeus into posterir surfae of calaneum

Tibial nerve

S1, 2

Together with gstrocnemus and plantaris is powrful platar fleor of anle t; provdes main propulive forc in walkng and unning

Dee Group

1146

snell

Poplieus

Lateral surface of laterl condye of femur

Postrior surace of haft of tibia aove solel line

Tibial nerve

L4, 5 S1

lexes lg at kne t; nlocks kee t by laterl rotatin of femur on tibia and sackens lgaments of t

Flexo digitorm longus

Posterio surface of shaft of tibia

Bases f distal phalange of lateral four toes

Tibal nerv

S2,

Flexs distal phalanges of laeral for toes; lantar fexes foo at ankl t; upports medial nd lateral longiudinal arches of foot

Flexr hallucs longus

Poterior srface o shaft o fibula

Bse of dstal phaanx of ig toe

Tibal nerv

S2, 3

Fexes dital phalnx of bi toe; pantar flxes foot at ankle t; spports mdial logitudina arch o foot

Tibiais posteior

Posteior surfce of shafts of ibia and fibula ad

Tuberosity o naviculr bone ad other

Tibil nerve

L4, 5

lantar lexes fot at anke t; inverts foot at

1147

snell

interoseous mebrane

eighborig bones

ubtalar nd transerse tasal s; suppts medil longitdinal arch o foot

he predoinant nrve root supply s indicaed by bldface tpe.

Clinicl Notes Gatrocnemus and Sleus Mule Tear earing o the gastrocnemis or soeus musces will produce severe ocalized pain ovr the damaged uscle. Selling ay be pesent.

Rupturd Tendo alcaneus Ruture of he tend calcaneus is cmmon in iddle-agd men nd frequntly ocurs in tnnis plyers. The rupture occurs at its narrowes part, bout 2 i. (5 cm) above is inserton. A suden, shrp pan is fel, with mmediat disabilty. The gastrocnmius an soleus muscles retract proximaly, leaving a palable gap in the endon. It is imossible or the patient t activey planta flex te foot. he tendon shoul be sutured as soon as possibl and the leg immbilized with the ankle oint plantar fleed and he knee t flxed.

Rupure of the Plantris Tendn upture f the plntaris tendon is rare, although earing o the fiers of te soleu or partal tearng of th tendo calcaneus is freqently dignosed a such a upture.

Plataris Tedon and utograft Te plantais muscl, whic is oftn missin, can be used for tendon autograts in reairing evered fexor tenons to te finges; the ndon of the palmris longs muscl can als be used for this purpoe. P.618

1148

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Muscles of the Psterior Fascial ompartmnt of th Leg: Dep Group The mucles are seen in Fiures 1043, 10-5, 10-48, and 10-9 and are descibed in Tale 10-7. Note th followig: 



The politeus mscle arses insie the sule of the kne t ad is insrted int the uper part f the osterior surface f the tiia. The tendon sparates he laterl ligament of the knee jint from the latral meniscus so hat the meniscus is not ethered o the lgament ad is frer to moe and adapt to he surfaes of th condy of the femur an the tiba. The poplteus musle is rsponsibe for “unlockig― th knee t.

Artery of t Posteior Fascal Comprtment f the Le Poserior Tibial Artry The posterior tbial artery is oe of the termina branche of the opliteal artery (ee page 00). It begins at the level of the lowr border of the opliteus muscle nd s downward deep o the gstrocneius and oleus nd the dep trasverse fscia of the lg (Figs. 1041, 10-2, an 0-44). It lie on the osterio surface of the ibialis posterior muscle bove an on the osterior surface f the tiia below In the ower par of the leg the rtery is covered only by skin and fascia. The artey e behind he media malleols deep to the flexr retinaulum and terminaes by dividing into medial nd laterl planta arteries (ig. 10-9).

Branhes 

   

Proneal atery, which is a large artery tat arise close t the oriin of th posterir tibial artery (Fig 10-44. It desceds behind the fiba, eith within he substnce of te flexo halluci longus uscle or posterior to it The peroneal artery gives off numeous musculr branchs and nutrient artery to the fibul and nds by tking par in the nastomoss around the ankle t. A prforatin branch pierces the interosseous membrane to reach the lowe part of the fron of the leg. Mscular banches are disributed o muscle in the osterior compartmnt of th leg. Nutrint arter to the bia Anatomotic banches, which oin othe arterie around he ankle t Medial ad latera plantar arteries (see pags 624 and 625). Vae comitantes f the poterior tbial artry hose of he anteror tibia artery n the popliteal fosa to fom the politeal vein.

Clinical Notes Dep Vein Trombosis and Lon-Distanc Air Trvel engers wo sit imobile for hours n long-istance flights are very proe to dee vein trombosi in the egs. Thrmbosis of the vins of te soleus muscle ves ris to mild pain or ightness in the calf and calf musle tenderness. However, dee vein thombosis can also occur wih no sigs or symtoms. Shuld the hrombus ecome dislodged, it es rapidly o the hert and lngs, cauing

1149

snell pulmnary emolism, wich is ten fatl. Preventative mesures include sretching of the lgs every hour to mprove te venous circulaton

Nerve of the Psterior ascial Cmpartmen of the eg Tibil Nerve The tiial nerv is the larger terminal branch of t sciatic nerve (Fig 10-17) in the lower thrd of th back of the thig (see page 04). I descend through the poplteal fosa and pases deep to the gstrocnemus and soeus musces (Figs. 1-43 and 1053). t lies o the poterior srface of the tibilis postrior and lower dwn the g, on th posterior surfce of th tibia (Fig 10-43). The erve accmpanies the posterior tibil artery and lies t first n its mdial sid, then cosses poserior to it, and inally les on it latera side. Th nerve, ith the rtery, psses behnd the mial malleolus, between th tendons of the fexor digitorum lous and te flexo halluci longus Fi. 10-49). It i covered here by he flexo retinaculum and divides into the mdial an lateral plantar erves.

Braches in he Leg (Blow the opliteal Fossa)    

Mscular banches to the oleus, fexor digtorum longus, flexor hallucis longus, and tbialis psterior Cutaneou: The meial calcneal brach suplies the skin ovr the medial surfae of the heel (Fig. 10-49) Articula branch to the ankle jint Media and latral planar nerve: see pages 626 and 627.

The Region of the Ankle Bfore leaning the anatomy f the fot, it is essentia that a student ave a sond knowldge of te arrangment of he tendons, arteres, and erves in the region of the ankle jont. From the clinical stadpoint, he ankle is a comon site or fractures, sprins, and dislocatons. A ransvere sectio throug the anke t s shown n igure 1048; n it, idntify th structues from edial to lateral. t the sae time, examine our own nkle and identify as many o the structures s possie.

Aterior Apect of he Ankle Strctures Tat nterior o the Exensor Reinacula rom Medil to Latral (Fig. 1-48)  

Sahenous nrve and reat sapenous ven in front of the mdial maleolus) uperficil peronel nerve medial ad latera branche)

Strctures Tat eneath o Through the Extesor Retiacula Frm Medial to Laterl Fig. 10-8) 1150

snell   

Tibilis anteior tendn Extenor hallucis longus tendon Anterior tibial atery with venae cmitantes P.69

  

Deep peroneal nerve Extnsor digtorum logus tendns Peroeus tertius

As ach of te above endons es beeath or through the extensor retinacula, t is surrounded y a synoial sheah. The endons of extensor digitoru longus nd the proneus trtius shre a common synoial sheath.

Structres That in ront of he Media Malleolus (Fgs. 10-4 and 10-1)  

Great aphenous vein Sapenous neve

Psterior spect of the Ankl Stuctures hat Behind te Medial Mallelus Beneth the Flexor Retiaculum Frm Medial to Latera (igs. 10-8 and 1049)     

Tibialis posterio tendon lexor diitorum logus Postrior tibil artery ith vena comitantes Tibal nerve Fexor halucis longs

As ech of thse tendon es eneath th flexor rtinaculum it is srrounded y a synoal sheat.

Structurs That ass Behid the Lteral alleolus Superfical to the Sperior Proneal Rtinaculu (Fig. 10-48)  

The sual nerve mall sapenous ven

Structues That ass Behid the Laera Malleols Beneat the Suprior Perneal Retinaculum The proneus lngus and brevis tndons (Figs 10-48 and 10-49) share common ynovial heath. Lwer down beneath the infeior peroeal retiaculum, hey have separate sheaths.

1151

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Structres That Lie Diretly Behid the Anle The fat and the arge teno calcaneus lie ehind the ankle (Fig. 10-48.

Th Foot he foot upports he body eight an provide leverag for waking and running. It is unque in tat it is construced in th form o arches, which enble it t adapt is shape to uneven surfaces. It als serves s a resiient sprng to absorb shocks, such as in jumping.

Te Sole o the Fo Skin Th sin of th sole of the foo is thick and harless. t is fimly boun down to the undrlying eep fasca by numrous fbrous bads. The kin shos a few lexure ceases at the sites of skin movemet. Sweat glands re preset in lare numbers. Th ensory nrve supp to he skin f the soe of the foot is erived from the medil calcanal branc of t tibial erve, whch innerates the medial sde of th heel; banches fom the meial planar nerve, whic innervae the medial two thirds of the sole and braches fro the latera plantar nerve, which inervate te latera third o the sol (igs. 10- and 10-54).

Deep Fasia Th pantar apneurosis is a riangula thickenng of th deep facia that protects the undelying neves, blod vessel, and mucles (Fig. 0-54). Its aex is atached to the medil and laeral tubrcles of the calaneum. Te base o the apoeurosis ivides ito five lips tha ito the tes.

Cliical Nots Plntar Fasiitis Plantar asciitis which ocurs in individuals who do a great deal of tanding r walki, causes pain and tenderness of the sole of the foot It is blieved t be causd by repated minr trauma Repeatd attack of this conditio induce ssificaton in th posterir attacment of he aponerosis, frming a calaneal spr.

Muscles f the Soe of the Foot The musles of te sole ae conveently described i four laers from the infeior laye superioly.   

First lyer: bductor allucis, flexor dgitorum revis, aductor dgiti minmi econd laer: Qudratus pantae, lmbricals flexor igitorum longus tndon, flxor hallcis longs tendon Third laer: Flxor hallcis bres, adducor halluis, flexr digiti minimi bevis

1152

snell 

Fourth layer: Interossi, peronus longu tendon, tibialis posterio tendon

nlike t small mscles of the hand the sol muscles have fe delicat functios and ar chiefly concerne with ing the archs of the foot. Alhough thir names would sugest conrol of individua toes, tis functon is raely used in most eople. The muscles f the soe are sen in Figur 10-55 through 10-59 an are desribed in Tale 10-8.

Lon Tendons of the Sle of th Foot Flexr Digitoum Longu Tendon The lexor diitorum lngus tenon enter the sole by ng behin the medl malleous beneah the flxor retiaculum (Fig. 10-47 and 10-56). It asses foward acrss the mdial surace of te sustenaculum tli and hen croses the tendon of exor halucis lonus, from which it receive a stron slip. I is here that it receves on is lateral border the insetion of e quadratus plantae muscle The tenon now P.62

P.61

divide into is four tndons of insertion, which forwad, givin origin to the lmbrical uscles. he tendons hen enter the fibrus sheats of th lateral four toe (ig. 10-5). Eah tendon perforats the corespondi tendon f flexor digitoru brevis and s on to be insert into te base o the disal phalanx. It shoud be notd that te method of inserion is smilar to that fond for te flexor digitoru profunds in the hand (se age 502).

1153

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Fige 10-54 Planta aponeursis and utaneous nerves o the sol of the ight foo.

1154

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Fiure 10-5 Firs layer o the platar musces of the right foot. Medi and latral plantar rteries nd nerve are als shown.

Flexor Hallucis Longus Tndon 1155

snell The fleor halluis longu tendon Fi. 10-56) entes the sole by pasing behind the meial mallelus beeath the flexor etinaculm. It rus forwar below th sustentculum tai and cosses dep to the flexor dgitorum ongus tenon, to wich it gves a srong sli. It then enters te fibros sheath of the bg toe an is inseted into the base of the dital phalnx.

Fbrous Fxor Sheahs: The infeior surfce of eah toe, fom the had of th metatasal bone to the base of th distal phalanx, provided with a strong fbrous shath, whih is attched to e sides f the phlanges (Fig 10-54). The arangemen is simir to that found i the finers (see pae 500) The firous sheth, togeher with the infeior surfaces of th phalanes and te interpalangal t, forms a blind unnel in which ie th flexor tenons of te toe (ig. 10-7).

Synovial Fexor Sheaths The tenons of the flexo hallucis longus and the flexor dgitorum longus ae surronded by ynovial sheaths (Fi. 10-49 and 10-57).

Perones Longus Tendon The poneus longus tendon (Fig. 10-59) eters the foot from behind the lateral mleolus and runs oliquely across te sole t be inseted into the base of the frst metaarsal P.622

P.623

P.62

bone ad the adacent pat of the medial cneiform. The tendn grooves the inferior surace of e cuboid where it is held n positin by the long plntar ligment and is surronded by synovia sheath Fi. 10-57). Table 10-8 uscles o the Sol of the oot

1156

snell

Muscle

Orgin

Nerv Nerve Spply Rootsa Acion

Inserton

First Layer

Abduct or hallucis

Medal tubersit y of calcaneu m and flexr retinalu m

Bas of proxmal phalnx of big toe

Media plantar nerve

S2 ,3

Flexes ad abduct big toe braces edial logitudina arch

Flexor digitoru m brevis

Medil tuberce of calaneu m

Four endons t four laeral tos— insrted into borders f middle phalanx; tendons erforate by thoe of fleor digitorum longu

Media plantar nerve

S2 ,3

lexes laeral fou toes; baces medal and lteral longitudinal arches

Abduto r digii minimi

Medal and lteral tuercles o calcneu m

Bas of proxal phalax of fifh toe

Lateral plantar nerve

S2 ,3

Flexe and abdcts fift toe; bres lateral longitdinal arh

Secnd Layer

1157

snell

Quadra tu plantae

Medal and lteral sides of calcaneu m

Tedon of fexor digtorum lonus

Lateral plantar erve

S2 ,3

ssists flexor digitorum logus in fexing laeral four toes

Lumbric ls (4)

Tendos of flexor digitou m longu

orsal extensor expansion; bases of proximal phalanges of laterl four tes

Fist lumbrca l: medal plantr nerve; remaind e: lateral plantar erve

S2 ,3

Extnds toes at interhalangea ts

Flexor igitoru m longus tndon

See Table 10-7

Fleor halluis longu tendon

See Tale 10-7

Medial planar nerve

S2 ,3

Flexes metatarsphalan gel joit of big toe; s

Tird Laye

Flexor hallucis bevis

Cuboid lateral cuneifor , tibials

Medial tendon into medal side of base f

1158

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posteror inseron

proximl phalan of big toe; laterl tendon into latral sid of base of proxil phalanx of big oe

medal longiudinal arh

Adduct or hallucis

Oblque head bases of second, hird, an fourth etatarsal bones; tansvers e head from plntar ligments

Latral side of base f proximl phalan of big oe

Deep ranch laeral platar nerv

S2 ,3

Flees metatrsophalag eal joit of big toe; hols togethr metatasal bones

Flexor digiti minim brevis

Bas of fift metatar al bone

Latral side of base f proximl phalan of litte toe

Lateral pantar neve

2,

Flxes metaarsophalng eal t of litle toe

Adjaent side of metaars

Bases f proximl phalages—f ist: medil

Lateal plantr nerve

S2 ,3

Abducion of toes; flexes metatasophalan eal s and

ourth Laer Interossi

Doral (4)

1159

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al boes

side of second oe; remander: laeral sids of seond, thid, and furth toes€”also drsal extnsor expnsion

Platar (3)

Inferir surfacs of thid, fourt, and fith metatas al bone

Media side of bases of proxima phalanges of lateral three toes

Peoneu s logus tendn

Se able 10-

Tbialis osterior tendon

See Tabl 10-7

a

extends intephalangeal oints

teral pantar neve

he predoinant neve root pply is indicate by boldfce type.

1160

2,

Adduction f toes; lexes meatarsophalan geal oints ad extends interphaangeal jints

snell

1161

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Figure 0-56 econd laer of th plantar muscles f the riht foot. Medial a lateral plantar arteries and nerves are als shown.

1162

snell

1163

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igure 1057 Synvial sheths of te tendon seen on the sole of the rght foot

Tibalis Poserior Tedon The tibilis postrior tendon (Fig. 1059) ters the foot from behind the medial malleous. It es beneath the lexor retinaculum and runs downward and forwrd above the sustenaculum tli to be nserted ainly ino the tberosity of the navicula. Small endinous slips pas to the cuboid ad the cuniforms nd to th bases o the secod, third and fourth metatasals. Th tendon is surronded by synovial sheath.

Arteries of the Sle of th Foot Medial Plantar Artery The medal plantr artery is the saller of the termnal branhes of te posteror tibia artery see page 618). It arises bneath th flexor etinaculu and pases forwad deep t the abdctor halucis musle (Fig. 1049). ends by supplyin the medal side f the bi toe (Fig. 0-55). During P.62

its curse it gives off numerous muscula cutaneos, and aticular ranches.

1164

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igure 1058 Tird layer of the lantar muscles of he right foot The dee branch of the ateral pantar neve and the lantar arterial rch are lso shwn.

Lateral Plntar Artery

1165

snell he latel planta artery is the lrger of the terinal branches of the posterior tiial artry (see age 618). It rises beeath the flexor retinaculm and pases forwrd deep o the aductor hllucis and the flexor dgitorum brevis (Figs. 10-49, 10-55 and 10-56). On eaching the bas of the ifth meatarsal one, th artery urves meially to form th pantar ach (Fig 10-58) and a the proimal end of the irst intrmetatarsal spae s he dorslis pedi artery F. 10-59). Duing its ourse, t gives ff numeous musular, cuaneous, nd artiular branches. The plantar rch give off platar digial arteres to te toes.

Doralis Peds Artery (the Doral Arter of the oot) On ntering he sole etween the two heds of th first orsal inerosseous muscle, he dorsais pedis artery mediatel s he laterl planta artery Fi. 10-59).

Branche The irst platar metaarsal artery, whih supplie the clet betwee the big and secod toes .626

1166

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Figure 1-59 ourth laer of th plantar muscles f the riht foot. The deep branch f the laeral platar nerv and the plantar arterial arch are aso show. Note te deep tansverse ligament.

Veins of the Sole of the Fot 1167

snell Medal and lateral plantar vei accopany th correspnding areries, ad they unite behid the meal malleolus to frm the psterior ibial veae comitntes.

Nrves of he Sole f the Fot Medial Plantar Nerve Th medial lantar nrve is a terminal branch o the tibal nerve (see page 68). I arises eneath the flexor etinaculm (Fig. 10-9) an runs forward deep to the abductor hallucis, with the edial pantar arery (Fig. 1-55). t comes o lie in the inteval betwen the aductor hllucis and the fleor digitrum brevs.

Branchs  

Muscular ranches to th abductr hallucs, the fexor digtorum brvis, the flexor hllucis brevis, and the first lumbrial muscl Cutneous brnches: Pantar diital neres ru to the ides of he media three ad a half toes (Fig. 0-54). The nervs extend onto the dorsum ad supply the nail beds and the tips of the tes.

P627

Compae with te distriution of the medin nerve n the pam of the hand.

Lateral Plantar Nerve The ateral pantar nee is a trminal banch of he tibia nerve (ee page 618). It rises beeath the flexor rtinaculu (ig. 10-4) and uns forwrd deep o the abuctor halucis an the fleor digitrum brevs, in copany with the lateral plantar arter (Fg. 10-56). On eaching he base f the fith metatarsal bon it divides into uperficil and dep branchs (F. 10-56).

Branche  



From the main trunk o the qadratus lantae and abductor digiti minimi; ctaneous ranches to the sin of the lateral part of the sole From th superfiial termnal branh to the flexr digiti minimi ad the interosseous muscles of the fourth inrmetatarsal space. Planta digital branches to te sides f the lateral one and a half toes. The nerves extend onto the dorsum d supply the nail beds an tips of the toes Fro the dee termina branch (Fg. 10-59). Th branch curves medially with the laeral plantar artery and pplies te adductor hallucs; the scond, thrd, and ourth lmbricals and all the inteossei, ecept thoe in the fourth ntermetaarsal spce (see uperficil branch above).

Compare with the distribuion of te ulnar erve in he palm of the hand.

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The Drsum of he Foot Skin The skn on the dorsum o the foo is thin, hairy, and freely mobile o the undrlying tndons an bones. The sesory nere supply (Fig. 10-) to the skin on the dorsum of e foot is derived from the superfical peroeal nerve, assiste by the eep peroeal, sapenous, and sural erves. The suerficial peroneal nerve merges fom betwen the peoneus brvis and te extensr digitoum longu muscle the lowe part of the leg see page 65). I now divdes into medial and latera cutaneos branchs that spply th skin on the dorsum of the oot; the medial sde of th big toe; and the adjacnt sides of the econd, thrd, fouh, and ifth tes. The deep peronea nerve supplie the ski of the djacent sides of the big nd secon toes (Fig 10-2. The saphenus nerv e ont th dorsum f the foot in font of te medial malleolus (Fig. 10-2). It suplies the skin alog the meial side of the fot as fr forwar as the ead of te first etatarsl bone. The surl nerve (Fig. 10-) eners the oot behind the lteral maleolus ad supplis the skn along the lateal margn of the foot and the lateal side of the lttle toe. The nail beds and the skin covering the dorsl surfacs of th termina phalange are suplied by he media and latral plaar nerves (see aove).

orsal Veous Arch (or Netwrk) The dorsl venous arch lie in the subcutaneous tissu over te heads f the meatarsal bones an drains on the medal side into the great sahenous vin and o the lateral side nto the mall sahenous vin (Fig. 1019). he great saphenou vein leves the orsum of the foot by ascening into the leg n front f the meial mallolus. It further ourse is describe on pag 570. Th small sahenous vin ascens into te leg beind the lateral alleolus. Its course in the bck of th leg is escribed on page 615. The greater art of the blood fom the wole foot drains ito the rch via igital vins and ommunicating vein from the sole, whch through he intersseous saces.

Muscles f the Dosum of te Foot Extnsor Digtorum Brvis The musce is see in Figure 0-60 nd descried in Table 10-9

Te Inserton of th Long Exensor Tedons The tendon of etensor dgitorum ongus pases beneah the sperior etensor reinaculu and throgh the iferior etensor etinaculm, in company with the peroeus tertus muscl (ig. 10-60) The tedon divies into four, whic fan out over the dorsum o the foo and pas to the lateral four toes.

1169

snell Opposite the metaarsophalgeal jonts of te second third, nd fourth toes, eah tendon is e on its lateral ide by a tendon o extenso digitorm brevis (Fg. 10-60). On te dorsal surface f each te, the eensor tedon s the fascial expasion caled the extesor expasion. Near th proxima interphalangeal jint, the extensor expansio splits into thre parts: a centra part, wich is iserted io the bae of th middle halanx, nd two lteral parts, which converg to be iserted ito the bse of th distal halanx (Fig 10-60. Th dorsal xpansion, as in the fngers, rceives te tendon of inseion of the interosseous ad lumbrical muscles.

Synoial Sheah of the Tendon o Extenso Digitorm Longus The extesor digiorum longus and proneus trtius tdons are surroundd by a cmmon synvial sheth as thy bneath te extenso retinacla (Fig. 1060). he sheah extend proximally for a short ditance above the maleoli an distaly to the level of he base f the fift metatarsl bone.

Arery of te Dorsum of the Fot orsalis Pedis Arery (the orsal Arery of te Foot) Te dorsals pedis rtery beins in font of te ankle int as a continuaion of te anterir tibial artery (ee page 612). It erminate by ng downwrd into he sole etween th two heas of the first dorsal introsseous muscle, here it oins the ateral lantar atery and complete the plantar arch Fi. 1059). It i superfiial in psition an is crosed by th inferio extensor retinacuum and th first tndon of P.62

extenor digitrum brevs (Fig. 10-0). O its latral side lie the erminal art of te deep proneal nrve and the extensor digitorum lons tendon. On the medial sde lies he tendn of extnsor halucis lonus (Fig. 1060). Its pulsation can easly be fet.

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Figure 10-60 Structurs in the dorsal apect of the right foot. Table 1-9 Mucle of te Dorsum of the Fot

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uscle

Orign

xtensor igitorum brevis

Insertio

Anteior part of upper surface f the cacaneum ad from the inferor extenor retinculum

Nerve Nerve Suply oots Actin

By four tedons nto the roximal phalax of big to and log extensr tendons to secnd, thid, and furth toes

Deep peronel nerve

S1 S2

Extends tes

Brances   

Lteral tasal artey, wich croses the orsum of the foot just beow the akle t (Fig. 1060) Acuate arery, whic runs laerally nder the extenso tendon opposie the baes of te metatrsal bons (Fig. 1060). It gives ff metatrsal brnches to the toes. First dorsal mtatarsal artery, whic supplie both sies of te big to (Fig. 10-0)

Neve Supply of the Dorsum o the Foo Deep Perneal Nere Th deep peoneal neve enters the dorum of the foot by ing deep to te extensr retiacula on the lateal side f the dsalis pedis arter (see page 614). t divids into trminal, medial, nd laterl branchs. The mdial branch suppes the sin of th adjacen sides o the big and secon toes (Fig. 1060. The lteral branch supples the etensor dgitorum revis mucle. Bot terminl branche give aricular banches o the jonts of te foot.

ts of the Lowe Limb The hi t i fully dscribed n page 57.

Knee Jont The knee jont is the largest and most complicated t in the ody. Basically, it consist of two ondylar oints beween the medial nd lateral condyle of the emur and the corrsponding condyles of the ibia, an a gliding t, etween te patell and the patellar surface of the feur. Note that the fibula i not dirtly involved in he t

Artculation

1172

snell Above are the unded condyles o the femr; below are the cndyles o the tiba and thir cartiaginous enisci (Fig 10-35); in frnt is th articultion beteen the lower end of the feur and te patela. The rticular surfaces of the fmur, tiba, and ptella ae covere with hyaline cartlage. Ne that te articuar surfaes of te medial and lateal condyes of th tibia re often referred to clincally as the medil and laeral tibia plateau.

ype The t beween the femur an tibia i a synoval of the inge varety, but some degee of roatory moement is possibl. The jont betwen the patella and femur is a synovil t of the pane glidg variet.

Capsul The sule is attached to the mrgins of the artiular sufaces and surroun the sids and psterior apect of he . On te front f the jont, the apsule i absent, permittig the syovial mmbrane t pouch uward benath the quadriceps tendon, forming the suprapatllar bura (Fig. 1-35). On each side of he patella, the sule is strengthned by expansions from the tendons of vastu laterals and meialis. Bhind the t, he capsue is strngthened by an exansion o the semmembranos muscl called the oblique opliteal ligament (Fig. 10-5). A opening in the sule beind the lateral tibial condye permit the tenn of the opliteus to emerge (Fig. 0-3).

igaments The lgaments ay be diided int those tat lie otside th capsule and thos that lie within he capsue.

Extracasular Liaments The ligantum patellae s attachd above o the loer border of the atella ad below o the tuerosity of the tibia (ig. 10-5). I is, in act, a ontinuaion of te centra portion of the cmmon tedon of te quadriceps femris musce. The latera collateal ligamnt is cordlike and is atached aove to te latera condyle of the femur and below to he head f the fibula (Fig. 10-35). he tendo of the opliteus muscle itervenes between he ligament and th lateral meniscus (ig. 10-61. The medial collaterl ligamet is a flat bnd and i attache above t the medial condye of the femur an below t the medal surfae of the shaft of the tibi (ig. 10-3). It is firmly atached t the edg of the edial meiscus (Fg. 10-61). The obliqe poplital ligamnt is tendinos expanson derivd from te semimebranosus muscle. t strenghens the posterior aspect the capule (Fig. 10-35).

Intrasular Lgaments

1173

snell The crucate ligaments re two srong intacapsula ligamens that coss each other wihin the oint cavty (Fig. 1035). Tey are nmed anteior and osterior accordig to ther tibial attacments (Fig 1061). Thse imporant lgaments re the main bond between the femu and the tibia troughout the joit's range of movment.

Anteior Crucate Ligaent The anteror cruciate ligaent is attached o the aterior itercondlar area of the ibia and es pward, bckward, and lateally, be attached to he posteior part of the medial srface of the latral femoal condle (Fis. 10-35 and 10-61). he anteror crucite ligamnt prevets posteior dislacement of the emur on he tibia With th knee jont flexe, the anerior cuciate igament prevents he tibia from being puled anterorly.

Posterior Cruciate Ligamen The posteror crucite ligamnt is atached to the pterior intercondylar area of the tbia and asses upard, forard, an mediall to be attached to the anteior part of the lteral suface of the medial femorl condyle (igs. 10-5 and 101). he posteior crucate ligaent prevents anteror displcement o the feur on th tibia. ith the nee flexed, the postrior cruiate liament prevents the tibia fom bein pulled osterior.

Mnisci he menisi are C-haped shets of fbrocartiage. The peripheal borde is thic and attched to he capsue, and te inner border i thin and concave and form a free dge (Figs. 0-35 ad 0-61). The uppr surfacs are in with the femoral codyles. Te lower urfaces re in P.629

with the tibial cndyles. heir funtion is o deepen the artcular sufaces of the tibil condyls to recive the onvex feoral codyles; tey also erve as ushions between t two bones.

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Figure -61 Relations f the right knee oint.

Each meniscus is attaced to th upper srface of the tiba by antrior and posterio horns. ecause te medial meniscus is also attached to the mdial colateral lgament, it is relaively imobile.

Syovial Membane The snovial mmbrane lnes the apsule ad is attched to he margins of the rticular surfaces (igs. 10-5 and 10-1). n the frnt and ave the t, it orms a puch, whih extend up benath the uadricep femoris muscle fr three ingerbredths aboe the ptella, fming the sprapatelar bursa. This s held i positio by the ttachmen of a smll portin of the vastus intermediu muscle, called the articulais genus muscle (Fig. 10-3). At te back o the joit, the snovial mmbrane i proloned downwrd on th deep suface of he tendo of the popliteus forming te popliteal bursa A bursa is inteposed beween the medial had of th gastrocemius an the medal femoal condyl and the semimembanosus tndon; ths is termed the semiembranosu bursa, and it frequentl communiates wit the synovial caviy of the t. 1175

snell The synovial membrane is refleted forwrd from te posteror part f the capsule around te front f the crciate ligments (Fig. 10-61). As a result, the cruciate ligament lie behnd the snovial cvity and are not bthed in ynovial luid. In th anteror part f the jnt, the synovial membrane is refected bakward fom the psterior urface f the liamentum patellae to form the infraptellar fold; the free orders o the fold are temed the alr folds (Fig. 10-61).

Burse Relate to the Kne t umerous bursae are related to the nee t. They ae found wherever skin, mucle, or tendon rbs againt bone. Four are situate in fron of the t an six ar found bhind th t. e supraptellar brsa and the poplteal bura alwys commnicate wth the jint, and the semimembranosu bursa my communicate with the oint.

Anteior Burse 

The suprapatellar bursa lies benath the uadrices muscle and comunicates with the t cvity (Fig. 10-35). It is escribed above. P.630

  

The prpatella bursa lies in the sucutaneos tissu between the ski and the front of the loer half of the ptella an the uper part f the lgamentum patella (Figs. 1-35 and 10-1). The suerficia infrapaellar brsa les in te subcutneous tssue beteen the skin and the front of the ower par of the igamentum patelle (Fig. 10-35). he deep infrapatella bursa lies btween th ligamenum patelae and he tibia (Fg. 10-35).

Posteior Burse  

The poplteal busa is ound in ssociatio with th tendon o the poiteus and communiates with the cavity. t was dscribed reviously. Te semimebranosus ursa is foun related o the insrtion o the semiembranosu muscle and may cmmunicat with the t caity. It ws descried previosly.

The rmaining our bursa are foud related to the endon of insertio of the bceps femris; relatd to the tendons of the sarrius, gracilis, an semitendinosus uscles a they pas to thir inserion on he tibia beneath the lateal head f origin of the astrocnius musle; and eneath te medial head of rigin of the gatrocnemis muscl.

Nrve Suppy Th femoral obturatr, commo peronel, and tbial neres suppy the knee t

Movements 1176

snell The kne t n flex, extend, ad rotate As the kee t assumes te positi of full extensin,* medal rotaton of the femur esults i a twistng and ightenig of al the majr ligamets of th t, and the knee becomes mechancally rigd structue; the catilaginous menisci re compreed like ubber cusions betwen the femoral an tibial cndyles. Te extendd knee is said to b in the lcked positon. Beore flexin of the nee t can occu, it is essentia that te major lgaments e untwisted and slakened to permit movments beeen the oint surfces. This unlocking or untwising proces is aclished b the popiteus musle, which laterally rotates he femur on the tia. Once gain, the menisci hve to adat their shape to te changin contour the femral condyles. The ttachment of the popliteus t the laeral menscus reslts in that struture beng pulled backward also. When th knee joit is fled to a rght angle a consderable rage of rotion is possible. In the flxed posiion, the tibia ca also be oved vely forwrd and bckward on the femur This i possibl because he major ligaments especially the cruciate ligamens, are sack in tis position. The followin muscle produce movemens of the nee .

Flexion The biceps femor, semitndinosus and semmembranous musces, assited by te gracils, sartrius, an poplites muscle, produe flexio. Flexio is limied by the of the bck of th leg wh the thigh.

Extensio The quadrices femori producs extenson. Extnsion is limited y the tesion of ll the major ligments of the .

Mdial Roation The sarorius, gacilis, nd semiendinosu produce medial rtation.

ateral tation The bceps femris prodces lateal rotaton. The sability f the kne t epends n the toe of th strong uscles acting on the and the strength of the igaments Of thes factors the ton of the uscles i the mos importnt, and t is th job of he physitherapis to buil up the strengt of these muscles, especially the qadriceps femoris after njury to the knee t.

Importan Relatios  

Anteriorl: The prepatelar bursa (Fg. 10-61) Psteriorl: The popliteal vessel; tibial and commn peronel nerves lymph ndes; ad the mucles tha form te boundaies of te poplital foss, namely, the semmembranous, the emitendiosus, th biceps emoris, the two eads of he gastrcnemius, and the lantaris (ig. 10-6)

1177

snell  

Medilly: Sartoris, gracis, and semitendnoss muscles Fig. 1-61) aterally: Bceps femris and ommon proneal nerve (Fig. 0-61)

Clinical Notes Stregth of te Knee t he strenth of th knee jont depens on the strength of the igaments that bin the feur to th tibia and on th tone of the mucles actng on te t. The mos important muscle grou is the quadriceps fmoris; proided hat his is wel develped, it s capale of tabilizig the kne in the presence of torn ligament.

Knee Injury ad the Syovial Mmbrane Th synovia membrane of th knee jont is etensive, and if the aticular urfaces, menisci, or ligamnts of te t re damaed, the arge synvial cavity becom distendd with fuid. The wide cmmunicaton betwen the sprapatelar burs and th t cvity results in thi structure becomig distened also. The swelling of the knee extends hree or our finerbreadts above the patela and laterall and meially beeath th aponeurses of insertion of the vastus lteralis nd medialis, respectivel.

Ligametous Injry of th Knee Jont Four liamentsâ€the medil collatral ligment, th latera collateral ligment, th anterir cruciae ligamnt, and he postrior cruiate ligment—are commonly injurd in the knee. Srains o tears ccur depnding on the degre of fore applie.

Medial Collaterl Ligamnt Fored abducion of he tibia on the emur can result i partial tearin of the edial cllateral ligament, which an occur at its emoral o tibial attachmets. It i useful o rememer that ears of the menici resut in loclized tederness n the jont line, whereas sprans of te medial collatel ligamt resul in tendrness over the emoral o tibial ttachmts of te ligament.

Lateral Collaterl Ligamet Frced addction of the tibia on the femur ca result n injury to the lateral ollaterl ligament (less common tan medil ligamnt injuy).

Crciate Liaments Ijury to the crciate liaments can occu when ecessive orce is pplied t the kne t. Tears o the antrior cruciate ligment are common; ears of the posteror crucite ligamnt are rare. The injury i always ccompanied by damae to othr knee structurs; the ollatera ligamens are comonly ton or the capsule may be amaged. The t avity quicly fills wth bood (hemarthrosis) so hat the t is swollen Examintion of atients ith a rutured aterior cuciate lgament hows tha the tibi can be ulled excessivel forward on the fmur; wit rupture of the psterior cruciate igament, the

1178

snell tibi can be ade to mve excessively bckward on the fmur (Fig 10-62). Because the tability of the kee t depends largely on the tone f th quarices femoris mucle and the integrity of the collteral lgaments, operatie repair of isolaed torn ruciate igamets is no alway attemptd. The nee is imobilize in sligt flexio in a cat, and ctive physiotherap on the uadriceps femoris muscle is begun at onc. Should however the casule of the and the collaterl ligamnts be trn in adition, rly opeative reair is esential

Meniscl Injury of the nee njuries of the mnisci a common The medal meniscus is amaged uch more frequenly than he lateal, and his is robably because f its strong attchment t the meial collateral liament of the kne t, which rstricts its mobiity. The injury ocurs whe the feur is rotated on the tibia, or th tibia i rotated on the emur, with the kee t partiall flexed nd takin the weiht of he body. The tibi is usally abducted on he femur and the medial eniscus s pulled into an abnormal position between he femoral and ibial codyles (Fig. 10-62A). A suden movemnt betwn the cndyles rsults in the menicus beig subjeced to a severe grinding fore, and t splits along it length Fig. 1063). When th torn prt of th meniscus becomes wedged etween te articuar surfaces, further movment is mpossible, and te t s said o “lok.― njury t the latral menicus is ss common, probbly becuse it i not attched to he lateral collteral liament of the kne t nd is consequently more mole. The opliteus muscle ends a few of is fibrs into he lateal menisus, and hse can pll the eniscus nto more favorable osition uring suden moveents of he kne t.

Pneumoathrograpy Air can be injected into th synovia cavity of the kee joit so tha soft tsues can be stuied. Thi techniqe is basd on the fact tat air i less raiopaque han strctures sch as th medial and latral menici, so heir outine can be visualized on a radiograh (Fig. 10-76).

Arthrocopy Arhroscopy invlves the introducion of a lighted instrument into he synoval cavit of the knee joit throug a small incisio. This tchnique ermits te direct visualization of structues, suc as the ruciate igaments and the enisci, or diagnostic prposes. P.631

Proxima Tibiofiular Joit Articulaton Aticulatin is beween he laterl condye of the tibia an the head of the fibula (Fig. 10-5). Te articar surfces are lattened and coveed by hyline carilage.

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Type This i a synoval, plan, glidin t.

Capule Te capsul surrouds the jint and is attaced to the margin of the rticular surfaces.

Ligamnts Anrior and posterir ligamets stengthen he capsle. The inerosseou membrane, which connects he shafs of the tibia an fibula together also gratly strengthens the t.

Snovial Mmbrane The snovial mmbrane lnes the capsule nd is atached to the margins of the articuar surfces.

Nerve Supply The coon peroal nerve supplie the joit.

Mvements A mall amout of gliing moveent taks place uring movements a the anke t.

Distal Tibiofibular Aticulatin Articulatio is betwen the ibular ntch at he lower end of the tibia and the lower ed of the fibula igs. 10-4 and 1065). he opposd bony srfaces re roughned.

Type The dista tibiofiular joit is a fibrous t.

Capsul There is no sule.

Lgaments The interosseous ligament is a strong, hick ban of fibous tisse that inds the two bone togethe. The P632

1180

snell

P.633

P.634

nterossous membane, hich conects te shafts of the tibia and fibula tgether, also gretly stregthens te t.

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snell

Figure 1-62 A Mechansm invoved in dmage to the medil menscus of the knee t rom playng football. Not that th right kne t s semifexed and that meial rottion of he femu on the tibia ocurs. The impact causes frced abdction of the tib on the emur, ad the meial menscus is pulled ito an abormal poition. Te cartilginous eniscus s then ground beween the femur ad the tiia. B. Test for intgrity of the anteior cruiate ligment. C. Test fr integrty of th posterir cruciate ligamnt.

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Figur 10-63 Tears of the meial menicus of te knee oint. A. Compete buckt handle tear. B The menscus is torn fro it peripheral attahment. C. ear of te posteror porton of th meniscu. . Ter of the anterior portion f the mniscus.

The anteior ad osterio ligamets ar flat bads of fibrous tisue conncting th two bnes together in front and behind he intersseous lgament. Th nferior ransvere ligamet rus from te medial surface of the upper part of the latera mallelus to te posterior bordr of the lower ed of the tibia.

Neve Suppl Dee peronea and tial nervs supply the t.

ovement A smll amout of movment taks place uring mvements t the anle t

Ankle t

1183

snell The anke t onsists f a dee socket ormed y the lwer ends of the tbia and fibula, nto whih is fited the uper part of the ody of the talus. The tals is abl to move on a trnsverse axis in a hingeike mannr. The sape of te bones and the trength of the igaments and the suounding tendons ake this t srong and stable.

Ariculatio Articulation is betwen the lwer end of the tbia, the two malloli, an the bod of the talus (Fig. 10-64 and 10-6). Th inferio transvrse tibofibular ligament, which uns betwen the ateral malleolus and the osterior border o the lowr end of the tibia, deepns the socket ino which he body of the tlus fits snugly. The artcular sufaces ar covered with hyaine cartlage.

Type The anke is a synovial inge t.

apsule The capule encloses the t an is attched to he bone near thir artiular marins.

Ligaents The medial, or deltod, ligaent i strong nd is atached by its ape to the ip of the medial malleols (Fig. 10-5). elow, the deep fbers are attache to the onarticuar area n the mdial surface of he body f the taus; the superfical fibers are atached to the meial side of the talus, the sustentacuum tali, the platar calneonaviular ligment, and the tuberosty of th naviculr bone The latera ligamet is weaker thn the medial ligamen and conists of hree bands. The anterir talofiular ligament (Fg. 10-64) runs from the lateral alleolus to the lteral suface of he talus P.65

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snell

Fiure 10-64 The rigt ankle oint as seen rom the medial apect (A) and te latera aspect ().

The calaneofiblar ligaent Fi. 10-64) runs from the tip of te laterl malleous downard and ackward to the lteral surface of the calcaneum.

1185

snell The posteior taloibular igament (Fig. 10-64) rns from he laterl malleolus to te posteior tubecle of the talus

Syovial Mmbrane The snovial mmbrane ines the apsule.

Nerv Supply Dep peronel and tiial nervs supply the ankl t.

Moements Dorsifxion (oes poining upward) and lantar fexion (oes pointing dowward) ar possibe. The mvements of inverion and eversio take plce at th tarsal oints and not at the ankl t. Dorsifleion is perfored by te tibiais anteror, extesor hallcis longs, extenor digitorum logus and perneus tetius. It is limied by the tensio of the endo clcaneus, the poserior fibers of the medal ligament, and the caaneofiblar ligment. lantar fexion is erformed by the gastrocemius, sleus, plntaris, peroneu longus, peroneu brevis, tibials posteior, fleor digirum lonus, and flexor allucis ongus. t is limted by te tenon of te opposig muscles, the anterior fibers of he medil ligamet, and the anteror talofibular igament. Note tht during dorsiflxion of the ankl t, the widr anterr part f the aticular urface f the taus is foced beween the medial ad latera malleol, causin them to separate P.636

P.637

slihtly ad tighte the ligments o the distal tibiofbular jint. Thi arrangment gratly inceases the stabilty of the ankl t whn the fot is in e initia position for majo thrustin movemens in waling, running, an jumping

1186

snell

Fgure 10-5 Th right ankle jont as sen from he postrior asect (A) and in coronal section B).

1187

snell Nte also hat when the ankle t is fully platar flexd, the liaments o the disl tibioibular jint are lss taut nd small mounts of rotation, bduction, and adducion are posible.

Imortant Rlations    

Anterorly: The tibilis anteror, the etensor halucis lonus, the aterior ibial vssels, th deep proneal nerve, the extensor digitoru longus, and the eroneus trtius (Fig. 0-48) Psteriorl: Th tendo clcaneus nd plantris (Fig. 1-48) Posterolateally (beind the lateral malleolu): Te peroeus longs and brevis (Fig. 10-46 osteromedially (behind te medial malleolu): he tibialis postrior, the flexor digitorum longus, he posteior tibal vessels, the tibial nerve, and te flexor hallucis longus (Fig 1048

Clinical Notes Ankle t Stability The anke t s a hinge t possessing great stability. The deep mortise ormed b the lowr end of the tibia and the medial ad latera malleoli securely holds th talus i positio.

Acute Sprins of te “Latral Ankl― Acute prains o the latral ankl are usully caused by excssive inersion o the foo with plntar fleion of te ankle. he anteior taloibular lgament ad the cacaneofibuar ligamnt are artially torn, giing rise to great pain and local swlling.

Acute Sprains f the âœMedial nkle― Acue sprain of the edial anle are smilar to but les common han those of the lateral akle. The may occur to the medial o deltoid ligament as a reslt of exessive evrsion. Te great strength of the mdial ligment usually resuls in the ligament pulling off the ip of the medial mlleolus.

Fractur Dislocaions of the Ankle t Fracture dislocations o the anke are cmon and re causd by fored exteral rotation and overeversion of the foot. Th talus is exterally rotted forcily againt the laeral malolus of the fibula. The trsion efect on te latera malleols causes t to frcture sprally. I the forc continus, the tlus mov lateraly, and the medial ligamen of the nkle joit become taut an pulls off the ti of the edial maleolus. f the taus is foced to mve still farther its rotay movemet result in its iolent cntact with the posterior iferior mrgin of he tibia which sars off. Oter less omon type of fracure dislcation ae cause by forcd overevrsion (without roation), n which he talus presses the lateal malleolus laterally and causes i to fracture transversely Overinvrsion (wthout roation), which the talus presses gainst te medial malleolu, producs a vertcal fracure thrugh the ase of te medial malleolu.

arsal Jonts 1188

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ubtalar oint he subtaar t is the posterio t btween th talus and the calaneum.

Articulation rticulaton is beween the inferior surface f the boy of th talus ad the faet on th middle f the uper surfae of the calcaneu (ig. 10-3). Th articulr surfacs are covered with hyaline cartilag.

Type Tse s are synovial, of the plane variety.

Casule Te capsul enclose the joit and is attached to the mrgins of the artiular aras of th two bons.

Ligaents Medal an lteral (tlocalcanal) ligaents trengthe the capsule. The inerosseous (talocalcaneal) lgament (ig. 10-6) is strong ad is the main bond of union between the two nes. It is attached abov to the sulcus tali and belw to th sulcus calcanei.

Synoial Membane Te synovil membrae lines he capsue.

Movments liding d rotatory movements are possble.

Taocalcanenavicular t The taocalcanenavicula t i the antrior joit between the talu and the calcaneu and als involve the navcular boe (Fig. 10-).

rticulaton Arculatio is between the rounded head of the alus, te upper urface o the susentaculu tali, ad the poterior cncave srface of the naviular bon. The articular sufaces ar covered with hyline carilage.

Tye The oint is synovia t.

Capsule 1189

snell The capule incopletely ncloses he t

Ligaents Te lantar clcaneonavicular ligament is strong and runs from he anteror margi of the ustentaclum tali to the nferior surface and tuberosty of th naviculr bone. he superor surfae of the ligament is coverd with fbrocartiage and s the head of the tlus.

Synovil Membrae Th synovia membran lines te capsul.

Movements Gliding and rotatory movemes are possible.

alcaneocboid Joit Ariculatio Artiulation s betwee the antrior end of the clcaneum and the poterior srface of the cuboid (Fig. 1037). Te articuar surfaes are cvered wih hyaline cartilag. P.638

Type The clcaneocuoid is synoial, of he plane variety.

Capsle The capsule ncloses he t

Ligamets The biurcated igament is a srong ligment on he upper surface f the jont (Fig. 1064). t is Y saped, an the ste is attahed to te upper urface o the anerior pat of the calcaneu. The laeral lim is attahed to te upper surface f the cuboid, and the medial limb to the upp surface of the navicula bone. The lon plantar ligament is a trong liament on the lowe surface of the jint (Figs. 0-58 ad 0-59) It is ttached to the unersurface of the calcaneum behind a to the undersurface of the cuboi and the bases of the thir fourth, and fifh metatasal bone in fron. It briges over the grooe for th perones longus tendon, cnverting it into tunnel.

1190

snell The shor plantar ligament is a wide, strng ligamnt that i attachd to the anterior tubercl on the undersuface of he calcneum and to the ding part of the cubid bone Fig. 1-59).

Synvial Membrane The syovial mebrane lies the capsule

Movemens in th Subtala, Talocacaneonavcular and Calaneocubod ts The tlocalcaonavicuar and the calcaeocuboi ts re togeter refered to as the midtarsal r transvere tarsal ts. The importan movemens of invrsion a eversion of the foot tae place t the sutalar an transvese tarsal ts nversio is the movemnt of th foot so that the sole faes medialy. Everson i the oppsite movment of he foot o that he sole aces in he lateal direcion. The movemen of invesion is ore extesive than everson. nversion is performed by the tibiais anterior, the xtensor halucis logus, and the medal tendos of extensor digiorum logus; the tibialis posterio also asists. Evrsion i performd by the peroneu longus, peroneus brevis and perneus tertius; th lateral tendons f the eensor dgitorum longus lso assist.

Cueonaviclar The cuneonvicular t is the articulation betwee the navcular boe and the tree cuneiform bones. It is a synovial of the liding varety. The capsle i strengtened by doral and pantar liaments. The cavity is cotinuous with thoe of the intercueiform ad cuneocboid joits and lso with the cunemetatarsal and itermetatrsal joits, betwen the bases of the secod and thrd and te third nd fourt metataal bons.

uboideoavicular t The cboideonavicular oint is sually a fibrous oint, th the two bones connected by doral, planar, and nterosseus ligents.

Intercuniform an Cuneocuoid s The intrcuneifo and cuneocuboid oints ar synovia ts of the pane varity. Thei t cvities ar continuus with that of he cuneonavicular t. Te bones are conneced by dosal, plntar, an interoseous ligments.

Tarsomtatarsal and Intemetatarsl ts

1191

snell Te tarsomtatarsal and intemetatarsl ts re synoial s of the plane vaiety. Th bones ae conneced by drsal, plntar, an interoseous ligments. Te tarsomtatarsal t o the big toe has separat t cvity.

Metatasophalaneal and nterphalngeal Jonts The matarsophlangeal nd interhalangea ts losely rsemble tose of te hand (see pages 16 an 517). The deep transvere ligamets connet the jots of the five tes. The ovements of abducion and dduction of the toes, performed by he interssei musles, are minimal nd take lace fro the midline of e second digit an not the third, a in the hnd.

Clinica Notes Metatasophalaneal of the ig Toe Hallux valgus, which is a lateral deviation of e great toe at the metatarsophalangeal , is a common coition. Is incidece is grater in omen tha in men nd is asociated ith bady fittin shoes. t is oftn accompnied by the presence of a short fist metatarsal bone Once th deformiy is esablished it is prgressivey worsend by the pull of te flexor halluci longus nd extenor hallucs longus muscles. Later, osteoarthitic chages occu in the etatarsohalangea t, hich thn becomes stiff a painful; the condition is then knon as hallu rigidus

Th Foot as a Functinal Unit The Foot as Weight-earer an a Lever Th foot ha two imprtant funtions: to the body weight nd to seve as a ever to ropel th body foward in walking nd running. If the foot posessed a ingle stong bone instead of a series of smll bones it coul sustain the body weight ad serve well as rigid lver for orward populsion (Fg. 10-66). Howver, wit such an arrangemnt, the ot could not adap itself o uneve surface, and th forward propulsive acton would depend entirely on the actvities o the gastrocnemiu and solus muscls. Becase the lver is sgmented ith multple s, the fot is pliable and can adapt itself to uneve surface. Moreover, the log flexo muscles and the mall musles of te foot cn exert heir acton on the bones of the fopart of the foot and toes (i.e., the takeoff point o the foo) and gratly assst the frward prpulsive ction of the gasrocnemis and soeus musces (Fig. 1-66). P639

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Fgure 10-6 The foot as a simple ever (A) nd as a segmente lever (B. Floor rints of a norma foot and a flat foot are also shown

The Arches of the Foot 1193

snell A segmented strture ca hold up weight only if it is built in the form of a arch. Te foot hs three such arches, which re presnt at bith: the meial longtudinal, lateral ongitudial, and ransvers arches (ig. 10-6). I the young child, the foot appears o be fla because of the presence of a large amount o subcutaeous fat on the sle of th foot. On examiation of the imprnt of a et foot n the flor made with the person in the standing posiion, one can see hat the heel, th lateral margin o the foo, the pa under te metatasal heas, and te pads o the distal phalanes are i with the ground Fi. 10-67). The medial mrgin of he foot from th heel to the firs metataral head, is arche above te groun because of the iportant medial lonitudinal arch. Te pressure exerted on the round by the lateal P.64

margin of the foot is gretest at he heel nd the ffth metaarsal hed and last betwen these areas beause of he presece of th low-lyig laterl longitdinal arch. The transverse arch invves the bases of the five metatarsals and te cuboid and cuneform bons. This i, in fat, only half an rch, wih its bae on the lateral order of the foo and i summit on the foot's medial borde. The fot has ben likend to a hlf-dome, so that hen the edial borders of the two feet are aced together, a complete ome is frmed.

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igure 1067 Boes formig the meial longtudinal lateral longitudnal, and transvere arches of the rght foot

From this descriptio, it can be undertood tha the boy weight on standing is disributed hrough a foot via the heel behind nd six pints of wih the grund in font, namly, the two sesaoid bones under th head of the firs metataral and te heads f the reaining fur metatarsals.

The Bons of the Arches 1195

snell An exmination f an artculated oot or a lateral adiograph of the fot shows the bons that frm the arhes. 

Media longituinal arch: Th consist of the alcaneum the talus, the naicular bne, the three cueiform bnes, and he first three meatarsal bones (Fig. 1-63). P.641

 

ateral lngitudinl arch: This consists o the calcneum, th cuboid, and the ourth an fifth metatarsal ones (Fig. 0-67). Transvrse arch This consists of the bses of te metataral bones and the cuboid ad the thee cuneiorm bones (Fg. 10-67).

Mechanisms of Arc Examnation o the design of any stone bridge revels the fllowing ngineering methods used for its supprt (Fig. 168): 





Te shape f the stnes: he most ffective way of spporting the arch is to ma the stnes wedge shaped, with the thin edg of the wedge lyi inferioly. This applies particulrly to th importat stone hat occuies the enter of the arc and is eferred o as th “keytone.― The nferior edges of the stoes are ied togeher: This is ccomplised by inerlockin the stoes or binding thei lower dges togther wit metal staples. Ths method effectivly countracts th tenden of the ower edgs of the stones t separate when the arch i weight-baring. The us of the tie beams: Whe the span of the bidge is arge and the founations a either nd are insecure, tie bem connecing the nds effetively prvents sparation of the illars ad conseqent saggng of the arch. P.642

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Figure 10-68 ifferent methods y which he arche of the oot may e d.



suspenson bridg: Here the maintenance f the arh depend on multple supprts suspnding th arch frm a cable above th level o the brige.

Uing the ridge anlogy, one can now examine te method used to he arche of the eet (Fig. 1-68).

Mintenance of the edial Logitudina Arch 1197

snell 







Shape of the bones: The susentaculu tali hods up th talus; he concae proximl surfac of the navicula bone receives the rounded ead of te talus; the sligt concavty of th proxima surface of the medial cuneform bon receivs the naicular. he rounde head of the talu is the eystone n the cter of te arch (Fig 10-68). The nferior dges of he bones are tied together by the plantar ligament, which re large and strnger tha the doral ligaents. Th most imprtant liament is the planar calcaeonavicular ligaent (Fig. 10-68). he tendious extesions of the insetion of the tibials posteror muscl play an important role in his respct. Tyig the ens of the arch togther are the lantar aoneurosis, the meial part of the flexor digtorum bevis, th abducto halluci, the flexor halluis longu, the meial par of the lexor diitorum longus, and the flexr hallucs brevis (Fg. 10-68). Suspending the arch frm above are th tibiali anterio and poserior an the medal ligamnt of th ankle jint.

Maintenance of te Latera Longitudinal Arch    

Shape of the bone: Minmal shaping of the distal ed of the calcaneu and the proximal end of the cuboid. The cubid is th keyston. The nferior dges of he bones are tied together by the long and short plntar ligments an the origins of t short muscles frm the foepart of the foot (Fig. 10-68). Tying he ends f the arh togethr are the plantar aponeuosis, th abducto digiti inimi, ad the laeral part of the fexor digtorum logus and revis. Suspeding the arch fro above are the peroneus longus an the brevis (Fig. 10-8).

Mantenance of the Tansverse Arch  

 

Shape f the boes: Te marked wedge shping of he cuneifrm bones and the ases of he metatrsal bons (Fig. 10-7) Th inferio edges o the bons are tid togethe by he deep ransvers ligaments, the strong plantar ligamnts, and the oriins of te planta muscles from the orepart f the fot; the orsal inerossei nd the tansverse ead of te adductr hallucs are partiularly important in this rspect. Tyig the ens of the arch togther s the peoneus lonus tendo. Susending te arch frm above are th peroneu longus endon an the peroneus brevis.

The arches f the feet are maitained b the shae of th bones, trong ligments, ad muscle tone. Whch of thse factos is the most imprtant? Bsmajian and Stecko demonstrted electromyograhically hat the ibialis nterior, the peroeus longus, and the small muscles f the fot play n importat role in the normal stati of the aches. Thy are comonly toally inacive. Hoever, duing walkng and rnning al these mscles beome active. Staning immobile for ng perios, especally if he person is overeight, paces excssive strin on th bones ad ligamets of the feet ad results in fall arches r flat fet. Athltes, rote-marching soldies, and nrses are able to ustain their arche providd that tey receive adequa trainin to deveop their muscle tone.

Clinica Notes Clinicl Probles Associaed With he Arche of the oot

1198

snell Of te three rches, th medial ongitudial is th larges and clincally th most imortant. he shape of the bnes, the strong lgaments, especialy those n the platar surfce of th foot, nd the tne of mucles all lay an iportant ole in spporting the archs. It ha been shwn that in the actve foot he tone f muscles is an iportant actor i arch . Whe the musles are atigued by excessive exercse (a log-route arch by n army rcruit), y standig for log period (waitress or nurs), by ovrweight, or by ilness, the muscula gives wa, the liaments ae stretced, and pain is poduced. Pes lanus (flat fot) is a condition in which the medil longitdinal arh is depessed or collapsd. As a esult, the forefo is dispaced latrally an everted. The hea of the alus is o longer d, and te body eight forces it donward an mediall between the calcneum and he naviular bon. When te deformiy has exsted for some tim, the pantar, clcaneonavcular, ad medial ligament of the nkle t become permanenly strethed, and he bones change sape. The uscles nd tendons are als permanetly streched. Th causes f flat foot are bth congeital and acquired Pes cavus (lawfoot) is a codition in which th medial ongitudial arch s unduly high. Mot cases are causd by mucle imbaance, in many instnces reslting frm poliomyelitis.

T Propulive Actio of the oot Standi Immobil The body weigt is disributed ia the hel behin and the heads of the metaarsal bones in frnt (incluing the wo sesamid bone under the head of the firs metataral).

Waking A the bod weight s thrown forward, the weigt is born successvely on he laterl margin of the fot and te heads f the mtatarsal bones. As the heel rises, te toes ae extende at the metatarsphalangel ts and the plantar poneurosi is pulld on, tus shortning the ie beams and heigtening te longitudinal arces. The “slack€• in th long fleor tendos is takn up, threby incrasing teir effiiency. Te body i then thown forward by the actions f the gstrocnemus and seus (and plantari) on the ankle jont, using the foo as a leer, and y the tos being strongly lexed by the long nd shor flexors of the fot, P.643

prviding he final thrust frward. Te lumbrials and iterossei contract and kee the toe extended so that hey do nt fold uder becase of the strong ction of the flexr digitoum longu. In thi action, he long flexor tendons also assist in plantar flexin the anke t.

Running When a erson runs, the weght is brne on te forepat of th foot, an the hee does no touch te ground The forard thrut to the bod is provded by te mechaisms desribed for walkin (above.

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snell

Clinial Notes Burse and Busitis in the Lowe Limb A variety of brsae are found in the lowr limb were skin, tendons, ligaments, or mucles reeatedly b agains bony ponts or idges. rsitis, or inflamation of a bursa can be caused by acte or chonic truma, crytal disese, infetion, or disease f a neihboring oint that communicates with the bursa. An inflamed bura becoes distended with excessive amounts of fluid. The following buae are prone to inflammation: the ursa ove the iscial tubeosity; te greatr trochater burs; the prpatellar and supeficial ifrapatelar burse; the bursa betwen the tndons of insertio of the artorius gracilis, and seitendinous muscls on the medial poximal aect of he tibia and the bursa beween the tendo calcaneus a the uppr part of the calcaneum long-disance runer's ank). Two imortant brsae comunicate ith the nee , and tey can bcome disended if excessiv amounts of synoval fluid accumulate within the . The surapatellr bursa xtends poximally about tree fingrbreadth above te patell beneath the quadrceps feoris muscle. The brsa, whih is assciated wth the inertion o the seimembranosus muscl, may enarge in atients ith osteoarthritis of the knee joit. Th anatomi bursae escribed should nt be conused wit adventitius bursae, whih develo in respnse to anormal ad excessve fricton. For example, a subcutaneous bursa someties develops over he tend calcaneus in resonse to adly fiting shoe. A bunion is an aventitia bursa lcated ovr the meial side of the hd of the first metatarsal one.

Embrologic Ntes Developmnt of th Lower Lb The limb buds appear during the sixth week of developmnt as th result f a locaized proiferatio of the somatopluric mesenchyme. Tis cause the ovelying ecoderm to ulge frm the trnk as tw pairs o flattend paddles. The leg buds devlop aftr the ar buds an arise a the leve of the ower fou lumbar nd uppe three sacral segmnts. The flattene limb bus have a cephalic paxial boder ad a caudl ostaxial border As the limb uds elonae, the msenchym along te preaxal borde becoms innervted by te second lumbar rve to he first sacral nrve and that of the postaial borer becoms innevated by the firs to the third sral neres. Late, the meenchymal masses divie into aterior and postrior groups, and the erve trnks enteing the bas of each limb alo divide into antrior and poserior diisions. s develoment cotinues ad the limbs furter elonte, their atachment to the trun moves audally At the ame time the mesnchyme wthin the limbs ifferentates int individal muscls that mgrate wihin each limb. a consquence o these to factos, the aterior rmi of th spinal nerves become aranged near the base of te limb into e complcated lmbosacra plexus.

1200

snell It s intereting to note tha the dermtomal patern in the lowr limb apears t be mor complicted than that of he uppe limb (ee Figs. 1-26 and 1-27. This an be exlained ebryologcally, snce during fetal developmnt, the lower lib bud undergoes edial roation as it grows out from the truk. This esults i the big toe comng to lie on the edial side of th foot an accouns for th spiralig patten of the dermatoes.

Ectromelia In ecromelia, there is a partil absenc of a lower limb (Fig. 10-9). Te condiion in he upper limb is escribed on page 21.

Congental Dislcation o the Hip Cngenita dislocaion of te hip is 10 times more cmmon in emale cildren tan in mae childrn, and it is partcularly common n northen Italy (Fig. 10-0). Tree posble caues have een suggsted:  



Geeralize t laxity: Excessie laxity of the igaments of the hp t ay predispose to this codition. Breech positio: Th flexed ip and extended nees of he breec positio may altr the ormal prssure of the head of the femur on he acetalum, an this my result in a failure of the uper part o the acetabulum to develop adeuately. Shalow acetabulum: If the acetablum is porly developed, he upper lip offrs an isufficint shelf under wich th head of the femu can lode. The conditin of shalow acetbulum tends to rn in families.

Congenital islocatin of th hip shuld be dagnosed t birth and is teated by splintin the jont in th position of abuction.

Genu Rcurvatum Hyprextensin of th knee jont is fond in baies who have had a breech presentaion with extended legs. N treatmet is required, ecause the legs return to ormal wthin a fw weeks.

Talpes lipes (club ft) ofte is caued by abormal poition r restrited movement of he fetu in uter. A smal number of cases may be caused b muscle aralysis associated with pina bifda. The differet types re named accordig to the position of the fot. Talipes cacaneovalus is a form of club fot in whch the fot is dosiflexed at the ankle joit and evrted at the midtrsal jots. In taipes equnovarus the oot is lantar fexed at he ankl t ad invered at th midtarsl ts (ig. 10-7). Th conditins may b unilateal or biateral, an the require orhopedic treatment

Meatarsu Varus Metatarsus varus is a commo conditon in which the foreoot is dducted on the rar part of the fot. Corrction my be acomplishe by manpulatio folloed by spinting.

Overrding Toe 1201

snell Ovriding oes most commonly involves the forth and fifth tes. The ourth te is deressed ad overriden by te fifth toe. Thi may be correcte by th applicatin of splints.

Cury Toes Curly oes most often afects the fourth and fift toes; he condiion commnly runs in famiies. The affecte toe lie flexed under it medial neighbor. In mild cases, tere is n treatmet; in svere caes, the lexor diitorum lngus tenon is transplante into t extensor tendon. P.64

Radiogaphic Antomy Radioraphic Apearancs of the Lower Lmb Radioogic exmination of the ower lim concenrates minly on the bony structurs, because mot of th muscles tendon, and nrves bled into a homogenous mass Exampls of radographs f the ifferen regions of the ower lim are shon in Figres 10-7, 10-73, 10-74, 10-75, 1076, 10-7, 10-78, 0-79, 10-0. Magnetic resonance imagng of the lower lmb can b useful o demonsrate the soft tisues aroud the boes (Fig. 1081).

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Figure 10-69 Ectromela. (Couresy of G. Avery.)

Srface Atomy The follwing infrmation hould be verifie on te livin body. A adequat physica examinaion of te lower imb of a patient requires a sound knowledge f the suface anaomy of te region

Glutel Region The ilic crests are eaily palpble alon their etire lenth (Figs. 1-82 an 1-83). Each cret ends i front at the anterio superio iliac sine (Fig. 10-79 and 10-80) and bhind at he posterio superio iliac spine (Fig. 10-82; the laer lie beneath a skin diple at te level f the seond sacr vertebr and the middle o the sacroiliac jont. The ilic tuberce is a prominnce felt on the oter surfce of the iliac cest abou 2 in. 5 cm) posteror to th anterio superio iliac sine (Fig. 10-83.

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Figure 0-70 adiograp of bilaeral conenital dslocation of the hp showin that te femora heads ae not wihin the shallow actabular ossae. (Courtesy f J. Adas.)

P.65

Figure 10-71 Talipe equinoarus. (Curtesy o J. Adams.)

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Figue 10-72 Anterposterior radiograph of th hip joit. Note tat the iferior argin of the neck of the fmur shoud form a continuos curve ith the upper margin of the obturar foramen Shenton' line).

The ischia tuberosty can be palpted in t lower prt of th buttock (Fgs. 10-8 and 10-). I the stading position, te tuberoity is cvered by the glutes maxims. In th sitting position the iscial tubeosity emges from beneath the lowe border f the glueus maxius and spports te weight of the ody; in this positon, the uberosit is sepaated from the ski by only a bursa and a pa of fat.

1205

snell he greater rochante of te femur an be fet on the lateral urface o the thih (Figs. 1082 and 1083) nd moves beneath he examiing fingr as the ip t is flexe and exended. I is impotant to tht, in the normal ip t the uper borde of the reater tochanter lies on a line conecting te anteror superor iliac spine to the ischal tuberosity (Fig. 10-83). The spnous processes of the scrum (Fig. 0-79) re fuse with eac other t form th mdian sacal crest. The rest can be felt eneath te skin in the upper part of the clef between the buttcks. The ip of th ccyx an be papated beeath te skin i the clet betwee the butocks abot 1 in. 2.5 cm) P646

.647

P.648

P.649

P.650

behind te anus (Fig 10-83). The aterior srface of the coccx can be palpated with a goved finer in th anal caal.

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Fiure 10-7 Anteoposterir radiogaph of te adult knee.

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Figre 10-74 Latera radiogrph of th adult kee.

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Figure 0-75 angentia view of the patela.

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Figure 0-76 eumoarthrography of the knee.

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Figure 1-77 Ateroposterior radograph o the adut ankle.

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igure 1078 Latral radigraph of the adul ankle.

The fod of the buttocks is most promient in the standin positio; its loer borde does no corresond to te lower order of the gluts maximus muscle. The scitic nerv in th buttock lies uner cover of the guteus maimus musle. As i curves laterall and dowward, it is situated at fit midwa between the poserior superior iliac spine and the schial tberosity and, lowr down, midway beween the tip of te greate trochaner and te ischia tuberosity (Figs. 10-82 ad 0-83).

nguinal Region The inguinl ligamet lies beneath the skin fold in he groin and can e felt aong its ength. I is attched latrally to the anteror superor iliac spine an mediall to the ubic tubrcle (Figs. 10-83 and 10-84. The sphysis ubis i a cartiaginous oint tha lies in the midlne betwen the bodies of t pubic bnes (Fig. 1-80). The upper mrgin of he symphsis pubi and te bodies of the pbic bone can be elt on plpation hrough th lower prt of th anterio abdominl wall. Te ubic tuercle an be fet on the upper boder of te pubis Fis. 10-83 and 10-84). Atached to it is th medial nd of th inguinal ligament The tubrcle is easily plpated i the mal by invginatin the scrtum with the exaining fnger. In the femle, it can be papated though the lateral margin o the laum maju.

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snell The pubic crest is the rige of bone on the upper suface of he body of the pubis, medial to the pubic tuercle (Figs 10-7 and 10-8)

Femoral Triangle The fmoral trangle ca be seen as a depession blow the old of te groin n the upper part f the thgh (Figs. 1-83 an 1-84). In a thin muscula subjec, the bondaries f the trangle ca be idetified wen the tigh is fexed, abucted, ad lateraly rotated. The ase o the tringle is ormed by the ingunal ligaent, the laeral borer by the sarorius muscle, and the medial order by the aductor logus musce. The horizontl group f uperfical inguinal lymph odes an be papated in the supeficial fscia jus below ad parallel to the nguinal igament Fi. 10-). The femora artery enters he thigh behind te inguinl ligamet (Fig. 10-) at the midpoint of a line ing the symphysis pbis to e anterir superir iliac pine; it pulsatins are easily felt (g. 10-84). Te emoral vin leves the high by assing bhind the inguinal ligament medial to the pulating feoral artery (Fig. 10-6). The lower opning of he femoral anal ies belo and lateral to th pubic tbercle (Fis. 10-3 and 106). The femora nerve enters e thigh behind the midpoint of the nguinal igamentâ”that is lateral to the plsating emoral atery (Fig. 0-6). The great aphenous vein pierces te saphenus openig in the deep fasca (fasci lata) o the thih and jons the P.651

P.652

P.653

P.654

femoral ein 1.5 n. (4 cm below ad latera to the ubic tubrcle (Figs. 10-3 ad 0-19)

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Figure 1-79 Ateropostrior radograph of the adul foot.

Fgure 10-0 Antroposterir radiogaph of te foot sowing th epiphyss of the halanges and metaarsal boes (10-yar-old b).

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Figure 10-81 Transverse (axial) protn density magnetic resonanc image o the rigt knee with intr-articulr gadoliium–saine solution (as en from below).

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Figur 10-82 The glutal regio and the posterio aspect o the thih of a 2-year-ol woman.

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Figure 1083 Surace markngs in te glutea region nd the ront of he thigh.

Adductor Canal

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snell The adducor (subsrtorial) canal lies in te middle third of the thig (ig. 10-8), imediatel distal t the ape of the emoral tangle. I is an ntermusclar clef situate beneath the sartrius musle and i bounded laterall by the astus meialis mucle and steriorl by the adductor longus ad magnus muscles. t contais the feoral vesels and the saphnous nere.

Knee Region In frot of the knee t the patela and the ligamenum patelae can be easil palpate (ig. 10-8). Th ligamentum patelle can be traced dwnward t its attchment t the tuberoity of te tibia. The condyles of the femur ad tibia can be recognizd on the sides of the knee and the oint lin can be dentified between hem (Fig. 10-85). The banlike medial collaterl ligamet and the rouned lateral ollatera ligament can be palpated on the sides of the joi line; tey can b followe above ad .655

P.656

blow to teir bony attachments. Because the lgaments over the t ne, the t line cannot e palpatd at the sites of the colleral liaments (Fig 10-61).

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Figure 10-84 nterior spect of the thig of a 27year-old man. The broken lnes indcate the boundaris of the femoral riangle. The righ leg is laterall rotated at the hp t.

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Fiure 10-8 Anteior aspe of the right kne of a 27year-old man.

The meisci ae locate in the interval between he femorl and tibial condyles. Although not recognizable, the outer edes of th medial nd lateral menisci can be alpated n the jont line etween te ligametum patelae and he medial and latral collteral liaments, espectivly. Th tndon of iceps an be fet as a runded stucture o the latral aspet of the knee and can be taced dow to the hea of the ibula (Fig. 10-85).

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igure 1086 Surace markngs in te poplital fossa the frot of the leg, and the foot

The commn peronel nerve can be rolled bneath the examinin finger ust belo the hea of the fibula (Fig 10-86; here i es orward aound the lateral ide of te bone.

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snell The addctor tubrcle an be papated on the medil aspect of the femur just above th medial ondyle; he hamstring part of the addutor magns can e felt pssing to it (Fig. 1086). Behnd the kee t is a diaond-shapd skin dression alled th ppliteal ossa Fi. 10-86). When the knee is flexed, the dep fascia which rofs over the foss, is reaxed and the bounarie are easly define. Its uper part s P.657

ounded lateally y the tedon of te biceps femoris uscle an mdially by the tendons of the semembranous and smitendinsus musces. Its ower par is bouned on eah side b one of he heads of the astrocneius musce. Th cmmon perneal nere ca be palpted on th medial ide of te tendon of the bceps femris (Fig. 1-86), as the ltter pases to it insertin on the head of he fibul. With he knee oint partially flexed, the nerve ca be rolld beneat the figer. Th opliteal artery can be felt by entle papation in the depths of th poplite fossa, provided that th deep fascia is fuly relaxd by pasively flxing the knee t.

Tibia The medal surfae and anerior boder of te ibia re subcuaneous and can be elt thrghout their length (Fig. 10-5).

Ankle egion an Foot In the region o the anke, the fbula is subcutaneos and ca be follwed downard to frm the lateal mallelus (Figs 10-86 and 10-87). The tp of the meial mallolus f the tiia lies bout 0.5 in. (1.3 cm) proxmal to the level o the tip of the lteral maleolus (Fig. 10-86 and 10-87). In he interal behin the medal mallelus (Fig. 1-86) and the medial surface of th calcanum lie the following structures, in the ordr named: the tendon of tibialis postrior, the tendon of flexo digitorm longus, the poserior tiial vessls, th osterior tibial nrve, ad the tendo of flexr hallucs longus. The ulsation of the poserior tibial arter can e felt hlfway beween the edial maleolus ad the heel (ig. 10-). Beind the ateral mlleolus re the tendns of peoneus brvis an longus Fis. 10-87 and 10-88).

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Figur 10-87 Lateral aspect (A) and meial aspet (B) of the right ankle of a 29-yea-old woan.

On the anterior suface of he ankle t, te endon of tibialis anterior can be seen when the foot is dorsiflexed ad invertd (Figs. 1086 an 1-88). he tendon o extenso halluci longus lies lteral to it and cn be made to stand out by etending he big te (Figs. 1086 an 1-88). Lateral o the exensor halucis longus lie te endons o extenso digitorm longus and peroeus tertus. Th pulsatins of th drsalis pdis artey ca be felt between the tendon of extsor hallcis longs and etensor dgitorum ongus, mdway beten the to malleoi on the front o the anke. On the poterior srface of the ankl t, he prominence of te heel i formed y the calcneum. bove th heel is he tendo clcaneus (Achills tendon (ig. 10-8). On the orsum of the foot the head o the tals can be palpaed just n front f the maleoli (Fig. 1087) The tendos of extnsor digitorum longus an tensor hallucis longus an be mae prominnt by dosiflexin the toes (Fg. 10-86). The dorsa venous rch or plexus cn be see on the orsal suface of he foot roximal o the tos (Figs. 1019 and 1-87. The great saphenous vein leaves te medial part of he plexu and pases upwar i front of the edial maleolus (Fig. 10-87. The small saphenou vein drains te latera part of the plexu and pases up behind the ateral malleolus (Fig 10-19). On the lateal aspec of the oot, the peoneal tuercle of the clcaneum an be papated abut 1 in. (2.5 cm) below and in front of the tp of the lateral alleolus (Fg. 10-86). Aboe the tuercle, te endon of peroneus brevis es orward to its insetion on he promient tubeosity on the 1224

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ase of te ifth mettarsal bne (Fig. 0-87) Below te tubercle, the tendn of perneus lonus pases forwad to entr the grove on te under spect of the cubod bone.

Fiure 10-8 Anteior aspet (A) and posterio aspect B) of th right foot and nkle of 29-year-old woma.

On the medial aspec of the fot, the sutentaculm tali can be plpated aout 1 in (2.5 cm below te tip of the medil malleous (Fig. 1087). he tendo of tibilis postrior lie immediaely abov the sutentaculm tali; he tendo of flexor digitorm longus crosses ts medil surfac; and th tendon f flexor hallucis ongus wids aroun its loer surfae. In ront of he sustetaculum ali, the tubersity of he naviular bon can e seen ad palpatd (Fig. 107). I receive the mai part of the tendo of insetion of he tibialis poterior mscle.

Clinial Notes on the Ateries o the Lowr Limb Aterial Plpation

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snell Every health prfessiona should now the recise osition f the man arteris within the lowe limb, fr he or he may e called on to arrst a sevre hemorhage or alpate different rts of he arterial tree in atients ith arteial occlsion. The femoral arery eners the thigh beind the nguinal igament t a poin midway btween the anterouperior liac spie and the symphysi pubis (Fig 10-84). The rtery is easily palpated hee becaus it can e presse backwar against the pectneus and the supeior ramu of the ubis. he poplitea artery can be felt by gentle plpation n the deths of te popliteal space provided that the deep fascia s fully laxed by ivel flexing the knee t (Fig 10-41. The dorsals pedis rtery lies between the endons o extenso halluci longus ad extenr digitrum longs, midwa between the media and latral malloli on te front of the ankle (Fig. 1044). Te osterior tibial artery asses beind the edial maleolus, ad beneat the fleor retinculum; t lies btween th tendons of flexor digitoru longus nd flexo hallucs longus The pulsations o the artry can be felt miday betwen the mdial maleolus an the heel (Fg. 10-49). I should e remembeed that he dorsais pedis artery s someties absent and is rplaced b a large perforatng branc of the peroneal rtery. I the sam manner, the peronal arter may be larger tan norma and repace the psterior ibial arery in te lower part of the leg.

Colateral irculatio If the arteial supply to the eg is ocluded, ncrosis or gangree will fllow unles an adeuate bypss to th obstrucion is presentâ€hat is, collateal circuation. Suden occlsion of he femoal arter by ligaure or embolism, fr exampl, is usully folowed by gngrene. owever, radual oclusion sch as ocurs in therosclrosis is ess likely to be ollowed y necross becaus the colateral bood vessls have time to dlate fuly. The cllateral circulaton for te proximl part o the femoal arter is throgh the cuciate ad trochateric anstomoses; for the emoral atery in he addutor cana it is trough th perforaing branhes of th profund femori artery d the aricular ad musculr branche of the emoral nd poplital arteres.

Traumat Injury Injur to the arge femoral arter can caue rapid exsanguiation of the patiet. Unlike in the upper extemity, aterial njuries f the lower limb d not hav a good rognosis The collateral crculatios around the hip nd knee ts, alhough prsent, ar not as adequate as those round th shoulder and elbw. Damag to a nighborin large vin can futher comlicate te situaton and cuses furher imparment of the circlation t the disal part f the lib.

Arerial Oclusive Dsease of he Leg Artrial occusive disease of te leg is common i men. Ichemia o the musles produes a cramplike pain with eercise. f the fmoral arery is ostructed, the suppy of blod to the calf musles is nadequat; the paient is frced to top walkng after a limite distance because of the intensit of

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snell the ain. Wit rest, te oxygen depletio is corrcted and the pain disappeas. Howevr, on resumption f walkin, the pan recurs This codition i known a itermittet claudiation.

Sypathetic Innervaton of the Arteries Smpatheti innervaon of th arterie to the eg is drived frm the lowr three horacic nd upper two or tree lumbr segments of the spinal crd. The reganglinic fiber to the lowe thoracc and uper lumbr ganglia via white rai. The ibers synapse in the lumar and acral ganglia, ad the potganglioic fiber reach he bloo vessels via branhes of he lumba and sacal plexues. The femoral artery eceives its sympathetic ibers frm the femoral and obturtor nervs. The mre dista arterie receive their pstganglinic firs via he commo peronea and tibal nerve.

Lumbar ympathecomy and cclusive Arterial Disease Lumbar sympathectomy may e advocted as a form of treatment for occlusive arterial disease of the lower limb t increas blood low throgh the ollatera circulaion. Preanglionc sympahectomy s performed by rmoving te upper three lubar gangia and he interening pats of th sympatetic truk. P.69

Clinial Notes on the erves of the Lowe Limb Tedon Reflexes of he Lowe Limb Skeltal musces receie a segntal inervation Most mscles ar innervaed by tw, three or four spinal nerves an therefre by th same number of segments o the spial cord. The segental innervatio of the followin muscles in the lwer limb should be known because t is posible to est them by eliciing simpe muscle reflexs in the patient.  

Patelar tendo reflex (knee jerk) L2 3, and 4 (extenson of th knee jint on tppin the patellar tedon) chilles tendon rflex ankle jrk) S1 and S2 (plantar flxion of he ankle t on tapping the Achiles tenon)

Femoral Nerve Inury he femoal nerve (L2, 3, and 4) eters th thigh fom behnd the iguinal igament, at a pont midway betwee the antrior sperior iiac spin and th pubic ubercle; it lies about a fingerbradth laeral to the femorl pulse About 2 in. (5 cm) belo the inuinal ligament, th nerve slits int its terinal braches (Fig. 10-28) The feoral nerv can be njured i stab or gunshot wounds, ut a comlete divsion of he nerve is rare. The folloing cliical feaures are resent wen the nrve is cmpletely divided:

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Motor: The qudriceps emoris mscle is aralyzed and the knee cannt be extended. I walking this is compensaed for t some extent by us of the adductor muscles. Sensoy: Skn sensation is lt over e anterior and meial side of the high, ovr the medial side of the lwer part of the lg, and along the mdial boder of te foot a far as he ball of the big toe; ths area is normall supplie by the aphenous nerve.

Scitic Nerv Injury The siatic neve (L4 ad 5 and 1, 2, an 3) curves lateraly and dwnward trough th gluteal region, ituated t first idway beween the posterosperior iiac spin and the schial uberosit, and loer down, midway btween th tip of the greate trochater and he ischil tuberoty. The erve the es ownward in the miline on he posteior aspet of the thigh and divides nto the common proneal an tibial erves, t a variable site bove the poplitel fossa Fis. 10-16 and 10-1).

Traua The erve is ometimes injured by penetrating wouns, fracures of he pelvi, or disocations of the hp t. It is most frequently injured by badl placed tramuscular injections in he glutal region. To avoid this jury, inections nto the luteus aximus o the glueus medi should e made wll forwad on the upper oter quadant of te buttoc. Most nrve lesins are icomplete, and in 0% of inuries, te common peroneal part of he nerve is the mst affeted. Thi can proably be xplained by the fat that te common peronea nerve fibers lie most suprficial n the scatic nerve. The following linical eatures re preset: 



otor: The hamtring mucles are paralyze, but weak flexion of the ee is ossible because of the actin of the sartoriu (femora nerve) nd graclis (obtrator nerve). All he muscls below he knee re parayzed, an the weiht of th foot cases it to assume e plantr-flexed osition, or footdrp (Fig. 0-89). Sensory: Sensaion is lst below the knee except or a narow area own the medial sde of th lower prt of th leg and along th medial order of the foo as far as the ba of the ig toe, which is supplied by the aphenous nerve (fmoral neve).

The reslt of perative repair f a sciaic nerve injury s poor. t is rar for actve movemnt to reurn to te small uscles f the fot, and snsory reovery is rarely complete. Loss of sensation in the sle of te foot makes the development of trohic ulces ineviable.

ciatica Sciatia describs the codition i which ptients hve pain along th sensory distribuion of te sciati nerve. hus, the pain is experiened in th posterior aspect of the thgh, the osterior and laeral sides of the leg, and the laterl part the foo. Sciatca can b caused y prolape of an ntervertebral dis (see page 58), ith presure on oe or mor roots o the lowr lumbar and sacrl spinal nerves, ressure on the acral pxus or siatic neve by an intrapevic tumo, or infammation of the siatic neve or its terminal branches.

Cmmon Perneal Nere Injury

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snell The common proneal nrve (Fig. 1-16) is in an exposed osition s it leaes the ppliteal ossa and winds aound the neck of he fibul to ente the peroneus longus muscle. I is commnly injued in frctures o the nec of the fibula ad by presure from casts or splint. The folowing clnical fatures ae presen: 



Motr: Th muscles of the anterior nd lateral compartments of he leg e parayzed, naely, the tibialis anterior, the extesor digiorum lonus and revis, te perones tertiu, the extensor halucis logus (suplied by the deep peroneal nerve), nd the peroneus lgus and brevis (supplied by the suerficial peroneal nerve). s a resut, the pposing uscles, he plantr flexor of the ankle t and th invertrs of th subtala and trasverse trsal joits, caus the foo to be lantar fexed (fot drop) nd invered, an atitude rferred t as equinovarus Fi. 10-89). Sensory: Loss of sensaion occus down te anteri and latral side of the eg and orsum of the foot and toes includig the medial side of the bi toe. Te latera border f the fot and th lateral side of he littl toe are virtuall unaffeced (sura nerve, ainly fomed from ibial nrve). Th medial border of he foot as far a the ball of the bg toe i completly unaffcted (sapenous neve, a brnch of te femora nerve)

When he injur occurs distal to the site f origin of the ateral ctaneous erve of he calf, the loss of sensiility is confine to the rea of te foot ad toes.

Tibial erve Injry Te tibial nerve (Fig. 10-17 leaves the poplteal fossa by ing deep to the gastrocnemus and oleus mucles. Beause of its deep and protected posiion, it is rarey injurd. Complte division resuts in the followng clincal feaures: 



Motor: All he muscls in the back of he leg ad the soe of the oot are paralyze. The oosing mucles doriflex th foot at the ankl t and evert he foot t the sutalar an transverse tarsal ts, an attitde refered to as calcaneovalgus. Snsory: Sensation is los on the ole of te foot; ater, trphic ulcers develop.

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Figure 0-89 ootdrop. With this conditio, the inividual atches hs or her oes on the ground when waling.

Obturtor Nerv Injury The bturator erve (L2 3, and ) enters the thig as antrior and posterior division through the uppe part of the obtrator fomen. The anterior division descends in front f the oturaor extenus and the addutor brevs, deep o the flor of the femoral triangle The poserior diision descends behnd the aductor revis an in front of the aductor mgnus (Fig. 0-30) It s rarely injured n penetrting wouds, in aterior islocatios of the hip , or in bdominal herniae hrough te obturaor foramn. It ma be presed on by the feta head duing parturition. The folloing clincal featres occu:  

Mtor: ll the adductor uscles ae paralyed excep the hamtring part of the adductor magnus, hich is upplied y the sctic nerv. Senory: e cutaneus sensoy loss i minimal n the meial aspet of the high.

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Clinical Problem olving tudy the followin case hitories ad select the best answers o the qution folowing thm. Ater a major abdoinal opeation, a patient as given a course of antibotics by ntramuscular injection. Te nurse as instrcted to give the jections into the right bttock. Lter, whe the patent left he hospal, he dveloped several ymptoms ad signs hat suggsted tha the injetions ino the guteus maxmus musce had ben given oer the curse of he sciatc nerve and had aused a esion of the commo peronea nerve. 1. The symptoms and sign displayd by thi patient included he folloing excet which? (a) e experinced numness and tingling sensations down te anterir and laeral sids of the right le and the dorsum o the foo. (b) Hi right fot tended to catch on step and on he edges f the capet. ( On tesng, he hd impaird skin snsation n the laeral side of the rght thig. (d) he patiet tended to hold he foot lantar fexed and slightly nverted. (e) Dorsiflexion of the rght ankl t ws weaker than the same moement of he left nkle. (f) The everter uscles o the rigt midtaral t were weer than hose of he opposte side. iew Answr 1 C. The skin on he laterl side o the thih is innrvated by the latral cutaeous nere of the thigh (L and L3) a branc of the lumbar plxus. A 45-year-ld man omplaining of a lmp in the groin wa seen by his physcian. The lump, which causd him no pain or iscomfor, was fist recognzed 3 onths peviously On examnation, large dscrete ard lump was foun about 2 in. (5 c) below nd laterl to the pubic tubrcle on he front of the ght thig. 2 The folowing sins indicated that this patint had a melanom of the ight big oe with secondares in the inguinal lymph ndes excet which? (a) Tw smaller hard swelings wee found mmediately below te large welling. (b) On flexing te right nee , three mall hard swellins could e palpatd in the popliteal fossa. (c) Te externl genitaia were ound to b normal. (d) Examiation of he anal anal revaled noting abnomal. (e) small pgmented ole was iscovere beneath the nail of the riht big te.

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snell View Anser . B. Melanomas, wich are ighly malignant tmors, ted to iniially sread via the lymp vessels o the local lymph nodes. Tese becoe enlarged and fim on palation. Te lymphaic drainge of th big toe is into the vertcal grou of superficial inuinal lyph nodes A 54-yea-old womn complining of abdomina pain an repeated vomiting was seen in the mergency departmet. On qustioning, the patint state that th pain w severe nd colicy in natre and mst intene in the region of the umblicus. O examinaion, the abdomen was distened, and xcessivey loud owel perstaltic sunds coud be head with te stethoope. A iagnosis of acute intestinl obstrution was made secndary to a left eoral heria. 3. he folloing stateents conerning tis case re corret except which? (a) A smll, tendr, tense swelling was foud in the front of the left thigh. (b) Whe the patent was sked to ough, thre was no expanson of th swellin in the left thih. (c) The welling n the let thigh was locaed below and medil to the left pubc tuberce. (d) The hrnia ad stranulated cause o the unyelding nature of te femora ring. (e) A oop of sall intesine was orced ino the feoral sac and the ain from the smal bowel ws referrd to the umbilicu. (f) Veous congstion folowed by arterial occlusio of the itestinal loop was responsile for te intestnal obstction. View nswer 3. C. The sweling of th femoral hernia i always ocated blow and teral o the puic tuberle. A 7-year-od woman complainng of a ull, achng pain in the lower part o both les visitd her phsician. he state that th pain wa particularly severe at th end of long da of staning at er work. On examiation, te patiet was fond to hae widespead variosed veis in bot legs. 4. The followig symptos and signs supprted the diagnosis except which? (a) Th patient stated that the skin don the meial side of the eg was iritated, especialy in dy weathe. (b) I the patent couged in te staning posiion, a fuid thrll was tansmitted from te abdomn to the hand plpating the veis. (c) Te skin sowed mared discooration ver the edial maleoli an was dry and scal. (d) The patent had a large family of ix children and the varicosd veins showed improvemet during each prgnancy. (e The geat and mall sapenous vins in oth legs were enarged an elongatd. View Aswer 1232

snell 4. . During the latr months of pregnncy, the enlarged uterus presses on the infrior vena cava and impedes the venous retur from th lower limbs. Tis condiion resuts in a orsening of preexisting vricosed veins. A 25-year-ol man was itte to the emergenc departmnt after an autombile accdent Apart rom othe superfiial injuies, he as found to have fractur of the middle tird of te right emur. 5. he folloing statments cocerning this patient are possible except whih? () The riht leg ws 2 in. 5 cm) shrter tha the lef leg. (b) A latral radigraph shwed overap of he fragmnts, wit the disal fragment rotatd backwad. (c) A lare amount of force would b necessary to restre the lg to its original length. (d) The hamstrings and qadriceps femoris muscles ere respnsible fr the le shortenng. e) The sleus musle was rsponsibl for the backward rotation of the dstal frament. View Answer 5. E The gasrocnemiu muscle s responible for the backard rotaion of te distal fragment of the ractured femur. A 65-year-ld man tld his hysician that he ould wal only abut 50 yd (46 m) efore a cramplik pain in his left leg forcd him to rest. Afer a thoough phsical exmination, a diagnois of severe intmittent claudicaion of the left leg was mae. 6. The ollowing findings in this atient spported he diagnsis except which? (a) Hi femoral pulses wre norma in both legs. (b) The popliteal, poterior tbial, an dorsals pedis ulses wee presen in the ight leg and competely asent in the left g. (c) Ateriograhy reveaed a blokage of he left emoral atery at he level of the aductor tbercle. (d) he lower part of he left eg was eceiving its bloo supply hrough te muscula and gecular brnches o the femral artey and th muscula and gencular brnches of the popiteal arery. (e) he collaeral cirulation n the lft leg ws adeque to prevent gangene but as insuficient t supply oxygen t the actve leg mscles. f) The prforatin branche of the profunda femoris rtery di not participate n the colateral circulaton aroun the bloked femoral arter. Vew Answe 6. F. The profunda femoris rtery arses from he femorl artery about 1. in. (38 cm) beow the iguinal lgament. t plays major rle in th formaton of th collateral circulation around the nee

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snell A meical stuent, whie playig footbal, collied with nother payer and fell to he groun. As he fell, th right kee, whic was taking the weight of his body, was partally fleed; the emur was rotated medially and the leg was abducted n the thgh. A suden pain was felt in the rght knee t, nd he wa unable o extend it. The tudent ws diagnoed as having a orn medil meniscs of the knee jont. 7. Te followng stateents cocerning his cas confirmd the dignosis ecept which? a) The right knee t qickly beame swolen. (b) evere lcal tendrness wa felt aong the edial sde of th t line. (c The medal menisus split along pat of it length, and the etached ortion bcame jamed betwen the aticular urfaces, limiting further xtension (d) he traum stimulaed the poduction of synovial fluid, which illed the t cvity. (e) Te distenion of te supraptellar brsa was esponsibe for th large amount of swelling bove the injured nee. (f) he pain ensation from the injured nee was onfined o the feoral nere as it scended to the cntral nevous sysem. iew Answr . F. Th sensatin of pai from th knee jont ascens to the central nervous ystem vi the femral, obturator, cmmon perneal, an tibial nerves. A 27-yer-old woan was found to have an nstable ight kne t fllowing a severe automobie accidet. On exmination it was ossible o pull te tibia excessivly forwrd on th femur. diagnoss of rupured antrior crciate liament wa made. 8. he folloing statments cocerning his patint are crrect exept which? (a) The anteior crucate ligaent is atached t the tiba in the anterior part of e interndylar rea. (b) Th anterio cruciat ligamen es pward, bckward, nd laterlly from its tibil attachent. (c) The anterior cruciate ligament is attaced above to the psterior art of te medial surface f the laeral femral condle. (d) he anteror crucite ligament is more commonly torn tn is the posterior cruciate ligamet. () Becaus the cruiate ligments ar locate outside the synoal membrane, bleeding fro a torn ligament does not enter th t city. View Anwer 8. E. Te synovil membrae coverig the crciate liaments is torn along with the ligaents, an the joit cavity quickly fills with blood.

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snell n 18-yea-old womn was rnning acoss some rough grund when she stumbed and oerinvertd her left foot. On examiation in the emerency deprtment o the local hospitl, the lteral sie of the left anke was teder and wollen. small rea of grat tendrness wa found below and front of the laeral maleolus. Xray examination of the ankl t ws negatie. A dignosis o sprain f the left ankle was made. 9. The fllowing tatements concering this patient are corrct excep which? (a) Te movemnt of inversion o the foo takes pace at te ankle oint. (b) Overiversion laces a train on the latral ligaents of he ankle t. c) The ocalized tendernes felt elow an in fron of the ateral mlleolus ould indicate tht some o the fiers of te anterir talofiular ligment had been torn. (d) The esulting hemorrhag from t torn lament was responsible for he swellng in th area. (e) B immobilzing the ankle jont with adequat splintig, the trn fiber of the nterior alofibulr ligamnt are repaired wih new firous tisue. View Answer 9. A. Normlly, the movemens of invrsion an eversio of the oot take place t the sbtalar ad transvrse tarsl ts of the fot. A 25-year-old man was running across a field whn he cauht his rght foo in a rabit hol. As he fell, th right fot was iolently rotated laterally and oveeverted. On attepting to stand, h could pace no wight on is rigt foot. n examination by a physicin, the right ankl was cosiderabl swollen especialy on te latera side. Ater furter examinaion, incuding a adiograp of the nkle, a diagnosi of sevee fractre disloation of the ankl t ws made. 10. Te following statements cocerning his patnt are correct ecept whih? a) This ype of facture islocatin is caused by forced extrnal rottion and overeversion of he foot. (b The taus is exernally otated aainst th lateral malleolu of the ibula casing it to fractre. (c) he torsn effect on the lateral mlleolus produces spiral fracture. (d) Th medial igament f the anle t is stron and nevr rupturs. (e) If the lus is orced to move father latrally an continus to rotte, the osterior inferior margin f the tiia will e sheare off. View Answer 10. D. Althogh the mdial ligment of he ankle t is strong, xtreme orce can result in rupture of the igament, or the lgament cn be ton from te medial alleolus or the ull on te ligamet can facture the medial malleolu.

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snell A 54-year-old m was told by his physician to redce his weight. He as prescibed a det and was advised to exrcise mor. One moning whie joggin, he head a shap snap ad felt sudden ain i his rigt ower cal. On exmination in the emergency epartmen, the phsician nted that the uppr part o the rigt calf ws swolle and a gp was aprent beteen the swelling and the eel. A dagnosis of rupture of the right Achlles tedon was ade. 11 The folowing sttements ncernin this patient are orrect ecept whih? () With te patien supine, gentle squeezing of the per part of the ight cal did not produce lantar lexion o the anke t. (b) The chilles endon is the tendon of insrtion of the gastocnemius and soleu muscles (c) The Achiles tendn is insrted int the poserior surface of te talus. (d) Ruture of he Achilles tendon results in the bllies of the gastcnemius nd soleu muscles retractng upwar, leaving a gap beween the divided nds of te tendon (e) Normally the gastrocnemius and soles muscles are the main musles respnsible fo plantar flexion f the anle t View Answer 11. The Achlles tenon is inerted ino the posterior suface of he calcaeum. A 7-year-od girl ws dealig drugs on a stree corner hen she ecame invlved in fight. During the brawl he receied a dee knife wund to th front o her riht thigh After a thorough xaminatin in the emergenc departmnt of te local ospital, it was deermined hat the nife poit had seered the trunk of the righ femoral nerve jut below he inguinl ligamnt. 12. Thi patient had the llowing igns and symptoms except whch? (a The rigt quadris femors muscle failed t contract when th patient as aske to exted her rght knee t. (b Skin snsation ws lost oer the aterior nd media sides o the thih. (c) Skin senation wa lost alng the mdial border of the big toe. (d Skin sesation ws lost o the lowr part o the leg and the edial boder of te foot a far as the ball of the ig toe. () Weak extension of the kee was pssible wen walking because of the ue of th adducto muscles. View Aswer 12. C. The skin covering the medal borde of the ig toe i innervaed by th superficial perneal nere. P.662

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P.63

Revie Questios Multile-Choice Questins elect th best anwer for each quetion. 1. Wich of te followng nerve innervaes at last one uscle that acts n both te hip an knee jints? (a) ioinguial nerve (b) Femoral erve (c) Saphnous nere () Common peroneal nerve (e) Sperficia peronea nerve View Answe 1. B. The moral nrve innervates th rectus emoris mscle. 2 In walkng, the ip bone of the spended leg is raised by which of he folloing muscles acing on te ed side of the body? (a) Gluteus maximus (b) bturator internus (c) luteus mdius d) Obturtor extenus e) Quadrtus femoris View Aswer 2. C. he glutes medius muscle cts with the glutus minims muscle to raise the pels on th opposit side. 3. Which of the follwing musles is a flexor o the thih? (a) Superior gemellus (b) Aductor longus

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snell () Gracilis (d) Psoas () Obturator inteus View nswer 3. D 4. Whih of the following muscles dorsiflees the fot at the ankle t? (a Peroneu longus (b) Exensor diitorum bevis (c) Tibilis poserior (d) Extensor halucis brevis (e) Tibials anterir View Answer .E Completion uestions Selec the phrse that est completes each statemet. 5. A fmoral hernia desends thrugh the emoral cnal, and the nec of the ac lies (a) beow and lteral to the pubic tubercle. (b) abov and medal to th pubic tbercle. (c) at the sphenous pening. (d) i the obtrator caal. () latera to the liacus muscle. Vie Answer 5. A 6. Th peronea artery s a branh of the (a anterio tibial artery. (b) popliteal atery. (c) postrior tibal arter.

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snell (d arcuate artery. (e) laeral platar artery. View Anwer 6. C 7. nlockin of the knee t to permi flexion is cause by the ction of the (a) vastus medialis mscle. (b) artcularis enu musce. (c gastrocnemius muscle. (d) bices femori muscle. (e) oplites muscle. iew Answr 7. E. The rotatory ction of the poplteus musle slackns the liaments f the exended kne t, thus peritting fexion to ake plac. 8. In the adult the chif arteral suppl to the ead of the femur s from te (a) perior crcumflex iliac arery. (b) obrator arery. c) brances from he medial and latal circuflex femral arteies. (d) deep externl pudendl artery () inferor gluteal artery. iew Answr 8. C. Since the epiphyseal late is o longer present n the nek of the femur, ranches rom the edial an lateral circumfl femoral arteries can ascnd throuh the feoral nec to the ad of te femur. 9. The lmph draiage of te skin cvering the ball o the big oe is ino the () verticl group f superfcial inginal nods. (b) poplieal node. (c horizonal group of supericial inuinal noes. (d) xillary nodes. (e) intenal ilic nodes.

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snell iew Anser 9. A. Th lymphatc vessels follow the cours of the eat sapenous ven. 10. The lmph drainage of he skin covering the medil side the knee t is into he ) poplieal node. () internl iliac odes. (c) vetical grup of suerficial inguinal nodes. () horizotal grou of supeficial iguinal odes. (e) obturato nodes. Viw Answer 10 C 11. The lymp drainag of the kin of te buttok is int the (a axillar nodes. (b) sperior guteal nodes. ) vertial group of supericial inuinal noes. (d) horizonta group o superfiial ingunal nods. (e) intrnal ilic nodes. iew Answr 1. D 12. The lymp drainag of the kin of he calf is into te (a) vetical grup of suerficial inguinal nodes. (b) internal iliac noes. (c) horiontal grup of suerficial inguina nodes. () popliteal node. (e) obturator nodes. Viw Answe 12 D. The lymphatic vessels ollow te course of the sall saphnous vei. 13. Hperextenion of te hip jont is prevented y the

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snell (a obturatr interus tendo. (b ischioemoral lgament. (c) tnsor fasia latae muscle. (d) liotibil tract. (e) igamentu teres. Viw Answe 13 B Fil-in-the-lank Quetions Fill in the blan with th best anwer. 14. Th _______ prevent dislocaion of te femur ackward t the kne t. (a) psterior ruciate igament (b) terior ruciate igament (c) mdial colateral ligament (d) lteral colateral igament (e) tedon of the poplitus mucle View Answer 14. B 15. The _______ prevent abductin of the tibia at the knee t. (a) postrior cruiate ligment (b) antrior cruiate ligment (c) lateal collaral ligament (d) lateral menisus (e medial collatera ligamen View Aswer 15. E 1. The _______ is attached to the had of the fibula. () latera meniscu

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snell (b) ateral cllateral ligament (c) nterior ruciate igament (d) osterior cruciate ligament (e) edial menscus View nswer 16. B Multiple-hoice Quetions Select he best nswer fo each qustion. 17. The calcaneum parcipates n the fomation o which ach(es) o the foot (a) Mdial lonitudinal arch onl (b Medial and lateral longitdinal arhes (c) Transverse ach only (d) Mdial lontudinal nd transverse arces (e) Lateal longiudinal ad transvrse archs View nswer 17. B 18. Th talus prticipats in the formation of which arch(es) of the fot? (a) Transverse arch oly () Latera longituinal arc only (c) Medal longiudinal ach only (d) edial an lateral ongitudial arche () Transvrse and edial logitudina arches View Anser 8. C 19. Th cuboid articipaes in th formatin of whih arch(e) of the oot? (a Medial ongitudial arch nly (b) Lateral longiudinal ach only

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snell (c) ransvers arch only (d) Medial lngitudinl and trasverse aches (e) Laeral lonitudinal and tranverse arhes Vie Answer 19. 20. The sesamoid bones uder the ead of te first etatarsa bone paticipate n the frmation f which rch(es) f the fot? (a) Lteral logitudina arch ony (b) Medial longitudinal ach only (c) Medial lngitudinal and transverse rches (d) ransvers arch ony (e) Lateral ongitudial and tansverse arches View Anser 0. B 21 The following satements concernig the dosalis pdis artey are crrect exept whic? () It is continuion of he anteror tibia artery. b) It enters the sole of the foot y ing between the two eads of he first dorsal itersseous mscle. (c) t can be palpate on the foot betwen the tndons of tibialis anterior and the xtensor hallucis longus mscles. (d) It the latral planar arter. e) On it lateral side lie the teinal pat of the deep perneal nerve. View Anser 1. C. Te dorsals pedis artery ca be palpted on he dorsu of the foot as it lies btween th tendons of the extensor allucis lngus and the mos medial endon f the exnsor digitorum lngus musle; it cn also be palpated midwa between the medil and laeral maleoli on he front of the nkle. 22. Te followng strucures conribute t the bodaries o the politeal fssa except which? (a) he semimmbranosu muscle (b) he plantris

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snell () The bieps femoris muscle (d The medal head of the gstrocnemius musce (e) Th soleus Vie Answer 22. E 23. Th followig structres through he greater sciatic foramen except wich? a) The sperior guteal arery b) The sciatic nerve ( The oburator iternus tendon (d) The pudendal nerve (e) The nferior luteal vin View Aswer 23. C 2. The feoral rin is bouned by th follwing strctures except which? (a) The emoral vin (b) The launar ligament c) The sperior rmus of te pubis (d) he femoral artery (e) The inguinal ligant View nswer 24. D 2. The folowing sructures thrugh the ubsartoral canal except whic? (a) Th posterir division of the obturato nerve (b) The nere to vasts lateralis c) The moral arery d) The sphenous erve (e) The emoral vin

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snell View Anwer 25. B 2. The floor of the femoal trianle is fomed by te followng muscls except which? (a) Th pectineus (b) The addutor longs (c) The iliaus (d) The psoa (e) Te adductr brevis Vew Answe 26 E 27. Te followng statents conerning te ankle t are correct ecept whih? (a) It is stengthene by the eltoid (edial colateral) ligament (b) It is a hine t. (c) t is fored by th articultion of he talus and the istal ends of the tibia and the fibula. (d) It i most stble in te fully lantar-fexed postion. (e) It is a ynovial oint. Vie Answer 27. 28. Te foot i inverte by the ollowing muscles xcept whch? (a) he tibiais anteror () The exensor halucis logus (c) The extensor digitoru longus (d) The peroeus tertus () The tbialis psterior Vew Answe 2. D Rea the cas historis and seect the est answr to the question followin them.

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snell A 58-yar-old usinessman flew o Korea rom New York by lane. Exept for nfrequen visits to the oilet, h remaine in his seat sleeping or reding. Toward th end of he long light, h experinced mild cramplke pain in his ight cal. On feeing his eg, he fund it t be tendr but tought nohing more about t. On reching hi destinaion, he as walkng down he ramp from the plane, hen he sddenly cllapsed ith seere pain in his eft ches and was experiening extrme respiatory stress. The airprt physiian made the diagosis of ulmonar embolim, seconary to dep vein thromboss of the right caf. 29. The blood clot (embolus) reched the left lun via he following blood vesels ext whic? (a) The righ popliteal vein (b) The righ common liac vei (c The infrior ven cava (d) The pulmonar trunk (e) Th left pumonary vin View nswer 29. E A 65-yea-old womn suddenly woke up in be with exruciatin pain in the lef calf. Ater abot 20 minutes, te pain dminished leaving the cal very teder to ouch. On placing er left oot on te ground she exprienced urther ain in hr calf. fter coducting thoroug examinaion, her physicin noted hat the pper thid of the left cal was ver tender on deep palpatio and tha there as a blue skin discoloraton in th lower hird of he leg aongside the Achilles tendon. A dianosis of torn mucle fibes in the left cal was mad. 30. In view of he histoy and th clinica finding, the mot likely muscle t have ben torn i this paient was the () soleus (b) flexor dgitorum ongus. (c) fexor halucis lonus. d) popliteus. e) tibiais posteior. View nswer 30. A * Note hat when the foot is firly plantd on the ground wen a peron is stnding, the femur is medally rotted on te tibia o lock ad stabilze the kee t Howeve, if the foot is aised of the ground, the tibia ma be latrally roated on he femur to lock he knee oint.

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snell Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

12. 11. The Head and Neck A 8-year-d woman woke up one mornig to fin that the right side of h face flt “peuliar an heavy.╠On looing in th mirror she saw that the corner of her muth on te right side was drooping and her ight lowr eyelid seemed t be lower than hr left. When sh attemped to smie, the rght side of her fce remaied immoile and oardlike While eating her breakfast she notced that her foo tended to stick on the iside of er right cheek. O taking her dog or a wal, she fond to he amazemet that se could not whise for his return to her side; her lps just ould not pucker. When examined by her physician, she was fond to hae paralsis of te muscle of the ntire riht side of the fae. She alked with a slighly slurrd speech and her lood presure was very hih. To mae the dignosis, he physiian had o have kowledge f the fcial muscles, the laryngeal muscles, and thei nerve spply. The facial paralysi, slurre speech, high blod pressue, and asence of any othr abnorml findins suggesed a dianosis of a left-sded cerbral hemrrhage (stroke), scondary o high bood presure. Hoever, beause a lft-sided cerebral hemorrhae would ause parlysis o only te muscls of the lower pat of the right sie of the face, tis was nt the diagnosis. This patent had paralysis f the muscles of he entir right side of the face; this could only be caused by a lesi of the right facial nerve, which supplies he muscls. Fortuately, tis patint was sffering rom Bells palsy, the progosis was excellen, and se had a omplete ecovery. .668

Chapter Objectivs 

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Head inuries frm blunt rauma an penetrting missiles are associatd with hgh mortaity and evere sability Headachs are usally caued by noserious ondition such a sinusits or neualgia; hwever, tey can rpresent he earlist manistations of a life-threateing disese. Facil, scalp, and mout injuri are comonly enountered in practce and vry in seiousness from a sall ski laceraton to maor maxilofacial trauma. ven an untreated oil on he side of the noe can be life-thratening. Facial palysis and unequal pupils may indiate the xistence of a serous neurlogic deficit. Mny vital structurs are prsent in he neck Injurie or presure on te larynx or tracha can copromise he airwy. Swellngs can ndicate the existece of a umor of he thyrod gland or the pesence o a maligant secodary leson in a ymph nod. Clearly, many signs nd symptms relatd to th region of the head and neck are dermined the antomic arrangement of the vrious stuctures. This chater discsses the basic aatomy of this comlicated egion an highligts the cinical elevance of the sructures considered. It spcificall exclude consideration of the detaled struture of he brain which i coverd in a eurology text.

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Basc Anatom The ead and eck regin of the body conains man importat structres compressed into a relaively smll area.

The Head The hea is form mainly y the skll with he brain and its covering meninges enclosed in the canial caity. The special senses, he eye ad the ea, lie wihin the kull bones or in the cavities bouned by thm. The bin gives rise to 12 pairs f crania nerves which lave the rain and thrugh foraina and issures in the skull. All he cranil nerves are distibuted t structues in th head ad neck, xcept he 10th which aso supples structures in he chest and abden.

Bones f the Skull Cmpositio The sull is cmposed of seval sepate bones united a immobil ts alled sutres. The connective tissue betwen the boes is caled a sutual ligamnt. Th mandibl is an eception o this rle, for t is unied to th skull b the moble tempoomandibular t (see page 75). The boes of th skull cn be divded into those of the cranum and tose of te face. he vault is the uper part of the canium, ad the base f the skll is the lowet part of the craium (Fig. 1-1). e skull bones ar made up of external and intenal tabls of cmpact boe separaed by a ayer of pongy boe called the diploë (Fig. 112). Te internl table s thinne and moe brittle than th externa table. The bone are covred on the outer nd inner surfaces with perosteum. The cranim conists of he folloing bone, two of which are paired Fis. 11-3 and 11-4):      

Frontal bone: 1 Parietal bones: 2 Ocipital one: 1 Teporal boes: 2 Sphnoid bon: 1 Ethmod bone:

The facia bones consist f the folowing, wo of whch are sngle:     

Zygomatic boes: 2 Maillae: 2 Nsal bone: 2 Lacrial bones 2 Vomer: 1

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Palatine bones: 2 nferior onchae: Mandibl: 1

It i unnecesary for students of medicie to kno the detiled structure of each individual sull bone However P.670

students hould b familiar with th skull as a whole and shoul have a dried sll available for reference as they read the ollowing descripion.

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Figure 11-1 Bones the antrior aspct of th skull.

Exteral Views of the Sull Anterior View of the Skull The frntal bo, or orehead one, cures downwrd to mae the uper margis of the orbits (Fig 11-1). The superiliary arches cn be see on eithr side, nd the suprorbital otch, or foramen, can be recognized. Medially, te fronta bone ariculates with the frontal processe of the axillae nd with he nasal bones. Lterally, the frotal bone articulaes with he zygomtic bone Th orbital mrgins re bouned by th frontal bone supriorly, he zygomtic bone laterall, the mxilla ineriorly, and the rocesses of the mxilla an frontal bone medally. Within the frontl bone just above the bital margins, ar two holow space lined wth mucou membran called he fronta air sinuses. Tese commnicate wth the nse and srve as vice resoators. Te wo nasal bones form the bridge o the nos. Their ower borers, wit the maxillae, make the anteror nasal aperture. The asal cavity is divided into two by the bony nsal septm, which is largely formed by the vomr. The sperior and middle conchae are sheves of bne that roject ito the nsal caviy from the thmoid on each ide; the inerior cochae re separate bones. The two maxille form the uppr jaw, the anterior part of the har palate, part of he latel walls of the nsal caviies, and part of he floor of the rbital avities. The two ones mee in the idline a the intermxillary uture and form the lowe margin of the nasal aperture. Belo the orbit, the maxilla is perforate by the infraorbita foramen. The P.671

P.672

P.673

alveolar process projecs downwad and, tgether wth the fllow of he opposte side, forms th aveolar ach, wich carries the uper teeth Within ach maxila is a arge, pyamid-shaed cavit lined wth mucou membran called he maxillary sinus. This cmmunicats with te nasal avity an serves s a voic resonatr.

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Figure 11-2 Coronal ection o the uppr part o the hea showing he layer of the scalp, the sagial sutue of the kull, th falx ceebri, th superio and inerior saittal veous sinues, the rachnoid granulatons, the emissar veins, nd the relation of cerebral blood vesels to he subaachnoid pace.

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Figure 11-3 ones of he lateral aspect of the sull.

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Figure 11-4 ones of he skull viewed rom the poerior (A and suerior (B) aspect.

Th zgomatic one orms the prominnce of the cheek and part of the lteral wal and foor of he orbial caviy. Medialy, it aticulate with th maxilla and lateally it articultes with the zyomatic pocess of the temporal boe to for the zygomatic arch. Th zygomatc bone i perfored by two foramia for he zygomticofacial and zygomaticotemporal erves. Th andible, or loer jaw, onsists f a horiontal boy and tw vertical rami (for detail, see page 15).

Lteral Viw of the Skull The frontl bone forms te anterir part o the sid of the kull and articulaes with he parieal bone at the conal suture (Fig. 11-3). Te arietal bones orm the ides and roof of he cranim and ariculate ith each other in the midlne at th sagittal suture. They artculate wth the ocipital one behid, at th lmbdoid sture. he skull is complted at te side b the squmous par of the ocital boe; pats of th tmporal bne, namely, the suamous, ympanic, mastoid rocess, tyloid pocess, and zygomac proces; and the reater wng of te sphenod. Note the position of the external auditory mtus. Th ramus and body of the mandble lie inferiory. Noe that te thinnet part o the latral wall of the kull is where the anteroinferior coner of te parietl bone rticulats with the greater wing of he sphenid; this point is referre to as te pterion. Clincally, te pterio is an iportant rea becase it ovrlies th anterior division of the midle menineal artey and ven. Idetify the suerior and inferio tempora lines, which begin as a single ine from the posterior margn of the ygomatic rocess o the fronal bone ad diverge as they ach backwad. The tempoal fossa lies elow the inferior tempral line. he infrateporal fssa ies belo the infratmporal crest n the grater win of the sphenoid The pterygaxillary fissure is a vertical fissue that les within the fosa between the pterygoid procss of the sphenoid bone and back of he maxila. It lads medilly int the ptergopalatne fos. he inferior orbital issure is a horizontal fisure beteen the grater wing of the spenoid bon and the axilla. It leads foward into the orbit The pteygopalatie fossa is a smll space behind an below th orbital avity. I communiates laerally wth the ifratempoal fossa hrough th pterygoaxillary fissure, edially ith the naal cavit through he sphenopaltine formen, speriorly ith the sull throuh the formen rotunum, and ateriorly ith the obit throuh the infeior orbitl fissure

Posteror View f the Skll

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snell he posteior parts f the tw parieta bones (Fig 11-4) with the intervenng sagittal suture are seen bove. Belw, the paietal bons articulte with t squamou part of he occipial bone at the lambdod suture. On eah side th occipita bone artculates wth the teporal bo. In the midline of the ocital boe is a roghened elevation alled th eternal occipital potuberanc, whic gives aachment o muscles and the ligamentum nuchae. O either sde of the protuberce the supeior nucha lines extend lterally tard the emporal bne.

Superio View of the Skull Anterorly, the frontal bone (Fig. 11-4) articulats with te two paietal bons at the cornal suture. Occasonally, he two haves of th frontal one fail o fuse, eaving a idline metopc suture. Behin, the two arietal bones articlate in te midlin at the sagital suture

Inferir View o the Skull If the mndible is iscarded the antrior par of thi aspect f the skll is see to be frmed by he hard palate (Fig. 11-5). The paltal proceses of the maxillae and th hrizontal lates of he palatie bones can be ientified. n the midine anteiorly is he ncisive fssa an framen. Posteroaterally re the greter and esser paatine foramina. Above the posterior ge of th hard plate are the choanae (posteior nasa aperturs). Thes are seprated frm each other by th posterir margin of the vomer and re boundd lateraly by th mdial pteygoid pltes of the spheoid bone The infrior end of the medil pterygid plate is prlonged a a curved spike of bone, te terygoid hamulus. Posterolateral to the lateal pteryoid plat, the greater ing of te sphenod is pieced by he large foamen ovae and the smal framen spnosum. Posterolteral to the foraen spinoum is th sine of te sphenod. Behind the spine of the sphnoid, in the inteval beteen the greater wing of the sphenoi and the petrous art of te temporal bone, is a groove for the artilagius part of the audiory tube. The opening of the bony part of he tube an be idntified. Th mndibular fossa of the tmporal bne and te articular tubercle fom the upper articlar surfaces for e temporomandibular t. Separatng the mndibular fossa frm the typanic plte posteiorly is the squamotympanic fissure, through the medal end o which te chorda tympani erve exis from te tympanc cavity Te styloid rocess of the tmporal bne projets downwrd and frward frm its inerior asect. The opening f the carotd canal can be seen on he inferior surface of the etrous prt of th tempora bone. The medial ed of the petrous part of the temporal bone is irregur and, together with the asilar part of the occipita bone ad the grater win of the phenoid, forms th framen laerum. During ife, the foramen acerum i closed ith fibrous tissu and ony a few mall vesels through his foramen from te cavity of the kull to he exteror.

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snell The tympanic plte, whch forms part of he tempoal bone, is C shaed on setion and forms th bony pat of the eternal aditory matus. While exmining tis regio identif the supramatal cret on he laterl surfac of the uamous prt of th tempora bone, te uprameatl triange, and the supramatal spine. .674

Figure 1-5 Inerior suface of he base f the skll.

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snell In the nterval etween te styloi and masoid procsses, the sylomastod forame can be seen. Medial t the styoid procss, the etrous part of he tempral bon has a dep notch which, ogether ith a shllower ntch on he occiptal bone forms th ugular framen. Behind te posteror apertres of te nose ad in frot of the foramen agnum ar the sphnoid bo and the basilar art of te occiptal bone The pharyneal tubecle i a small prominene on the undersurace of te basila part of he occiptal bone in the mdline. Th occipital condyles shoud be idetified; ey articlate wit the suprior aspct of th latera mass of the firs cervica vertebr, the atas. Superior to the occipal condye is the hyoglossal canal for tranmission f the hyoglossal nerve (Fig. 11-6). Posterio to the oramen magnum in he midlie is the externa occipitl protuberance. Te superior nuchal lines should be entifie as they curve laterally on each sid.

The Crnial Cavit The cranal cavit contain the bran and it surrouding mennges, portions of the cranal nerve, arteris, veins and venus sinuss.

Vault o the Skul The internal surface f the valt shows the coroal, sagttal, an lambdoi sutures In the idline i a shallw sagittl groov that lodes the suprior sagttal sins. On ach side of the goove ar several mall pit, called grnular pis, P.67

which lodge th teral lacunae nd arachnoi granulaions see page 68). Sevral narrw groove are preent for he anteror and psterior ivisions of the midde meningal vessels as tey p the sie of the skull to the vaul.

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Figure 11-6 Internal surface of the bas of the skull.

Base of he Skull The nterior f the bae of the skull (Fig. 11-6) is divied into hree craial fosse: anteror, midde, and psterior. The anteior cranal fossa is separted from the midde cranial fossa b the lesser wing f the spenoid, ad the midle cranal fossa is sepaated fro the poserior crial foss by the etrous prt of th temporl bone.

nterior ranial Fossa e anteror cranil fossa lodges th frontal obes of the cereral hemipheres. t is bouded anteiorly by the inne surface of the rontal bne, and n the miline is crest fr the atachment of the falx cerebri.

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snell Its psterior boundary is the shrp lesse wing of the spheoid, whih articultes latrally wih the frntal bon and mees the anteroinferir angle f the prietal bne, or te pterio. The meial end o the leser wing of the sphenoid rms the anerior clnoid procss on each sid, which ives atthment to the tentorum cereblli. Te median part of he anteror cranil fossa s limite posteriorly by th groove or the otic chiama. The foor of th fossa i formed y the riged orbial plate of the rontal bone laterlly and the cribrform plae of te ethmoi mediall (ig. 11-6). The crista gall is a sharp upard projction of the ethmid bone n the miline for he attahment of the falx cerebri. Alongsid the crista alli is a narrow lit in te cribriorm plat for the assage o the anterir ethmoial nerve into the nasa cavity. The uppe surface of the cibriform plate spports te olfactoy bulbs, and the mall perforations n the cibriform plate ar for the olactory nrves.

iddle Crnial Fosa The middle ranial fsa consists of a small median part and expaned laterl parts Fi. 11-6). The mdian raied part P.676

formed by the body of the sphenoi and the expanded lateral arts for concaviies on either side which ldge the temoral lobs of he cerebral hemispheres. It is boundd anterirly by te lesser wings of the sphnoid and posterioly by th superio borders of the petrous parts of t temporal bones. Laterally lie the quamous arts of he tempoal bone, the grater wins of the sphenoid and the parietal bones. The floor of each latral part of the mddle craial fosa is fored by th greater wing of he sphenid and te squamos and ptrous pats of th tempora bone. The sphnoid bon resembls a bat aving a entrally placed body with greter ad esser wigs tha are outtretched on each side. The ody of te sphenod contais the sphenid air snuses, which ae lined with mucus membrne and cmmunicate with th nasal caity; the serve a voice rsonators Anteriorly, te optic caal trasmits th optic nrve and he ophtalmic arery, a branch of he interal carotd artery to the rbit. Th sperior obital fisure, which is a slitlike opening betwee the lessr and grater wins of the sphenoi, transmits the larimal, fontal, tochlear, oculomoto, nasocliary, ad abducet nerves, together with the superior ophthalmc vein. The sphenparietal venous snus runs medially along th posterior borer of th lesser wing of the sphenoid nd drais into the cavernous sinus The foramn rotundm, whch is stuated ehind te medial nd of th superio orbital fissure, perforaes the geater wig of the sphenoid and tranmits the maxillary nerve fom the tigeminal ganglion to the erygopaltine fosa.

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snell Te oramen oale les posteolateral to the framen roundum (Fig. 11-6) It perforates the greater wing of he sphenid and tansmits he large sensory root and small moor root of the madibular erve to he infrtemporal fossa; te lesser petrosal nerve al es through it. Th small formen spinsum les posteolateral to the framen ovle and aso perfoates the greater wing of he sphenid. The oramen tansmits he middle meningeal artery from the infrateoral fosa (see pag 750) into the cranial avity. Te artery then run forward and lateally in a groove on the uper surfce of th squamou part of the tempoal bone and the reater wng of th sphenoi (ig. 11-2). After a short distace, the rtery diides into anterior and postrior brnches. Te anterir branch es frward an upward to the ateroinferior angle of the rietal bone (Fig. 11-131A) Here, he bone s deeply grooved r tunneld by the artery for a short distanc before t runs bckward ad upward on the prietal bne. It i at this site that the arery may e damaged after a blow to te side o the hed. The psterior ranch pases backard and pward acoss the squamous part of he temporal bone to reach the parital bone he large and irreularly saped foramn laceru lies etween te apex o the petous part of the tmporal bne and te sphenod bone (Fig 11-6) The nferior openng of th foramen lacerum n life i filled y cartiage and ibrous tisue, and only smal blood essels pss throuh this issue frm the craial caviy to the neck. The caotid canl opes into he side f the foramen laceum above the closd inferir openin. The iternal crotid arery entes the foamen thrugh the arotid canal and immediately turns upward t reach te side o the bod of the sphenoid one. Her, the arery turns forward n the caernous snus to each the region of the anteior clinid proce. At this point, he intenal caroid artery turns vetically pward, mdial (Fig. 1-20) to the anerior clnoid proess, and emerges rom the avernous sinus (se pge 750). teral t the foramen lacerm is an mpressio on the pex of te petrou part of the temporal bone for the trieminal gnglion On the anterior surface of the petrous bone are two rooves fr nerves the larest medil groove is for te reater ptrosal nrve, a branch o the facal nerve the smaler laterl groove is for te esser perosal nerve, a branch o the tymanic pleus. The reater ptrosal nerve enters the foamen lacerum dee to the tigeminal ganglion and the deep ptrosal nrve (smpatheti fibers rom around the intrnal cartid artey), to fm the nerv of the terygoid canal. The lessr petrosl nerve sses forard to te forame ovale. Th abducent nerve bends shaly forwrd across the apex of the etrous bne, medil to the trigeminl ganglin. Here, it leave the poterior canial fosa and eters the cavernou sinus. Th acuate emnence is a rouded eminnce foun on the anterior urface o the petrous bone and is cused by the underling superor semicrcular cnal. The tegmen tympani, a thn plate of bone, is a forard extenion of te petrous part of the temoral bon and adjins the quamous art of te bone (Fig 11-6) From bhind forard, it orms the roof of he mastod antrum the typanic cavty, and he auditry tube. This thi plate o bone is the onl major barrier tha separats infecton in th tympani cavity rom the temporal obe of te cerebrl hemispere (Fig. 1-30).

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snell The median part o the mile cranil fossa s formed by the bdy of th sphenoi bone (Fig. 11-6) In fron is the sulus chiasatis, hich is elated t the optc chiasm and leas lateraly to the otic cana on each side. osterior to the slcus is n elevaton, the tubrculum sllae. Behind th elevatin is a dep depresion, th slla turcca, whch lodge the pituitry gland. The lla turcica is bonded poseriorly y a squae plate f bone clled the dosum selle. The superior angles o the dorum sella have two tubercle, called the posterir clinoi processs, whh give ttachment to the fixed margin o the tenorium ceebelli. The cvernous snus is diectly reted to te side of the body f the sphnoid (Figs. 1-9 a 1-10). It carris in its ateral wal the thir and fourh crania nerves an the opthalmic ad maxillay divisios of the ifth craial nerve (Fg. 11-12). The iternal crotid artey and the sixth craial nerve forwrd throug the sinu.

Poserior Crnial Foss The posterior cranial ossa is dep and loges the prts of th hindbrai, namely, the cerebelum, pons, and medull oblongat. Anteiorly the fossa is ounded b the suprior borer of th petrous part o the teporal bon, and poteriorly t is bouded by the interna surface f the squmous par of the cipital one (Fig. 11-6). The floor of t posterior fossa is formed y the baslar, conylar, an squamou parts of the occiital bone and the mstoid par of the emporal bone. P.677

Th roof of the fossa is formed by a old of dra, the tenorium ceebelli, which ntervene between the cereellum below and t occipital lobes of the cerebral heispheres above (Fig 11-10. The forame magnum occupis the cntral ara of the floor an transmis the meulla oblngata an its surounding meninges, the ascending spial part of the accessory nerves, nd the to vertebal arteries. Th hypoglossa canal is situted abov the antrolatera boundar of the oramen mgnum (Fig. 1-6) nd transmits the hypglossal nerve. The jugular foramen lies etween te lower order of the petrus part f the teporal boe and the condylr part o the occipital bone. It transmits th followig strucures fro before backward: the inferir petrosl sinus; the 9th, 0th, nd 11th craial nervs; and the larg gmoid snus. he inerior perosal sius descends in the groove o the lowr border of the etrous prt of the temporal bone to each the foramen. The sigoid sinu turns dwn through the formen to bcome the internal jugular vei. he internal acoustic meatus pierce the poserior suface of he petro part of the temporal bone It trasmits th vestibuocochlea nerve ad the moor and snsory rots of te facial nerve. Th iternal ocipital est uns upwad in the midline osteriory from te forame magnum o the interal occiptal protberance; to it is attacd the smll falx ceebelli over the ocipital snus.

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snell n each sde of the internal occipitl protubrance is a wide goove for the transvese sinus (Fig. 11). Tis groov sweeps round on either side, on the internl surfac of the occipital bone, to reach th posteronferior ngle or orner of the parietal bone The grove now psses onto the mastid part f the tmporal bne, an here th transvese sinus becomes he sigmoid sinus. The superir petrosal sinus runs bckward aong the pper borer of th petrous bone in a narrow roove an drains nto the igmoid snus. As he sigmoi sinus dscends o the juular formen, it deeply groves the ack of te petrou bone ad the matoid part of the tmporal bne. Here it lies directly posterir to the mastoid atrum. Table 11-1 Summary of the ore Impotant Opeings in he Base f the Skull and the Structres That Thrugh Them Opeing in Sull

Bone f Skull

Sructures Transmited

Anteror Cranil Fossa

Prforatios in cririform pate

Ethmoi

Olftory neres

Middle Cranial Fossa

Opti canal

Lesser wing of phenoid

Opti nerve, phthalmi artery

Superior orbital issure

Betwen lesser and greaer wings of sphenid

Lacriml, frontl, trochear, ocuomotor, asociliary, and abucent neves; suprior ophhalmic vin

Foraen rotundum

Geater wig of sphnoid

Maxillry division of the trigeminl nerve

Foramen ovale

Greater wing of phenoid

Mandibular diision of the trigminal nerve, lessr petrosl nerve

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Framen snosum

Greate wing of sphenoid

Middle menigeal artry

Foramen lacerum

Beteen petrus part f temporl and spenoid

Intrnal cartid artey

Posterir Crania Fossa

Foamen magnum

Occipital

Medulla oblongta, spinl part o accessoy nerve, and righ and lef vertebrl arteris

Hypogssal canl

Ocipital

Hypoglossal nee

Jugular foramen

Betwen petros part o tempora and conylar par of occiptal

Glssopharygeal, vaus, and ccessory nerves; igmoid snus becoes interal jugular vein

Inrnal acustic meatus

Petrous art of tmporal

Vestbulocochlear and facial nerves

Tble 11-1 provides a summry of te more iportant penings n the bae of the skull an the strctures tat hrough tem.

Neoatal Skul The newborn kull (Fig. 1-8), compare with th adult sull, has a disproortionatly large cranium relative to the face. In chldhood, he growt of the andible, the maxllary siuses, an the alvolar proesses of the maxilae resuts in a great inrease in length of the face The bones of the skull e smoot and unilaminar, tere beig no dipoë presnt. Most of the sull bone are ossfied at irth, bt the prcess is incomplete, and the bones a mobile n each oher, being connected by fibrous tissue or cartilage The bons of the vault are ossifie in membane;

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snell the bones of the base are ossiied in artilage The bons of the vault ar not cloely knit at suturs, as i the adut, but are separaed by unssified embranou intervas calle P.68

P.679

fontaelles. Clinicaly, the aterior ad posteror fontaelles ar most imortant and are eaily examned in te midlin of the vault.

Clnical Noes Frctures of the Skul Frctures o the skul are comon in te adult ut much less so n the yong child In the nfant skll, the ones are more reilient tan in the adult sll, and hey are eparated by fibros suturl ligamets. In te adult, the inne table o the skull is paricularly brittle. Moreover the sutual ligamnts begi to ossify during middle ae. The tpe of frcture tht occurs in the sull depeds on te age of the patient, the severity f the blw, and te area of skull rceiving he traum. The adult skull may be likened to an eggshll in tht it posesses a ertain lmited resilience eyond whch it spinters. A severe, ocalized blow prouces a ocal indntation, often accmpanied y splintring of he bone. Blows t the vaut often rsult in series f linear fracture, which radiate ut throuh the thin areas of bone. e petrou parts o the teporal boes and te occipitl crests strongly reinforc the bas of the skull an tend to deflect inear frctures. In the youn child the skll may b likened to a tabe-tennis ball in hat a loalized bow prodces a deression ithout slinterin. This cmmon type of circumscribed lesion i referre to as a “pond― fracture

Factures f the Anterior Crnial Fosa n fractues of th anterio cranial fossa, te cribrform plae of the ethmoid one may e damage. This uually rsults in earing o the ovelying meinges and underlyig mucopriosteum The patent will have bleding fro the nose (pistaxis and leakage of cerebrosinal flud into te nose (cerbrospina rhinorrea). Fracture involvin the orbtal plat of the rontal bne result in hemorhage beeath the conjunctva and ito the obital avity, cusing eophthalms. The frontal ir sinus may be ivolved, ith hemorhage ino the nose.

Fracture of the iddle Crnial Fosa

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snell Fractures of the mddle craial foss are comon, becuse this is the wakest pat of the base of he skull Anatomcally, tis weaknss is caused by th presenc of numeous formina and canals in this region; the avities f the midle ear nd the phenoidal air sinues are prticulary vulnerble. The leakage f cerebrospinal fuid and lood fro the extrnal audory meats is comon. The seventh nd eight cranial erves may be invved as tey through he petros part o the temporal bon The thid, fourt, and sxth cranal nerve may be damaged if the latal wall f the cvernous inus is orn. Blod and cerbrospina fluid my leak ito the phenoida air sinses and ten into he nose

Factures f the Poterior Canial Fossa In ractures of the pterior canial fossa, blood may escape into the nape of the nck deep o the pstvertebrl muscle. Some days latr, it trcks betwen the mucles and appears n the psterior riangle, close to the mastid proces. The mucous membrane of he roof f the naopharynx may be trn, and lood may escape thre. In ractures involvin the juglar foraen, the th, 10th, and 11th cranial nerves my be damged. The strong bny walls of the hpoglossa canal sually potect th hypogloal nerve from injry.

Fratures of Facial Bnes Bone Inuries and Skeleta Developent The devloping bnes of a child's ace are ore pliale than an adult', and frctures my be incmplete o greenstck. In dults, te presene of welldevelope, air-filed sinues and te mucopriosteal surfaces of the aveolar parts f the upper and lwer jaw means tat most acial frtures shuld be cnsidered to be opn fractres, susceptible t infectin, and rquiring ntibioti therapy.

Anatmy of Comon Facil Fractues Automobie accidents, fisticuffs, ad falls are commo causes of facial fracture. Fortuntely, th upper prt of th skull i develoed from membrane (hereas te remainer is developed fm cartilage); threfore, his part of the sull in cildren i relativly flexible and cn absorb considerble force without esulting in a frcture. Sgns of factures f the facial bone include deformiy, ocula displacment, or abnormal movement accompanid by crpitation and maloclusion f the teth. Aneshesia or paresthesa of th facial kin will follow facture o bones trough whch branchs of te trigenal nere pss to th skin. The muscles of the face are thin and wek and cae littl displacment of he bone ragments Once a racture f the milla has been reduced, for example, prolonge fixatio is not needed. owever, n the cae of the mandible the strng muscls of matication can creae consierable dsplacemet, requiing long periods of fixaton. The ost commn facial fracture involve the nasal bones, ollowed y the zyomatic bne and ten the mndible. T fractue the maillary bnes and he suprarbital rdges of he front bones, an enormus force is requied.

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Nasl Fractues Fractures of the nas bones, ecause f the proinence f the noe, are te most cmmon facal fractres. Becase the bnes are lined wih mucoperiosteum, the fracure is cnsidered open; th overlyng skin ay also be lacerad. Although most re simpl fractues and are reduced under loal anestesia, soe are asociated ith sevee injuris to the nasal seum and rquire caeful tretment uder generl anesthsia.

Maxilofacial Fracture Maxllofacia fracturs usuall occur a the reslt of mssive facial trauma. There s extenive faci swelling, midface mobility of the underlyig bone o palpatin, maloclusion o the teeh with anterior pen bite and posibly leaage of crebrospial fluid (cerebropinal rhnorrhea) secondar to fractre of th cribrifrm plat of the ethmoid boe. Doubl vision iplopia may be resent, owing to orbital wall damage. Invoement of the infraorbital nerve wth anesthesia or paresthes of the kin of te cheek nd upper gum may occur in fracture of the ody of te maxill. Nose beeding my also occur in maxillary fracture Blood enters the maxillar air sins and ten leaks into the nasal cavity. he sites of the factures wre clasified by e Fort a type I, II, or II; thes fracturs are summarized in Figure 1-7.

lowout Fctures o the Maxlla A sever blow to the orbi (as fro a basebll) may cause the content of the obital cavity to xplode downward through th floor o the orbt into te maxillry sinus Damage o the ifraorbital nerve, resultin in alteed sensation to th skin of the chek, upper lip, and gum, may occur.

Fractres of te Zygoma or Zygomtic Arch Te zygoma or zygomtic arch can be factured y a blow to the ide of te face. lthough t can ocur as an isolated fracture as fro a blow rom a clnched fit, it ma be assocated wit multipl other ractures of the fce, as oten seen in autombile accdents.

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Figur 11-7 e Fort classification of axillofacial fractures. Th red lin denotes the fracure line

Te nterior ontanell is damond shped and ies betwen the to halves of the fontal boe in frot and th two paretal bons behind (Fg. 11-8). The fbrous mebrane foming the floor of the anteior fontnelle is replaced by bone nd is clsed by 1 months f age. Te osterior fontanele is triangulr and lis betwee the two parietal bones in front and the ocital boe behind By the nd of th first yar, the ontanell is usully closed and can no longr be paated. The tmpanic prt of the temporal bone is mere a C-shaed ring t birth, compared with a Cshaped crved plte in th adult. his mean that th external auditory meatus i almost entirel cartilainous in the newbrn, and the tympanic membrane is narer the surface. Although he tympaic membrne is nerly as arge as n the adlt, it fces more inferiory. During childhod the tmpanic pate grow laterally, forming the boy part o the meaus, and the tympanic membrane comes to face ore diretly lateally. The mastoid process is not present t birth Fi. 11-8 and devlops latr in resonse to he pull f the strnocleidmastoid uscle whn the child moves his or hr head.

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snell At birth, the astoid atrum lie about 3 mm deep to the floor of th uprameatl triange. As growth o the skul contines, the ateral bny wall hickens o that t pubert the antrum may le as muc as 15 m from he surfae. Th mandibl has rigt and let halves at birth united n the miline wit fibrous tissue. he two hlves fus at the symhysis meti by he end o the firt year. The angl of the andible at birh is obtse (Fig. 118), te head bing placd level ith the pper marin of th body an the coonoid prcess lyig at a sperior lvel to te head. It is only after ruption of te permanent teeth that the ngle of he mandile assues the ault shape and the head and neck grow so that the head comes lie higher than he coronid proces. In old ge, the ize of te mandibe is redced when the teeh are lot. As the alveola part of the bone becomes maller, the ramus becomes oblique i positio so that the head is bent osteriory. .680

linical otes linical eatures f the Nenatal Skll Fontaneles Palpation of the fntanelle enables the physcian to determine the progess of gowth in the surrunding ones, th degree of hydraion of te baby (.g., if he fontanelles are depresse below he surfae, the by is deydrated) and the state of the intrcranial pressure (a bulgig fontanlle indiates raied intraranial pessure). amples o cerebropinal flid can be obtaine by pasing a log needle obliquel through the anteior fontanelle ino the sbarachnod space r even ito the lteral vetricle. Cliically, t is usully not ossible o palpat the anerior fotanelle fter 18 onths, bcause th frontal and parital bons have enlarged t close t gap.

Tmpanic Mmbrane At birt, the typanic mebrane faes more ownward nd less laterall than in maturity when exmined wih the otscope it therefoe lies mre obliquely in the infant than in te adult

Foreps Deliery and the Facil Nerve In the newbrn infan, the matoid proess is nt develped, and the facil nerve, as it emrges fro the styomastoid foramen is clos to the urface. us, it cn be damged by frceps in a diffiult deliery.

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Figue 11-8 Neonata skull a seen frm the anerior (A) and latal (B) apects.

P.68

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Figure 11-9 Interior of the sull showing the dra mater and its ontained venous inuses. ote the onnections of the veins of the scal and the veins o the fac with th venous inuses.

The Meinges The brai in the skull is surrounde by thre protectve membanes, or meninges: the dura mater, the arachoid mater, and the pia matr. (The pinal cod in the vertebra column s also srrounded by thre meninge. See page 871.)

Dur Mater o the Bran Th dura maer is coventionaly descrbed as to layers the endsteal laer and t meningel layer Fi. 11-2). These are closly unite except long cerain line, where hey sepate to frm venou sinuses The endoseal laye is nthing moe than the ordinay periosum covering the iner surfce of th skull bnes. It dos not exend trough th foramen magnum t become cotinuous wth the dua mater of the spnal cord Around te margin of all te foramin in the sull it beomes coninuous wih the

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snell perosteum on the outsie of the kull bones. At th sutures i is contiuous wit the sutual ligamets. It s most stngly adhrent to th bones ovr the bas of the skll. The menngeal laer is he dur mater roper. I is a dese, stron, fibrous membrane covering te brain nd is coninuous though the oramen manum with he dura mter of te spinal ord. It rovides tbular sheths for the cranial nerves a the later rough te foramin in the sull. Outside the sull the sheaths use with the epneurium f the nrves. The meningel layer ends inwrd four epta tha divide the cranal cavit into frly commnicating paces loding the ubdivisios of the rain. Th functio of thes septa i to restict th rotator displacment of the brai. Te falx cereri is a sickle-haped fod of dura mater tht lies in the midlne betwee the two cerebral hemisphres (Figs. 1-9 and 1113). ts narrow end in frnt is atached to e internl fronta crest and the crista galli. ts broad posterior art blend in the mdline wit the uper surfac of the tetorium ceebelli. The superir sagittl sinus uns in is upper ixed margin, the iferior sgittal sis runs n its lowr concave free margn, and th straight sinus ru along it attachmnt to the tentorium cerebelli he tentoriu cerebelli is a crescent-saped fold of dura mater that oofs ove the poserior crnial fossa (Figs. 11-, 11-10 and 11-11). It overs the uper surace of te cerebelum and upports he occiital lobe of the crebral hispheres In front is a gap, the tentorial notch, for th P.82

ge of the midbrain Fis. 11-11 and 11-12), thus roducing an inner free border and an oter attahed or fied borde. The fied border is attachd to the osterior clinoid processe, the surior borders of the petrous bones, and the argins o the grooes for t transvese sinuse on the ocipital boe. The free borer runs orward t its tw ends, cosses the attached border and i affixed to the nterior clinoid pocess on each side At the point whre the two borders cross, he third and fourh crania nerves forard to eter the ateral wll of the cavernos sinus Fgs. 11-11 and 11-2).

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Fiure 11-1 Diapragma selae and entorium cerebell. Note te positin of the venous snuses.

Close to the aex of th petrous part of he tempoal bone the lowr layer f the tentorium i pouched orward bneath th superir petrosl sinus o form a recess for the trieminal nrve and the trigminal gaglion (Fig. 11-11. The falx cerbri and he falx erebelli are attahed to he upper and lower surfaces of the tentorium, respectely. The straigh sinus rns alon its attahment to the falx cerebri, the suprior petosal sins along ts attacment to he petro bone, ad the tansverse sinus alng its atachment to the ocipital ne (Fig. 1-10). Te falx cerbelli s a smal, sickl-shaped old of dra mater that is ttached o the iternal ocipital rest and projects forward etween te two cerebellar emisphers. Its psterior ixed marin contans the ccipital sinus. The diaphragma selle is small crcular fld of dua mater hat form the roo for the sella tucica (Fig. 1-6). A small oening in its centr allows age f the stlk of th pituitay gland (Fig. 1-12).

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Dural Nerve Supply Brnches of the trigminal, vgus, and first thee cervial nerve and braches from the symathetic system to the dura. Numrous senory endigs are in the dur. The dua is sesitive t stretching, which produce the sensation of headache Stimulation of the sensory ending of the rigemina nerve ave the evel of the tentrium cerbelli prouces refrred pai to an aea of sin on th same sie of the head. Stmulation of the dal endis below the leve of the entorium produces referred pain to he back f the nck and bck of th scalp aong the istributon of th greater occipitl nerve.

Dral Arteial Suppy Nuerous areries suply the dura mate from th internal carotid, maxillary, ascending pharngeal, ocipital, and P.683

verteral arteies. Frm a clincal stapoint, he most importan is the middle eningeal artery, which i commonl damaged in head injuries

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Figre 11-11 Lateal view of the kull shoing the alx cerebri, tenorium ceebelli, brainstm, and tigeminal ganglio.

he middle meningeal artery arises from the maxillar artery n the inratemporl fossa (see page 70). t enters the cranl cavit and run forwar and laterally in a groove on the per surface of te squamos part o the temporal bone (Fg. 11-2). To enter the cranial cavity, t e through the formen spinsum to lie between the menigeal and endostel layer of dura. Its further course in the midle cranal foss is desribed on page 75. The aterior (rontal) ranch deply grooes or tunnels te anterinferior angle of the paretal bon, and it course orrespons roughy to the line of the underlying pecentral gyrus of the brai. The osterio (parietl) branc curves backward and suppies the posterir part f the dua mater.

ural Veous Draiage The menigeal veis lie in the endosteal layer o dura. Te middl meningel vein fllows the braches of he midd meningal arter and drains into the ptergoid venous pleus or th sphenoprietal inus. Th veins lie laterl to the arterie.

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Aachnoid ater of he Brain The arachnoi mater i a delicte, impemeable mmbrane overing te brain nd lying between the pia ater internally an the dua mater xternall (ig. 11-2). It s separaed from he dura y a potetial spae, the subdral spac, and from the pia by the ubarachnid spce, wich is flled wit crebrospnal flui. The arahnoid brdges ove the suli on the surface o the brin, and n certai situatins the aachnoid and pia ar widely separate to form the subaracnoid cisernae. In certain areas the arachnoi project into th venous sinuses t form arachoid vill. The arachnoi villi ae most numerous alng the sperior sgittal snus. Aggegations f arachnid villi are refered to a aachnoid ranulatins (Fig. 11-2) Arachnod villi srve as stes wher the cerbrospinal fluid difuses ino the blodstream It is importan to remeber tha structues ng to ad from he brain to the sull or its foramna must ass thrugh the subarachoid spac. All the cerebral arteris and vens lie i the sace, as do the canial nerves (Fig. 11-2) The archnoid uses wit the epieurium o the neres at thir poin of exi from th skull. n the cae of the optic neve, the .684

archnoid orms a seath for the nerv that exends int the orbtal caviy throuh the opic canal nd fuses with the sclera o the eyeall (Fig. 1-25). Thus, th subaracnoid spae extend around he optic nerve as far as he eyeball (see pa 697).

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Fgure 11-2 A. The forebrain has been remoed, leaing the idbrain, the hypophysis erebri, and the interna carotid and baslar arteies in osition. B. Sagital secton throuh the sella turcica showig the hyophysis cerebri. C. Cornal secton throuh the body of th sphenoi showin the hypphysis erebri ad the caernous snuses. ote the osition f the crnial nrves.

The cererospina fluid is produced by te horoid pexuses within the lateal, thir, and forth venticles of the brai. It esapes fro the venricular system f the brain throgh the tree formina in

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snell the roof of the fourth vetricle ad so entrs the ubarachoid spac. It now circulates both pward over the srfaces the crebral hmisphere and downward arund the pinal cod. The pinal subarachnid space extends down as ar as te second acral vetebra (see Fig. 12-7). Eentually the flud enter the P.685

blodstream y in into th arachnid villi and diffsing through teir wall.

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Figure 1-13 agittal ection o the hea and nec.

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snell In addiion to rmoving waste prodcts associated wit neuronal actity, the cerebrospinal flid provies a flid mediu in whih the brin float. This mchanism effectivly protcts the rain from traum.

Pia Mate of the rain The ia mate is a vascuar membrne that closely nvests e brain coverin the gyri and decending nto the eepest lci (Fig. 11-2. It exends ovr the crnial neres and fses with their pineurim. The erebral rteries entering the subsance of he brain carry a sheath o pia wih them. P.86

Clinicl Notes Intracanial Heorrhage Intracranial hmorrhage may resut from trauma o cerebral vasculr lesion. Four vrieties re considered her extradral, subural, suarachnoid and cerbral. Extradurl hemorrhge rsults frm injuris to the meningea arteries or veins. The most common artery o be damed is th anterio divisio of the iddle meingeal atery. A omparatiely mino blow to the side of the hed, resuting in racture of te skull n the region of the anteroinferior portion of the prietal bne, may ever the artery. Te arteril or veous injuy is espcially lible to ccur if the artery ad vein enter a ny cana in this region. Bleeding occurs nd strip up the meningel layer of dura rom the nternal urface of the skul. The itracrani pressur rises, ad the enlrging blod clot eerts local pressur on the uderlying otor area in the prcentral grus. Bloo may al outard throuh the frature lin to form a soft swlling uner the tmporalis muscle. To stop the hemorhage, th torn arry or ven must be ligated or plugge. The bur hole though the ull wall hould be placed abut 1 to 15 in. (2.5 to 4 cm) above the idpoint f the zyomatic arh. Subdral hemorhage rsults fom tearing of the uperior ceebral vens at ther point f entrance int the suprior sagttal sins. The cuse is uually a low on th front or the back of the had, causg excessve anteropsterior isplacemet of the rain withn the skul. This condition which is much more common thn middle meningeal hemorrhae, can b produce by a suden minor low. Onc the ven is tor, blood nder low pressure begins o accumuate in he potntial spce betwen the dua and th arachnod. In about half the cases the contion is bilateral. Acte and cronic foms of th clinica conditin occur, dependig on the speed of accumulaion of fuid in te subdurl space. For exale, if te patien starts o vomit, the venous pressur will se as a esult of a rise i the intathoraci pressur. Under hese cicumstancs, the sbdural bood clot will increase rapidly in se and poduce acte symptms. In te chroni form, oer a couse of seral moths, the small blod clot ill attrct fluid by osmosi so tha a hemorhagic cyt is fored, whic gradualy

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snell expands and prouces prssure symptoms. In both forms he bloo clot mu be remoed throuh burr oles in he skull. Subaachnoid emorrhage reslts from leakage r ruptur of a cogenital aeurysm o the cirle of Wllis or, less commonly, fro an angima. The ymptoms, which are sudden n onset, include evere hedache, siffness o the nec, and lss of consciousnes. The dignosis i establihed by wthdrawing heavily blood-stined cerbrospinal fluid though a lmbar puncture (spnal tap) Ceebral heorrhage is geerally cused by upture of the thinwalled lnticulosriate atery, a ranch of the midde cerebrl artery The hemrhage inolves th vital orticobulbar and crticospial fiber in the nternal apsule nd producs hemiplgia on te opposie side o the bod The patient immdiately oses conciousness and the paralysi is evidnt when consciouness is egained.

Intracrania Hemorrhae in the Infant Inracranil hemorrage in te infant may occu during birth and may resut from ecessive olding o the hea. Bleedig may ocur from the cerebal veins or the vnous sinses. Excssive anteroposterior compession o the hea often tars the aterior ttachmen of the alx cerebi from te tentorum cereblli. Bleding thn takes pace from the great crebral vins, he straight sinus, or the inferior sagtal sinus.

he Venou Blood Sinuses The veous sinues of th cranial cavity ae blood-filled spaes situaed between the layers of th dura maer (Fig. 112); hey are lned by edotheliu. Their alls are hick and composed of fibrus tissu; they hve no mucular tiue. The inuses hve no vlves. Thy receive tributares from he brain the dipoë of the skull, the orbi, and th internal ear. he superio sagittal sinus lies in the upper fixed boder of te falx cebri (Fig. 11-9). It runs ackward and becoms continous with the right transvere sinus. The sinu communictes on ech side ith the venus lacune. Numrous arahnoid vili and grnulation project into the lacunae Fig. 11-2. The suerior saittal sins receivs the superor cerebal veins The inferior sagittal sinus lies in he free ower marin of th falx cerbri. It uns bacard and s th great crebral vin to form the stright sins (Fig. 11-). It eceives erebral eins fro the medal surfa of the cerebral hemispher. The straigh sinus lies at he juncton of th lx cerebi with te tentorum cereblli (Fig. 1-9). Frmed by he union of the iferior saittal sius with he great cerebral vein, it drains into the left transvrse sinu. The riht transerse sins begins as a ntinuatin of the superior sagittal sinus; th eft tranverse sins is sually a continuaton of th straigh sinus (Fig. 11-9 and 11-10). Each sinus lis in the lateral ttached argin of the tentorium cerbelli, ad they ed on each side by ecoming he sigmod sinus. The sigoid sinues are a direct continution of he transerse sinses. Each sinus tuns downard behid the matoid antm of the temporal bone and then leaes the kull throgh the jgular foamen to ecome th interna jugular vein (Fig. 1-30)

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snell Te ccipital sinus lies i the atached magin of the falx cerebelli. It commucates wth the ertebral veins thugh the oramen mgnum and the tranverse sinuses. Each caverous sinu lies on the lteral sie of the ody of te sphenod bone (Fig 11-9. Anteriorly, the sinus reeives the inferior ophthalmc vein ad the cntral vein of the etina. Te sinus rains poteriorly into the transvere sinus through th superio petrosa sinus. Intercaverous sinses connct the tw cavernos sinuses through he sella turcica. P.87

Imporant Strutures Asociated ith the avernous Sinuses    



The inernal arotid rtery an the sith cranil nerve, which trvel throgh it (Fig. 11-12 In th lateral wall, the third and fourth cranial erves, ad the ophhalmic ad maxillry divisons of te fifth ranial nrve (Fig. 1-12). Th pituitay gland, which lie mediall in the ella turica (Fig. 1-12) The veins of the face which ar conneted with he caverous sinu via the facial ven and ierior ohthalmic vein, an are an mportant oute for the spred of infction fom the fae (Fig. 11-) The superir and inerior perosal siuses, which run along th upper ad lower brders of the petrus part f the teporal boe (ig. 11-9)

Pituitay Gland Hypophyss Cerebr) he pituiary glan is a smll, oval structur attached to the udersurfae of the brain by the infundbulum (Fg. 11-12). The gland is well proected by virtue o its loction in he sella turcica f the spenoid boe. The pituitary gand is vtal to lfe and is fully described n page 85.

Prts of te Brain For detaile descripion of the gross structue of the brain, textbook of neuoanatomy should e consulted. In the followng accunt, onl the main parts f the brin are dscribed.

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Th brain i that pat of the entral rvous sytem tha lies inide the anial caity. It s continous with the spinl cord hrough th foramen magnum.

Cerebrum Te erebrum is the largest rt of te brain ad consiss of two ceebral heispheres conneted by a mass of hite mater called the orpu calloum (Fig. 11-13). Each hemisphee extend from th frontal to the ocipital ones; abve the aterior ad middle cranial ossae; and, posterorly, abve the tentorium erebelli The hemspheres re separted by a eep clef, the lontudinal issure, into wich projcts the fal cerebri (Fig. 1113). The srface laer of eah hemispere is clled the cotex ad is comosed of gra matter (Fig. 11-). The cerebral cortex i thrown nto fold, or gyri separated by fisures, or suci. By this mens the urface aa of the cortex i greatly increased. Severa of the arge suli convenently subdivide th surface of each hemisphee into lobe. The lobes are named fo the bons of the cranium under whi they li (ig. 11-1). The frontal obe is situated in front of the cenral sulcs (Fig. 1-14) nd above the lateral sulcus. The parieal lobe is situted behid the cetral sulus and aove the lateral sucus. The ocipital obe lis below he parieto-ccipital ulcus Below te latera sulcus i situate the temporl lobe. Te recentra gyrus lies imediately anterior to the cntral sucus and s known s the motor area (Fig 11-14). The arge motr nerve clls in tis area ontrol vluntary movements n the oposite sde of th body. Mst nerve fiber cross over to he oppoite side n the meulla oblngata as they desend to th spinal cord. In the motor area, the ody is represented in an inverted osition, with the nerve cels contolling th movemens of th feet loated in te upper art and hose controlling the movemets of te face ad hands n the loer part Fi. 11-14).

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snell he postcenral gyru lies mmediatey posteror to th central sulcus ad is know as the sensory area (Fig. 114). The smal nerve clls in ths area rceive an interprt sensatons of ain, temerature, ouch, an pressur from th opposit side of the body The superio tempora gyrus lies immdiately elow the lateral ulcus (Fig. 11-14. The midle of this gyrus s concered with he recepion and interpretaion of sund and s known a the auditry area. Broca's rea, or the motor speech area, lis just aove the ateral slcus (Fig. 1-14) It conrols the movement employe in speech. It is ominant n the lft hemishere in rght-handd person and in he right hemisphere in left-handed ersons. The viual area is siated on he posterior pole and medial aspect of the crebral hmisphere in the rgion of e calcarine sulcus (ig. 11-1). It s the reeiving aea for vsual imprssions. Te cavity present ithin each cerebrl hemisphere is cled the lateal ventrcle. The lateral ventrices commuicate wih the third ventrile throuh the interentriculr foramia (Fig. 11-13).

iencephaon The diencephalon is most completely idden fro the surace of te brain. It consits of a orsal thalmus (Fig. 11-13) and a vetral hypotalamus The thlamus is a large mass of gry matter that lie on eithr side o the thrd ventrcle. It is the gret relay tation o the affrent sesory patway to the cerebra cortex. The hypothalamus fms the lwer part of the lteral wll and foor of te third ventricle The folowing stuctures ae found in the foor of te third ntricle rom befoe backwad: the opti chiasma (Fig. 115), te uber cinreum ad the infunibulum, the mammilary bodes, an the posteror perfoated subtance. P.688

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Figur 11-14 A. Rig side of the brain showing some imprtant loalized aeas of erebral unction. Note tha the motr speech area is most comonly loted in he left rather tha the rigt cerebrl hemispere. B. Lateral urface of the cereral hemiphere shoing area supplie by the cerebral arteries. In this nd the nxt figure, areas lored ble are spplied b the antrior cerbral artey; those colored ed, by te middl cerebra artery; and those colored green, b the postrior ceebral arery.

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C. Mdial surace of te cerebr hemisphre showig the aras suppld by the ceebral ateries.

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Figure 1-15 rteries nd cranal nerve seen o the infrior surace of te brain. To sho the couse of te middle cerebral rtery, te anterir pole o the left tempoal lobe has been removed.

Midbain

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snell The mibrain is the narow part of the bain tha es through he tentoial notc and conects the forebran to the hindbrai (Fig. 1113). The midbrain compises two lateral alves caled the ceebral peuncles; each of these is divided nto an aterior prt, the cru cerebri, and a posterio part, te egmentum, by a igmented band of ray matr, the substantia nira (Fig. 11-12) The narow cavit of the idbrain s the cerebal aquedct, which conects the third an fourth entricles The tectum is th part of the midbrin posteior to te cerebrl aqueduct; it ha four smll surfa swellins, namel, the two sperior (Fg. 11-12) and two inferior colliculi. The olliculi are deepl placed etween te cerebelum and he cerebral hemisheres. Th pineal body is a small glndular sructure hat lie between the superior colliculi (Fig. 1-13). It is atached by a stalk o the reion of te posterior wall o the thid ventrile (see lso page 81). The pineal cmmonly clcifies n middle age, and thus it can be visalized o radiogrphs.

Hindbrin Th pons is situated on the aterior srface of the cereellum beow the mdbrain ad above he medulla oblonga (Fig. 11-13). t is comosed maily of nerve fibers which cnnect te two hales of the cerebelum. It lso contins asceing and escendin fibers connectig the foebrain, he midbran, and te spinal cord. Soe of th nerve cells withi the pon serve a relay sations, hereas ohers form cranial nerve nulei. P.69

The medull oblongaa is cnical i shape and connects the pon above t the spial cord elow (Fig. 113). A median fssure s presen on the nterior urface o the medula, and n each sde of ths is a selling caled the pyramid (Fig 11-15. The pramids ae compos of bundes of neve fiber that oriinate in large nrve cell in the ecentral gyrus of the cereral cortx. The yramids tper belo, and hee most o the desending fbers cros over t the oppsite sid, formin the decusstion of he pyramids. Posteior to te pyramis are th oives, which are oval eleations oduced by the undrlying olivary nuclei (Fig. 1-15). Behind the olives re the infeior cereellar peuncles which connect th medulla to the crebellum On he posteior surface of the inferior part of he medula oblongta are te racile and cuneat tubercls, prouced by he medialy place underlying nuceus gracilis ad the laterally laced unerlying nuleus cuntus. The cerellum ies withn the poterior cranial fossa beneath the tetorium cebelli (Fig. 11-13). It i situate posterio to the ons and he medula oblongta. It consists o two hemspheres onnected by a medan portin, te ermis The cerbellum i connectd to the midbrain by the supeior cereellar peuncles to the ons by te iddle ceebellar eduncles, and o the medulla by the inferior cerebellr pedunces.

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snell he surfae layer f each crebellar hemisphee, calle the cortex, is cmposed of gray mater. The cerebella cortex s thrown into folds, or folia, seprated by closely et transerse fissures. Certain masses of gra matter are foun in the nterior f the cerebellum, mbedded n the wite matt; the lagest of hese is nown as the dentate ucleus. The crebellum plays an importan role in the control of musce tone ad the cordination of muscle movemet on the same sid of the body. The cavity of the hidbrain i the fouth ventrcle (Fig. 1-13). This is ounded i front b the pon and the edulla olongata nd behin by the suprior ad nferior medullary vela and the erebellu. The fourth ventrcle is cnnected bove to he third ventricl by the erebral ueduct, nd below it is cotinuous ith the entral cnal of the spinal ord. It ommunicaes with he subaachnoid pace through three opening in the ower part of the oof: a mdian and two lateal openis.

Ventriles of te Brain The entricle of the rain conist of te two laeral venricles, he third ventricl, and th fourth entricle The two leral venricles communiate with the third vntricle through the intervetricular foramina (Fig. 1113); te third entricle communicaes with he fourt ventricl by the cerbral aquduct. The fourh ventrie, in tun, is cotinuous ith the arrow centrl canal of the spinal crd and, hrough te three oramina n its rof, with the subarchnoid sace. The ventricls are filed with erebrospnal flud, which is producd by the chroid pleuses of the two latral venticles, he third ventricl, and th fourth ventrice. The size and hape of he cerebal ventrcles may be visulized clnically sing comuted tomoraphy (C) scans and magntic resnance imging (MR) (Figs 11-127, 11-128, and 11-129).

Blod Supply of the Bain Arteries of the Brain he brin is supplied by the two internal carotid ad the to vertebal arteres. The our artries anasomose on the infrior surace of te brain d form the circle o Willis (circulus arterosus). The internal carotid arterie, the vtebral arteries, and the circle of illis ar fully dscribed n page 750 and 751.

Veis of the Brain The veins of the brain ha no musular tisue in their thin walls, an they posess no alves. ey emerge from the brain nd drai into th cranial venous snuses (Fig. 11-2). Cerebral and cerebellar vins and eins of he braintem are resent. The great ceebral ven is frmed by he union of the to internal cerebral veins nd drain into th straigh sinus (Fig 11-9)

Clincal Note Bran Injuris 1287

snell Injries of he brain are prodced by dsplacemet and dstortion of the nuronal tissues at the momet of impct. The brain ma be likeed to a log soaked with water floatng submeged in wter. Th brain i floatin in the erebrospnal flui in the ubarachnid spac and is apable o a certan amount of anteroposterior movemen which is limited by the ttachmen of the uperior erebral eins to the supeior sagital sinus. Lateral displacement of the brai is limted by te falx ceebri. Th tentorim cerebeli and te falx erebelli also resrict dislacement of the bain. t follos from these anatomic facs that bows on te front or back f the hed lead t displacment of he brain, which may produ severe cerebral damage, sretching and distrtion of the branstem, ad stretcing and ven tearng of th commissres of te brain The ters oncussio, contuson, and aceratio are ued cliically to describe the degree of brai injury. Blo on the side of the head produce lss cerebrl displcement, nd the ijuries t the bran consequently ten to be ess sevee. P.691

Th Cranial Nerves i the Craial Cavity The 12 pirs of canial neves are amed as ollows:            

I. Olfatory (sesory) II Optic (ensory) II. Oculmotor (mtor) IV. Trochlea (motor) V. Trigeinal (mied) VI. Aducent (otor) VII. Facial (mixed) VII. Vestbulocochear (senory) IX. Glossopharyngel (mixed X. Vags (mixed XI. ry (moor) XII. ypoglossl (motor

The erves emrge from the brai and are transmited through forama and fisures in the base of the kull. All the nervs are dstribute in the ead and eck excet the vaus, whic also supplies sructures in the torax and abdomen. The olfactory, optc, and estibuloochlear erves ar entirely sensory; the oculmotor, rochlear abducen accessory, and hpoglossa nerves re entirey motor and the remaini nerves are mixed The oriins and ourses o the crnial neres are dscribed n page 757. Th cranial nerves, heir comonent pats, thei functin, and te openins throug which tey exit rom the kull are summarizd in Table 11-6.

The rbital Rgion

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snell he orbit are a pir of boy cavitis that cntain th eyeball; their ssociate muscles nerves, vessels, and fat; and most of the acrimal apparatu. The orital openng is gurded by wo thin, movable folds, te eyelid.

Eyeids The eyelids protect the eye fom injury and excessive light by tir closure (Fig. 1116). Te upper yelid is larger ad more mbile tha the lowr, and tey meet ach other at the medal and lteral anles. Te alpebral fissure is th elliptial opening between the eyelds and i the entance int the cojunctival sac. Whe the eye is close, the uper eyeli complely coves the conea of the eye. Whn the ey is open and looing straght ahea, the uper lid just covers the uppe margin f the crnea. Th lower lid lies jst below the cornea when the eye is open and rises ony slighty when te eye is closed. Th superfiial surfce of th eyelids is coverd by ski, and th deep suface is overed b a mucou membran, called the conjunciva. The eyelashe are sort, cured hairs on the fee edges of the eelids (Figs. 1-16 and 1-17) They ae arranged in doube or trile rows t the muocutaneos juncton. The ebaceous glands (gands of eis) ope directl into th eyelash follicls. The ciliry gland (glans of Mol) are moified swat gland that opn separaely between adjact lashes The tarsal glands are log, modifed sebaceous glan that por their ily secrtion ont the margin of th lid; thir openigs lie bhind the eyelashes (Fig. 11-16). Thi oily maerial prvents the overflow of tears and help make th closed yelids atight. Th more ronded medal angle is separted from the eyebll by a mall spae, the lacu lacrimais, n the ceter of which is a mall, redish yelow elevaion, the cauncula lcrimalis (Figs. 1-16 an 1-17). A reddis semilunar fold, clled the pca semilunaris lies on the lateal side f the cauncle. Ner the mdial angle of the ye a small elevaton, the apilla acrimali, is present On the ummit of the papilla is a small hole, the punctm lacrimle, wich leads into the cnaliculu lacrimais (Figs 11-16 and 11-17. The pailla lacimalis projects io the laus, and he punctm and caaliculus carry tears down ito the se (see pag 694) The conunctiva is a thn mucous membrane that lins the eylids and is refleted at the superior and infeior fornces ono the anerior suface of he eyebal (Fig. 11-6). Its epithelium is continuou with tht of the cornea. The uper laterl part the suerior forix is pieced by the ducts of the lacrmal gland (ee below. The conjunctia thus foms a potential spce, the cojunctival sac, wich is oen at the ppebral fssure. Beneath te eyelid is a grooe, the subtrsal suls, which runs clse to and parallel wth the mgin of th lid (Fig. 1-16). The sulcus tends o trap mall foreign particls introuced into the conjunctival ac and is thus clinically important. The fraework of he eyelids is forme by a fibous shee, the orbita septum (Fig. 11-1). Ths is attched to he perioteum at he orbitl margin. The orital sepum is thkened at the margins of the lids to frm the serior an inferior rsal plaes. Te lateral ends of the plaes are atached by a band, the lateral palpebral ligament, to a bony tubercle ust withn the orital marin. The edial ens of the plates are attache by a bad, the media palpebrl ligamen, to te crest o the lacmal bone Fig 11-16) The tarsl glands are embeded in th posterio surface f the tarsal plates

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snell The supeficial surface of th tarsal lates and the orbitl septum are covered by th palpebra fibers f the orbiularis ouli muse (Tale 11-16) The aponurosis of insertion of the levatr palpebre superiois muscle pierces the orbial septum o reach te anterir surface of the suerior taral plate nd the skn (ig. 11-16).

Movents of t Eyelids The osition o the eyeids at rst depens on the tone of the orbiculris oculi and the vator ppebrae superioris muscles and te position of te eyebal. The eylids are closed by the cntractio of the rbiculars oculi nd the rlaxatio of the evator alpebrae uperioris muscles. he eye is opened b the levatr palpebae superiris raisig the uppr lid. On looking uward, the levator alpebrae uperioris contract, and th upper li moves with the eeball. On looking downward, bth lids mve, the uper lid continue to cove the uper part f the crnea, an the lower lid is pulled downward slightly by the cnjunctiv, which s attachd to the sclera nd the lwer lid. he origis and inertions f the mucles of he eyels are smmarized in Table 1-2. P692

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Figure 1-16 A Right ye, with the eyelds separated to sow the oenings o the tasal glans, plica semilunaris, carunula lacrmalis, ad puncta lacrimais. B. Lft eye, showing th superir and ierior

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tasal plats and th lacrimal gland, sc, and uct. Not that a all windw has ben cut in the orbial septum to show the undelying larimal glnd and at (yellow). C. Sgittal stion through the upper eyelid, and the supeior forni of the conjunctva. Note the presnce of smoth musce in the levator palpebra superiois.

P.63

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Figure 11-17 Left eye of a 29-ear-old oman. A. The name of structures seen in the examinaion of te eye. B. An enlared view f the meial angl between the eyelds. C. Te lower yelid puled downard and lightly verted t reveal he punctm lacrimle.

.694

able 11- Muscles of th Eyeball and Eyelids uscle

Origin

Insertio

Nerve Suply

Action

Extrinic Muscls of Eyeall (Strated Skeetal Musle)

Superir rectus

Teninous rig on poserior wall of orbtal cavit

Superir surfac of eyeball just posterior o corneocleral jnction

Oculomotor nerve third crnial nere)

Raises cornea uward and edially

Inferio rectus

Tendious ring on posteior wall of orbitl cavity

Inferior surface o eyeball just poserior to corneoscera l junction

Oculomotor nerve (tird cranal nerve)

Deresses crnea donward an mediall

Media rectus

Tendinou s ring on posteior wall of orbitl cavity

Medial srface of eyeball jst posteior to crneoscleal junctn

Ocuomotor nrve (thir cranial nerve)

Roates eyeall so that cornea looks meially

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Lateral ectus

Tendinos ring o posteri wall o orbital cavity

Laeral surace of eeball jut posteror to coneosclera junctio

Abducnt nerve (sixth canial neve)

Rotats eyebal so that cornea looks laterally

Sperior olique

Posteror wall f orbita cavity

es through pulley and is atached t superio surface of eyebal beneat superio rectus

Troclear nere (fourt cranial nerve)

Rotates eyeball so tat corne looks dwnward ad lateraly

Inerior obique

Floor o orbital cavity

Laterl surfac of eyebll deep o latera rectus

ulomoto nerve (hird craial nerv)

Rotates eyeball o that crnea loos upward and laterally

Sphincte r pupillae f iris

arasympahetic vi oculomtor nerv

Constrics pupil

Dlator puillae of iris

Symathetic

Dilats pupil

Intrnsic Musles of Eyeball (Smooth Musce)

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Cliary mucle

Parasympathet c via oclomotor erve

Contols shape of lens; in accomodation , makes les more gobular

Striatd muscle oculomotr nerve, smooth mscle symathetic

Raises uper lid

scles o Eyelids

Orbiculais oculi (Tble 11-4)

Levaor palperae supeioris

Bac of orbial cavit

Anerior suface and upper magin of sperior tarsal plat

Lacriml Apparaus acrimal land The lacrial gland onsists of a lare rbital prt and a small paebral part, wich are ontinuou with eah other round th lateral edge of he aponurosis o the levtor palpbrae suprioris. t is situated aboe the eeball in the anteior and upper part of the bit postrior to the orbial septu (ig. 11-1). The gland opns into he laterl part o the suprior forix of th conjunciva by 1 ducts. Te arasympahetic seretomoto nerve spply s derive from th lcrimal ncleus of the fcial nee. The peganglioic fiber reach te pterygpalatine ganglio (sphenoalatine anglion) via the ervus inermedius nd its reat petosal brach and via the neve of the pterygid canal The potganglinic fibes leave the ganglin and jon the maillary nrve. Thy then ps into is zygomaic branc and the zygomaticotempora nerve. They reah the lacimal glad within the lacrmal nerve. The symathetic ostganglonic nere supply is frm the inernal caotid pleus and tavels in the deep petrosal nerve, he nerve f the ptrygoid cnal, the maxillar nerve, te zygomtic nerv, the zyomaticotmporal nrve, and finally he lacrial nerv.

acrimal ucts he tears circulat across he corne and accmulate i the lacus acrimali. Fro here, te tears nter the caaliculi acrimale throuh the punca lacrimlis. Te canaliuli lacrmales pas medialy and opn into

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snell te acrimal ac (Fig. 11-16) which les in th lacrima groove ehind th medial alpebral ligament and is te upper lind end of the nsolacriml duct. The nasolcrimal duct is about 0. in. (1. cm) lon and emeges from the lowe end of he lacrial sac (Fig 11-16. The dct desceds downwrd, backard, and aterally in a bo canal ad opens into the inferior meatus o the nos. The opning is uarded b a fold of mucou membrane P.69

known as the lacrima fold. This prevents air from being forced up the dct into he lacrimal sac on blowing the nose

The Orbit Desription The orit is a yramidal cavity wth its bse in frnt and is apex bhind (Fig. 1-18). The orbita margin is fored above by the fontal boe, the lteral magin is frmed by the procsses of he frontl and zyomatic bnes, the inferior margin formed y the zygomatic bone and te maxill, and th medial argin i formed y the prcesses o the maxlla and he frontl bone. The obital wals are sown in Figure 11-18. 

Roof Formd by th orbital plate o the frotal bon, which eparates the orbtal caity from the antrior craial fos and th frontal lobe of the cerbral hemsphere P.696

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Figue 11-18 A. Rigt eyebal exposed from in ront. B. Muscles nd nerves of the left orbi as seen from in ont. C. ones foring the alls of he right orbit. D. The opic canal and the uperior nd inferor orbitl fissues on th left sie.

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snell   

Lateal wall: Formed by the zgomatic bone and the greaer wing f the spenoid (Fig. 1118) Foor: ormed by the orbital plate of the mxilla, wich sepaates the orbital avity frm the mallary sius Media wall: Formed from befe bakward by the frotal procss of te maxill, the acrimal one, the orbital plate of the ethmid (whic separats the obital caity from the ethmod sinuse), and te body o the sphnoid

Openings Into th Orbital Cavity The openings into the orbital cavity ar shown in Fgure 11-8.   

 





Orbital opening: ies anteiorly (Fig. 11-18. About ne-sixth of the eye is expoed; the remainde is protected by te walls f the orit. Supraorbital notch Foramen) The upraorbial notc is situted on th superio orbital margin (Fig 11-18). It trnsmits te supraorbital nerve and blod vesses. Infraorital grove and cnal: Stuated o the flor of the orbit in the orbial plate of the mxilla (Fig. 11-19; they tansmit the infraorital nere (a coninuation of the mxillary erve) and blood vssels. Nasolarimal caal: Loated anriorly on the medial wall; it commuicates wth the iferior matus of he nose Fi. 11-16). It tansmits he nasolcrimal dct. Inferio orbital fissure: Locatd posterorly beteen the axilla ad the grater win of the phenoid Fi. 11-18); it cmmunicats with te pterygpalatine fossa. It transmit the maillary nrve and ts zygomtic bran, the inerior opthalmic ein, and sympatheic nerve. Suerior orital fisure: Located psteriorly between the greater and lesser win of the sphenoid (Fg. 11-18); it ommunicaes with he middl cranial fossa. t transmts the lacrimal nerve, the frontal nerve, te trochlear nerve, the oculmotor nrve (uppr and loer divisons), th abducen nerve, he nasocliary nerve, and he superor ophthlmic vei. Opic canal Locaed posteiorly in the lessr wing o the sphnoid (Fig. 1-18); it commuicates wth the mddle craial foss. It trasmits th optic nrve and he ophthmic artey.

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Figue 11-19 Muscls and neves of te right obit viewd from te latera side. The maxillry nerve and the terygopaltine ganlion are also shon.

.697

Orital Fasia Te orbita fascia s the peiosteum f the bones that form the alls of he orbit It is losely atached to the bone and is continuos throug the formina and fissures with the periosteu coverg the ouer surfaces of th bones. he muscle f Mülle, or orbtalis mucle, is a thin layer of smooth mscle tha bridges the infeior orbial fissre. It i supplie by sympthetic nves, and its funcion is unknown.

Nrves of he Orbit 1299

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Opti Nerve The opti nerve entrs the oit from he middl cranial fossa by ing hrough the ptic canl (Fig. 120). It is accompanie by the phthalmic artery, hich lie on its ower laeral sid. The neve is surounded y sheath of pia ater, archnoid maer, and ura mater (Fg. 11-25). It uns forard and laterally within the cone of the rcti musces and ierces the sclera at a poit medial to the posterior ole of te eyebal. Here, the meniges fuse with the sclera s that th subarahnoid spce with ts contaned cererospinal fluid exends forward from the midde crani fossa, round th optic nrve, and through the opti canal, s far as the eyebll. A rie in presure of the cererospinal fluid within the anial cavity therefore is transmited to th back of the eyball.

Lacimal Nere The lacrimal nerve arses from the ophtalmic divsion of the trigminal neve. It eters the orbit though the upper pat of th superio orbital issure (Fig 11-18) and pases forwrd along the uppe border f the lateral rects muscle (Fg. 11-20). It i ed y a branh of the ygomatictemporal nerve, wch later leaves i to ente the lacrmal glan P.698

(parasypathetic secretomtor fibes). The lacrimal nrve ends by suppling the kin of te latera part of the uppe lid.

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Figure 1-20 ight and left orbtal caviies viewd from aove. The roof of he orbi, formed by the obital plte of th frontal bone, has been reoved fro both sies. On te left sde, the evator plpebrae superioris and the superior rectus mscles hae also een remoed to epose the underlyin structues.

Frntal Nere The frontal erve aries from he ophthlmic divsion of the trigeinal nere. It eners the rbit thrugh the pper par of the superior orbital fssure (Fig. 11-18 and pases forward on the upper suface of the levato palpebre superiris beneh the rof of the orbit (Fig. 11-20) It divies into he supratrohlear nd supraorbtal nervs tht wind aound the upper marin of th orbital cavty to suply the skin of he forehad; the upraorbial nerve also suppies the ucous mmbrane o the frotal air nus.

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Trchlear rve The trochlear nerve enters te orbit hrough te upper art of te superir orbita fissure (Fg. 11-18). It uns forwd and suplies th superio oblique muscle (Fig 11-20.

Oclomotor erve The superio ramus of the oulomotor nerve eners the rbit thrugh the ower par of the uperior rbital fssure (Fig. 11-18). It suppies the uperior ectus mucle, the pierces it, and upplies the levator palpebre superiris musce (Fig. 11-8). The infrior rams of te oculootor nere enters the orbi in a silar manner and supplies the inferior rectus the medal rectu, and th inferor obliqe muscle. The nrve to he inferior obliue gives off a branch (Fig. 11-19) hat s to the ciliary anglion nd carris parasympathetic ibers t the sphncter puillae an the cilary musce (see blow).

Nasciliary erve The nasoiliary nerve arise from the ophthalic diviion of te trigemnal nerv. It entrs the obit throgh the lwer par of the uperior orbital fisure (Fig. 1-18) It croses abov the optc nerve, runs forard along the upper margin of the dial recus muscl, and ens by divding int the anterir ethmoial an ifratrochear nervs (Fig. 1-20).

Branchs of the Nasociliry Nerve 



 



The communiating brnch to th ciliary ganglion is a sensory erve. Th sensory fibers fom the eeball pas to the ciliary anglion via the hort cilary nervs, hrough te ganglon withot interrption, ad then jin the nasociliary nerve b means o the communicatin branch. The long ciiary neres, t or thr in number, arise from the nasociliry nerve as it crsses the optic neve (Fig. 1120). hey contin sympahetic fiers for he dilatr pupillae muscle. The nerves forward wth the sort ciliry nerve and piece the sclera of the eyeball. They ontinue orward btween th sclera nd the horoid to reach the iris. The poterior ehmoidal erve supplies he ethmoidal and shenoidal air sinues (Fig. 1120). The infratochlear erve asses foward belw the puley of t superi oblique muscle and supplies the sin of th medial art of te upper yelid an the adacent pat of the nose (Fig. 1-16). The antrior ethoidal neve psses thrugh the nterior ethmoidal oramen ad enters the anterior craial foss on the pper surace of te cribriorm plat of the ethmoid (Fig. 11-20). It eners the asal caity throgh a slilike openng alongide the rista gali. Afte supplyng an ara of mucus membrae, it apears on he face s the exteral nasal branch at the lower borer of th nasal boe, and spplies te skin of the noe down as far as te tip (se age 729).

Abducent Nrve Te abducet nerve nters th orbit trough th lower prt of th superio orbital fissure Fi. 11-18). It suplies th lateral rectus mscle.

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Ciliry Ganglon Te ciliar ganglio is a paasympathtic gangion abou the siz of a pihead (Fig. 1-19) and sitted in the posterior part f the orit. It rceives is pregaglionic arasympahetic fibers from the oculmotor neve via the nerve to the iferior oblique. The postganlionic fbers leae the gnglion i the short iliary nrves, which entr the bak of the eyeball nd suppl the sphncter puillae an the cilary musce. A nuber of smpatheti fibers ass from the intenal carotid plexus into th orbit nd run trough te ganglin without interrution.

Blood Vessels nd Lymph Vessels f the Orit Ophthamic Artey Th ophthalmic artery is a brach of te internl caroti artery after that vessel eerges frm the cernous snus (see page 750. It entrs the obit through the opic canal with the optic neve (Fig. 11-20). It runs orward ad crosse the optc nerve o reach he media wall of the orb. It gives off numerous branches, whih accompany the nves in he orbial cavity.

Banches o the Ophthalmic Arery 

   

The cetral artry of the retina is a smll branc that pirces the meningea sheaths of the otic nerv to gain entrance to the nrve (Figs. 1-25 ad 1-26) It runs in the sbstance f the optc nerve and eners the yeball a the cener of th otic disc. Here, it divids into banches, hich may be studied in a paient thrugh an ohthalmoscope. Th branche are end arteries The muscuar brances Th cliary areries can be ivided ito anterr and poterior goups. Th former roup eners the yeball nar the crneoscleal juncton; the atter group enters near th optic nrve. he lacrimal artery to the acrimal land Te upratroclear nd supraorbtal arteies a distribted to the skin f the fohead (see pge 729).

Ophthalmic Veins The superio ophthalic vein communcates in front wih the faial vein (Fg. 11-9). The infrior ophhalmic vin comunicate through the infeior orbial fissue with te pterygid venos plexus Both vens backward through the superio orbital fissure and drain into th cavernos sinus. P.699

Lymph Vssels No lymph vesels r nodes re presnt in th orbital cavity.

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Th Eye Mvements f the Eyball Ued in Decribing Eye Movemnts The cener of th cornea r the ceter of te pupil s used s the antomic â€anterior pole― f the ey. All moements of the ey are the related to the direction of the movment of he anteror pole as it rotates o any one of the hree axe (horizontal, veical, ad sagittl). The erminoloy then ecomes a follows: Eevation is the rotation of the eye upward, dpression is the rotation of the ye downwrd, abductin is he rotaton of th eye latrally, ad dduction is th rotatio of the ye medialy. Rotaory moveents of the eyeball use the upper m of the cornea or pupil) as the marker. Th eye roates eiter medialy or laerally.

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igure 11-21 The actions of the four reti muscls in proucing moements of the eyeall.

Extinsic Mucles Proucing Moement of the Eye Tere are ix voluntry muscls that rn from te posteror wall f the orital cavty to th eyeball (Fg. 1118). Thes are the superior rectus, he inferior rectus, the media rectus, the lateal rectu, and he superior and inferor obliqe muscle.

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snell Becaus the superior and the iferior ecti are inserte on the medial ide of the vertial axis f the eeball, they not nly raie and deress the cornea, spectivey, but aso rotate i mediall (Fig. 1-21). For the superior rectus muscle to rise the ornea diectly upard, the inferio oblique muscle mst assist; for the inferior rectus depress the corea direcly downwrd, the uperior blique mscle mus assist Fis. 11-21 and 11-22). Not that th tendon f P.700

the suerior obique musle e through a fibrocrtilaginous pulley (trochla) attaced to th frontal bone. Th tendon ow turns backward and lateally and is insered into he scler beneath the superor rects muscle

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Figure 11-22 Th actions of the superior and inferior obliqe muscles in producing movments of the eyebll.

he origs, insertions, neve supply, and acions of he muscls of the eyeball re summaized in Table 11-2. Study arefully Fiure 11-2.

Clnical Teting for the Actins of th Superio and Infrior Reci and th Superio and Infrior Oblque Muscls Because he actios of the superior and infeior rect and th superio and infeior oblque muscles are complicated when a atient i asked t look vetically pward or verticaly downwad, the hysician tests th eye movments whre the sngle acton of each muscle predomites. Te origin of the uperior nd inferor recti are sitated abot 23° mdial to heir insrtions, nd, therfore, whn the patient is asked to turn the ornea laterally, these muscles are laced i the optmum posiion to rise (suprior recus) or lwer (infrior retus) the cornea. Using th same raionale, he superior and inferior oblique mscles ca be testd. The plley of he superor obliqe and te origin of the iferior olique mucles lie medial ad anterir to thir inserions. Th physicin tests he actio of thes muscles by askig the patient fir to look medially, thus plcing thee muscle in the optimum osition o lower superior oblique) or raise (inferior oblique the corea. In oher word, when yu ask a atient to look mdially ad downwa at the tip of his or her ose, you are testng the uperior blique a its bes positio. Converely, by sking th patient to look medially and upwad, you are testing the infeior oblque at is best psition. ecause te latera and medal recti are simpy placed relativ to the yeball, sking th patient o turn his or her cornea irectly aterally tests the lateral ectus an turning the corna direcly medialy tests the medi rectus. P.701

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Fgure 11-3 Acions of te four rcti and wo obliqe muscle of the ight orbi, assuming that each muscle is acng alone. The postion of he pupil in relaion to te verticl and hoizontal lanes shuld be nted in ech case The actions of the sperior ad inferior recti ad the obique mucles in he livin intact ye are tsted clincally, a deidoub on pae 700.

P.702

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Figre 11-24 The ardinal ositions of the rght and eft eyes and the actions o the reti and olique mucles principally responsibl for the movement of the eyes. A. Right eye, supeior rectu muscle left ey inferio oblique muscle. B. Both ees, superior rect and inferior obliue muscls. C. Riht eye, nferior blique mcle; left eye, suerior retus musce. D. Rigt eye, lteral retus musce; left eye, medial rectu muscle. E. Prima position, with te eyes fxed on a distant ixation pint. F. ight eye medial ectus muscle; left eye, latral rects muscle G. Right eye, infrior recus muscl; left ee, superor oblque musce. H. Bot eyes, iferior rcti and uperior blique mscles. I. Right ey, superir obliqu muscle; left eye, inferio rectus uscle.

The cardnal posiions of he eyes nd the ations of the recti and obliue muscls are shwn in Figu 11-24.

Intrinsi Muscles The ivoluntar intrinsc muscle are the ciiary musle and the constrctor, nd the dilaor pupilae of th iris take no art in te movemet of the eyeball nd are dscussed ater.

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Fascial Sheath o the Eyball The facial shth surronds the yeball fom the otic nerv to the orneosclral juncion (Fig. 1-25). It sepaates the eyeball rom the rbital ft and provides it with a scket for free movment. I is perfated by the tendos of the orbital muscles nd is relected oto each f them a a tubulr sheath The sheaths for the tends of the medial and latera recti ae attaced to th medial nd lateal walls of the obit by tiangular ligamens called the medial and laterl check igaments. The ower par of the ascial seath, whch e beneath the eyeball and connects e check igaments is thicened and serves t suspend the eyeall; it s called the suspensry ligamnt of the eye (Fig 11-25. By this means te eye is suspende from th medial nd laterl walls f the orbit, as if in a hammock.

tructure of the Ee Th eyeball (Fg. 11-25) is emedded in orbital at but i separatd from i by the ascial seath of he eyebal. The eeball P703

cosists of three cots, whic, from wthout inard, are he fibros coat, he vascuar pigmeted coat and the nervous oat.

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Figure 11-25 A. orizonta section through he eyebal and th optic nrve. Not that te centra artery nd vein f the reina cros the subrachnoid space to reach the optic rve. B. heck ligments an suspensry ligamnt of th eyeball

Cats of te Eyebal Fibous Coat The fibrous coat is mad up of a posterio opaque art, the sclera, nd an anerior trnsparent part, th cornea Fi. 11-25).

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The clera he opaqu sclera s composd of dene fibrou tissue and is wite. Poseriorly, it is pirced by the opti nerve ad is fued with he dural sheath of that nere (Fig. 11-25). Te amina crbrosa is the aea of th sclera hat is pierced by the nerv fibers of the optic nerve. The sclera is also pierced by the ciliary arteries a nerves and their associated vein, the venae vorticosae. The sclera directly continous in font with the corna at the corneosceral juction, o limbus. P.704

he Corne The ransparet ornea is largely responsible for the refrtion of the ligh entering the eye (Fig. 1125). It i in contct posteiorly wih the aqeous humr.

Bood Suppy The cornea i avascular and deid of lmphatic drainage. It is nourished b diffusin from e aqueou humor ad from he capilaries at its edge

Nerve Suply Log ciliary nerves frm the opthalmic dvision o the trigeinal ner

Funcion of te Cornea The corne is the mst importat refracive mediu of the ye. This efractive power occrs on th anterior urface of the corna, where the refrative index of the crnea (1.8) diffes greatl from that of he air. he imporance of the tear flm in maitaining he normal environmet for the corneal eithelial ells shoud be strssed.

Vascular Pgmented Cat Th vascular pigmented coat conists, fro behind foward, of he choroi, the cilary body and the iris.

The Choroid The chorid is coposed of an outer pigmente layer a an inner, highly ascular lyer.

The liary Boy

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snell The cilary body is coninuous psteriorly with the horoid, ad anterioly it lie behind te peripheal margi of the iis (Fig. 11-). It s composed of the cliary rin, the ciiary processes, and the ciliay muscle The cilry ring is the psterior part of te body, nd its srface as shallo grooves, the ciliay striae. The ciliay proceses are radially arranged olds, or idges, to the postrior suraces of which re conneted the uspensor ligamens of the lens. The ciliary uscle (Fig 11-25 is compsed of meidianal ad circula fibers o smooth mscle. The meridianl fibers un backwd from th region o the cornoscleral junction o the cilary proceses. The ircular fbers are ewer in nmber and lie internal to the meridiana fibers. 



Nerve suply: The iliary mscle is suppied by te parasmpatheti fibers rom the culomoto nerve. After syapsing i the cilary ganglion, the postganglionic fiers forwar to the eyeball i the short ciliar nerves. Acion: Contracton of th ciliary muscle, speciall the meridianal fibers, pulls the iliary bdy forwad. This relieves te tensio in the suspensoy ligamet, and te elasti lens becomes more convex. This inreases te refracve power of the lens.

The Iris and Pupi The ris is a thin, contractile, pigmented diaphrgm with a cetral apeture, th pupil (Fig 11-25). It i suspended in the queous hmor betwen the crnea and the lens The periphery of the iris is attahed to te anterio surface of the iliary bdy. It divides th space bween the lens and the corna into n nterior and a poserior chmber. The mucle fibers of the iris are involunary and nsist o circular and radiating fibers. The circular ibers fom the sphinter pupilae a are arrnged arond the mrgin of he pupil The radal fiber form the dlator puillae nd consit of a tin sheet of radia fibers tat lie cose to te posteror surface. 



Nerve spply: he sphincter pupillae is upplied y parasypathetic fibers fom the oulomotor nerve. Ater synpsing in the ciliry ganglon, the ostganglonc fibers forward to the eeball i the shot ciliar nerves. The diltor pupilae i supplied by sympahetic fiers, whih frward to the eyebal in the long cilary nervs. Acton: Te sphinter pupilae consricts the pupil in the presnce of bight ligt and dring accmmodatio. The dilator pupilae dilaes the ppil in te presece of liht of lo intensit or in the presee of excessive smpatheti activit such as ccurs in fright.

Nervous oat: The Retina The reina conssts of a oter pigmnted layr and an inner nevous lay. Its outer suface is n with the choroid, and its nner surace is i ith the itreous ody (Fig. 1-25). he posteior thre fourths of the rtina is the receptr organ. Its anteior edge forms a wvy ring, the ora serrata, and the ervous tsues end here. Te anterio part of the retia is noreceptive and conssts merey of pigent cell, with a deeper ayer of columnar epithelim. This nterior art of te retina covers he ciliry procsses and the bac of the ris.

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snell t the ceter of te posterior part f the reina is an oval, yelowish aea, the macla lutea, whic is the rea of the retina or the mst distict visio. It has a centra depressin, the fovea centras (Figs. 1125 and 11-26. Te optic erve leaes the reina abou 3 mm t the medil side o the macla lute by the ptic disc. The optic disc is slightl depressd at its center, here it is pierce by the cenral arter of the etina At the ptic disc is a comlete absnce of rods and cones so tht it is nsensitie to ligh and is eferred o as the “blind spot.― On ophthlmoscopi examination, the ptic dis is seen to be pae pink i color, uch pale than the surroundng retin.

Contens of the Eyeball The ontents f the eyeall consst of th refractve media, the aqueus humor the viteous bod, and th lens.

Aquous Humo The queous hmor is a clear flid that ills the nterior nd posteior chambers of the eyeball (ig. 112). It is belieed to be a secretion from te ciliar processs, from hich it enters th posterir chambe. It the flows ito the anterior chamber though the pupil an is draied away through th spaces t the iidocornel angle ito the canal of Schmm. Ostructio to the raining of the aueous hmor resuts in a ise in itraocular pressure called glacoma. This can produce degeneratie change in the retina, wih conseqent blinness. The unction f the aqeous humr is to upport t wall of the eyeall by eerting iternal pessure ad thus mintainin its opical shap. It als nourishs the corea and te lens ad remove the prducts of metabolism; these unctions are impotant becuse the cornea and the len do not ossess a blood suply. P.70

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Fiure 11-2 The eft oculr fundus as seen ith an ohthalmosope.

Vitreus Body The vireous boy fills he eyebal behind the lens (Fg. 11-25) and s a tranparent gl. The hyaloid canal is a narrow cannel tht runs trough the vitreous body fom the optic disc to the sterior surface of the len; in the fetus, i is filld by the hyaloid rtery, wich disapears beore birth The function of the vtreous bdy is to contribue slighly to th magnifyng power f the eye. It s the posterio surfac of the ens and assists in holding he neura part of the retna againt the pimented prt of th retina.

The Lens The ens (Fig. 1-25) i a tranparent, iconvex tructure enclosed in a trasparent apsule. t is siuated beind the ris and front o the viteous bod and is encircled by the ciliary pcesses. The lens consists of an elstic capsule, whih envelos the stucture; cboidal eithelium, whic is confined to th anterio surface of the lns; and len fibers, which are formed from th cuboida epithelum at th equator of the lns. The ens fiber make up the bulk of the lns. The elastic ens capsle is uner tensin, causig the lns constntly to ndeavor assume a globulr rather than a disc shape. The equtorial rgion, or crcumference, of th lens is attached to the

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snell iliary pocesses f the ciiary bod by the susensory lgament The pull of the radiatin fibers f the supensory lgament tnds to eep the lastic lns flattned so that the ee can be ocused o distan objects

ccommodaion of te Eye To accmodate te eye fo close ojects, te ciliar muscle contract and puls the ciiary bod forward and inwad so tha the raiating fbers of he suspensory ligaent are elaxed. his allws the eastic les to assme a mor globula shape. With advancin age, th lens beomes dener and lss elasic, and, as a reslt, the bility t accommoate is lssened resbyopi). This isabilit can be vercome y the us of an dditiona lens in the form of glasss to assit the ey in focuing on earby obects.

Contriction of the Ppil Duri Accommoation of the Eye To nsure tht the light rays throgh the cntral prt of the lens so pherical aberration is dimnished dring acommodatin for ner object, the sphincter puillae mucle s so the pupi becomes smaller

Convergene of the Eyes During Accomodation the Lens In humas, the rtinae of both eye focus o only on set of objects single bnocular ision). hen an oject movs from a distance toward a individal, the ees convege so tht a singe objec, not tw, is see. Converence of he eyes sults from the cordinate contracion of the medial ectus mucles. P06

Cinical Ntes ye Traum Although the eeball is well protected by the surounding ony orbi, it is protected anteriory only fom large objects, such as ennis bals, whic tend to trike the orbital margin ut not te globe. The bony orbit prvides no protectin from smll objets, such as golf alls, whch can cuse sevee damage to the ey. Carefl examintion o the eyeall relive to the orbital argins hows tha it is last protcted fro the latral side Blowout fractures f the bital floor involving the maxillary sinus comonly ocur as a esult blunt frce to te face. f the foce is applied to the eye, e orbitl fat exlodes ineriorly nto the axillary inus, frcturing the orbial floor. Not only can blowut fractres caus displacent of e eyebal, with rsulting ymptoms f doubl vision diplopi), but also the racture an injur the infaorbital nerve, poducing oss of ensation of the sin of the cheek and the gum on that ide. Entapment f the inerior retus musce in the fracture may limit upward gze.

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Stabismus Many cses of srabismus are nonparalytic and are cased by an imbalance in t action of opposng muscles. This type of strabismus is known as concomiant straismus nd is comon in ifancy.

Pupilary Reflees Th pupillar reflexes€”that i, the rection of the pupls to liht and accomodation€”depend on the itegrity f nervou pathwas. In the drect ligt reflex, the normal ppil reflxly s whe a light s shone ito the ptient's ee. The nevous implses pas from the retina along te optic nerve to the optc chiasm and the along the optic tract. Befre reacing the ateral gniculate body, th fibers concerned with thi reflex leave th tract and to the oculomotor nulei on bth sides via the pretecta nuclei. From the parasympahetic pat of the nucleus, efferen fibers lave the idbrain n the oclomotor nrve and each th ciliary ganglion via the erve to the inferir obliqu. Postgnglionic fibers pss to th constricor pupilae muscls via th short iliary nerves. The consenual ligh reflex is tested by shning the light in one eye and noting the contraction of the ppil in te opposie eye. Tis refle is possble because the aferent pthway jut descried traves to the parasympthetic nulei of oth oculmotor neves. The accommodatin reflex is th contracion of te pupil hat occus when a erson sudenly focuses on a near oject aftr having focused on a distt object The nerous implses from the retina via the opic nerve the optc chiasm, the otic trac, the lateral geniulate boy, the otic radition, and the cerbral corex of th occipit lobe of the brai. The viual corex is conected to the eye ield of he frontl cortex From hee, effernt pathwys o the parasympatheic nucles of the oculomotr nerve. From thee, the eferent impulses rech the cnstricto pupilla via the oculomotr nerve, the ciliry ganglon, and the short iliary erves.

Th Ear he ear onsists of the external ea; the midle ear, or tympic cavit; and th internal ear, o labyrinh, which contains the orgs of hearing and alance.

Extenal Ear The external ea has an uricle ad an extrnal audtory meaus. Th uricle has a caracterstic shae (Fig. 11-7A) nd collets air vbrations It conssts of a thin plae of elatic cartlage covred by sin. It pssesses oth extrinsic and ntrinsic muscle, which re suppled by the facial nrve. The exteral auditry meatu is a curved te that leads from the aurcle to the tympanc membrane (Figs. 1127 and 1128). It conducts sound wves from the aurile to th tympani membran. The framework of the ter thid of the meatus i elasti cartilae, and te inner wo third is bone formed y the tmpanic pate. The meatus i lined b skin, ad its ouer third is provided with airs nd

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snell sebaceos and cerminous gands. The lattr are moified swat gland that serete a yelowish bown wax The hais and th wax proide a stiky barrir that pevents te entrace of foeign bodes. The senory nere suppy of the lining sin is deived fro the aurculotempral nerv and the auricula branch of the vas nerve. The lymp drainag is to the superficial parotid, mastoid, and supericial cerical lyh nodes

Clinial Notes Tympnic Membane Examnation Otosic examnation of the tymanic memrane is facilitad by firt straigtening te externl auditoy meatus by genty pullin the aurcle upwd and backward in the adult, and staight bakward or backward and downard in te infant. Normall, the tympanic embrane is pearly gray and concave. that in he adul the extrnal meaus is abut 1 in. (2.5 cm) long and s narrowst abou 0.2 in. (5 mm) fom the tmpanic mmbrane.

Middle ar (Tympnic Caviy) he middl ear is n air-cotaining avity in the petrus part f the teporal boe (Fig. 11-8) ad is lind with mucos membrae. It cotains th auditor ossicle, whose function is to trnsmit th vibratins of th tympani membran (eardrm) to th perilymh of the internal ear. It a narrow, oblique, slitlike cavity whose lng axis ies apprximately parallel to the lane of he tympanic memrane. I communiates in front trough he auditoy tube wth the nsopharyn and behnd with he mastod antru. The midle ear hs a roof floor, nterior all, poserior wall, lateral wall, and medal wall. P.707

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Figure 11-27 A. Diferent pats of th auricle of the eternal er. The arow indiates th directin that te auricl should be pulled to straigten the external auditory meatus bfore insrtion of the otosope in te adult. B. Extenal and iddle potions of the righ ear viewed from in front. C. The riht tympaic membrne as seen through the otosope.

P.708

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Figure 1-28 A Parts o the rigt ear in relation to the tmporal bne viewe from abve. B. Te auditoy ossicles.

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Figure 1-29 A. Lateral wall of the right middle ear viewe from th medial side. Note the postion of he ossices and the mastoi antrum. B. Medial wall of the right middle ear viewe from th lateral side. Noe the poition of he facal nerv in it bony caal.

The roo is fomed by a thin plae of bon, the tegmen tympani, whic is part of the ptrous teporal boe (Figs. 1129 and 1130). t separaes the tpanic cvity from the meniges and he tempoal lobe f the brin in th middle ranial fssa. The floor is fored by a thin plte of bone, whic may be artly relaced by fibrous issue. I separates the tpanic caity from the supeior bulb of the iternal ugular vin (Fig. 1130). Th aterior wll is formed blow by a thin plae of bon that searates te tympanc cavity from the internal carotid rtery (Fig. 11-30. At th upper prt of th anterior wall are the openngs int two canls. The lower an larger of these leads into the audiory tube and th upper ad P.710

P.711

maller s the entrance into the canal for th tensor ympani mscle (Fig. 11-29) The thn, bony eptum, wich sepaates the canals, s proloned backard on te medial wall, where it rms a shlflike pojection

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Fiure 11-3 A. Th middle ar and is relatins. Bony (B) and embranous () labyinths.

The posterio wall has in it upper prt a lare, irreglar openng, the adtus to te mastoi antrum (igs. 11-9 and 1130). Blow this is a smal, hollo, conica projecton, the pyrmid, rom whos apex emrges the tendon o the stapedus muscl.

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snell The latral wall is larely formd by the tympanic membrane (Fgs. 11-2 and 11-9). The medial wall s formed by the lateral wall of the inner ea. The grater par of the all show a rounded projection, called the promontoy, whih result from th underlyng first turn of he cochla (Figs. 1127 and 1129). bove and behind te promonory lies the fenestr vestibui, whch is ovl shaped and closd by the base of he stapes. On the medial ide of te window is the peilymph o the scaa vestibli of te internl ear. Blow the osterior end of te promonory lies the fenestr cochlea, whic is roud an closed y the secndary typanic mebrane. On the mdial sid of this window i the perlymph of the blin end of he scala tympani see page 71). Th bony shlf derivd from te anterir wall etends bckward o the medal wall bove the promontoy and abve the fnestra vestibuli. It suppots the tnsor tympani musce. Its psterior nd is crved upwrd and frms a puley, the processus cochleariformis, around wich the endon of the tesor tympani bends laterally to reach its insetion on he handl of the alleus (Fig 11-29. ronded rige runs orizontaly backwrd above the promontory and the fenstra vesibuli an is know as the prminence f the faial nerv canal. On reahing the posterior wall, it curves ownward ehind th pyramid The tymanic memrane (Fig 11-27) is a hin, fibous membane that is pearl gray. The membrae is obiquely plaed, facig downwad, forwad, and lterally. It is cncave laterally, nd at th depth o the conavity is a small depressio, the umbo, prodced by the tip of the handle of the malleus. When th membrane is illumnated though an otoscope the conavity prduces a €œcone o light,â• which adiates anteriory and ineriorly rom the mbo. The tymanic memrane is ircular nd measues about 1 cm in diameter The cirumferenc is thicened and is slotted into a groove the boe. The goove, or typanic sucus, s deficent supeiorly, hich fors a noth. From he sides of the ntch, two bands, termed th aterior and posteior mallolar olds the laeral proess of te malleu. The smll trianulr area on the tympanic membrane that is bounded by the olds is lack and is called the pars faccida (ig. 11-2). The reainder o the memrane is ense and is calle the par tensa. The handle of the malleus s bound down to he inner surface f the typanic membrane b the mucus membrne. he tympic membane is extremely senstive to ain and is innevated on its outer suface by the auriulotempoal nerve and the aurcular branch of te vagus.

Audiory Ossicles The auditor ossicle are the malleus incus, and stapes Fgs. 11-28 and 1129). The maleus s the lagest osicle and possesss a head a neck, a long pocess o handle, an anteior procss, and lateral process The head is ronded and articulates postriorly wth the icus. The neck is he consticted prt below the head The handl pases downwrd and ackward nd is firmly attached to the medil surfae of th tympani membran. It can be seen through he tympnic memrane on otoscopi examinaion. The anerior pocess is a scule of bone tha is connected to the antrior wal of the tympanic cavity

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snell by a ligament. The ateral rocess rojects aterally and is attached to the nterior nd posteior mallolar fos of th tympanic membrne. Te incus posseses a large body nd two pocesses Fig. 11-29). Te body s rounde and artculates nteriory with te head o the maleus. he long prcess escend behind and parllel to he hande of the malleus Its lowr end bnds medally and articlates wih the hed of th stapes. Its shaow on th tympanc membrae can smetimes e recogized on toscopi examinaion. The shot process projcts backward and is attaced to te posteror wall of the tmpanic cavity by a ligament. The staps has a head, neck, two limbs and a bse (Fig. 11-28). The head is smll and aticulate with the long process of the incu. The neck is nrrow and receive the insrtion of the stapdius musle. The tw limbs diverge from th neck an are atached to the oval bse. Te edge o the bas is atthed to he margi of the enestra estibuli by a rin of fibrus tissu, the anula ligamen.

Muscle of the Ossicles Thse are the tensor ympani and the stapedius mscles. Te muscl of the ossicle, their erve supply, and their acions are summarized in Table 11-3 Tabl 11-3 Muscles of the Mddle Er uscle

Orgin

Insetion

Nere Suppl

Action

Tesor tympni

all of auditory ube and wall of its own anal

Hadle of mlleus

Mandiular dvision f trigemnal nerve

Dampens down vbrations of tympnic membane

Stapedius

yramid (ony proection o posterr wall f middle ear)

Nck of stpes

Facial nerve

Dampens own vibrtions of stapes

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Movements o the Auitory Osicles The malleus nd incus rotate n an antroposteror axis that rus throuh the liament cnnecting the antrior proess of te mallus to he anteror wall f the tmpanic cavity, te anterir procss of th malleu and th short pocess of the incu, and th ligamet connecing the short prcess of he incus to the osterir wall f the typanic cavity. When he tympnic membane moves medialy (Fig. 1-31), the hndle o the maleus also moves meially. Te head o the maleus and the bod of the ncus mov lateraly. The lng proces of the incus mves medially with the stapes. The ase of te stapes is pushe medialy in the fenestra vestibul, and th motion s communcated to the perlymph in the scal vestibui. Liqui being icompressble, th perilyph causs an ouward buging of the secodary tyanic mebrane i the fenstra cochleae at the lowe end of the scal tympani (Fig 11-31). The abov movements are reversed i the tymanic memrane movs laterlly. Exessive lteral moements o the hea of the alleus cuse a mporary separatin of the articulr surfacs betwee the maleus an incus s that th base of the staps is not pulled lterally ut of he fenestra vestbuli. Duing ge of te vibratons from the tympnic membrane to the periymph via the smal ossicles, the everage increass at a rte of 1. to 1. Mreover, he area f the tmpanic embrane is abou 17 time greate than tht of the bas of the tapes, ausing he effecive presure on te perilmph to increase y a tota of 22 to 1.

Auditory Tube he auditry tube onnects he anteror wall f the typanic caity to te nasal harynx (Fi 11-27). Its osterior third is bony, an its antrior two thirds i cartilginous. As the tub descends it es over the uppe border f the sperior cnstrictor muscle (Fi. 11-80). It srves to qualize ir pressures in th tympani cavity nd the nsal pharx.

Mastod Antrum The mstoid anrum lies behind te middle ear in te petrou part of the tempral bone (Fg. 11-28). It ommunicaes with the middle ear by the aditus (g. 11-29).

Relatios of the Mastoid ntrum These are impotant in nderstaning the pread of infectio. Anterior wall s relate to the middle ea and conains the aditus t the masoid antrum (Fig. 1130). Posteror wall separats the anrum from the sigmid venou sinus ad the ceebellum Fi. 11-30). Laeral wal is (1.5 cm) thick and orms the floor of the supreatal trangle (se age 838). Medal wall is relted to te posteror semicrcular cnal (Fig. 1-30). Sperior wll s the thn plate of bone, the tegmn tympan, which i related to the mninges of the middle cranal fossa and the emporal obe of te brain Fig. 11-30).

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snell ferior all is perforatd with hles, thrugh whic the antm communcates wih the matoid air cells (Fig. 130).

Mastoid ir Cells The astoid pocess beins to dvelop during the second yr of lif. The matoid air cells ar a serie of commnicating cavities withi the proess that are continuous above with the antru and th middle ar (Fig. 1130). Tey are lned with mucous mmbrane.

Facia Nerve The entre course of the facial neve is decribed o page 76. On reacing the ottom of the intenal acoutic meats (see page 764), the facial nerve enters th facial cnal (Fig. 1-28). The nere runs lterally bove the vestibule of the internal er until it reachs the meial wall of the mddle ear Here, th nerve epands t form te sensor gniculate ganglion (Figs. 1-29 an 1-30). The nerv then beds sharpy backwad above he promontory. On ariving at the postrior wall of the iddle ea, it cures downwrd on th medial ide of te aditus of the mstoid anrum (Fig. 1-30). It desceds in th posterir wall o the midle ear, ehind th pyrami, and fially emeges through the stlomastoi foramen into the neck.

Importan Branchs of the ntrapetrus Part f the Faial Nerv 

The grater petosal nerve ariss from te facial nerve at the geniulate gaglion (Fig. 11-30 It cotains preganglionic parasymathetic ibers tht t the ptrygopalaine gangion and re there relayed hrough te zygomaic and acrimal erves to the lacrimal gland other pstganglinic fibes hrough te nasal nd palatne nerve to the glands of the muco membrane of the nose and palate. t also cntains mny tast fibers from the ucous mebrane of the palae.

The nerve merges on the superior surace of t petrous part of the temporal bone and is eventuall ed b the deep petrosa nerve from th sympatetic pleus on te nternal arotid atery and forms the nerve o the pteygoid caal. Tis e forward and enters the pterygopalatine foss where it ends in the pterygopalatie ganglin.  

Te erve to he stapeius arises fom the fcial nere as it escends n the faial cana behind the pyramid (Fig. 11-0). It supplies the musce within the pyraid. The chorda tympani arses from the facil nerve ust abov the styomastoid foramen Fi. 11-29). It eters the middle er close o the poterior brder of he tympaic membane. It hen runs forward ver the ympanic embrane nd crosss the rot of th handle f the malleus (Fig. 1-29). It lies in the iterval btween th mucous embrane nd the fbrous lyers of he tympac membrne. The erve leaves the middle ear through the petrtympanic fissure nd enter the infrtemporal fossa, here it oins the lingual erve (se pge 765. The choda tympai contais:

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snell Tase fibers from the muco membre covering the anterior tw thirds f the togue (not the valate papllae) and the floo of the outh. Th taste fbers are the perpheral pocesses f the cels in th geniculte ganglon. P.73

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Figre 11-31 A. Virations f music assing ito the external aditory matus caue the tmpanic mmbrane t move meially; te head o the maleus and ncus moe laterally, and e long process o the incs, with he stapes, moves laterall . The edial moement of the base of the sapes in he fenesra vestiuli causes motion (arows) in the prilymph n the scla vestiuli. At he apex f the cohlea (te helicorema), te compresion wave in the perilymph es dwn the cala tymani, cauing a laeral buling of te secondary tympanic membrne in th fenestr cochlea. . Movment of the perilyph (arrows) after movement of the bse of th stapes. Note the osition f the bailar fibrs of th basilar membrane

P.714

Pregaglionic prasympatetic secetomotor fibers that rech the sbmandibuar ganglon and ae there elayed t the subandibula and subingual slivary gands

Tympnic Nerv The ympanic erve aries from he glosspharyngel nerve, just belw the juular formen (see pae 765). It es through the flr of the middle er and ono the prmontory Fi. 11-30). Here t splits into branches, whch form he tympanic plexus. The tyanic plexus supplies the lning of he middl ear and gives of the lesser petrosal nerve which snds secrtomotor ibers to the paroid gland via the tic gangion (see pae 787. It leaes the sull through the foramen ovae and jons the oic ganglon.

Clinial Notes Infetions an Otitis edia Pathogenc organims can gin entrance to th middle ar by acending hrough te auditoy tube fom the nsal part of the pharynx. Acute inftion of the middle ear (otits media) producs bulgin and reess of the tympanc membrne.

Comlication of Otits Media Inadquate tratment o otitis edia can result in the spread of t ifection nto the astoid atrum and the mastid air ells (acute mastoiitis). Acute astoidits may be followe by the urther sread of he organims beynd the cnfines o the midle ear. The meniges and the tempral lob of the rain lie superiory. A sprad of the infetion in his dirction cold produe a menigitis and a cerebrl absces in the temporl lobe. Beyond te medial wall of he middl ear lie the facil nerve and the nternal ear. A spread of th infectin in thi directin can cuse a faial nerv palsy ad labyinthitis with verigo. The posterior wall of the mastoid anrum is lated to the sigmoid venous sinus. If the ifection preads

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snell i this diection, thrombosis in the sigmid sinus may well take plae. These various omplicatons empasize th importane of knwing the anatomy of this egion.

Th Internal Ear, or Labyrint Te labyrith is siuated in the petrus part f the teporal boe, media to the iddle ea (ig. 11-2). It consists of the bny labyrnth, comrising a series o cavitie within the bone and the membranos labyrith, compising a eries of membranus sacs nd ducts containe within he bony labyrinth.

Bny Labyrnth The bony labyrith consits of thee parts: the vestibule, the semicicular canls, and he cochle (g. 11-30). Thes are caviies situatd in the ubstance f dense ne. They re lined by endostum and cotain a clar fluid the perilymh, in which is sspended the membranus labyrith. The vstibule, the cetral part of the ony labyrnth, lies posterio to the ochlea ad anteror to the semicicular caals. In ts laterl wall ar the fenesa vestibuli, which is closed by the bae of the stapes and its aular ligaent, and he fenestra ochleae, which is closed by the secndary typanic mmbrane Lodged within th vestibul are the sacule and uricle f the mebranous labyrinth (Fig. 1-30) The tee semicirular canals—superior, osterior, and lateralâ€open int the posrior par of the vstibule. ach canal has a swlling at ne end caled the ampula. Te canals pen into the vestbule by fve orifics, one of hich is common to two of th canals. odged witin the caals are the semicircuar ducts (Fig. 11-30). The superior semicirclar canal is vertical and laced a right angles to te long axi of the petrous bo. The poterior cnal is alo verticl but is placed parallel with the ong axis f the perous bone. The lateal canal is set i a horiontal psition, nd it les in the medial wall of th aditus o the matoid antum, abov the faial nerve canal. The cochlea resemles a snai shell. t opens ito the anerior part of the vstibule (Fig. 11-30. Basicly, it cosists of central illar, te odiolus, around which a ollow bon tube make two and one half piral tuns. Each successiv turn is of decresing radus so tat the wole struture is cnical. The apex facs anterolterally ad the bas faces psteromedilly. The irst basal turn of he cochlea is responsible or th promontry seen n the medial wal of the iddle ea. The modiolus has a brad base, which is situated at the ottom of the intenal acoutic meats. It is perforatd by braches of the cochear nerv. A spirl ledge, the spiral amina, winds arund the modiolus and projects into he interor of th canal ad partialy divid it. The bsilar mebrane tretches from the free edg of the piral lamina to th outer bny wall, thus dividing the ochlear canal ino the scala vestibul above and the sca tympani belw. The prilymph ithin th scala vestibuli separatd from te middl ear by he base f the stpes and he anula ligamen at the fenestra estibuli The perlymph in the scal tympani is separted fro the midle ear by the secondary tympanic merane at the fenestra cochleae.

Membranous Labyrinth 1331

snell he membrnous labrinth is lodged wthin the bony labyinth (Fig. 1-30) It is illed wih endolyph and srrounded by perilmph. It consists the uricle an saccule which ae lodged in the bny vestiule; the three semicircula ducts, hich lie within te bony smicirculr canal; and th duct of the cochla, which lies witin the bny cochea. All hese strctures freely commnicate wth one aother. Te tricle is the arger of the two estibula sacs. I is indiectly conected t the saccule and the ducts endolymhaticus y the ducts utricuosaccularis. The saccul is globular and is connected t the utrcle, as escribed previouly. The uctus edolymphaicus, afer being ed b the ductus utricuosacculais, pases on to end in a small blnd pouch the saccus endolympaticus (ig. 11-3). Thi lies beeath the dura on he posteor surfae of the petrous art of te tempora bone. P.715

ocated o the wals of the utricle nd saccue are secialize sensory receptor, which re sensiive to te orienttion of the head o gravit or othe accelertion fores. The semicicular duts, lthough uch smaller in diaeter tha the semcircular canals, ave the same coniguratio. They ar arrange at righ angles o each oher so that all tree plans are reresented Wheneve the hea begins r cease to move, or wheneer a movment of he hea acceleraes or dcelerate, the enolymph in the semiircular ucts chages its peed of movement relative o that o the wals of the semicirclar duct. This hange is detected in the ssory retors in the ampulae of te semicrcular ducts. The duct f the cohlea i trianguar in crss sectin and is connecte to the accule b the ductus reuniens. The highly speialized pitheliu that lis on the bailar memrane orms the spiral ogan of Crti and ontains he sensoy receptos for haring. Fr a detaled desciption of the spirl organ, a textbok of hitology sould be onsulted.

Vestiblocochler Nerve On reching the ottom o the intrnal acoustic meaus (see pge 765), the nrve divids into vstibular nd cochlar portios (Fig. 11-2). The vestibuar nerve is expnded to frm the vesbular gaglion. The braches of te nerve ten pierc the lateal end o the internal acoustic meaus and gan entrane to the embranous labyrint, where hey suppy the utrcle, the saccule, nd the amullae of the semiircular dcts. Te cochlar nerve divies ino branchs, which enter foamina at the base of the mdiolus. he sensry ganglon of ths nerve takes the orm of a elongatd piral gaglion that is lodged i a canal winding around the modiolus in the ase of the spial lamina. The peripheral branches o this nve rom the ganglion to the spirl organ f Corti.

Th Mandibl 1332

snell The mandble or lwer jaw s the lrgest an strongest bone of the fce, and t articuates wit the skul at the temporoandibular t. he mandible consists of a horsesho-shaped bod and a pair of rai. The body of he mandile meets the ramu on each side at he angle of the mandble (Fig. 11-32. Th bdy of th mandibl, on its extenal surfce in th midline has a faint ridge indicatng the ne of fusion of he two haves durig develoment at he symphysi menti The mental foramen can be seen blow the econd prmolar toth; it tansmits he termial brances of th inferio alveolar nerve and vessels. n the meial surfce of th body of the mandble in te median plane ar seen th mntal spies; tese give origin t the genglossus uscles aove and he genioyoid musles belo (ig. 11-3). The mylohyoid line cn be see as an olique rige that rns backwrd and lterally rom the area of he menta spines to an ara below nd behin the thid molar tooth. he submandbular fosa, fr the superficia part of the submndibular salivary gland, les below the postrior par of the ylohyoid line. Th sblingual fossa for the sublingul gland, lies aboe the anerior part of the mylohyoid line (Fig. 11-32) The upper border of the dy of t mandible is calld the alveolar part; in th adult i contain 16 sockts for te roots of the teeth. The lower border of the body of the mandible is called th base. he digastri fossa is a smal, roughned deprssion on the base on eithr side o the symhysis meti (Fig. 1132). I is in tese fosse that te anterir bellie of the igastric muscles ae attachd. The ramu of the andible is verically plced and as an anerior coronid proces and a posteror condyloi process, or head the to proceses are sparated y the mandiular noth (Fig. 1-32). n the lateral surface of the ramus are markgs for the attachent of te massetr muscle On the edial suace is te mandibulr foramen for te inferir alveolr nerve nd vesses. In frnt of th foramen is a projection of bone, caled the linula, or the attachment of the spheomandibuar ligamnt (Figs. 11-32 and 11-33. The foamen leas into te andibula canal, which oens on te latera surface of the bdy of th mandibl at the menal foramn (se above). The incisiv canal is a coninuation forward f the mndibular canal beyond the mntal formen and elow the incisor eth. The coronid proces receves on is medial surface he attacment of he tempoalis musle. Belo the condyloid process, or hed, is a short nec (Fig. 1132). The imortant mscles an ligamens attachd to the mandible re shown in Figure 11-32.

Clinica Notes Fractres of te Mandibe Th mandibl is horsshoe shaed and frms part of a boy ring wth the to tempormandibulr ts and the ase of te skull Traumatc impact is transitted around the ring, causing a sgle frature or ultiple ractures of the mandible, often far removed rom the point of impact.

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Temporomandibular oint Articulation rticulaton occur between the artiular tubrcle and the antrior porion of te mandiblar foss of the emporal one abov and th head (condyloid process) the manible belw (Figs. 1133 an 1-34). he articlar surfaces are overed wth fibroartilage.

Type of The tmporomanibular jint is snovial. he articlar disc ivides te t nto uppe and lowr cavitis (Fig. 11-5).

Capsul The sule suounds th t ad is attched aboe to th articulr tuberce and th margins of the mndibular fossa ad below to the nck of th mandible P.716

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Figure 1-32 A. Mandible B. Hyoi bone.

.717

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Figre 11-33 Tempormandibulr t s seen fom the lteral (A) and medil (B) asects.

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Figur 11-34 A dissection of the left temporomadibular oint. Th capsule and latral tempromandiblar ligaent have been remved to rveal the interio of the t. Note the articular tuercle an mandibuar fossa of the temporal bone and the head f the mdible. Te articuar disc is preset within the cavity n the uper surfae of the head of the mandble.

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Figure 11-35 Temporomandibular t wih mouth losed (A and wit the mouh open (B. Note e positin of the head of he mandile and aticular isc in relation t the articular tubercle in each cas. . The ttachmen of the uscles o masticaion to the mandibl. The arows indiate the irection of their ctions.

Ligments The latera temporomandibular ligament stregthens he laterl aspect of the sule, ad its fiers run downward nd backwrd from he tuberle on th root of the zygom to the lateral urface o the nec of the andible Fi. 11-33). This igament imits th movemen of the mandble in a posterior directio and thu protect the external audiory meats. The sphenomandiular ligaent les on th medial ide of te t Fi. 11-33). It i a thin and that is attaced above to the spine of th sphenoi bone ad below o the ligula of he mandiular formen. It represent the remins of te first haryngea arch in this regin. The styomandibuar ligamnt lis behind and medil to the t an some ditance frm it. It is merely a band of thickned deep cervical fascia tat extens from te apex f the stloid proess to te angle f the madible (Fig. 11-33) The aticular isc dvides th t ito upper nd lower cavities (Fig. 1135). It is an val plat of fibroartilage that is P.720

attached circumfeentially to the sule. It is also ttached n front to the tendon of the lateral pterygid muscl and by ibrous bnds to he head f the madible. Tese band ensure hat the isc move forwar and bacward with the head of the mndible dring protaction nd retration of he mandile. The pper surfce of th disc is concavoonvex frm before backward o fit th shape o the artcular tercle an the manibular fssa; the lower suface is oncave t fit th head of the mandble.

Synvial Memrane This lins the casule in te upper nd lower cavities of the jint (Fig. 1-35).

erve Suply Auiculotemoral and masseterc branchs of the mandibulr nerve

Moveents The mandile can be depresse or elevted, proruded or retractd. Rotatin can alo occur, as in chwing. In the posiion of rst, the eeth of the upper and lowe jaws ar slightly apart. closu of the aws, the teeth coe into cntact.

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Deprssion of he Mandile s the moth is opned, the head of he mandibe rotate on the undersurace of te articuar disc round a horizontal axis. To prevent the angl of the aw impining unnecssarily n the paotid glnd and te sternoleidomasoid muscl, the madible is pulled orward. his is acomplishe by the ontractin of the lateral terygoid muscle, hich puls forward the neck of the mandible and the articula disc so that the latter mves onto the artiular tubercle (Fig. 1-35). The forard moveent of te disc i limited by the tsion of he fibrelastic issue, which tethes the dic to the temporal bone poteriorly. epressio of the andible s brough about b contration of the digastics, the geniohyods, and he mylohoids; th lateral pterygois play a importat role b pulling the mandible forwrd.

Elevation of te Mandibe Te movemets in dpression of the mndible ae reversd. First the hea of the andible nd the dsc move ackward, and the the hea rotates n the loer surfae of the disc. Elevaton of th mandibl is brouht about by ion of the temoralis, he masseer, and the medial pterygois. The ead of te mandibe is pulled backwad by the posterio fibers f the tmporalis The artcular dic is puled backwrd by th fibroelstic tisue, whic tethers the disc o the teporal boe posteiorly.

Protrion of te Mandibe Te articulr disc i pulled frward ono the anerior tbercle, arrying the head o the manible wit it. All movement thus taes place in the uper caviy of the t. I protrusin, the lwer teeh are drwn forwad over the upper teth, whih is broght abou by ion o the latral ptergoid muses of boh sides, assisted by both medial ptrygoids.

etractio of the andible The articula disc and the head of the ndible ae pulle backwar into the mandibulr fossa. Retractin is broght abou by contraction o the poserior fiers of te temporis.

Lteral Chwing Movents These ae accomplished by lternatey protruing and retractig the madible on ach side For thi to take place, a certain amount o rotation occurs, and the mscles reponsible on both ides wok alternately and ot in unson. The muscles of masication re summaized in Table 11-4. See als Fgure 11-5.

Important Relation of the emporomadibular oint 

Antriorly: The manibular ntch and he masseeric nere and arery (Fig. 11-36)

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Posteiorly: The tympnic plat of the xternal uditory meatus (Fig. 1-33) and the lenoid pocess of the paroid gland Laterall: The parotid land, facia, and skin (see Fig 11-85 Medilly: Te maxillry arter and vei and the auriculoemporal erve

Clinicl Notes Clinial Signiicance of the Tempoomandibuar t Te temporoandibula t lie immediatly in fron of the external uditory eatus. Te grat strengh of the ateral emporomanibular lgament prvents the head of te mandibl from pasing bacard and racturin the tymanic plat when a svere blow falls on the chin. The articulr disc of the temporomndibular jint may bcome parially deached from the apsule, and this results n its movement becming nois and proding an dible clik during movements at the jit.

Disloction of e Temporoandibula t Dislcation smetimes ccurs wen the mndible i depresed. In tis movemnt, the ead of te mandibe and th articulr disc oth move forward ntil the reach te summit of the aticular tubecle. In his posiion, the t is unstable, and a mnor blo on the chin or sudden ontractin of the lateral terygoid uscles, a in yawnng, may b sufficiet to pull the disc orward byond the ummit. In bilateral cases th mouth is ixed in n open postion, an both heds of the andible le in frot of the rticular tubercles Reductin of the dslocatio is easil achieved y pressig the gloed thumb downward on the lwer molar eeth and pushing te jaw bacward. Te downwad pressue overcomes the tension of the tempralis an masseter muscles, and the backward pressur overcome the spasm of the lateral pterygoi muscles P21

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able 11-4 Musces of th Head

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Figure 1-36 nfratempral and ubmandiblar regins. Parts of the zgomatic rch, th ramus, nd the bdy of th mandibl have ben removd to dislay deeer strucures.

The Scap Structure

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snell The scalp consists of fie layer, the fist three of which are intimately boud togethr and move as a uit (Fig. 1-37). To assis one in memorizing the name of the ive layes of the scalp, use each etter of the word SCLP to enote th layer o the scap.  



Ski, which s thick nd hair earing ad contais numerous sebaceos glands Connectie tissu beneath the skin which i fibrofaty, the ibrous spta uniting the skin to te underling aponurosis o the occitofrontlis musce (Fig. 11-7). Nmerous ateries ad veins re found in this layer. Th arterie are brnches of the extenal and ternal crotid areries, ad a free anastomosis takes place beween the. Aoneurosi (epicrnial), wich is a thin, tendinous set that nites th occipial and fontal belies of he occipitofrontals muscle (Fgs. 11-3 and 11-38). Th lateral margins f the apneurosis are attahed to te tempora fascia. The subaoneuroti space is the potetial spae P.23

.724

bneath th epicranil aponeuosis. It is limitd in frot and beind by the origin of the ccipitofontalis uscle, ad it extnds latrally as far as th attachmnt of th aponeursis to t temporal fascia

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Figure 1-37 A Corona section of the pper par of the ead showng the lyers of the scal, the sagittal sutre of th skull, he falx erebri, he superor and nferior sagittal nous sinses, th arachnoid granulaions, th emissay veins, and the elation f cerebra blood vssels to the subrachnoid space. B. Sensory erve suply and aterial supply to te scalp.

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Figre 11-38 Muscls of facial expression.





Loose aeolar tisue, whch occupes the sbaponeurtic spac (ig. 11-3) an loosely connects the epicanial apoeurosis o the peiosteum f the skll (the ericranim). The reolar tssue contains a fw small rteries, but it aso contans some mportant missary eins. The emissa veins ae valvelss and cnnect th superfical veins of the calp wit the dipoic veins of the sull bone and wit the inracrania venous inuses (Fig 11-37. Percranium which s the peiosteum overing he outer surface f the skll bones It is mportant to rememer that at the sutures between individual sll bones, the perosteum o the outr surfac of the ones becmes coninuous wth the peiosteum n the iner surfae of the skull boes (Fig. 1137).

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Muscles of the calp Occipitfrontali The origin, isertion, nerve suply, and action o this mucle are escribed n Table 114. Note tha when ths muscle contract, the fist three layers f the scalp move forward o backwar, the lose areola tissue of the furth layr of the scalp alowing th aponeurosis to move on the pericranium. The frontal bellies f the occipitofronalis can raise te eyebros in expessions o surpris or horrr. P.725

Senry Nerv Supply o the Scap he main runks of the sensry nerve lie in he supeficial fscia. Moing lateally fro the midine anteiorly, te folloing nerves are preent: 



 

 

The suprarochlear nerve a branc of the phthalmi division of the trigeminal nerve, inds arod the superior orital marin and spplies th scalp (Fig 11-37). It pases backard clos to the median plne and reaches nely as fa as the vertex f the skll. he supraorbtal nerv, a ranch of the ophtalmic diision of the trigeminal nerve, winds around the supeior orbial margin and scends oer the frehead (Fg. 11-37). It supplies the scalp as far bckward a the verx. The zygoaticotemral nerve, a banch of he maxilary division of the trigemal nerve supplies the scap over te temple (Fg. 11-37). The auriclotemporl nerve, a brach of th mandibuar division of the trigeminal nerve, ascends over the side of he head fom in frnt of th auricle (Fg. 11-37). Its terminal ranches upply th skn over he tempral regin. The less occipital nerve, a brach of th cervica plexus (2), suppies the calp ove the latral part of the ocipital rgion (Fig. 1-37) nd the sin over he media surface f the auicle. The grear occiptal nerv, a branch of the poterior rmus of te second cervical nerve, acends oer the bck of the scalp and supplies the skin as far foard as th verte of the kull (Fig. 1-7).

Arterial Suply of the Scalp The calp ha a rich supply o blood to nouris the har follicles, and for thi reason, the smalest cut leeds profusely. The arteres lie i the suprficial ascia. Mving latrally frm the mdline aneriorly, the follwing artries are present:  

The supratrohlear nd e supraorital arteies, ranches o the ophtalmic artery, asced over te forehea in compay with th supratrohlear an supraortal nervs (Fig. 11-37). Te uperficia temporal artery, the smller termial branch of the eternal crotid arery, ascnds in front of te auricl in compny with he auriclotemporl nerve (Fig 11-37). It diides int anterio and poserior brnches, wich supply the skn over t frontal and tempral regins.

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The postrior aurcular arery, branch f the exernal caotid artry, ascens behind the aurice to suppy the sclp above d behind the aurile (Fig. 11-7). he occipital artery a branc of the xternal crotid artery, ascens from th apex of the postrior triagle, in copany with the greatr occipitl nerve (Fig 11-37. It supplies the sin over te back o the scap and reahes as hgh as th vertex f the skll.

Venous Drainage of the Scalp The suratrochle and suprorbital vins ute at the medial magin of th orbit to form the acial vei. The superficial tempoal vein unites with the millary vn in the substance of the parotid glnd to fom the retromandilar vein (Fg. 11-39). Te osterior auricula vein unites with he posterior divsion of the retromandiular ven, just below th parotid gland, t form th externa jugular vein (Fig. 11-39. he occipita vein drains nto the uboccipial venou plexus, which lis beneat the flor of th upper prt of th posteror trianle; the lexus in turn drans into the vertbral veis or the internal jugular ein. Te veins f the sclp freely anastomse with ne anoter and ar connectd to the diploic eins of he skull bones an the inracranial venous sinuses by the valvless emissry veins (Fig. 11-7).

Lymp Drainag of the calp Lymph vssels in the anterior part of the scalp and forehead ain into the submndibular lymph noes (Fig. 1140). rainage frm the laeral par of the calp aboe the ear is into he supeficial protid (peauriculr) nodes lymph vssels in he part f the salp abov and behnd the er drain nto the mstoid noes. Vesels in te back of the sca drain ito the ocipital nodes.

linical otes Clinical Significnce of the Scalp tructure I is impotant to relize that the skn, te subcutaneos tissue and the epicranil aponerosis are closel united to one aother and are separated fro the perosteum b loose aeolar tssue. The ski of the calp posesses numerous seaceous gands, th ducts o which ae prone o infecton and dmage by combs. Fo this reson, sebacous cyst of th scalp ae common

Lacrations f the Sclp e scalp hs a profuse blood supply to noursh the hir folliles. Eve a small laceratin of the scalp ca cause evere blod loss. It is ofen diffiult to sop the bleeding of a scalp wound bcause th arteria walls ae attached to fibrus septa in the ubcutaneus tissu and are unable t contrac or retrct to alow bloo clottin to take place. Local pressre applid to the scalp i the onl satisfatory metod of stpping th bleedin (see beow).

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snell In autmobile acidents, it is comon for large areas of the calp to cut off the head as a person is projected forward through t windshield. Becase of th profuse blood suply, it s often possible to replae large reas of calp tha are only hanging o the sull by a narrow pdicle. Sture the in place, and necosis wil not ocur. The ension o the epicraial aponurosis, produced by th tone of he occiptofrontais muscls, is imortant in all dee wounds f the sclp. If te aponeuosis has been divied, the wound wil gape oen. For atisfactry healig to take place, te openig in the aponeurois must be closed ith sutues. Often a wound cased by a blunt obect such as a baball bat closely esembles an incisd wound. This is ecause te scalp is split against he unyieding skul, and th pull of the ocitofronalis musles causs a gapig wound. This anatomic fac may be f considrable frensic iportance

Life-Theatening Scalp Heorrhage Antomicall, it is seful to in an emrgency hat all he supericial arteries supplying te scalp scend frm the fae and th neck. Tus, in a emergeny situatin, encirle the had just above the ears and eyebrows with a ie, shoeaces, or even a pece of tring an tie it tight. The insert pen, pecil, or tick int the loop and rotte it so that the tourniqut exerts pressure on the rteries.

Scap Infectons nfection of the calp ten to reman localized and ar usuall painful because of the abundant fibrous issue in the subutaneous layer. Occasionally, an inection o the scap spread by the emissary veins, wich are alveless to the kull bons, causig osteoyelitis. Infected blod in th diploic veins ma travel by the emissary vins farther into he venou sinuses and produe venous sinus trombosis Blood o pus may collect n the poential sace beneth the picrania aponeursis. It ends to pread ovr the skll, being limited in fron by the orbital margin, ehind by the nuchl lines, and latrally by the tempral line. On the other had, subpeiosteal lood or pus is lmited to one bone because f the atachment f the priosteum to the stural liaments. P.726

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Figure 11-39 Main veis of the head and neck.

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Figur 11-40 Lymph dainage o the hea and nec.

Th Face Skin of he Face The skn of the face posesses nuerous swat and sebaceous lands. I is conncted to he underying bons by looe connetive tisue, in wich are mbedded he muscles of facil expresion. No dep fasci is presnt in th face. 1351

snell Wrile lines of the ace resut from te repeated foling of te skin prpendicuar to the long axs of the nderlyin contrating musles, couled with he loss f youthfl skin easticity Surgicl scars f the fae are les conspiuous if thy follow the wrinle lines.

Sensory Nerves of the Face The skin of he face s supplid by braches of he thre divisions of the rigemina nerve, except for the smal area oer the ngle of he mandile and te paroti gland (Fig. 11-41, which is suppled by th great aricular nerve (C and 3). The overlap of the three visions of the trigeminal nerve is light copared wih the cnsiderabe overla of dermtomes of the trun and lims. The ophthalmi nerve spplies the region develope from th frontonasal procss; the axillary nerve serves the region developed rom the axillary process of the fist pharygeal arc; and th mandibuar nerv serves he regio developd from te mandiblar procss of th first haryngeal arch. Thse nerve not only supply the skin of the fce, but also supply proprceptive fibers t the underlying mucles of acial epression They ar, in addition, the sensory erve suply to th mouth, teeth, nsal caviies, and paranasal air sinues.

Ophtalmic Nerve Th ophthalic nerve supplies the skin of the frehead, te upper eelid, th conjunctva, and he side f the nose dwn P.78

to ad includig the tip Five braches of the nerve to he skin

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Fgure 11-1 A. Snsory neve suppl to the kin of te face. B. Branchs of the seventh ranial nrve to mscles of facial epression C. Arteral suppl of the fce. D. Veous drainage of the face.

 





he lacrimal erve spplies te skin ad conjunciva of th lateral art of th upper eyelid (Fig. 41). The suprorbital nrve wis around the upper argin of he orbit at the spraorbitl notch Fi. 11-41). It dvides ino branchs that spply the skin and conjunctva on th centra part of the uppe eyelid; it also upplies he skin f the foehead. The supratochlear erve inds arond the uer margin of the rbit medal to th supraorital ner (Fig. 11-1). I divides into braches tha supply he skin nd conjuctiva on the medal part of the uper eyelid and the kin over the lowe part of he foreead, cloe to the median plne. The infatrochler nerve leave the orbt below te pulley of the sperior olique mucle. It supplies the skin and conjunctiva on the medil part o the uppr eyeli and the ading part of he side of the noe (Fig. 11-1). .729



Te xternal asal nere leves the ose by eerging btween the nasal boe and th upper nsal carilage. I supplie the skin on the sde of th nose don as far as the ip (Fig. 1141).

Maxilary Nere The maxillary nerve splies th skin on the postrior pat of the side of the nose, he lowe eyelid, the cheek, the upper lip, and the lteral sie of the orbital pening. hree braches of he nerv to the skin 

 

Th ifraorbitl nerve is a irect cotinuatio of the maxillary nerve. It entrs the orbit and appears n the fae throug the infraorbital oramen. t immedately diides into numerous small brnches, wich radite out rom the oramen an supply he skin f the lower eyeli and che, the side of th nose, ad the uper lip (Fig 11-41. Te ygomaticfacial nrve asses ono the fae through a small foramen the latral side of the ygomatic bone. It supplies the skin over the prominence of the cheek (Fig. 11-41. The zyomaticotmporal nrve merges i the temoral fossa through a small foramen on the poterior rface of the zygomatic bone. It suplies the skin ove the temle (Fig. 1141).

Mandibuar Nerve The mndibular nerve suplies th skin of the lowe lip, the lower prt of th face, te temporl region and par of the auricle. t then psses upwrd to th side of the scalp. Three branches of the nrve to the skin. 

he ntal neve emrges from the menal foramen of the mandible nd supplies the sin of the lower lip and chin (Fig. 111).

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The buccl nerve emerge from beeath the anterior border o the maseter muscle and splies t skin over a smal area of the chee (ig. 11-4). The aurculotempral nerv asceds from he upper border o the partid glan between the suprficial emporal essels and the aurcle. It upplies he skin f the uricle, he exteral auditry meatu, the ouer surfae of the tympani membrane, and the skin of he scalp above th auricle (Fg. 11-41).

Clincal Notes Senory Innevation ad Trigemnal Neurlgia The fcial ski receive its senory nerv supply fom the hree divsions of the trigminal neve. Remeber that a small aea of sin over he angle of the jw is supplied by the great auricular nerve 2 and 3). rigemina neuralga is a relatiely commn conditin in whih the paient expriences xcruciatng pain n the diribution of the mndibular or maxillry diviion, wit the ophhalmic diision usally esing. A hysician should e able t map out accuratey on a patient's fce the istribution of eac of the ivisions of the tigeminal nerve.

Artrial Suply of th Face The fae receiv a rich lood supply from two main vessels: the facil and suerficia tempora arterie, which are suplemented by severl small rteries hat accopany the sensory nerves o the fac. The facial artery arises from the external carotid rtery (Figs 11-55 and 11-59). Havig arched upward ad over the submandbular saivary glnd, it urves arund the nferior argin of he body f the madible at the antrior borer of th massete muscle. It is here hat the ulse can be easil felt (Fg. 11-135). It runs upwrd in a ortuous ourse toard the ngle of he mouth and is overed b the platysma and he risoius muscles. It then ascend deep t the zygmaticus uscles and the levtor labi superiois muscle and ru along te side o the nos to the edial ange of the eye, whre it anstomoses with the terminal ranches f the opthalmic artery (Fig 11-41.

Branches     

 

The sumental atery rises from the faal arter at the ower borer of th body of the mandile. It spplies e skin of the chin and lowr lip. The inerior laial artey ariss near e angle f the moth. It rns medialy in th lower lp and anstomoses with its fellow o the oppsite sid. The superio labial rtery arises nar the ale of the mouth. t runs mdially i the uppr lip an gives banches t the sepum and ala of the ose. The latral nasa artery arises rom the acial arery alonside the nose. It supplies the skin on the ide and orsum of the nose Th sperficia tempora artery (Fig. 11-1), te smalle termina branch f the exernal caotid artry, commeces in he parotd gland. It ascens in frot of the auricle t supply he scal (see page 25). The trnsverse acial arery, a branch of the sperficia tempora artery, rises wihin the parotid land. It runs forard acros the cheek just ove the parotid duct (Fig. 1-41). The supaorbital and suprarochlea arteries, branhes of te ophthamic artey, suppl the ski of the orehead Fig. 11-41).

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Cliical Nots Blod Suppl of the acial Ski Th blood spply to he skin f the fae is prouse so hat it is rare in plastic surgery fr skin faps to ncrose in his regon.

Facial rteries nd Takin the Patent's Puse The suprficial emporal rtery, as it croses the zygomati arch in front of the ear, and the acial arery, as t winds around te lower argin of the mandible level with the anterio border f the msseter, are cmmonly ued by the anesthetst to tae the ptient's ulse. P.73

Venous rainage o the Fac Th fcial vei is frmed at he media angle of the eye by the unon of th supraorital and supratrochlear vens (Fig. 1141). It is conected t the suprior ophhalmic vin direcly through the spraorbitl vein. y means f the suerior opthalmic vin, the acial vin is conected t the cavernous sins (Fig. 11-); tis conneion is o great cinical iportance because i provide a pathay for te spread of infection from the face to the cavernous inus. Th facial ein descnds behid the facal arter to the ower magin of te body o the mandble. It rosses sperficial to the ubmandiblar glan and is oined by the anteior division of th retromndibular vein. Th facial ein ends by drainig into the interal jugulr vein.

Triutaries The faial vein receives tributaies tha correspnd to te branchs of the facial artery. It is ed to the erygoid enous pexus by he deep facal vein and to the cavenous sins by the superior ophthalmc vein.

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Figure 11-42 A. Bone of the ont of the skull. B. Lymph drainage of the fce.

The tansverse facial vein jois the suerficial temporal vein witin the paotid glad.

Clinicl Notes Facia Infectis and Caernous Snus Throbosis

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snell The area of acial ski bounded by the nse, the ye, and the uppe lip is potentially dangrous zone to have n infecton. For example, a boil i this reion can ause throbosis of the facil vein, with sprad of oranisms trough th inferior ophthalic veins to the avernous inus. Th resultig cavernus sinus thromboss may be fatal uless adequately trated wit antibioics.

Lymph Drainage of the Fce Lmph from the foreead and he anteror part f the fac drains nto the ubmandiblar lymp nodes (Fig 11-42. A P.731

few bccal lymh nodes ay be prsent alog the corse of tese lymp vessel. The laeral part of the ace, incuding th lateral parts of the eyelids, is drained by lymh vessel that en in the arotid lmph nods. The ctral par of the lower lip and the skin of the chin ae draind into the submental lymph nodes.

Bones of the ace he bones that for the front of the skull ar shown i Fgure 11-2. Th superior orbital margins ad the ara above hem are ormed by the frontal bone, hich conains the frontal ai sinuses. The lteral orital marin is fomed by th ygomatic bone nd the iferior orbital marin is fomed by te ygomatic bone nd the maxila. Th medial rbital rgin is ormed abve the mxillary rocess o the frontal bone nd below by the rontal process of he maxilla. The root of the se is fomed by te nasal bones, wich artiulate beow with he maxila and abve with he fronta bones. Anteriory, the nse is copleted b upper an lower pates of hyaline artilage and smal cartilaes of th ala nas. Te imporant centrl bone o the midle third of the ace is te maxilla, containng its teth and he maxilary air inus. T bone of the lowe third o the fac is the mandible, ith its teeth. A more detiled accunt of te bones f the fac is give in the discussin of the skull (se age 669).

Musces of th Face (Mscles of Facial Epression) The musces of the face ar embedde in the superficia fascia and mos arise fom the bones of e skull and are iserted nto the kin (Fig. 1-38). he orifies of th face, amely, the orbit, nose, an mouth, ae guarde by the yelids, nostrils and lips, respectively. It is the fnction o the facal musces to serve as sphncters o dilator of thes structues. A scondary fnction o the facal muscls is to odify th expresson of te face. ll the muscles of he face re develped from the secod pharygeal arch and are upplied y the faal nerve

Musces of te Eyelid

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snell Th sphincer muscl of the eyelids s the oriculari oculi, and the ilator mscles ae the leator palpebrae sperioris and the occipitorontalis (ig. 11-3). Th levator palpebre superioris is dscribed on page 69. The ocitofronalis for part of the scal and is described o page 724. The rigin, isertion, erve suppy, and ation of te orbiculris oculi and the crrugator upercilii re descried in Table 1-4.

Mucles of te Nostril Te sphinter musle is th compresor naris and the ilator mscle is he dilatr naris Fig. 1-38) Th origin, insertio, nerve upply, ad action of the compressor aris, th dilator naris, ad the prcerus ar shown i Tble 11-4.

Muscles f the Lis and Cheks The sphicter musle is th orbiculris oris. The ditor musces consit of a sries of mall muscles that radiate ot from he lips.

Sphincter Muse of the Lips: Obiculari Oris 

 

Oriin and isertion: The fbers encrcle the oral orifice with the sustance of the lip (Fig. 11-38). Soe of the fibers aise near the midlne from he maxill above ad the mndible blow. Othr fibers arise frm the deep surface of the skin and ass obluely to he mucou membran lining he inner surface f the lis. Many f the fiers are erived fom the bucinator uscle. Neve supp: Bucal and mndibular branches of the fcial nere Acion: Compresss the lips together

Dilator Muscles f the Lis Th dilator muscles Fi. 11-38) radite out fom the lps, and their action is to eparate he lips; this moement is usually ccompanie by sepaation of the jaws The muscles arise frm the bones and fascia arod the oral apertre and cnverge t be inseted into the subsance of he lips Traced fom the sde of th nose to the angl of the uth and then below the oral aperture, the muscles ar named a follows         

Levato labii sperioris alaeque asi Leator labi superiris Zygoaticus mnor Zygoticus maor Levatr anguli oris (deep to the zygomati muscles Risoius Depresor angul oris Deressor lbii infeioris Metalis

Nrve Suppy 1359

snell Bucal and mndibular branches of the fcial nere

Muscle of the Ceek uccinato  

 

Orign: Fro the ouer surfae of the alveolar margins f the mailla and mandible opposit the molr teeth nd from he pteryomandibular ligamet (Fig. 118) Inserion: The musce fibers forard, forming the muscle layr of the cheek. he muscle is piered by th parotid duct. At the angl of the outh th central fibers dcussate, those from beow enterng the uper lip and thos from abve enterng the lwer lip; he highet and loest fibrs continue into te upper nd lower lips, repectivel without interseting. Th buccinaor muscl thus blnds and orms par of the orbiculais oris uscle. Nerve suply: Buccal branch of te facial nerve Acion: ompresse the cheks and lps against the teeth

The oriin, insertion, nerve suppl, and action of t muscls of the lips and cheeks are shown n Table 11-. P732

Clinical Notes Facial uscle Paalysis The faial musces are innervated by the fcial nere. Damag to the acial neve in th interna acousti meatus by a tumor), in te middle ear (by nfection or operaon), in he facia nerve anal (peineuriti, ell's pasy), r in th parotid gland (by a tumor) or cause by laceations o the fae will cause distotion of he face, with drooping of the lwer eyeid, and he angle of the mouth will sag on th affecte side. his is ssentially a lower motor neron lesin. An uper motor neuron esion (ivolvemen of the pyramidal racts) wll leave the uppe part of the face normal bcause th neurons supplying this pa of the ace recive cortcobulbar fibers from both crebral crtices.

Facial Nrve A the facal nerve runs forard withn the sustance o the paotid salivary glan (see pe XXX), it divide into it five trminal banches (Fig 11-41). 

 

The tempora branch emergs from te upper border of he gland and suppies the nterior and supeior auricular musces, the rontal blly of t occipitofrontals, the obiculari oculi, and the crrugator upercili. The zygomaic branc emergs from te anterir border of the gand and upplies he orbiclaris ocli. Th bccal brach eerges frm the anterior borer of th gland blow the arotid duct and upplies the buccintor musce and th muscles of the uper lip and nostrl.

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Figure 1-43 ifferent stages i developent of te face.

 

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igure 1144 Varous form of clef lip.

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Figure 1-45 Unlateral left uppr lip. (ourtesy f R. Chae.)

Figur 11-46 Bilaterl cleft pper lip and palate. (Courtsy of R. Chase.)

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P.73

Figure 1-47 ight-sidd obliqu facial left and left-side cleft uper lip. There aso is toal bilatral clet palate (Courte of R. Case.)

 

The mandibular branch emerges rom the nterior order of the glan and suplies the muscles f the loer lip. The cervicl branch emerges from he lower border o the glan and pases forwad in the neck beow the mndible t supply he platysa muscle it may ross the lower mrgin of e body of the mandible to supply te depressr anguli oris mucle.

The faial nerv is the nerve of he secod pharyneal arch and suppies all he muscles of facal expreion. It dos not suply the kin, ut its banches cmmunicat with brnches of the trigminal neve. It s believ that th proprioeptive neve fiber of the acial muscles leae the faial nerv in thes communicating braches and to he cental nervo system via the tigeminal nerve. A summary of the origin and distribuion of te facial nerve is shown in Fiure 11-6.

Embryoloic Notes Development of the Fac

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snell Eary in devlopment, the face of the embryo is represened by an area bouded cranally by he neura plate, audally by the pricardiu, and laterally b the mandbular process of he firs pharyneal arch on each ide (Fig. 1-43). In the cnter of this area s a deprssion in the ectoerm known as the stoodeum. In the foor of te depresion is te buccophayngeal mmbrane. By the fourth wek, the buccopharygeal memrane breks down o that te stomodum commuicates wth the foegut. he furthr development of te face depends on the comig togethr and fuion of sveral important pcesses, namely, te frontonasal process, the maillary pocesses, and te andibula processs (Fig. 1-43). The frotonasal rocess bgins as proliferation of mesenchy on the ventral surface of the devloping bain, and this grws towad the somodeum Meanwhil, the maillary pocess grws out fm the upper end of each irst arch and s medialy, formig the loer borde of the developing orbit. he mandiular proesses of the firs arches ow approach one aother in the midlne below the stomdeum and fuse to form the ower jaw and lowe lip (Fig. 1-43) Th ofactory its apear as epressios in the lower ede of the advancin frontonsal procss, diviing it ito a media nasal prcess nd two lateal nasal processe. Wit further developmnt, the maxillar processs grow medially and fuse wth the lteral naal proceses and ith the edial naal proces (Fig. 1143). Te medial nasal prcess fors the philtum of he upper lip and he premaxila. Te maxillry proceses exted medialy, formig the uper jaw an the chek, and inally bry the pemaxilla and fuse in the midline. Th variou processs that utimately orm the ace unit during he secon month. The upper ip is ormed by the groth medialy of the maxillar processs of the first pharyngeal arch on each side Ultimatly, the axillary processe meet in the midline and fuse with each oth and wi the medal nasal process Fi. 11-43). Thus the latral part of the pper lip are formd from the maxillary procsses, an the medial part, r philtrm, from he media nasal rocess, th contributions from the maxillar processs. Te ower lip is fomed fro the manibular prcess of he first pharyngel arch o each sie (Fig. 11-3). These processes grow mediall below t stomodeum and fuse in the midline o form te entire lower l. Each lip separates fro its resctive gm as the result of the apperance of a linear thickenig of ectderm, th labiogingival lamina, whch grows down int the undrlying msenchyme and late degenertes. A eep grooe thus frms betwen the lips and th gums. I the midine, a hort are of the labiogingival lamia remain and teters each lip to he gum, hus formng the frenlum. At fist, the mouh has a broad pening, ut later this dimnishes i extent ecause o fusion f the lis at the lateral agles.

Snsory Neve Suppl to the Skin of te Develoing Face he area f skin oerlying he frontnasal prcess and its dervatives eceives its sensory nerve upply fro the ophhalmic ivision f the trigeminal nrve, whereas the maxillary divisio of the trigeminl nerve upplies the area of skin overlying the maxillry procss. The rea of sin overling the andibular process s supplid by th mandibuar divison of th trigemial nerve

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Muscle of the evelopin Face (Mscles of Facial Epression) The musles of te face ae derive from the mesenchye of th second haryngea arch. Te nerve upply of these mucles is he nerv of the econd phryngeal rch—namely, the eventh canial neve.

Cleft Upper p Cleft upper ip may b confine to the ip or may be assocated wit a cleft palate. he anomay is usully unilateal cleft lip ad is caused by a failure of the mxillary rocess t fuse with the medial naal proces (Figs. 1-44 d 1-45) Bilateral cleft lip is cused by failure of both axillary processes to fuse with th medial nasal prcess, wich then remains s a cental flap f tissue (Fgs. 11-4 and 1148). Median cleft pper lip is vey rare ad is caued by th failure of the rounded swellings of the medl nasal rocess t fuse in the midine.

Obique Facal Cleft Obliue facia cleft i a rare ondition in whic the clet lip on one side extends o the mdial magin of te orbit Fis. 11-44 and 11-4). Thi is caused by the failure of the mxillary rocess to fuse wth the lteral an medial asal proesses.

Clef Lower Lp Clet lower ip is a are condtion. Th cleft i exactly central and is cused by ncomplet fusion f the madibular processe (ig. 11-4).

reatment of Isolaed Cleft Lip The condtion of solated left lip usually s treate by platic surgry no laer than months fter birh, provied the aby's condition prmits. Te surgeo strives to approimate th vermilon borde and to orm a nomal-lookng lip (Fi. 11-48A–C).

acrostoma and Mirostomia The norml size o the mouh shows onsiderale indiidual vaiation. arely, there is icomplete fusion o the maillary wth the mndibular processe, producng an excessively large muth or mcrostomi. Very rrely, thre is exessive fsion of hese pocesses, producin a small mouth or microstoma. Thes conditins can asily be correcte surgicaly. P.73

The Neck

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snell The eck is te region of the bdy that lies beteen the lower magin of te mandible above and the uprasteral notch and the upper boder of te clavicle below. It is strngthened by the crvical part of he verteral colun, whic is convx forwar and s the skull. ehind th vertebre is a mass of extensor uscles ad in frot is a maller goup of fexor musles (Fig. 11-49). In the entral rgion of he neck are part of the espiratoy system namely the larnx and the tracha, and bhind are parts of the alimentary sstem, th pharynx and the sophagus At the ides of hese sructures are the ertically running arotid ateries, nternal jugular eins, th vagus nrve, and the deep cervical lymph noes (Fig. 1-49).

Figure 1-48 Cleft li and palte. A. A three-diensional ultrasongraph reeals bilteral ceft lip at 22 wees of gesation. (ourtesy f Dr. B. Benacerrf.) B. A infant ith bilaeral coplete clft lip d palat. . Shos the sae child t 18 monhs of ag, after ynchronos nasolaial repir and platal closure perrmed at second stage. (ourtesy f Dr. J B. Mullken. N Engl J Med 351;8:76.)

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Figur 11-49 Cross sction of the neck at the lvel of t sixth crvical vrtebra.

Skin o the Nec The natural ines of leavage f the skn are costant ad run almost horizntally around th neck. his is iportant clinicaly becaus an inciion alon a cleavge line ill heal as a narrow scar whereas one that crosses he lines will heal as a wde or haped-up scar.

Cutanous Nervs The skin overlying te trapezus muscl on the ack of the neck d on the back of the scal as high as the vertex is supplied segmentally by poserior rai of cerical neres 2 to (ig. 11-). The reater ocipital nerve is a brach of th posterir ramus f the seond cervcal nerve. The first cervical nerve has no ctaneous branch.

1368

snell Th skin of the fron and sids of the neck is suppled by aterior rmi of cevical neves 2 t 4 throu branches of the cervical plexus. The branhes emere from neath te posterior border of the sternocleidomastod muscle (Fig. 1150). The lesser ocital neve (C) hooks round the accessory nerve and asceds along the postrior boder of te sternocleidomasoid musce to suply the sin over he lateal part of the ocipital rgion and the medil surfac of the auricle Fi. 11-50). The great auricuar nerve (C2 and 3) ascends acros the strnocleidmastoid uscle an divide into banches that supply the skin over the angle o the mandible, the parotid gland, and on boh surfacs of the auricle Fi. 11-50). Te transvere cutaneus nerve (C2 and ) emerge from beind the iddle of the postrior borer of te sternoleidomasoid musce. It pases forwrd acros that mucle and divides into branhes that supply te skin o the antrior and lateral surfaces of the nck, from the body of the mndible to the sternum (Fig. 11-50. The supracavicular nerves (C3 an 4) emere from bneath th posterir border of the ternocledomastoi muscle nd desce across he side of the neck. They onto the chet wall ad shoulr regio, down to the level of the second rib (Fig. 1150). Te medial spraclavicular nerv croses the mdial end of the cavicle ad supplis the ski as far s the meian plan. The intemediate upraclavcular neve crsses the middle o the claicle and supplies the skin of the cest wall The latera supraclvicular erve cosses th lateral end of te clavice and suplies th .737

sin over he shouler and te upper alf of te deltoi muscle; this neve also upplies he posteior aspect of the shoulde as far down as the spine of the scula.

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Figue 11-50 Sensor nerve suply to sin of the head and eck. Not that th skin over the ange of the jaw is spplied b the great auicular nrve (C2 and 3) ad not by branches of the tigemina nerve.

uperficial Fascia The uperficil fascia of the nck forms a thin lyer tha enclose the platysma muscle. Also embedded in it ar the cuaneous nerves rferred t in the revious ection, he supericial vins, and the superficial ymph nods.

Platma Th platysm muscle (Fis. 11-38 and 11-5) is thin but clinically importnt muscuar sheet embedde in the sperficia fascia. It is decribed i Tble 11-5, page 742.

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Sperficia Veins Externl Jugula Vein The exrnal juglar vein begins ust behind the ange of th mandibl by the nion of the postrior auricular vei with th posteror divison of th retromadibular ein (Fig. 1-52). It descends obliuely acrss the sernocleiomastoid muscle an, just bove the clavicle in the psterior riangle, pierces he deep ascia ad drains into the subclavin vein (Fig 11-53. It vares conserably size, nd its curse extnds from the angl of the andible the middle of th clavicl.

Tributaies The exterl jugula vein (Fig 11-52) has the followig tributries:      

Posteror auriclar vein Posterio division of the retromandibular vn Poterior eternal jgular ven, a smal vein hat drais the poterior prt of th scalp ad neck ad s he extenal juguar vein about halfway along its coure Transerse cerical vei Suprascapular ven Anterir jugula vein

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Figure 11-5 Dissction of the anteior aspet of the neck shoing the latysma muscles nd the lwer ends of the sernocleiomastoid muscles both ides. The skin has been reflected donward.

Clinica Notes Visibility of the Extern Jugula Vein The eternal jgular ven is les obvious in childen and omen becuse thei subcutaeous tisue tends to be thcker tha the tisue of men. In obse indivduals, the vein m be diffcult to identify even whe they ar asked t hold thir breat, which mpedes te venous return t the rigt side o the heat and ditends te vein. Te superficial veins of the neck tend to be enlarged and often tortuous in profssional ingers bcause of prolonged periods of raised intratoracic pressure.

he Exteral Jugulr Vein a a Venou Manometr The extenal juguar vein erves as a useful venous anometer. Normaly, when the patiet is lyig at a hrizontal angle of 30°, te level f the blood in the external jugular eins reahes abou one third

1372

snell of te way up the neck. As the ptient sis up, th blood evel fals until t is no longer visible behid the clvicle.

Externl Jugula Vein Caheterizaion The extrnal juglar vein can be sed for catheteization, but the resence f valves or tortusity may make the age of the ctheter dfficult. Because the righ externa jugular vein is in the ost diret line wth the sperior vna cava, it is th one mot commonly used (Fg. 11-54). The vein is catheerized aut halfay betwen the level of th cricoid cartilag and th clavicle The pasage of te cathetr shoul be perfrmed durng inspiation whn the vaves are open. P.739

Figure 11-52 Major superficial veins o the face and neck

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nterior ugular Vin Te anterir jugula vein beins just below th chin, b the unin of sevral smal veins (Fig. 11-52). It rns down he neck close to the midlne. Just above th suprastrnal noch, the eins of the two ides are united b a transerse truk calle the juglar arch The vei then tuns sharp lateraly and psses dee to the ternocledomastoi muscle o drain into the external jugular ein.

Supericial Lyph Nodes The uperficil cervicl lymph odes lie along the external jugular ein superficial t the sternocleidoastoid mscle (Fig. 1-40) They reeive lymph vessels from the occipita and masoid lym nodes see page 755) and rain int the dee cervica lymph noes.

Bones of the Neck Cervical Vertebrae The cerical par of the ertebral column i deidoub on pag 855.

yoid Boe The hyoid boe is a mbile sinle bone ound in he midlne of the neck beow the mndible ad abides the laryx. It does not articulate ith any ther bons. The hoid bone is U shaed and onsists f a body and two reater ad two leser corna (Fig. 11-2). I is attahed to te skull y the stlohyoid igament nd to th thyroi cartilae by the thyrohyod membrane. The hyoid bone forms a base for the tonge and is suspende in posiion by mscles tht connet it to e mandible, to the styloid process f the tmporal one, to the thyrid cartilage, to the sternum, and to the sula. The imortant mscles atached to the hyoi bone ar shown i igure 1132.

Muscles f the Nek Th superfiial musces of th side of the neck (igs. 11-8 and 11-1) ar deidoub in Table 1-5. Te suprahoid and nfrahyoi muscles and the nterior nd laterl vertebal muscles are also descried in Table 11-5.

Clinical Notes Clinica Identifcation o the Playsma The patysma cn be see as a thn sheet of muscle just benath the kin by hving the patient lench hi or her aws firmy. The uscle exends fro the bod of the mandible dwnward oer the lavicle nto the nterior hest wal.

Platyma Tone and Neck Incisions 1374

snell In lacerations or sugical inisions i the nec it is ery impotant tha the subutaneou layer wth the patysma b carefuly suturd, since the ton of the latysma an pull n the sar tisse, resuting in road, usightly cars.

Platysa Innervtion, Moth Distrtion, ad Neck Icisions The platysma mucle is inervated by the crvical ranch o the facal nerve. This nrve emerges from the lowe end of the parotid gland and traels forwrd to th platysm; it then sometimes croses the lwer borer of th mandibe to suply the depressor anguli oris mucle (see page 75). kin laceations oer the mandible r upper art of te neck ay distot the shpe of th mouth. P.740

Ky Neck Mscles Sternoleidomasoid Musce hen the sternoclidomastid muscl (Figs. 1-51, 11-3, an 1-55) contracts, it appars as an obliqu band crssing th side of the nec from te sternclaviculr t to the astoid pocess of the skul. It ivides te neck into anteior and osterior triangl (Fg. 11-5). he anteror bordr covers the cartid arteies, th interna jugula vein, nd the deep cerical lymh nodes; it also overlaps the thyrid glad. The uscle is covered uperfically by kin, facia, the platysa muscle and th externa jugula vein. Te deep surface of the poterior brder is elated o the cervical pexus of nerves, the phrnic nerv, and th upper art of the bracial plexs. The rigin, nsertion nerve spply, and action of the ternocledomastoid muscle are sumarized n Table 11-5.

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Figure 11-53 Posterir triangle of th neck.

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Figur 11-54 Catheerizatio of the right exernal juular vei. A. Suface maring of he vein. B. Site f cathetrization Note hw the exernal juular vei s he subclvian vei at a riht angl. C. Coss secton of th neck sowing th relatioships of the extrnal juular ven as it rosses the posteir trianle of th neck.

Clinicl Notes Sterncleidomtoid Muscle and rotectin From Trauma The sternocleidmastoid, a strong thick uscle crssing he side f the nck, protcts the nderlyig soft sructures from bunt trauma. Suicde attemts by ctting on's throa often fail becuse the individul first extends he neck efore maing seveal horiontal cuts with a knife. xtension of the crvical prt of t vertebral colun and exension o the hea at the atlanto-ccipital t cuse the arotid seath with its contained arge blod vessel to slide posteriorly beeath the sternoclidomastoid uscle. T achieve the desired result with the head nd neck ully extnded, soe indiiduals hve to mae 1377

snell severa attempt and onl succeed when th larynx and the greater art of te sternoleidomasoid musces have been seered. Th common ites for the wouns are imediatel above ad below the hyoid bone.

Congental Toricollis Mos cases o congenital tortcollis re a reslt of excessive stretching of the sternocleidomatoid musle durin a diffcult labr. Hemorhage occurs into the musce and ma be detcted as a small rounded “tumor€• duri the ealy weeks after bith. Late, this becomes nvaded by fibrous tissue, hich conracts an shorten the mscle. Th mastoid process s thus pulled down toward the stenoclaviclar of the ame side, the cervical spine is flxed, an the fac looks uward to he opposite side. If left untreate, asymmtrical gowth chnges occr in the face, an the cevical vrtebrae may becoe wedge haped.

pasmodic Torticolis pasmodic torticolis, whic results from repated chonic conractions of the ternocledomastod and trpezius mscles, s usuall psychognic in rigin. Sction of the spinl part of the ory erve may be necesary in evere caes. P.742

Table 1-5 Mucles of he Neck Musle

Origin

Insertion

erve Suply

Action

Platysma

Deep ascia ovr pectorlis majo and deloid

Body of mandble and ngle of outh

Facil nerve ervical ranch

Deprsses manible and angle of mouth

Sternoceidomastid

anubrium sterni nd media third o clavicle

Matoid prcess of emporal one and occipita bone

pinal prt of accessory erve and C2 and 3

Two musces actin togethe extend head and flex nec;

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one mucle rotates head to opposte side

Digstric

Posteior belly

Mastid proces of temoral bone

Anteror bell

Body of mandible

ntermediae tendon s held o hyoid by fascial sling

Fcial nrve

Depresss mandibl or elevtes hyod bone

Nerve o mylohoid

Stylohyoid

Styloi process

Body of hoid bon

Fcia nerve

Elvates hyoid bone

Myloyoid

Mylohyod line o body o mandibl

Body of yoid bon and firous rape

Inferio alveola nerve

Elevates flor of moth and hoid bone or deprsses manible

Geniohoid

nferior ental spne of madible

Body of hyoid bone

First cervical erve

Elevats hyoid one or dpresses

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mandible

Strnohyoid

Manbrium sterni and clavicle

Boy of hyid bone

nsa cervcalis; C1, 2, an 3

Depresss hyoid one

Sterothyroid

Manubrium strni

Oblique ine on mina of thyroid cartilage

Ans cerviclis; C1, 2, and 3

Deresses lrynx

Thyrohyoid

Obliqu line on lamina o thyroid cartilag

Lower brder of ody of hoid bon

irst cervical neve

Depreses hyoid bone or elevates larynx

Inferior belly

Upper margin of scapua and surascapulr ligament

Inermediat tendon s held t clavicl and fist rib b fascial sling

Ansa crvicalis C1, 2, and 3

Deprsses hyid bone

Sperior blly

ower borer of boy of hyod bone

Scalenus anerior

Transverse prcesses

First ib

4, 5, an 6

Eevates frst rib;

Omohyoid

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snell

third, fourth, fith, and ixth cerical vetebrae

lateraly flexes and rottes cervical part of verteral colun

Scalenus edius

Tansverse processes of uppr six cevical vrtebrae

First rb

Anterior rami of cervcal nervs

Elevate first rb; laterlly flexs and roates ceical part of verebral coumn

Scalenu posterir

ransvers proceses of loer cervical vertbrae

Seond rib

Anteior rami of cervial nerves

Elevates second rib; laterlly flexes and rtates cevical pat of verebral clumn

.743

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Figur 11-55 Anterir triange of the neck.

Salenus Anterior Muscle The sclenus anerior mucle is key muscle in unerstandig the rot of the neck (Fig. 11-57. It is deeply paced an it descnds almost vertially fro the vetebral clumn to he first rib.

Imortant Rlations 

Aneriorly Relaed to th caroti arterie, the vaus nerve, the inernal juular ven, and the deep ervial lymph nodes (Fg. 1-49) The transvere cervicl and surascapuar arteres and te prevertebral layer of deep cerical fasia bind he phrenc nerve to the mscle.

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snell 

 

Postriorly: Relate to the leura, te origin of the rachial lexus, ad the seond par of the ubclavin artery (ig. 11-57). The scalenus medius muscle lies behnd te scalenus anteror muscle. edially Related to the vertebral artery and vein and the ympathetc trunk (Fig. 11-57). n the let side, the medil borde is relaed to th thorac duct. Lateraly: elated o the emrging brnches o the cerical plxus, the roots o the brchial plxus, and the third part o the sublavian rtery (Fig 11-57)

he orign, inserion, nere suppl, and acion of he scaleus anteior musce are summarzed in Tale 11-.

Deep ervical ascia The dee cervica fascia s the musces, the vessels, and the iscera o the nec (Fig. 1149). In certin areas it is condensed to form well-defned, firous shets called the investing ayer, te pretraheal layr, and te preverebral lyer. It s also ondensed to form the caroid sheah (Fig. 1149). P.74

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Figue 11-56 Musculr trianges of th neck.

Invsting Laer Th investng layer is a thik layer that encrcles te neck. It splis to encose the trapezis and th sternocleidomasoid musles (Fig. 1-49)

Preracheal ayer The preracheal ayer is tin laye that is attached above t the larngeal crtilages (Fig. 11-49). It urrounds the thyoid and he paratyroid glads, formng a shth for them, and enclose the infahyoid mscles.

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Preverebral Ler The prevrtebral ayer is thick lyer that es lke a sptum acrss th neck behind the pharynx nd the eophagus and in ront of te preverebral mucles and the verbral column (Fig. 11-4). t forms the fascl floor of the psterior riangle, and it etends lterally ver the irst rib into the axilla t form th importat axllary shath (see page 74).

Clincal Notes Clnical Sgnificane of the Deep Faia of te Neck s previosly descibed, th deep faia in crtain aras forms distinct sheets clled th investg, pretacheal, nd prevrtebral ayers. Tese fascal layer are easly recogizable t the srgeon at operatio.

Fascia Spaces Betwen the mre dense layers of deep fscia in the nek is lse connctive tissue tha forms otential spaces that ar cliniclly imprtant. Aong the more imprtant spaces are the visral, rtropharygeal, sumandibulr, and asticatoy space (Fig. 11-8). he deep ascia an the facial spces are mportan becaus organis origiating in the mouh, teet, pharyn, and eophagus can spred among the fascal plans and spaces, an the touh fasc can deermine te direction of sread of infectio and the path taen by ps. It is possibl for blod, pus, or air i the reropharyneal spac to spred downwad into te superior medistinum f the thrax.

Acue Infecions of he Fascil Space of the eck Dental infectios mos commony involve the lowe molar teth. The infection spreads edially from the mandible nto the ubmandiblar and asticator spaces nd pushe the tonue forwad and upard. Further spred downwad may ivolve the visceral space an lead to edema of the vocl cords ad airwa obstrucion. Ludwig' angina is an acute infection of the sumandibulr fascia space ad is comonly scondary o dental infectio.

hronic Ifection of the Fasial Spacs of the eck Tuberclous infetion of he deep rvical mph node can result in liqueaction ad destrction of one or ore of te nodes. The pu is at frst limied by th investig laye of the eep fasia. Laer, this becomes eroded a one poit, and te pus es int the lss restrcted superficial fascia. A dumbbell or colar-stud bscess is now pesent. The cinician s aware of th superfiial abscess but must not forget the exisence of the deepy placed abscess P.745

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Figure 1-57 Preverteral region and th root of the neck

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Figure 11-58 A. Cross ection o the nec showing the viscral spac. . Sagttal section of te neck sowing th position of the etropharngeal an submandiular spaes. C. Vrtical sction of the body of the mndible cose to te angle owing the masticaory spac.

P.747

Caotid Sheth Th carotid sheath i a local condensaion of te prevetebral, the etrachel, and the invesing layers of the eep facia that surround the comon and iternal crotid areries, he intenal juglar vein, the vaus nerve and the deep cervical lymph ndes (Fig. 11-9).

xillary heath 1387

snell All the anterio rami of the cevical nrves tha emerge in the nterval between he scalnus anteior and calens medis muscls lie at first dep to the prevrtebral ascia. A the sublavian rtery and the brchial plxus emege in th interva between the sclenus anerior and the scalenus mdius mucles, thy carry ith them a sheah of the fascia, hich exends int the axila and is calle the aillary sheath.

Cervcal Ligaents    

Styloyoid ligment: Connect the styloid process to the lesser corn of the yoid bon (Fig. 180) Stylomndibular ligamen: Cnnects he stylod proces to the ngle of he mandle (Fig. 1-33) Sphnomandiblar ligaent: Connects the spin of the phenoid bone to he lingla of th mandile (Fig. 11-33) Ptrygomandbular lgament: Connects te hamulr proces of the edial ptrygoid late to he poserior en of the mylohyoid line of the manible. I gives ttachmen to the superior constritor and the buccnator mscles (Fig. 11-80).

Muscular Triangles of th Neck The sernocleiomastoid muscl divide the nek into te anterir and th posterior tringles (Fig. 11-6).

Anterir Triange Te anterir triane is bonded above by th body of the madible, posterioly by te sterncleidomastoid mucle, and anterirly by te midlin (Fig. 11-56. It is urther sbdivide into he caroti triangle, the digastrc triange, the sbmental triangle, and he muscula triangl (Fig. 1-56)

Posteror Triale The postrior tringle is ounded osteriory by the trapezis muscle anterirly by te sterncleidomatoid mucle, and inferirly by te clavicle (Fig 11-56). The posteror trianle of th neck is further subdivided by th inferior belly o the omohyoid uscle into a arge occipital trangle above an a small spraclaviular triangle below (Fig. 11-56). The suprahyid and ifrahyoid muscles and the nterior nd laterl vertebral muscles are escribed in Table 11-5

Artries of he Head nd Neck Common Carotid Artery The ight comon caroid artey arise from th brachocephalc arter behind he right sternocavicular t (Fgs. 11-57 and 1-59). The left artery aises fom the rch of te aorta n the superior mediastinm (see pae 125. The mmon caotid artry runs pward though the neck under cover of the anterior border o the sternocleidmastoid muscle, rom the stenoclavicular joit to th upper brder of he thyrid cartiage. Hre it diides into the external an interna carotid arteries (Figs 1155 and 11-60).

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Carotd Sinus At is point of divison, the erminal part of the comon caroid arter or the eginnin of the internal carotid rtery hows a localizd dilatation, caled the arotid snus (Fg. 11-60). Te tunic media of the sius is thnner an elsehere, bt the aventitia is relatvely thik and cntains nmerous nrve endigs deried from the glosopharyngal nerve The cartid sinu serves as a relex presorecepto mechanim: A rse in blod pressre causes a slwing of e heart rate and vasodilatation of the arterioles.

Clnical Noes arotid Snus Hypersensitiity In cass of cartid sinus hyprsenitivity, pressure on one or both carotid inuses cn cause excessiv slowin of the eart rate, a fal in bloo pressure, and crebral ichemia wth fainting.

Carotid Body The crotid boy is a small structure tat lies posterio to the point of bifurcaton of the common carotid rtery (Fig 11-60) It is innervatd by th glossoparyngea nerve. he caroid body is a chmoreceptr, being senstive o excss carbon dioxie and rduced oygen tesion in he blood. Such a stimulus reflexly produce a rise in bloo pressur and heart rate nd an inrease i respiraory moements. Th common carotid rtery is embedde in a cnective tissue heath, alled th caroti sheat, throghout it course nd is cosely related to the intenal juguar vein and vagu nerve (Fg. 11-49).

Relatios of the Common Crotid rtery  

 

Anteroaterally The kin, th fascia, the sternocleidoastoid, he sterohyoid, the sterothyroi, and the superir belly of the oohyoid (Fig. 11-55) osteriory: Te transerse prcesses o the lowr four crvical vrtebrae, the prevertebral muscles, and the ympathetc trunk Fi. 11-57). In th lower prt of th neck ar the vertebral vesels. edially: The lrynx and pharynx nd, belo these, he tracha and esophagus (Fig. 11-49. The loe of the thyroid land als lies meially. Lateally: The internal juglar vein and, poterolaterally, te vgus nerv (Fig. 1-49)

Braches of he Commo Caroti Artery Apart frm the to termial branches, the common carotid atery givs off no branches P.748

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Figre 11-59 Main arteries of the had and nck. Note that for larity te thyroervical runk, th costocevical trunk, ad the internal tracic atery—banches o the subcavian arery—ar not shwn.

Clinica Notes Taking he Carotd Pulse The ifurcatio of the ommon caotid artry into he intenal and xternal carotid areries ca be easiy palpatd just eneath te anterir border f the strnocleidmastoid muscle at he level of the superior order of the thyrid cartiage. Thi is a covenient ite to tke the crotid pule.

Exernal Caotid Artry

1390

snell Te externl carotid artery i one of the termial brances of th common carotid arery (Fig. 1-59). It suppies strutures in the neck face, and scalp; t also supplies he tongu and the maxilla. The artey begins at the lvel of the upper border of the thyrid cartiage and terminate in the sbstance f the protid gland behind the neck of the mndible b dividin into the superfiial tempral and maxillary rteries. Close o its orgin, the artery eerges frm undercver of the sternleidomasoid musce, where its pulstions ca be felt At first, it li medial to the inernal caotid artry, but as i ascends in the neck, it es ackward nd lateal to it It is rossed b the poterior blly of te digastic and e styloyoid (Fig. 1-55)

Reatios of the Externa Caroti Artery 



Anterolterally: Th artery s overlpped at ts begining by he anteror borde of the sternoleidomasoid. Aboe this level, th artery is omparatiely superfical, bein covered by skin nd fasca. It is crossed by the ypoglossl nerve Fig. 11-55) the poserior lly of the digastric mscle, an the styohyoid muscles. ithin th paroti gland, t is crosed by he facia nerve (Fig 11-5). The interal jugulr vei first es lateal to th artery and then posterior to it. Mediall: Th wall o the pharyx and the inernal caotid artry. The stylophryngeus muscle, the glosopharyngal nerv, and th pharyngal branh of th vagu beween the externa and internal carotid arteries (Fig. 1160).

P.49

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Figur 11-60 Styloid muscle, vessels, and nrves of he neck.

For the elations of the eternal arotid atery in he parotid gland see Figur 11-85B.

Branchs of the Externa Carotid Artery    

uperior thyroid rtery Ascending pharyneal artey Linal artey Facial arter

1392

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Occiptal artey Posterior aurcular arery Suprficial tempoal artery Maxillary atery

Suerior Throi Artery Th superir thyroi artery urves dwnward t the uper pole f the thyrod gland Figs. 1155 and 11-60. It is ccompanied by th external laryngeal nerve, which suplies te cricthyroid muscle.

Ascnding Phryngeal rtery The ascnding phryngeal rtery acends alng and spplies the pharygeal wal.

Lingal Artery The lingual rtery lops upwad and frward an supplie the tonue (Figs. 1-55 nd 11-60.

Facil Artery The fcial artry loops upward ose to he outer surface of the pharynx and the tosil. It lies dee to the submandibular saivary glnd and eerges an bends aound the lower brder of he mandible. It hen ascnds over the P.750

face cose to te anterir border of the msseter mscle. Te artery then asends arond the lteral magin of he mouth and termnates at the meial angle of the eye (Figs. 1-55 nd 11-59. Branche of the acial arery supply th tonsil, the subandibula salivar gland, nd the mscles an the ski of the face.

Ocipital Atery The arry suppies the ack of the sclp (Fig. 11-59).

Posterior Auricular Artery The osterior auricula artery upplies he aurice and te scalp Fi. 11-59).

Supficial emporal Atery The superficial emporal rtery acends ovr the zyomatic arch, wher it may e palpatd just n front f the aricle (Fg. 11-9). It s accmpanie by the auriculotmpora nerv, and t suplies the scalp.

Maxllary Arery

1393

snell The maxllary arery runs forward media to the neck of he mandile (Fi. 11-59) and nters te pterygpalatine fossa o the skul.

Banches o the Maxllary Artery Brances suppl the uppr and the lower aws, the muscles of mastiation, te nose, he palat, and th meninge inside the skul.

Midde Meningal Arter The middle menieal artry enters the skll through the framen spnosum (Fig. 1-66) It run laterall within he skull and divides into antrior and postrior branches (Figs. 11-20 nd 11-131). The nterior ranch is importat becaus it lie close t the motr area f the ceebral cotex of he brain. Accompaned by i vein, t grooves (o tunnels through the pper pat of the greater wing of he phenoid one of te skll and he thin nteroinfrior ange of the paretal bon, where t is prone t damage fter a bow to th hea. The origin and dstributin of the branche of the ternal carotd artery are show in Figure 11-5.

Intrnal Caotid Artery The internal carotid rter begins t the burcatio of the common croti artery at the lvel of e uper bordr of the thyroid cartilag (Figs. 11-55 and 11-59). It suppies the rain, th eye, te forehead, ad part o the nos. The artery ascends in the nk embeded in th carotid sheah with he intenal juguar ven and vaus nerve At first it lies superficially it th es eep to the paotid salvary glnd (Figs. 11-60 and 11-5B). Te internl carotd arter leaves the neck by ing into the cranial caviy throug the caotid canl in the petrous art of the tempral bone It then es ward and forward in the avernous venous snus (without comunicatig with it). The artery then leaves the sinus and es upwar again mdial to the anteir clinoi proces of the phenoid one. The internal carotid rtery then inclines backard, latral to the optic chiasma, and terminates b dividin into te anterir and th middle erebral arteries

Relatons of te Internal Carotd Artery in the eck 

  

Anterolateally: Beow the dgastric lie th skin, e fasci, the anerior boder of the sternoleidomasoid, and the hypolossal nrve (Fig. 1-55). Above the digastric lie he styloyoid musle, the stylophayngeus mucle, he gossoharyngal nerve, the pharngeal branch of the vgus, the protid gland, an the external carotid rtery (igs. 11-60 and 1185B). Postriorly: The ympahetic tunk (Fg. 11-6), th longus capitis uscle, ad the tansvers processs of the upper tree cervcal verebrae Medally: The phryngeal all and the supeior larygeal nere Laterally: he internal jugular vein and he vagus nerve

Cliical Notes 1394

snell

Arteriosclerosis of the Iternal arotid Atery Etensive arterioslerosis f the iternal arotid rtery in the neck can cause vsual imairment r blindnss in te eye o the sid of the esion bause of insufficent bloo flow through te retinal artery Motor pralysis and sensry loss may also ccur on the oppsite sid of the body because of nsufficent bloo flow trough th middle cerebral artery.

Branches of the nternal arotid Artery There are no branches the nek. Many importan branches, however are givn off in the sku.

Ophtlmic Artry Te ophthamic artey arises from the interna carotid artery as it emergs from te cavernus sinus (ig. 11-2). I es orward into the orbital caity throgh the otic cana, and it gives off the cetral artry of the retina, hich entrs the otic nere and rus forward to enter the eyebll. The entral atery is n end atery and the only lood suply to th retina.

Posterir Communcating Atery The poterior cmunicating artery runs backward to oin the osterior cerebral artery Fi. 11-15).

Anerior Ceebral Arery he anteror cerebal arter is a teminal brnch of te internl caroti artery (Fi. 11-15). It es foward between the erebral emisphers and thn winds around te corpus callosu of the brain to supply the media and the superoateral srfaces o the cerbral hemsphere. t is joned to t arter of the opposite sde by th nterior ommunicating artry.

Middle Crebral rtery The midle cereral artey is the largest erminal branch o the intrnal cartid artey (Fig. 1-15), and it runs aterally in .751

he laterl cerebrl sulcus of the bain. It upplies the entie laterl surfac of the cerebral hemispher except the narro strip long the superolteral magin (whih is suplied by he anteror cereral artey) and the occipital pol and infrolateral surface of the hemisphee (both f which are suppied by te posteior cereral artry). The middle erebral rtery ths supplis all th motor aea of te cerebrl corte except he leg rea. It also give off cenral braches tha supply entral msses of gray mater and te internl capsue of the brain.

Crcle of illis

1395

snell The circle of illis lis in the subarachoid spac (see pag 683) at the ase of te brain It is frmed by he anasomosis between the branchs of the two intenal caroid arteres and te two vertebral arteries (Fig. 11-1). Th anterio communcating, osterior cerebral and baslar (fored by te junctin of th two verebral arteries) are all ateries tat contrbute to he circe. Cortial and cntral brnches arse from the circe and spply th brain.

Subclavian rteries Right Subcaian Arty The riht subclaian artey arise from th brachiophalic atery, beind the ight stenoclaviclar (Figs. 1157 and 11-59) It arces upwar and latrally or the peura and between the sclenus aterior ad medius muscles. At te outer border f th first rib it become the axllary arery.

Left Sublavian Atery The lef subclaian artey arises from th arch of the aort in the horax. I ascends to the rot of th neck and then arces lateally in manner imilar t that of the righ subclavian artery (Fig. 1157). The scalenus aterior uscle es anterior o the artery on each sde an divdes t into three arts.

Frst Part of the ubclavia Artery The first prt of th subclavan arter extends from th origin of the sbclavian artery t the medal borde of the calenus anterior muscle (Fig 11-57). This art gives off the ertebral artery, the thyroervical runk, an the intrnal thorcic artry.

Branhes he vertebral arter acends in the nec through the foramina in he transverse prcesses f the upper six ervical ertebrae (ig. 11-5). I es edially above th posteror arch f the alas and hen asends thrugh the foraen magnm into te skull On reacing the anterio surface of the edulla olongata f the brin at te level f the ower borer of the pons, i s the vessel of the posite ide to orm the basilar artery. The basiar arter (Fig. 1-15) ascends n a groove on the anterio surface of the pns. It gves off branches to the pns, the erebellu, and th interna ear. It finally divides into th two posterior crebral arteries. O each sie, the poserior cerebral atery Fi. 11-15) curvs lateraly and backward around te midbran. Cortial branche supply the inferolateral urfaces of the temporal obe and he vsual crtex on the lateral and te media surface of the ccipital lobe.  

ranches in the nck: pinal an muscula arterie Branhes in te skull: Menineal, antrior and posterio spinal, posterio inferio cerebelar, medllary arteries

The thyrocervical trun is a short tunk that gives of three trminal banhes (Fig. 11-57). 1396

snell Te nferior thyroid rtery ascends to the psterior urface f the troid glad, where it is cosely reated to the recurrent layngeal erve. It supplies the thyoid and he inferor parayroid glands. Te superfical cervial arter is a small brnch that crosses he brachal plexus (Fig. 11-5). The suprscapular artery runs laerally oer the bachial lexus and follows the uprascaplar nere onto te back o the scaula (Fi. 11-57). The internal thoraic arter descnds int the thoax behin the fist costa cartilae and i front o the plera (Fig. 1-57). It descnds verically oe fingerreadth lteral t the stenum; in he sixth intercstal spae, it diides into the suerior epgastric nd the usculophenic artries.

Secon Part of the Subcavian Atery The econd prt of th subclavan artey lies bhind the scalenus anterior muscle (Fi. 11-57).

Braches The costoervical runk uns backard over the dom of the leura and divide into th uperior intercosal arter, whih supplis the frst and he secon intercostal spces, and the deep crvical atery which spplies te deep mscles of the nec.

Thir Part o the Subclavian rtery The third pat of th subclavan artey extend from th lateral border f the sclenus aterior mscle (Fig 11-57 across the poserior tiangle o the nek to the lateral border o the fist rib, where i becomes the axillary rtery. Hre, in te root o the nk, it i closely related to the nrves of he brachal plexs.

Branhes he third part of the subcavian atery usually has no branhes. Occsionally however the suerficial cervica arteres, the suprascaular artries, or both arise from his part

Clinicl Notes Papation nd Comprssion of the Sublavian Atery in atients With Uppr Limb emorrhag In severe raumatic accident to the pper lib involing laceation of the brahial or xillay arteres, it i importnt to tat the hmorrhage can be stpped by exertng strong prssure dwnward ad backwad on the third pat of the subclavan arter. The use of a lunt objct to exrt the pressure is of grea help, and te artery is comressed aainst th upper srface o the firt rib. P.752

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Veis of the Head and Neck The vens of th head an neck my be divded into  

The veins of the brin, venous sinuse, diploi veins, nd emissry veins The veins of te scalp, face, an neck

Veins f the Brin e veins of the brain re thin walled ad have no valvs. They onsist f the ceebral vins, the erebella veins, and the veins of the braistem, all of whih drain nto the neighborng venous sinuse.

Venos Sinuse The venous inuses ae situatd between the peiosteal nd the meningeal layer of the dur mater Fg. 11-3A; se also page 686). They hae thick, fibrous walls, bt they pssess no valves. They reeive trbutaries from the brain, the skull bones, th orbit, and the internal ear. Th venou sinuse include the suprior and inferior sagittl sinuses the staight sius, the ransvers sinuses the simoid sinuses, te occiptal sinu, the caernous snuses, nd the uperior nd inferor petrosal sinuses (Fig 11-9. All tese sinues are escribed on page 686 and 87.

Diplic Veins The iploic vins ocy channls withn the boes of te vault of the skul (Fig. 119).

Emissary Veins The emssary vens are vlveless eins tha trough th skull bnes (Fig. 11-9) They cnnect th veins o the scap to the venous inuses (nd are a importat route or the sread of infection).

Veis of th Face an the Nec Facial ein Te facia vein is ormed a the medal angle of the ye by th union f the suraorbita and supratrochlear veins (Fg. 11-3). It is connected trough th ophthalmic vein with th cavernous sinus The facal vein descends down the face wit the faial artey and asses arund the ateral sde of th mouth. It then rosses te mandile, is jined by he anteior diviion of te retromndibular vein, nd drais into te internal ugular vin.

Superfical Tempoal Vein

1398

snell The superfical tempral vein is formed on the side of he scal (Fig. 11-9). t follow the superficial temporal artery ad the auiculoteporal nerve ad tn enter the partid saliary glad, where it the millary ein to frm the retromandiblar vein

Maxillary Vein he maxilary vein is formed in th infrateporal fosa from he pteryoid venus plexu (Fig. 1139). he maxillary vein s te superfcial teporal ven to fom the retromandiular vein.

etromanibular Vin Te retroandibula vein is formed y the unon of th superfiial tempral and he maxilary vens (Fig. 1-39). On leaving the protid saivary glnd, it dvides ino an antrior banch, whch the facal vein and a psterior branch, hich s the osterior auricula vein to form the external jugular vein.

Extenal Juglar Vein The externa jugular vein is formed bhind th angle o the jaw by the union of the sterio auriculr vein wth te posteror diviion of te retroandibular vein (Fig. 11-9). It desceds acros the strnocleidmastoid uscle and beneath the pltysma mucle, and it drains into te subclaian vein behid the iddle of the clavicle.

Tributaris    

Psterior xternal jugular ein from the ack of te scalp Trnsverse ervical ein from he skin and the ascia over the posterior tiangle Suprscapular vein rom the ack of te scapul Anterior juguar vein

Anterir Jugula Vein The anterior juguar vein descends in te front f the nck close to the idline (Fi. 11-39). Jut above he sternum, it i ed o the opposite vin by t jugulr arch. The anteior juglar vein s the externl jugulr vein eep to he sterncleidomatoid musle.

Interna Jugula Vein The inernal juular vei is a lrge vein that recives blod from he brain, face, and neck (Fi. 11-9). It strts as a continuaion of the sigoid sinu and leaes the sull thrugh the jugular foramen It then descend through the neck in the arotid seath latral to e vagus nerve an the intrnal and common arotid ateries. It ends y ig the suclavian ein behid the mdial end of the lavicle o form te brachocephalc vein (Fgs. 11-3 and 11-7). Troughout its course, it i closely related o the deep cervical lymph ndes. The ve has a dlatatio at its upper en called he superio bulb and anoter near ts termnation clled the iferior bulb. irectly above te inferir bulb s a bicupid valve.

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Relations o the Intrnal Jular Ven 



Anterlateraly: he skin, the fascia, the sternoclidomastod, and the protid slivary gland. ts lowe part is covered y the strnothyrod, sternhyoid, nd omohoid musces, whic intervene betwen the ein and he sterocleidomstoid (Fig. 11-55). Highr up, it is crosed by th stylohyid, the osterior belly of the digatric, an the spnal part of the ory erve. Th chain o deep cevical lmph node runs aongside he vein. Posterioly: he transerse proesses of the cervcal vertbrae, th levator scapula, the sclenus meius, the scalenus anterior the cerical plxus, the phrenic nerve, P753

te thyrocrvical tunk, the vertebra vein, ad the fist part of the subclavian artery (Fi 1157). On the left sde it pases in front of he thorcic duc. 

Medialy: Aove lie the internal cartid artry and he 9t, 10th, 11th, an 12th cranial nrves. Beow lie he commo caroti artery nd th vagus nerve.

Tibutaris of the Internal Jugular Vein      

Iferior etrosal inus (ig. 11-0) Fcial ven (Fig. 1-39 Pharyngel veins Lngual ven Superior thyroid ein (Fig 11-55 Middle hyroid ven (Fig. 1-110

Clinicl Notes Penetrating Wouds of th Interna Jugular Vein The emorrhag of low-ressure enous blod into the loos connectve tissue beneath the inveting layer of dee cervica fascia may presnt as a large, slowly expaning hemaoma. Air embolism is a srious coplicatio of a laerated wll of th interna jugular vein. Bcause the wall of his larg vein cotains litle smooh muscl, its injry is no followe by ion ad retracion (as occurs wth arteral injures). Morover, th adventiia of th vein wll is atached to the deep fascia o the carid sheat, which hinders he collase of th vein. Blind clampng of th vein is prohibied becaue the vagus and hpoglossa nerves are in he viciity.

Intenal Juguar Vein atheteriation The internal gular ven is remarkably constant in positin. It decends though the neck frm a point halfway between te tip o the masoid procss and te angle f the ja to the sternoclvicular oint. Abve, it i overlaped by the anterior border f the strnocleidomastoid scle, an below, t is covred lateally by this musce. Just bove the sternoclvicular oint the vein lie beneat a skin epressio between the steral and clavicular eads of the sterocleidomstoid mucle. In he posteior

1400

snell apprach, the tip of he needl and the catheter are intrduced ino the ven about wo fingerbreadths above t clavicl at the osterior border o the strnocleidmastoid uscle (Fig. 11-61. In the anterio approach, with the patiens head trned to he opposte side, the tringle fored by th sternal and clavcular heds of th sternoleidomastoid muscle and th medial end of te clavice are ientified A shallow skin depession usually oerlies te trianle. The needle nd catheer are nserted nto the vein at he apex f the riangle n a cauda direction (Fig 11-61).

Sublavian Vin he subclvian vein is contiuation of the axllary ven at the outer border of the firt rib (Fig. 11-7). It s the intenal juguar vein o form te brachocephali vein, nd it reeives te external jugular vein. n additin, it oten recives the thoracic duct on he left ide and he right lymphatc duct n the riht.

Relatns   

nteriory: The clavice Posterorly: The scalnus anteior musce and te phreni nerve Inferirly: he uppe surface of the first rib

Clinica Notes Subcavian Vin Thromosis Spontanous thrombosis o the suclavian nd/or aillary eins occsionally occurs ater excssive an unaccustomed us of the arm at the shulder jint. The close rlationshp of thse veins to the first rib and th clavice and th possibiity of epeated inor trama frm these tructure is proably a fctor in its develoent. Seondary trombosis of subclvian an/or axilary veis is a cmmon coplicatio of an indwellin venous atheter. Rarely, the conition may follow a radica mastectmy with block dssectio of the lymph noes of te axilla Persisent pain heavinss, or edma of te upper imb, espcially after execise, i a complcation of this ondition

Anatom of Subclavian Ven Cathetrizatio The sublavian vin is located i the lowr anterir corner of the osterior triangle of the neck (Fig. 162), where it lies immediately posterio to the medial third of the clavicl.

Infraclaicular Aproach Since the subcavian ven lies close to the undersurface of the medil third f the clvicle (Fig 11-62, this s a relaively sae site fr cathetrization. The vein is slightly more mediall placed n the let side tan on th right sde.

Aatomy of Procedur

1401

snell Th needle hould be inserted through he skin ust belw the loer borde of the lavicle t the juction of the medial third and oute two thirds, coinciding with the posterior boder of te origi of the lavicula head of the sterocleidomstoid mucle on the upper border o the claicle (Fig. -62). The neede pierce the folwing structures:     

Ski Sperficia fascia ectoalis majr muscle (clavicuar head) Claviectoral ascia and subclavius muscle Wall f subclaian vein

The needle is pointed upard and osteriory toward the midde of the suprastenal notc.

Antomy of roblems   

Hittig the clvicle: The neede may be “walke― alon the lowr surfac of the lavicle ntil its posterio edge is rehed. Hiting the first ri: The needle may hit th first rb, if th needle s pointe downwar and not upward. Htting th subclavan arter: A ulsatile esistan and bright red bood flow indicate that the needle as e posterir to the scalenus anterior muscle ad perfoated the subclavin artery

Anaomy of Cmplicatins Rfer to Figue 11-62. 

   

Pneumothrax: The neede may pirce the ervical ome of te pleura permitting air to enter he pleurl cavity This complication is more common in children, in wh the plural reflction is higher han in adlts. Hemothoax: Te catheter may pirce the osterior wall of te subclaian vein and the leura. Subclavian artery puncure: he needl pierces the wall of the atery durig its inertion. Intrnal thoacic artry injury: Hemrrhage my occur nto the uperior ediastinu. aphragmtic paralysis: his occus when te needle damages e phrenic nerve.

Te Procedre in Chldren The needle pierces the skn in the deltopeoral grove abou 2 cm frm the clvicle. The atheter s tunneld beneat the ski to entr the suclavian ein at te point here the lavicle and the first rib cross. The more blique aproach in children minimize the posibility of enterng the suclavian rtery.

Supraclavcular Approach This aproach (Fig 11-62) is preerred by many fo the folowing antomic resons.  

The ite of pnetratin of the vein wal is lager, sine it lie at the unction f the iternal jgular ven and te subclavian vein, which akes the procedur easier. The needle is ointed dwnward ad medialy towar the medastinum, away from the plura, avoding the compliction of pneumthorax.

1402

snell 

Te cathetr is insrted alon a more irect corse into the bracocephali vein an superio vena caa.

Anatomy of the Procedure With he patiet in the Trendeleburg postion (patient supne with ead tiltd downwad) or siple supie position and the head tuned to th opposite side, th posterir border of the cavicular origin o sternoceidomastid muscl is palpted (Fig. 11-62). The neele is inerted though the skin a the site where th posterir borde of the lavicular origin o sternoceidomastid is atached to the uper border of the clvicle. A this poit, the nedle lie latera to the ateral brder of calenus nterior muscle an above the first ib. The eedle pirces the followin structus (Fig. 11-62):    

kin Superfcial fasia and platysma nvesting layer of deep cerical fasia Wal of the subclavin vein

he needl is direted downwrd in t direction of the opposit nipple. The neede enters the juncion of te internl jugula vein ad the suclavian vein. It is importt that te oerator understads that the pleua is not being peetrated and that it is posible for the neede to lie in a zon between the ches wall an the cervical dom of the arietal leura bu outside the pleual space (cavity.

natomic omplicatons The folowing coplicatios may ocur as th result f damage to neighbring anaomic strctures (Fig 11-62):   

Paralysi of the iaphragm Ths is caused by inury to te phreni nerve a it descnds postrior to the intenal juguar vein n the surface of e scaleus anterior muscl. Pneumohorax or hemothora: Thi is causd by damge to th pleura nd/or inernal thoracic arery by the needle ing osteriory and donward. Bachial pexus injury: his is cused by he needle ing posteriory into te roots r trunks of the pexus.

P.754

Lymh Drainae of the Head and Neck The lymph nodes of the had and nck (Fig. 140) re arraned as a regional collar that extends from bew the chn to th back of the hed and as a deep vrtical trminal goup that is embeded in te caroti sheath n the neck (Fig. 11-5).

Regioal Nodes The reional noes are aranged a follows

1403

snell  



 

ccipital nodes: These ae situatd over te occipial bone n the bak of the skull. Tey receie lymph rom the ack of te scalp. Retroaricular mastoid) nodes: These ie behin the ear over the mastoid rocess. They receive lymph from the scalp above the ar, the auricle, and the xternal auditory meatus Parotid nodes: These ae situaed on or within te paroti salivar gland. hey receive lymp from th scalp aove the arotid gland, the yelids, he paroid gland the aurcle, and the extenal audiory meats. Bucal (facal) node: On or two odes lie in the ceek over the buccinator muscle. They drain lmph that ultimatey es into the submandiular nodes. ubmandiblar node: Thse lie uperficil to th submandiblar saliary glan just beow the ower marin of th jaw. Thy receiv lymph from the frnt of th scalp; the nose the chek; the upper lip nd the loer lip (xcept th centra part); he frontl, maxillary, and ethmoid sinuses; e upper and lowe teeth (xcept th lower icisors); the anteior two hirds of the tonue (excet the tip); the flor of th mouth nd vestiule; and the gum. P.75

1404

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Fgure 11-1 Catheterizatin of the right inernal juular vei. . Poterior aproach. ote the osition of the caeter relative to the sterocleidomstoid mucle and he commo carotid artery. B. Anteror approach. Note that th cathete is inseted into the vein close t the apex of the tiangle frmed by he sternl and clvicular heads of the sterncleidomatoid musle and te clavice.



 

Submental node: Thse lie i the subental trangle jut below he chin. They dran lymph from th tip of te tongue the flor of the anterior part of he mout the incisor teet, the ceter part of the lwer lip, and the skin ove the chi. Anterir cervicl nodes: These lie alon the couse of th anterio jugular veins in the fron of the neck. Thy receiv lymph fom the sin and sperficia tissues of the front of the neck. Superfical cervial nodes These lie along the curse of he exteral jugulr vein o the sid of the neck. Thy drain ymph fro the skin over the angle o the jaw, the skin over th lower prt of th parotid gland, and te lobe o the ear.

1405

snell   

Rtropharygeal nods: These lie ehind the pharynx and in frnt of th vertebrl column They rceive lyph from he nasal pharynx, the audiory tube, and the vertebra column. aryngeal nodes: These le in frot of the larynx. hey receve lymph from the larynx. Trachel (paratacheal) odes: These le alongsde the tachea. Tey receie lymph rom neigboring sructures includig the throid glad.

P.756

Fgure 11-62 Subcavian ven cathetrization . Infrclavicular approach. Note he many important anatomic structus located in ths region . Supaclavicuar approch. The atheter nters th subclavian vein close to its junction wit the intnal jugular vein to form the brachiocephalic vein.

Dee Cervica Nodes The deep cervical nodes rm a vetical chin along the course of the internal jugular ein withn the caotid sheth (Fig. 1149). Tey receie lymph rom all he group of reginal node. The juguldigastri node which i located below and behind the angl of the aw, is minly conerned wih drainae of 1406

snell the tonsil ad the togue. The juulo-omohoid node, which is situaed clos to the omohyoid scle, is mainly asociated with drainage of he tongu. he effent lymph vessels rom the deep cervical lymp nodes oin to frm the jgular trnk, whic drains nto the horacic duct or he right lymphati duct (Fig. 11-40.

Clinial Notes Clincal Sigificance of the Crvical Lmph Node Knowledge of the lymph dranage of an organ r region is of geat clincal impotance. Eaminatio of a paient may reveal a enlargd lymph ode. It s the phsician's responsiblity to etermine the cae and be knowledgeable about the ara of the body tha drains its lymp into a articula node. Fr exampl, an enlarged submandibul node can be caused by a pthologic conditio in the scalp, te face, he maxilary sinus, or the tongue. An infectd tooth of the pper or ower jaw may be rsponsibl. Often physician has t search ystematically the various areas knon to dran into a node to discover the caus.

Eaminatio of the eep Cervcal Lymp Nodes Lymh nodes n the nek should be examied from ehind the patient. The exaination s made easier by asking the patient to flex the neck slighly to reuce the ension o the musles. The groups f nodes hould be examined in a defnite ordr to avod omittig any. After th identifcation o enlarge lymph ndes, posible sits of infction or neoplastc growth should b examine, incluing the ace, scap, tongu, mouth, tonsil, nd pharyx.

Crcinoma etastase in the eep Cervcal Lymp Node In he head nd neck, all the ymph ultmately dains ino the dep cervical group of nodes. Secondar carcinoatous deosits i these ndes are common. The primary growth my be eas to find On th other hand, at certain anatomic sits the primary rowth ma be smal and ovrlooked, for examle, in te larynx the phaynx, the cervica part of the esophgus, and the extenal audiory meats. The ronchi, reast, ad stomac are somtimes th site of the primry tumo. In thee cases, the secodary groth has spread far beyond te local lymph nodes. When ervical etastase occur, he surgen usuall decide to perform a block dissecion of te cervicl nodes. This procedure involves the removal en bloc f the internal jugular ven, the fascia, te lymph odes, an the subndibular salivary gland. Te aim o the opeation is removal f all th lymph tssues on the affcted side of the neck. The carotid teries and the vaus nerve are carfully prserved. t is oftn necessry to sarifice te hypoglssal an vagus nrves, which may b involved in the cancerous eposits. In patints with bilatera spread, a bilateal block dissectin may be necessry. An iterval o 3 to 4 eeks is ecessary before rmoving te secon interna jugular vein. P.757

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Cranial Nerves Organzation of the Cranial Nervs he cranil nerves are name as follws:            

I. Olfactor I. Optic II. Oculmotor IV. Trochlea . Trigenal VI. Aducent VII Facial VII. Vestiblocochlear IX. Gossophayngeal X Vagus XI. Accessor XII. Hypglossal

Te olfactry, opti, and vetibulocohlear neves are entirely sensory; the oculmotor, tochlear, abducent accessoy, and ypoglossal nerves are entily motor and the remainin nerves re mixe. The diferent cmponents of the canial neves, ther functins, and the openngs in t skull through which the nerves leae the canial caity are ummarize in Table 1-6.

Olfatory Neres Th olfactoy nerves arise frm lfactory receptor nerve cels i the olfctory muous membane. The olfactor mucous embrane s situaed in th upper prt of the nasal cavity abov the level of th superir concha (Fg. 11-63). Bundes of thse olfacory nerv fibers through the openings of the ribrifor plate o the ethoid bone to enter the olfactoy bulb in the canial cvity. Th olfactor bulb is connecte to the lfactory area of he cerebal corte by the olfctory trct.

Optic Nerve he optic nerve is compose of the xons of he cell of the gaglionic layer of he retia. The otic nerv emerge from th back o the eyeall and leaves he orbital cavit throug the optic canal to enter the cranal cavty (Fig. 11-11) The optc nerve hen unies with he opti nerve the oposite sie to fom the opti chiasma (Fig. 1-63) In the ciasma, te fibers from the medial alf of each retia cross he midlne and eter the opic trac of te opposite side, hereas the fiber from th lateral half of each retina pas posteriorly in he optic tract of the same side. Mst of te fibers of the optic trat terminate by snapsing ith nere cells in the latral geniulate body (Fig. 1-63) A few fbers pas to the pretecta nucleus and the uperior olliculus and are concernd with light reflxes.

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snell The axon of the erve cels of the lateral eniculat body pas posterorly as he optic rdiation and teminate i the visual cortex of the erebral emispher (ig. 11-6).

Oculomotor Neve Te oculomtor nerve emerges on the anterior surface f the midbrain (Fig 11-64). It es forard between the osterio cerebra and suprior ceebellar arteries (g. 11-1). It then coninues ito the iddle crnial fossa in th lateral wall of he caverous sinus. Here, it divids into a sperior and an inerior raus, wich enter the orbtal cavity throuh the suerior orbital fissure (Fig. 11-18. The culomoto nerve spplies te followng:  

The extrinsic muscle of the eye: te levat palpebrae superioris, suerior rectus, medal rectu, inferr rectus and inerior oblique (Fig. 1-64; see also Fis. 11-1 and 11-19) Th intrinsc muscle of the ye: he constictor puillae of the iris and the iliary mscles ar suppled by th parasyathetic componen of the culomoto nerve. These fiers synase in th iliary anglion and reach the eyeball in the short iliary nrves (Fi. 11-19).

he oculootor nere, therfore, i entirel motor. It is rsponsibl for lifting the upper eelid; tuning the eye upward, downard, and medially; constrcting th pupil; and accomodation of the eye. P.75

Tale 11-6 Cranil Nerves erve

Components

Fnction

Oening i Skull

I.

Olfatory

Sensory

Smell

Openngs in cribrifor plate o ethmoi

II.

Optic

Senory

ision

Optic cnal

III.

Oculootor

Motor

Lifts upper eyelid, turns yeball pward, ownward, and meially; constrict pupil;

Superior rbital fssure

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ccommodtes eye

Motr

Assists in urning eeball donward ad laterally

Suprior orbital fissre

Ophhalmic ivision

Sensory

Corne, skin f forehed, scal, eyelis, and nse; also mucous mmbrane of paranal sinuses an nasal avity

Superir orbital fissure

Maillary ivision

Senory

kin of ace over maxilla nd the pper lip teeth f upper aw; mucos membrae of nos, the mxillary air sinu, and plate

Framen roundum

Mndibula division

otor

Muscles of masication mylohyod, anteior bell of digstric, tensor veli alatini, and tenor tympi

Foramen ovale

Snsory

Skin o cheek, kin ove mandible, lowe lip, an side o

IV.

rochlea

V

Tigeminal

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head; teth of lwer jaw d temoromandiular jont; mucos membrae of mouh and anerior tw third of tonge

VI.

Abducet

Motor

Lteral retus musce: turns eyeball aterall

Superio orbital fissure

VII.

acial

Motor

Muscle of face cheek, nd scalp stapedis muscl of midde ear; sylohyoid and poserior bely of diastric

Internal acousic meatu, facial canal, tylomastid foramen

Sensory

Tate from nterior wo thirds of tonge, floor of mouth, and palate

Scretomotr

Sbmandiblar and ublingul salivay parasmpatheti glands, lacrimal gland, nd gland of nose and pale

III.

Vestibulcochlear

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IX.

X.

Vestiblar

ensory

Positio and movment of ead

Cochler

Senory

Haring

Glosspharyngel

Mtor

Sylopharygeus musle: assits swallwing

Seretomoto parasymathetic

Protid slivary gand

Sensoy

Geeral senation an taste fom posteior thir of tonge and phaynx; cartid sinu and cartid body

Motor

Consrictor mscles o pharynx and itrinsic uscles f larynx involuntary muscle of trchea and bronchi heart, limentary tract from pharnx to spenic flexure of clon; livr and pncreas

Sensory

Taste from epilottis and

Vagus

1412

Interna acousti meatus

Jugular foramen

Jugular formen

snell

vallecla and aferent fibers from structurs named bove

X.

XI.

Accssory

Craial root

Moto

Musces of soft palate pharynx and larnx

Spinal rot

Mtor

Sernocleiomastoid and trapzius musles

Hoglossal

Moto

Musces of tonue contrlling is shape nd movemnt (except palatogossus)

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1413

Jugula foramen

Hpoglossa canal

snell

Figure 11-63 A. Distriution of the olfactory nerves on te nasal septum and the lateal wall f the

1414

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noe. B. Th optic neve and is connecions.

Trochler Nerve The trchlea nerve i the mos slender of the canial nerves. Havng crossd the neve of th opposite side, it leaves te posteior surfae of the midbrain (Fg. 11-64). It hen s forwar through the midde crania fossa i the latral wal of the cavernous inus and enters te orbit through t superio orbita fissure (Fgs. 11-1 and 11-1). The trochlar nerve upplies:  

The supeior oblique muscl of the yeball (xtrinsic uscle) (Fig 11-20) Te trochlar nerve is entirly motor and assits in tuning the eye dowward and laterall.

Trigeminl Nerve The trgeminal erve is he larget crania nerve (Fig 11-65). It leaves the nterior spect of the pons as a smal otor roo and a large sensory root, and i es orward, ut of th posterir crania fossa, o reach he apex f the perous par of the mporal bne in th middle ranial ossa. Her, the lage sensoy root epands to form the trgeminal anglon (Fig. 11-11 and 11-6). Th trigemial ganglon lies within a pouch o dura maer calle the trigemnal cave. The motor rot of the trigeminal nerve is situated below te sensor ganglin and is completey separae from i. The opthalmic V1), maxillary (), and mandibular (V3) nerves arise from the anterior border f the gaglion (Figs 1111 and 11-65). P.760

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snell

Figure 1-64 A. Origin ad distriution of the oculmotor neve. B. Orgin and istributon of th trochler nerve.

Ophtalmic Nerve (V1) The ophthalmic nerve is purely snsory (Figs 11-65 and 11-50). It rns forwad in the lateral all of te cavernus sinus n the mddle craial foss and divdes into three branches, the lacrim, fronal, and asociliar nerves, which enter te orbital cavity rough the superior orbital fissure

ranches The lacrial nerve runs orward o the uppr border of the lateral retus musce (Fig. 11-8). I is d by the zygomatiotempora branch f the maillary nerve, which contains the paasympathtic

1416

snell secrtomotor ibers to the lacrmal glan. The larimal neve then nters the lacrimal gland an gives ranches o the cojunctiva and the in of th upper eelid. The frontl nerve runs foward on he upper surface f the leator palebrae suerioris uscle an divides into the suraorbita and supratrochlear nerves (Fig. 11-0). Tese nerves lave the orbital avity an supply he frontl air sinus and the skin of the foreead and he scalp The nasciliary erve rosses te optic erve, runs forwar on the pper borer of th medial ectus muscle (Fig. 1120), nd contiues as te nterior thmoid erve through he anteror ethmoidal formen to eter the ranial cvity. It then decends though a slit at te side o the crita gall to ente the naal cavit. It gies off to internal nasal banches and it then supplies the skin of the tip o the nos with th external asal nere. Its branches include he folloing:    

ensory fbers o the ciiary ganlion (Fig. 1-20) Long cliary neves that contain sympahetic fibers to te dilato pupilla muscle nd sensory fiber to the crnea (Fig. 1-20) Infrarochlear nerve that supplies the skin of he eyelis Postrior ethmoidal neve that is senory to the ethmoid and spheoid sinues

P.761

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snell

Fiure 11-6 A. Ditributio of the rigemina nerve. B Origin and distribution of the abucent nerve.

Maxillary Nerve V2) The maxilary nere arises from the trigeminl gangli in the middle canial fosa. It psses forard in te latera wall of the cavrnous sius and laves the skull though the foramen otundum Fi. 11-11) and crosses the pterygoplatine fssa to eter the rbit thrugh the iferior obital fisure (Fig. 1-19). It

1418

snell then continue as the nfraorbial nerve in the ifraorbitl groove and it emerges n the fae throug the infaorbital foramen. It give sensory ibers to the skin of the fce and the sid of the ose.

Branhes  

Meningal brances Zygomati branch (Fig. 11-9), wich divies into he zygomticotempral .762

ad the zyomaticofcial neres that upply th skin of the face The zyomaticotmporal banch giv parasympathetic secetomotor fibers to the lacimal glad via th lacrima nerve. 

  

Ganglioic brances, wich are two short nerves hat suspnd the perygopaltine ganlion in he pteryopalatin fossa (Fig 11-19). They contain sensory fiers that have pased throu the ganlion frm the nse, the plate, an the phaynx. The also cotain posganglionic parasypathetic fibers tat are oing to he lacrial gland Postrior suprior alvolar nere (Fig. 11-19, which upplies the maxilary sins as wel as the pper mor teeth and adjoiing part of the um and te cheek iddle suerior aleolar neve (Fig. 11-19, which upplies he maxilary sins as we as the upper premolar teth, th gums, ad the cheek Anterir superir alveolr nerve (Fig. 1119), hich suplies the maxillay sinus s well s the uper canie and th incisor teeth

Perygopaatine Gaglion The terygopaatine gglion i a paraympathetc ganglion, whih is susended fm the axillary nerve in the ptrygopalaine fossa (Fig. 1-19). It is seretomoto to the lacrimal and nasal gland (see page 694).

Brnches   

Orbital ranches, which entr the orbit through he infeior orbial fissure Greatr and leser palaine neres (Fig. 11-19, which supply te palat, the tosil, an the nal cavit Pharngeal brnch, which spplies he roof f the nsopharyn

Mndibular Nerve (3) he mandbular neve is boh motor and sensry (Figs. 11-11 and 11-65). The ensory rot leav the trgeminal anglion nd es out of the skul through the foamen ovale to ener the nfratempral fos. The otor roo of the rigemina nerve aso leave the skull throug the foamen oval and jois the sesory roo to form he trunk of the andibula nerve, nd then ivides ito a smal anterio and a lrge poterior dvision (ig. 11-6).

Branhes From the Main runk of the Mandibular Nere 

Meingeal branch 1419

snell 

Nerve o the meial ptergoid musle, which supples not oly the mdial pteygoid, t also he tensor veli paltini musle.

Brnches Frm the Anerior Diision of the Mandbular Nerve    

Masseeric ner to te massetr muscle (Fg. 11-36) Dee tempora nerves to the temporals muscle (Fg. 11-36) Nere to the lateral terygoid muscle Buccal nrve t the ski and the ucous membrane of the chee (ig. 11-3). The buccal nrve does nt supply he buccinato muscle (whh is sulied by the facia nerve) and it s the only ensory banch f the anerior diision of the mandbular neve.

Banches Fom the Psterior ivision f the Madibular erve 







Auiculotemoral nerv, whih supplis the skn of the auricle Fi. 11-66), the external auditory meatus, he tempoomandibuar t, and the scalp. Tis nerve also coneys postanglioni parasymathetic secretomtor fibes from te otic ganglion to te paroti salivar gland. Linual nerv, whic descen in frot of the nferior lveolar erve and enters te mouth Fis. 1136 and 11-6). It hen runs forward n the sie of the tongue ad crosse the subandibula duct. I its couse, it i ed y the chord tympani nerve (Fis. 11-3 and 11-6), and it supples the mcous memrane of he anteror two tirds of he tongu and the floor of the mout. It als gives of reganglinic paraympahetic scretomotr fibers to he submadibular anglion. Infeior alvelar nerv (Figs. 1-36 ad 1-66), which ters th mandibular canal to supply the teet of the ower jaw and emeges throuh the metal foraen (mentl nerve) o supply the ski of the hin (Fig. 1-50). Before etering th canal, t gives ff the myloyoid nere (Fig. 136), which suplies th mylohyod muscle nd the aterior blly of te digastrc muscle Communicting brach, which freqently runs from the inferir alveol nerve t the linual nerv

The banches o the posterior division of the mandiular nere are sesory (exept the erve to he mylohoid muscl).

linical otes njury t the Lingual Nerve The lingual erve pases forward into te submandbular rgion fro the infatempora fossa b running beneath he origin of the superor constictor mucle, whih is attched to he posteior borer of the mylohyoid line o the manible. Here, it is closely related t the las molar toth and s liable to be daaged in ases of clumsy etraction of an imacted thrd molar

Otic Gnglion The oti ganglio is a paasympathti ganglio that is located medial t the manibular nrve just below th skull, nd it is adheren to the erve to he media pterygid muscl. The reganglinic fiers orignate in the glosopharyngeal nerve, and they reach te ganglon via te lesser petrosal erve (see page

1420

snell 76). The postgangionic seretomoto fibers each the parotid salivary gand via he auriclotemporl nerve.

Sumandibulr Ganglin Th submandbular gaglion is a parasypathetic ganglion that lies deep to the subndibular salivary gland an is attahed to he lingual nerve b small nrves (Figs. 11-36 and 11-66). reganglinic paraympathetc fibers reach te ganglin P.763

from the facial nrve via he chord tympani and the ingual nrves. Pstganglinic secrtomotor ibers pas to the submandiular and the subingual slivary gands.

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snell

Figre 11-66 Infraemporal nd submadibular egions. arts of he zygomaic arch, the raus, and he body of the manible hav been reoved. Mylohyoid ad lateral pteygoid mucles hav also ben remove to dispay deepe structres. The outline f the sulingual land is hown as solid lack wavy line.

The trgeminal erve is hus the ain sensry nerve of the ead and inervates the musces of matication It also tenses the soft plate and the tympnic membrne.

Abucent Neve 1422

snell Thi small erve emeres fom the anterior urface the hndbrain between th pons and the meulla obongata (Figs 11-11 and 11-5). t es forward ith the internal arotid atery thrugh the cavernos sinus n the midle cranal fossa and entes the orit throgh the sperior obital fisure (Fig. 1-18). The abducent nere supplis the laeral rectus musce (Fig. 115) ad is theefore reponsible for turning the ee lateraly.

acial Neve Th facial erve has a motor oot and sensory root (nervu intermeius) Fi. 11-67). Te nerve merges o P764

th anterio surface of the hndbrain etween te pons ad the edulla blonata. Th roots pss laterlly in te posteror cranil fossa ith the vestibulcochlear nerve an enter te internal acoustc meatus n the ptrous pt of the temporal bone (Fig. 11-28) At the bottom o the meaus, the erve entrs the fcial canl that uns lateally thrugh the nner ear On reacing the edial wall of the middle ar (tympnic caviy), the erve swels to fom the sensory geiculate anglion (Fig. 11-67; see also Figs. 1-29 nd 11-30) The neve then ends shaply backard abov the proontory ad, at th posteror wall f the midle ear, bends don on the medial sde of th aditus of the mastoid anrum (see pae 712) The neve desceds behin the pyrmid and t emergs from te temporl bone hrough the stylomastoid foamen. Th facial erve no es forward hrough te parotd gland o its ditributio (ig. 11-67).

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snell

Figure 11-67 A. Distriution of the facil nerve. B. Branhes of te facial nerve wihin the etrous prt of th tempora bone; he taste fibers ae shown n black. The glosopharyngal nerve is also shown.

P.75

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Importnt Branches of the Facial Nerve 

 





reater ptrosal nrve aises fro the nere at the geniculae ganglin (Fg. 11-67). It contains preganglonic parsympathetic fibers that synapse in e pteryopalatin ganglio. The potganglioic fiber are secetomotor to the acrimal land and the glans of the nose and the palae. The reater ptrosal nerve also contains taste fibrs from he palat. erve to tapedius supplies the stapedius muscle in the middl ear (Fig. 11-67) Chrda tymni arses from the facil nerve n the faial cana in the sterior all of he middl ear (Fig. 1-67). It runs orward oer the mdial surace of te upper art of te tympanc membrae (Fig. 11-9) and leaves the middle ear throgh the pettympani fissure, thus entering the infrtemporal fossa an ing the lingal nerve. The chorda tympani contains preganlionic prasympatetic secetomotor fibers o the sumandibulr and th sublingal salivary gland. It als contais taste ibers frm the aterior wo thirs of the tongue an floor f the moth. Posterio auriculr, the posterior belly of the distric, nd the stylohyoid nerves (Fig. 11-67 are musculr branchs given ff by th facial erve as t emerge from th stylomatoid foramen. ive termnal branhes to te muscle of facial expression. Tese are he temporal, the zygmatic, the buccal, the mandibular and th ervical ranches (Fig. 11-67).

The faial nerv lies wihin the parotid alivary land (Fig. 11-85B) after leaving the stylomastoid foramen, an it is lcated beween the superfical and te deep parts of the gland (ee page 78). Here, it gives off te terminl branchs that eerge fro the anterior borer of th gland ad to the musces of th face an the scap. The bucal branc suplies th buccintor musle, and the cervcal branch supples the latysma and the epressor anguli ris musces. The facal nerv thus cotrols fcial expression, salivaton, and acrimaton and is a pathwy for tste senstion fro the anerior pat of the tongue nd floor of the muth and from the palate

estibulocochlear Nerve The estibuloochlear nerve i a sensory nerve that conists of to sets o fibers: vestibuar an cochlear. They eave the anterior urface o the bran betwen the pos and the medulla oblongat (ig. 11-6. They cross the posterio cranial fossa an enter te interl acousic meatu with th facial erve (Fig. 11-28)

Vestibuar Fiber The vestibulr fibers are the entral processes of the erve cels of the vestibulr ganglin situatd in the internal acousti meatus Fi. 11-68). The estibula fibers originat from th vestibue and th semicirular canals; theefore, thy are concerned wth the snse of psition ad with ovement f the hed.

Cochlear Fibers

1425

snell The cochear fiber are the central processes of the nerve cell of the spiral gangion of te cochle (Fig. 1168). he cochlear fibers origina in the spiral organ of Corti and are therefre concened with hearing.

Glossopharyneal Nerve The glossophryngeal erve is a motor ad sensor nerve (Fig 11-68). It eerges frm the anerior suface of the medula oblongta between the olive and the inferir cerebelar peducle. It asses lterally in the poterior canial fosa and laves the skull by ing hrough te jugulr forame. The superor and iferior snsory gaglia re locatd on the nerve as it e throug the formen. The glossoharyngea nerve hen descends thrugh the pper par of the eck to the back the tongue (Fi. 11-68).

Importat Branchs of the Glossopharyngeal Nerve 



  

Typanic brnch psses to he tympaic plexu in the iddle ea (ig. 11-6). Preanglioni parasymathetic ibers fo the partid saliary gland now leave the plexus a the lesse petrosa nerve and the synapse in the oic ganglon. Caroti branch contans sensoy fibers from the carotid inus (prssorecepor mechnism for the reguation of blood prssure and the caroid body nd chemreceptor mechanis for the regulatin of heat rate ad respiation) (Fig 11-68). Nerve to the stylopharyngeus muscl Pharygeal braches (Fig 11-68) run to the pharyneal plexs and lso receve brances from he vagus nerve an the symathetic trunk. ingual ranch Fi. 11-68) es to the mcous merane of the postrior thir of the ongue (icluding he vallae papille).

The glosopharyngeal nerv thus asists swallowing and promote salivaton. It aso conduts sensaion from he pharyx and te back o the tonge and caries implses, whch influnce the rterial blood presure and respiratn, from he carotd sinus nd carotd body.

Vagus erve The vagus nerve is composed of motor and sensry fibers (Fig. 11-69). It emerges rom the anterior urface o the medlla oblogata beteen the olive an the infrior cerbellar pduncle. The nerve es aterally through he posteior cranal fossa and leavs the skull throgh the jgular foramen. The vgus nerv has both sperior ad inferir sensry gangla. Belw the inerior gaglion, te ranial rot of th accessoy nerve s he vagus erve and is distrbuted manly in is pharyneal and ecurrent laryngea branches Te vagus erve desends thrugh the eck alonide the arotid ateries ad internl jugula vein wihin the arotid sath (Fig. 1-49). It e through the medistinum o the thox (Fig. 11-69), pssing beind the oot of the lung, d enters the abdomen throuh the esphageal pening i the diaphragm. P.766

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Figure 1-68 A Origin nd distrbution o the vestibulococlear nere. B. Disribution of the gossopharngeal neve.

Imporant Branhes of te Vagus erve in he Neck 

Meningeal and auricuar brances

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

Phayngeal banch contain nerve fbers fro the craial part of the ory erve. Tis branc s te pharyngal plexu and suplies all the musces of th pharynx (except he styloharyngeu) and of the soft palate (ecept th tensor eli palatini). Suerior layngeal nve (Fig. 11-69 divides into the internal nd the eternal lryngeal erves. Te nternal aryngeal nerve s sensor to the ucous memrane of he pirifrm fossa and the lrynx dow as far s the voal cords The externl laryngal nerve is moor and s locate close o the suerior thyroid artery; it supples the cicothyrod muscle P.77

Figure 11-69 Dstributon of th vagus nerve.

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

Recurrnt larygeal nee (Fig. 11-69). On th right sde, the erve hoos aroun the first part of he subclvian artry an then aends in he grooe betwee th trachea and the esophagu. On th left sde, the erve hoos aroun the rch of the aorta and hen ascds into the neck between the tracea and te esophaus. Th nerve i closel related to the iferior tyroid arery, and it suplies all the muscles of te larynx, except the ricothyrid muscle, the ucous mebrane of the laryx below he vocal cods, and he mucou membrae of th uppr part f the trchea. Cardac branhes (two or tree) arse in the eck, desend int the thoax, and nd in the cardia plexus Fg. 11-69).

The vagus nerve thus innervats the hart and reat vssels wihin the horax; te laryn, trache, bronci, and lungs; and much of the aimentary tract frm the phrynx to the plenic flexure of the con. It also spplies gands assciated wth the aimenary trct, such as the liver and pncreas. The agus nerve has the ost extensive ditributio of all the cranal nerve and suplies the aforemetioned sructures with afferent ad efferet fibers

Accessory Nerve The accessor nerve i a motor nerve. It consits of a ranial rot (part) and a spinal roo (part) ig. 11-7).

Craial Root The cranial rot emerges from he anteor surfce of he medula oblongta betwen the olve and te inferr cerebllar peuncle (Fig. 11-70. The neve runs aterally in the posterior cranial fossa an s te spina root. P.768

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Figue 11-70 A. Orgin and distribuion of he ry nerve. B. Ditributio of the hypoglosal nerve

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pinal Rot The spnal root arises rom nerv cells n the anerior gay colum (horn) f the uper five segments of the crvical prt of te spina cord (Fig 11-70). The erve ascnds alogside th spinal ord and enters th skull trough th foramen magnum It then turns lterally o te crania root. The wo roots unite and leae the skll throuh the jgular foamen. Th roots ten sepaate: The cranial root s the vagus neres and i distriuted in its braches to he musces of th soft alate and pharyn (via th pharyneal plexs) and t the musles of he laryn (except the criothyroid muscle) The spial root runs downward ad lateraly and nters th deep srface of the strnocleidmastoid muscle, hich it supplies, and then crosse the poterior riangle f the nck to suply the rapezius muscle (ig. 11-5). The ory nrve thus brings aout moveents of he sof palate, pharynx, and larynx and ontrols the moveents of the stenocleidomastoid and rapezius muscles, two larg muscles in the neck. P.69

Clinial Note Injry to the Spinal Part of he Accssory Neve The sinal par of the ccessory nerve cosses th posteror trianle in a elativel superfiial posion. I can be injured t operaton or frm penetrting wounds. The trapezis muscle is parlyzed, he musce will sow wastng, and he shouler will rop. Th patien will xperienc difficuty in elevating he arm aove the head, hving abdcted it o a righ angle b using the deltod musce. Clinica examinaion of his nerv involves asking the patent to rtate the head to ne side against resistace, causng the ternocleidomastod of the opposite side to come into action. Then th patiet is asd to shug the shoulders, causing he trapeius musces to ome into action.

Hypogossal Neve he hypolossal nrve is a motor nerve. It merges o the aterior srface of the medulla oblogata between the pyramid and te olive, crosses the poserior crnial fossa, ad leave the skul throgh the hpoglossl canal. The nerv then pses downward and forward in the nck and cosses th interna and extrnal caotid areries to reach th tongue ig. 11-70). In the uppr part o its couse, it i ed y C1 fibrs from the cervical plexus.

Important Braches of he Hypogossal Neve 

Menigeal brach

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  

Desceding brach (C1 fibers) es dwnward ad s he descendng cervical nerve (C2 ad 3) to orm the ansa cervicalis. ranches rom thi loop suply the omohyoid the sternohyoid, nd the sternothyoid musces. Nere to the thyrohyd muscl (C1). Musculr brances to al the muscls of th tongue except the paatoglosus (pharngeal plxus) Nere to th geniohyid muscle (C1). The hypoglossa nerve tus innerates the muscles of the tngue (ecept P.770

P.771

he palaglossus and theefore cotrols te shape nd movemnts of te tongue.

Cliical Nots Cinical Tsting o the Craial Neres Systemtic examnation o the 12 ranial nerves is an important par of the xamination of every neurlogic paient. It may reeal a leion of a cranial nerve nuleus or its cental connections, or it may show a interrtion of the lowe motor nurons.

Teting the Integrit of the lfactor Nerve Th olfactry nerve can be ested by applyin substanes with different odors o each nstril i turn. I should e rememered that food favors deend on te sense f smell nd not o the sene of taste. Fratures of the anteior cranal fossa or cerebral tumos of th frontal lobes ma produce lesions f the ofactory erves, with consquent los of the sense of smell (anomia).

Teting th Integrity of the Optic Neve The optc nerve s evaluaed by fist askin the patent whether any changes n eyesigt have ben noted The acuty of vsion is then tesed by usng chars with lnes of pint of vrying sie. The retinas and optic discs shuld then be examied with n ophthamoscope. When exmining te optic isc, it hould be ed that the intraranial subarachnoid space extends fward around the optic nerve to the back of the eyeall. The retinal rtery ad vein un in th optic erve and cros the sbarachnod space of the nerve sheth a short distnce behd the eeball. A rise in cerebrospinal flid presure in te subarachnoid sace will comprss th thin wlls of the etinal vin as it crosses the spae, resuling in cngestion of the retinal veins, eema of te retina and buling of he optic disc (papiledema). Te visua fields sould thn be tesed. Th patient is askd to gaz straigh ahead a a fixe object ith the eye unde test, the oppoite eye being coered. A small object is ten moved in an ac aroud the 1432

snell priphery of the feld of vision, nd the atient i asked whether e or she can see the objet. It i important not t miss los or imairment f vision in the entral aea of the field (centrl scotoa). Blidness in one half of each visual ield is called emianopa. Leions of he optic tract and optic adiation produce the same hemianopa for boh eyes, that is, homonmous heianopia. Bitemporl hemiaopia is a lss of te latera halves of the felds of ision of both eys (i.e. loss of function of the edial haf of bot retinas. This onditio is mos commonl produced by a tumor o the pititary gand exeting prssure o the optc chiasm.

Testin the Integrity of the Ocuomotor, Trochlea, and Aducent Nrves Th oculomoor, troclear, an abducent nerves innerva the mcles tht move the eyebll. The culomotr nerve upplies ll the rbital uscles ecept the superior oblique and the lateral ectus. It also upplies the levaor palperae supeioris an the smooth muscles concrned with accomodation€”namely the sphincter pupillae ad the cliary mscle. Th trochler nerve upplies the supeior obliue musce, and he abdcent neve supples the lteral rectus. To exaine the cular mscles, te patient's head is fixe and he r she is asked to move th eyes in turn to he left, to the ight, uward, an downwar, as far as possble in ech diretion. I complete third nrve paraysis te eye cannot e move upward, downwar, or inwrd. At est the ye look lateraly (extenal strabismus) becuse of the actiity of he laterl rectu and downward beause of the acivity o the suprior obique. The patient sees double iplopia. Droping of the uppe eyelid (posis) occurs because of paralyis of th levator palpebra superiris. The pupil i widely dilated and nonreactive to light bcause of the paralysis f the spincter ppillae ad the uopposed action of the dilator pupillae (supplie by the sympatheic). Accmmodatio of the eye is aralyzed. In fourth nerve paalysis the patient complains of doule visin on looing stright dowward. his is bcause th superir oblique is parlyzed an the eye urns meially as the infrior recus puls the ey downwar. In sixth nerv paralyss te patient canno turn th eyeball lateraly. When looking traight ahead, he lateal rects is parlyzed, ad the unopposed edial retus pull the eyeball meially, causing iternal srabismus

Testing the Intgrity of the Trigeminal Nrve The rigemina nerve has sensoy and motor root. The sensory root es to the rigeminal ganglin, from hich emrge the ophthalic (V1), maxillay (V2), nd mandiular (V3 divisins. The motor oot the mndibula divisio. he sensry functin can be tested y using cotton wisp ovr each rea of te face supplied y the dvisions f the tigemina nerve (Fig. 11-0).

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snell The motr functon can b tested by askin the patient to clench te teeth. The masster and the temporlis musces, whih are inervate by the mandibulr divisn of th trigemnal nerve, can b palpated and elt to arden a they cotract.

Testing the ntegrity of the cial Nerv The faial nere supplis the mucles of acial xpressio; supples the ateror two hirds of the tongu with taste fibs; and s secretmotor to the lacrmal, sumandibulr, and ublingua glands he anatmic reltionship of this nerve t other tructure enables a physician to localize lsions of the nerv accuraely. If the sixt and sevnth nervs are no functioing, thi would uggest lesion ithin te pons o the bran. If th eighth nd sevnth nervs are no functioing, this would uggest a lesion n the internal coustic meatus If the patent i excessiely senstive to sound i one ea, the leion prbably involves te nerve to the tapediu. Loss o taste oer the terior wo thids of th tongue imlies that the seveth nerv is damaed proximal to the oint whre it gves off he chora tympan. To tes the facial nerv, the paient is asked t show the teeth y separaing the ips wit the teh clenced, and hen to close th eyes. Tste on each alf of he anerio two thrds of te tonge can be tested ith sgar, sal, vinega, and qunine for the swet, salt sour, and bitte sensatins, respctively t shoul be emembered that the par of the facial erve nuceus that control the mucles of he upper part of the face receivs corticobulbar ibers frm both crebral crtices. herefore in patents wit an uppe motor nuron leson, only the musces of th lower art of te face wll be paalyzed. However, i patient with a lower moor neuro lesion, all the uscles o the afected sie of the face wil be parlyzed. he lower eyelid wll droop and the angle o the moth will ag. Tear will flw over he lower eyelid, and salia will ribble from the corner of the mout. The atiet will be unabl to clse the ee and canot expse the eeth fuly on th affecte side.

Testing the Interity of the Vestibulcochear Nerve Th vestibuocochlear nerve innervaes the uricle an saccu, which are senitive to static changes i equilibium; the semiciular caals, whih are sesitive to change in dynaic equiibriu; and te coclea, whih is sensitive t sound. Disurbances of vestiular fuction iclude diziness (vertigo) and nystamus. he lattr is an uncotrollable pendlar moveent of te eyes. Disturbnces of cochlear function reveal temselves as deafess and ringing n the ers (tinitus). The ptient's bility to hear a voice o a tunin fork shuld be ested, with ech ear tested separatey.

Testing the Interity of the Glosopharyngal Nerv The glssopharygeal nere supples the sylopharygeus muscle and sends seretomotor fbers to the paroti gland. Sensory fibers nnervate the postrior one third o the tongue. The intgrity of this erve may be evalated by esting the patint's geeral senation and that o taste on th posterir third of the tonge.

Testing the Interity of he Vagus Nerve 1434

snell The vagus erve innrvates mny imporant orgas, but h examintion of his nere depends on tesing the unction of the ranches o the phrynx, sft palate, nd larynx. The pharyngel reflex may be tested b touchig the laeral wal of the pharynx ith a satula. Tis shoud immeditely caue the paient to gag—tht is, te pharygeal muscles wil contrat. The inervatio of the oft palte can e tested by askig the paient to ay “a.― Norally, te soft plate rises and te uvula moves backward i the midine All the musles of te larynx are suplied by he recurent layngeal banch of he vagu, except the cricthyroid muscle, which is supplied by the xternal laryngel branch of the uperior aryngea branch of th vagus. Hoarsenss or abence of he voce may cur. Layngoscopc examintion may reveal aductor paralysi (see page 807).

Testig the Inegrity of the ory Nrve The ccessor nerve spplies te sternoleidomasoid and the trapzius mucles by eans of ts spinl part. he patiet should be aske to rote the had to one sid against resitance, cusing th sterncleidomatoid of the oppoite side to come nto actin. Then he patent shoud be ased to shug the soulders causing he trapzius mucles to come into action.

Testing the Interity of the Hypolossal Nerve The ypoglosal nerve supplies the musles of te tongue. The ptient i asked t put ou the tonue, and f a lesin of th nerve i presen, it wil be noted that th tongue eviates toward he parlyzed sie (Fig 11-78). This can be xplained as follos. One o the genoglossus muscles, which pul the ongue foward, is paralyzed on the affected side. T other, normal enioglosus muscl pulls te unaffeted sid of the tongue orward, leaving the parayzed sid of the ongue stionary The result is the tip of the tongue's deviaion towd the paralyzed ide. In patients with log-standng paralsis, the muscles n the afected sde are asted, ad the tngue is rinkled n that sde. Table 1-7 Sumary of he Branches of te Cervicl Plexu and Ther Distriution Branche

Distribion

Cutaneous

Lesser occipitl

Skin of calp beind ear

Geater auricular

Skin ver parid saliary glan, auricle, and angle of jw

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Transverse cutaneo

kin over side and front of neck

Supraclaviculr

Sin over upper pat of chet and shulder

Muscular

Segmntal

Preertebra muscles levator scapulae

Asa cervcalis (C, 2, 3)

Omohyoid, sternoyoid, strnothyrod

C1 ibers via hypoglssal nere

Phrenc nerve (C3, 4, )

Thyohyoid, eniohyoi

Diaphragm (mst imporant musce of repiration)

Snsory

Phreic nerv (C3, 4, 5)

Pericarium, meiastinal parieta pleura and plera and pritonem coverig centrl diaphagm

Main Nervs of the Neck Cevical Pexus The cerical plexus is frmed by the anteior ram of th first fur cervial nervs. The ami are ed b conneting brnches, hich for loops tat lie n front of the oigins of the leator sulae ad the alenus edius muscles (Fig 11-57). The lexus i covered in fron by the preverteral laye of deep cervica fascia and s relate to the internal jugular ein withn the crotid shath. The cervical plexus supplies he skin nd the mscles o the hea, the nec, and th shouldes.

Brances

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Cutaneous branches Th lsser ocital neve (C), which supplies the back of the salp and he auricl The geater aucular nerve (C and3), hich suplies the skin ove the ange of the mandible The tansverse cervical nerve C2 and 3, which upplies he skin ver the font of te neck The suprclaviculr nerves (C3 and 4). The edal, nd interediate, and latel brances suppl the skin over the shouder regin. These nerves re imporant cliically, because ain may e referrd along hem from the phreic nerve (gallbladder disese).





Muscuar brancs to the neck muscles. Prevertbral muscles, sterocleidomstoid (popriocepive, C2 nd 3), evator scapulae (C and 4) and trazius (prprioceptve, C3 ad 4). A branch fom C1 jons the hpoglossa nerve. Sme of thse C1 fiers latr leave te hypoglssal as he desceding brach, whic unites wth the decending ervical rve C2 and 3), to form the ansa cevicalis (Fig. 11-0). Te first, second, and thir cervical nerve fiers withn the an cerviclis suppy the omhyoid, strnohyoid and stenothyroid muscles. Other C fibers ithin the hypoglosal nerve leave it as the nrve to the thyroyoid an geniohoid. Musculr branch to the diaphragm. Phrnic nerv

Phreni Nerve The phenic nere arises in the nck from the third, fourth, and fift cervica nerves of the crvical pexus. It runs vetically ownward cross th front o the scaenus anterior muse (Fg. 11-57) and enters te thorax by ig in frot of the subclavin artery Its furher course in the thorax i deidoub on page 127. The phrenic erve is he only otor nere supply to t diaphagm. It lso sends sensory branches to the pricardiu the meiastinal parietal pleura, nd the peura and peritonem coveri the upper and ower surfaces of te centra part of the diapragm. Table 11-7 ummarizes the braches of he cervial plexu and ther distribution.

Clinical Notes Phrenic Nerve Inury and aralysis of the Dphragm The phren nerve, hich aries from he anteror rami of the tird, forth, and fifth cevical neves, is f considrable cinical iportance because it is the ole nerv supply o the mucle of he diaphagm. Eac phrenic nerve suplies th correspoding hal of the diaphrag. The prenic nere can be injured y penetrting wouds in te neck. f that ocurs, th paralyzd half o the diahragm rlaxes an is pushed up into the thorx by the positive abdomina pressue. Conseuently, he lower lobe of he lung n that sde may ollapse. Aout one third of persons have an ory prenic nve. he root rom the ifth cerical nere may be incorpored in th nerve o the suclavius ad may jon the man phreni nerve tunk in te thora.

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Brachial Pxus The brachial plexus is forme in the osterior triangle of the eck by te union f the anerior rai of the fifth, sxth, seenth, an eighth crvical ad the fist thoracic spina nerves (Fig. 11-71). This lexus s divide into roots trunks, division, and cods. Th roots o C5 and unite t form th uper trun, the oot of C continues as the midle trun, and he roots of C8 an T1 unit to form the lower tunk. ach trun then diides into aterior and posteror divisions. Te anterir divisios of the upper an middle runks unte to form the laterl cord the antrior divion of te lower runk coninues as the medial ord, ad the poterior dvisions of all thee trunk to form the psterior cord. .772

Fgure 11-1 Brahial plexs and i branches.

he roots of the bchial plxus ente the bas of the eck betwen the salenus anterior ad the sclenus meius muscls (Fig. 11-7). he trunk and divsions crss the psterior riangle of the nek, and the

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snell cords ecome arranged arund the xillary artery i the axilla (see Fig 9-20. Here, he brachal plexus and the axillary artery ad vein ae enclosd in the axllary sheath.

Branhes Th branche of the rachial lexus an their dstributin are suarized i Tble 9-4.

Clinical Notes Injury to the Bachial Pexus The roos and trnks of te brachil plexus occupy te anterinferior angle of the postrior tringle of he neck. Incomplte lesins can rsult from stab or ullet wonds, tration, or pressure injurie. The clnical fidings in the Erb-chenne ad the Klmpke's esions ae fully dscribed n pages 36 and 57.

Brahial Pleus Nerve Block It will be rememered tha the axilary sheth, formd from he prevertebral layer of dep cervial fascia, enclose the brchial plxus and the axillay artery A brachal plexu nerve bock can easily b obtained by closg the distal part of the seath in he axilla with fnger presure, inerting a syringe eedle ino the proximal pat of the sheath, nd then njecting a local esthetic The ansthetic olution s massagd along he sheat, producng a nerv block. The syrige needl may be serted ito the aillary seath in the lower part of he posteior triagle of te neck o in the xilla.

ompressin of the rachial lexus an the Sublavian Atery At he root f the nek, the bachial pexus an the suclavian rtery ener the psterior riangle hrough a narrow uscularâ€bony tringle. Th boundares of the narrow tiangle ae forme in fron by the calenus nterior, behind by the scalnus medus, and elow by he first rib. In te presene of a crvical rb (see pag 50), the firs thoraci nerve ad the sbclavian artery ae raised and anguated as hey over the rib. Patial or omplete cclusion of the atery caues ischeic muscl pain i the arm which is worsened by exercise. Rarely, presre on th first horacic erve caues symptms of ain in te forear and han and wasting of the small muscles o the han. P.773

The Autoomic Nerous System in the Head and Neck Symathetic art ervical Part of th Sympathetic Trunk

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snell The cervical part of the sympathetic trunk extens upwar to the base of the skull and below to the nck of th first rb, wher it becoes continuous with the thorcic part of the smpatheti trunk. It lies irectly ehind th interna and common caroti arterie (i.e., medial t the vagus) and is embedded in deep ascia beween the carotid sheath an the preertebral layer of deep fasia (Fig. 1149). he sympathetic trunk posesses three anglia: he superor, midde, and nferior ervical ganglia.

Superio Cervica Ganglio Th superior cervica ganglio lies imediately below th skull (Fig. 11-60).

Banches 

    

The intrnal cartid nerv, consisting postganlionic fbers, acompanies the intenal caroid artey into te caroti canal i the temoral bone It divies into branches around te artery to form he interal carot plexus. Gray ram communicantes o the uer four anterior ami of te cervicl nerves Artrial braches to the comon and xternal arotid ateries. hese braches for a plexs around the arteies and re distrbuted alng the brnches of the extrnal cartid artey. Cranil nerve ranches, which the 9th, 10t, and 12th cranial nerves Pharyneal branhes, hich unie with te pharyneal branhes of te glossopharyngeal and vags nerves to form the pharyeal plexs Te superior ardiac branch, which descends in the neck and ends in the crdiac plxus in te thorax (see page 16)

Middle Cervical Ganglin Te middle cervical ganglion lies at he level of the cricoid cailage (Fig 11-57.

Braches   

ray rami communicntes to the anerior rai of the fifth an sixth crvical nerves Thyroid branhes, which pas along the infeior thyrid arter to the hyroid gand The midle cardic branch, whic descend in the eck and nds in te cardia plexus n the thrax (see pae 116)

Inerior Cevical Gaglion The inerior cevical gaglion in most peole is fued with he first thoracic ganglion to form he stellate ganglion. It ies in t interval between the tranverse prcess of he sevenh cervial vertebra and te neck o the firt rib, behind the ertebral artery Fi. 11-57).

Braches   

Gray rami communicates t the antrior ram of the eventh ad eighth cervical nerves Arteial branhes t the sublavian ad vertebal arteres he inferior cardiac ranch which dscends t joi the cariac pleus in th thorax see page 116)

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snell The par of the ympathetc trunk connecting the mddle cevical gaglion to the inferior or tellate ganglion is repreented b two or ore nerv bundles. The mot anterir bundle crosses n front of the irst par of the ubclavia artery and then turns upard behind it. his anteior bunde is refrred to s the ansa subclava (Figs. 11-57 and 11-60).

Clinial Notes Sympthectomy for Arteial Insuficienc of the pper Limb The sympthetic inervatio of the pper limb is as fllows: Te preganlionic fbers leae the spnal cord in the scond to the eighh thoraci nerves. On reachng the smpatheti trunk v the white rami, they ascnd withi the truk and ar relayed in the second thoracic, stllate, ad middle cervical ganglia. Postganglonic fiers then the roots of he brachal plexu as gray rami. Smpathectoy of the upper lib is a elativel common rocedure for the treatment of arteal insuficiency. From thi informaion, it is clear that the tellate nd the scond thoacic ganlia shoud be reoved to bock the ympathetc pathwa to the rm compltely. Removal of the stellate nglion lso remoes the sympatheti nerve spply to he head nd neck n that sde. This produce not onl vasodiltation of the ski vessels but also anhidrosis, nasa congeston, and orner's syndrome For thi reason the stelate gangion is uually lef intact n sympathectomies of the pper lim.

Horner's Syndrome Hornr's syndome includes constriction of the pupl, ptoss (droopng of th upper eelid), ad enophtalmos (dpression of the yeball io the obital cavity). It s caused by an inerruptio of the sympatheic nerve supply t the orbt. Pathoogic caues inclu lesion of the rainstem or cervial part f the spnal cord traumatc injur to the ervical art of te sympatetic truk; tracton of th stellate ganglion caused by a cerical rib and invlvement f the gnglion i cancerous growth which ma interrut the peipheral art of the sympatetic patway to te orbit.

Stllate Gaglion Blck A stellate ganglion block is performe by firs palpatng the lrge anteior tubercle (cartid tubercle) of the transerse proess of te sixth ervical ertebra, which lies about a fingerbeadth lteral to the crioid cartiage. The carotid heath an the stnocleidoastoid mscle are pushed lterally and the nedle of he anestetic syrnge is iserted trough the skin over the tubercle. e local nestheti is then injected beneath he prevetebral lyer of eep cervcal fasca. This rocedure effectivly blocks the ganion and its rami communicntes. P.774

Parasympatetic Part

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snell The canial potion of he cranisacral otflow of the parasympathetc part o the autnomic nevous sysem is loated in the nucle of the oclomotor 3rd), facal (7th) glossopharyngeal (9th) and vagus 10th) crnial neres. The parsympatheic nucles of the oculomotr nerve s called the EdingerWestphal nucleus; those of the faial nerv the lacrimtory ad the suerior saivary nulei; tat of th glossoparyngeal erve th iferior slivary nucleus; and that of the vgus nerv the dorsal nucleus o the vags. The axons o these cnnector erve cels are myelinated peganglioic fibes that eerge fro the brai within he cranil nerves These reganglioic fiber synapse in periperal ganlia locted clos to the iscera tey innerate. The ranial arasympahetic gaglia are he ciliary, the ptergopalatie, the sbmandibular, and te tic. n certai location, the gaglion cels are placed in nrve plexses, suc as the cariac plexs, the pumonary pexus, the myenterc plexus (Auerbachs plexus, and the mucosal plexus (eissner's plexus). The ast two lexuses re found in the gstrointestinal trat. The ostganglinic fibes are nomyelinatd, and thy are shrt in legth.

The Digetive Sysem in th Head nd Neck The Moth The Lips The ips are wo flesh folds that surrund the oral oriice (Fig. 11-72. They re coveed on the outside y skin ad are lined on the insie by muous membane. The substanc of the ips is made up b the oricularis oris musle and te muscle that raiate fro the lips into the face (Fi. 11-73). Also ncluded re the lbial blod vessel and neres, connctive tisue, and many sma salivar glands. The philtrum is he shallw verticl groove seen in he midlie on the outer surace of te upper ip. Medin folds f mucous membrane€”the labia frenula—conect the nner surace of te lips t the gums.

The Mouth avity The mouth extens from he lips to the pharynx. Te entrane into he phary, the oroparyngeal isthmus, is fomed on ech side y the paatoglossl fold (Fig 11-72. Te mouth is dividd into the vestible and the mouth cavity proper.

Vestibule Th vestibue lies btween th lips an the cheks extenally an the gums and the teeth inernally. This slilike spae commuicates wth the exterior through the oral fiure between the ips. Whn the jaws are clsed, it communicates with e mouth proper behind the third moar tooth on each ide. The vestibul is limied abov and belw by the reflectin of the mucous mmbrane fom the lips and heeks to the gums.

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snell The laeral wall of the estibule is forme by the cheek, wich is mde up by the buccnator mucle and s lined ith mucus membrane. The tone of th buccinor muscl and tht of the muscles of the lps keeps the wall of the stibule n contac with oe anothe. The duct f the potid salvary glad opens on a small papilla into te vestible opposte the uper secod molar ooth (Fig. 1-72).

Muth Propr The mouth prper has roof and a floor

oof of Muth The roof of the mouh is fored by th hard paate in front and the soft plate behnd (Fig. 1-72).

Floor o Mouth The flor is fored largey by the anterior two thirs of th tongue nd by th reflecton of th mucous mbrane fom the ides of he tongu to the um of th mandibl. A fold of mucou membrae called the frenulu of the ongue connects the undesurface f the tongue in the midline to the foor of te mouth Fi. 11-72). Lateral to the frenulum the mucus membrne forms a fringe fold, te lica fimriata Fi. 11-72). The submandiular duc of the ubmandiblar glan opens nto the loor of he mouth on the smmit of small ppilla on either ide of t frenulum of the tongue (Fig. 11-72. The sulingual land proects up nto the outh, prducing a low fold of mucou membran the subligual fold. Numeous duct of the land ope on the ummit of the fold P.775

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Figure 1172 A. Cavity of the mouth. Cheek on the lft side f the fae has ben cut awy to sho the bucinator muscle and the parod duct. B. Undersrface of the tonge.

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Figure 11-73 Arrangemnt of th facial muscles around the lips; th sensory nerve suply of te lips i shown.

ucous Mebrane of the Mout In the vestbule the mucous membrane i tethere to the buccinator muscle by elastc fibers in the sbmucosa hat prevnt redudant fols of mucos membrae from bing bittn betwee the teeh when he jaws re close. The muous membane of te gingiv or gum, is strongly attahed to te alveolr perioseum.

Sensory nnervatin of the Mouth   

Roof: The geater paatine an nasopaltine neres (Fig. 1174) fm the maxillary dvision of the trieminal nrve Flor: Th lingua nerve (ommon senation), branch f the madibular ivision of the tigeminal nerve. Te taste ibers trvel in t chorda ympani erve, a ranch of the facil nerve. Chee: The buccal erve, a ranch of the mandbular diision of the trigminal nerve (the buccinat muscle is innervted by te buccal branch o the faial nerv)

Clinical Notes Clinical Significance of e Examiation of the Mouth The mouh is one of the iportant reas of he body hat the medical rofessiol is caed on to examine Needless to say, the physcian mus be able to recogize all he strucures visble in te mouth and be fmiliar wth the nrmal varations in the color of the mucous mmbrane cvering

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snell uderlying structurs. The snsory neve suppy and lyph draine of th mouth cavity shoud be knon. The lose reltion of he lingul nerve o the loer third molar toth shoud be remmbered. he close relation of the sbmandibuar duct to the floor of th mouth my enable one to plpate a alculus n cases f perioic swellng of th submandbular salivary gland.

Embryoogic Nots Deelopment of the Muth he cavi of the outh is ormed frm two sorces: a depressin from te exterir, calle the stoodeum, wich is lned with ectoderm, and a part immeately posterior to this, drived frm the halic ed of the foregut and lined with entderm These to parts t first are sepaated by he buccoparyngeal membrane, but this breas down a disappears during the third week o developent (Fig. -75). If this membrane were to persist nto adul life, i would ocupy an imaginar plane etending bliquely rom the egion of the body of the phenoid, through he soft alate, ad down t the inn surface of the andible nferior o the inisor teeh. This eans tha the strctures that are situated in the mouth anterr to thi plane ae derive from etoderm. hus, the epithelim of th hard palate, sides of the mouth, ips, and enamel o the teeh are ecodermal tructurs. The scretory epithelum and clls linig the duts of th parotid salivary gland also are derived from ectode. On th other hand, the epithelium of the ongue, te floor f the moth, the alatoglosal and palatophryngeal olds, an most of the soft palate ae entodemal in rigin. Te secretry and dct epithlia of te sublinual and submandibular salivary glads also re belieed to be of entodrmal orgin. .777

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Fgure 11-4 A. ensory nrve suppy to the mucous mmbrane f the togue. B. ensory nerve suppy to th mucous membrane o the har and sof palate taste fbers run with braches of he maxilary nerv (V2) an te greate petrosa branch of the facal nerve

Figur 11-75 A. Sagital sectin of the embryo sowing th positio of the uccopharngeal mebrane. B. The face of the developing embryo showing t buccophryngeal membrane reaking own.

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he Teeth 1447

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Decidous Teet Ther are 20 eciduous teeth: fur incisrs, two canines, and four molars i each jaw. They begin t erupt aout 6 mnths aftr birth nd have ll eruptd by the end of 2 years. The teeth f the lwer jaw sually apear before those f the uper jaw.

Permannt Teeth There are 32 prmanent eeth: for incisos, two cnines, fur premoars, and six molars in eac jaw (Fig. 1-76). They bein to erpt at 6 ears of ge. The ast toot to erup is the third moar, whic may hapen betwen the ags of 17 nd 30. Te teeth of the lwer jaw ppear before those of the uper jaw.

The Tngue Te tongue is a mas of strited musce covere with muous membane (Fig. 1-77). The musles attah the togue to the styloid process and the sft palae above nd to th mandibl and the hyoid boe below. The tonge is diided int right ad left hlves by median fibous septm.

Mcous Memrane of he Tongu The mucous membrane o the uppr surfac of the tongue cn be divded into anteror and osterior parts by a V-shaed sulcu, the sulcus terminalis (Fig. 11-77. The apex of th sulcus rojects ackward nd is maked by a small pit the foamen cecm. The slcus seres to diide the ongue ino the aerior tw thirds, or oral art, and the postrior thid, or paryngeal part. Th foramen cecum is an embrologic remnant P.79

and marks th site of the uppe end of the thyroglossal dt (see pag 819).

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Figure 1-76 Sgittal sction though the lower ja and gum showing n erupte temporay inciso tooth ad a developing permanent tooth.

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Fgure 11-7 Dorsl surfac of the tongue showing the vallecule, the epiglottis, and he entrace into he pirifrm fossa on each ide (arrow).

Thre types f papille are prsent on the uppe surface of the anterior tw thirds f the togue: the fliform ppillae the fungifrm papilae, ad the vallae papille. The mucous membrane coverng the psterior hird of he tongu is devod of papllae but has an iregular urface (Fig 11-77, caused by the pesence o underlyng lymph nodules, the lingua tonsil. The mucous memrane on he inferior surfce of the tongue is reflected from the tong to the floor of the mout. In the midline anteriorly, the udersurfa of the tongue is connected to the floor of the mouh by a fld of muous membrane, the fenulum of the tonue. n the laeral side of the renulum, the deep lingual ein can e seen hrough te mucous membrane Lateral to the ligual vei, the muous memrane fors a fried fold alled th plica fimriata (Fg. 11-72).

Musles of te Tongue The muscles of the tongue are divided into two types: intnsic and extrinsi.

Intrinsic Mscles 1450

snell These mucles are confined to the tngue and are not attached to bone. They conist of lngitudinl, transerse, an verticl fibers.  

Nerve pply: Hypoglosal nerve ction: Alter te shape f the togue

Extrisic Musces Thse muscls are atached to bones an the sof palate. They ar the genoglossus the hyolossus, he stylolossus, nd the alatoglosus. 

Neve suppl: Hypglossal erve

Th origin, nsertion, nerve spply, and action of the tongue musces are smmarized in Table 118.

Blood Supply The ingual atery, th tonsillar brnch of th facial artery, nd the acending haryngea artery upply th tongue. The veis drain nto the nternal ugular vn.

Lymh Drainae   

Tip Submntal lymh nodes Sids of the anterior two thirs: Sumandibulr and dep cervicl lymph odes Posterior third: Deep ervical ymph nods

Sensory Innervaton  

Aerior to thirds: Lingal nerve branch o mandibuar divison of trgeminal erve (gneral sesation) nd chord tympani branch o the facial nerve (taste) Poserior thrd: Gossopharngeal neve (general sensaion and ste)

ovements of the Tngue     

Protrusin: Th genioglssus musles on bth sides acting together (Fig 11-78 Reraction: Stylogossus an hyoglosus muscls on bot sides ating togther Depressin: Hyoglossus muscles o both sides acting togethe Retration and elevatio of the osterior third: Styloglssus and palatoglossus musces on both sides acting toether Shpe changs: Inrinsic mscles

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Table 11-8 uscles o Tongue

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Muscl

rigin

Insetion

Nerve Supply

Acion

Ininsic Muscles

Mean septm and submucosa

Mucou membran

Hyoglossal nerve

Alters hape of ongue

Geniglossus

Superior genial spine o mandibl

Blends wth other muscles f tongue

Hpoglossa nerve

Protrues apex f tongue through outh

Hoglossus

Body and greaer cornu of hyoid bone

Bleds with ther musles of tngue

Hypoossal nerve

epresses tongue

Stloglossu

Styoid procss of teporal bone

lends wih other uscles o tongue

Hyoglossal nerve

Draws ongue upward and bckward

alatoglosus

alatine poneuross

Sde of tongue

Pharyngeal plexus

Pull roots o tongue pward an backwar, narrows orophargeal

Logitudina

Trasverse Verticl

Extrnsic Musles

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istmus

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gure 1178 Diarammatic represenation of the actin of the right an left geioglossu muscles of the tngue. A. The righ and lef muscles contract equally ogether nd as a result (B the tip of the tngue is rotruded in the midline. C. The rigt hypoglssal nere (which innervats the genioglossu muscle nd the intrinsic ongue mucles on he same ide) is ut and a a resut the riht side of the tongue is atrophied nd wrinked. D. Wen the ptient is asked to protrude the tongue, the t points to the side of the nerve leion. E. he origi and insrtion an directi of pull of the gnioglosss muscle

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Embrologic NOTES evelopmet of the Tongue At abot the forth week a media swellin called he tuberculm impar appear in the ntoderma ventral wall or loor of the pharyx (Fig. 11-79). little ater, anther sweling, caled the latral lingal swelling (drived frm the anerior en of each first phayngeal ach), appars on ech side f the tuerculum mpar. Th lateral ingual sellings ow enlage, grow medially, and fuse with eac other ad the tuerculum impar. Te lingual swelling thus fom the anerior tw thirds the boy of the tongue, nd since hey are erived fom the fist phayngeal aches, the mucous mmbrane o each sie will b innervad by th lingual nerve, a branch o the mandibular diision of the fift crania nerve (ommon senation). he chord tympani rom the eventh ranial nrve (tase) also supplies tis area. Meawhile, a second mdian sweling, caled the copula, ppears i the flor of the pharynx ehind th tuberculum impar. The copla extens forwar on each ide of te tuberclum impa and becmes V saped. At about this time, he anteror ends f the second, thir, and furth phayngeal aches are entering this regin. The aterior nds of te third arch on eah side oergrow te other arches and extend nto the opula, fsing in he midlie. The ula now disappeas. Thus, the mucos membrae of the posterio third of the tongue is fomed from the thir pharyngal arche and is nnervate by the ninth craial nerv (common sensatio and tase). he anteror two tirds of he tonge is seprated frm the poterior tird by a groove, the sulcus terminals, which repesents te intervl betwen the lingual swllings o the frst pharyngeal aches and the antrior ends of the third phryngeal arches. round the edge of he anterior two tirds of he tongu, the etodermal cells proiferate nd grow nferiorl into the underlyig mesenhyme. Laer, thes cells denerate so that his part of the ongue beomes fre. Some o the entdermal clls reman in the midline and help form the frnulum of the tonge. Rememer that he circumvallate paillae are situted on te mucous membrane just antrior to he sulcu terminlis, and that ther taste ds are inervated by the nnth craial nerv. It is resumed hat durig develoment the mucous membrane o the poserior thrd of th tongue ecomes plled anteiorly sightly, o that fbers of the ninth ranial nerve cros the sucus termnalis to supply these taste buds (Fig. 11-79. The muscles of the togue are erived fom the ocipital myotomes which a first ae closely related to the veloping hindbran and laer migrae inferioly and ateriorly around te pharyx and ener the togue. The migratin myotome carry wth them heir innrvation, the 12th cranial nrve, and this expains the long cuving course taken y the 12h crania nerve a it downwar and foward in he caroti triangle of the eck (see pe 769.

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linical otes Laceratin of the Tongue A woun of the ongue is often cased by te patien's teet followig a blow on the cin when he tongu is party protruded from the mouth. It can also occu when a atient acidentaly bites he tonge while ating, uring reovery fr an aneshetic, or during n epiletic attak. Bleedng is hated by gasping te tongue between he fingr and thmb posterior to the laceraon, thus occluding the branches of the lingual artey.

The Palate The palate foms the rof of te mouth and the loor of he nasal cavity. t is divded int two par: the hard palate in fron and the soft palte behind.

Hard Plate e hard late is formed by the paltine proesses of the maxillae and e horizontal plaes of th palatine bones (Fig 11-80). It is continuos behind with the soft palate.

Soft Palate The sof palate s a mobie fold atached t the poserior boder of te hard plate (Fig. 1-81). Its free posterio border resents in the miline a cnical prjection alled th uula. he soft alate is continuos at the sides wth the lateral wal of the pharynx. The sof palate i compose of mucos membrae, palatne aponerosis, ad muscle.

Muous Membane Te mucous membrane covers te upper nd lower surfaces of the sft palat.

Palatine Aponeurois he palatne aponerosis is a fibrous sheet attached t the poterior border of the hard alate. It is the expanded ndon of the tenor veli palatini muscle.

Muscles o the Sof Palate The uscles o the sof palate re the tnsor vel palatii, the leator vel palatin, the paatoglosss, the alatopharngeus, ad the muculus uvae (Fig. 1-81). The scle fibrs of the tensor veli palatini convrge as hey descnd from heir oriin to fom a narrw tendon which turns medilly aroud the ptrygoid hmulus. Te tendon togethe with th tendon of the oposite sde, expads to fom the palatine apoeurosis. When th muscles of the to sides

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snell cntract, he soft alate is tightend so tha the sof palate may be moved upward or downwrd as a tense shet. The muscles f the soft palate, their oigins, insertions, nerve suply, and actions re summaized in Tabe 11-9. P.782

Fgure 11-9 The loor of the pharynx showin the staes in th developmnt of th tongue

Nerve upply of the Palate 1457

snell Te greate and leser palatne nerve from th maxillry divison of the trigeminal nerve enter th palate hrough the greate and leser palatne foramna (Fig. 1174). he nasoplatine nrve, als a branc of the axillary nerve, eters th front o the har palate through the incisi foramen. The glossopharyngeal nerve also supplies te soft plate.

Blod Supply of the Plate The greaer palatne branc of the axillary artery, he asceding paltine brach of th facial rtery, ad the asending haryngeal artery

Lymh Drainae of the Palate Deep ervical ymph Nods Paatoglosl Arch The paatoglossl arch i a fold f mucous membrane containig the palatglossus uscle, which exends fro the sof palate o the sie of the tongue (Fig. 11-72 and 11-81). The paltoglossa arch maks where the mout becomes the pharnx.

Palatopharyngeal rch The alatophayngeal ach is a old of mcous memrane behnd the platoglosal arch Fis. 11-72 and 11-8) that runs dowward and aterally to he pharygeal wal. The mucle contined withn the fld is th platopharngeus mucle. Te alatine onsils, which re masse of lymphoid tissue, are located between the alatoglssal and alatophayngeal aches (Fig. 1-81) P.783

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Figure 1-80 A Three cnstricto muscles of the parynx. Te superior and recrrent layngeal nrves are also shon. B. Had palate.

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Figur 11-81 A. Juncion of th nose with the naal part f the phrynx and the mout with te oral prt of the pharynx Note the position of the tnsil and the opeing of te auditor tube. B Muscles of the soft palae and th upper prt of th pharynx C. Musces of the soft palte seen rom behid. D. Horzontal sction though the mouth an the oral part of he pharyx showin the reltions of the tonsl.

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Tble 11-9 Muscls of the Soft Palte Mscle

Origi

nsertion

erve Suply

Action

Tensor veli paltini

Spine f sphenod, auditry tube

Wih muscle of other side, forms palatine aponeurosi s

Nrve to mdial ptergoid fro mandibua r nerve

enses sot palate

Levator eli palaini

Petrous art of tmporal bne, audiory tube

alatine poneuross

Paryngeal plexus

Raises soft palte

Palatlossus

Palatne aponerosi s

Side f tongu

Pharyngea l lexus

Pulls root of ongue uward and backwar, narrow oropharngeal ithmus

Paltopharyneu

Palatine aponeuroi

osterior border o

Pharyngel

Elevtes wall of pharyx, pulls

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s

s

thyroid cartilag

plexus

palatophrynge al olds medally

Musculu uvulae

Postrior borer of had palate

Muous membane of uula

Pharyngel plexus

Elevates vula

Movemens of the Soft Palte he pharygeal istmus (the communicting chanel beteen the asal and oral parts of the pharynx) is close by raisng the oft palate. Closur occurs uring th producton of exosive cnsonants in speech. The oft palae is raied by th contracion of the levato veli paatini on each sid. At the same tim, the uper fiber of the superior constricor muscl contrac and pull the poserior paryngeal wall forward. The palatophayngeus mscles on oth side also cntract s that the palatophryngeal rches ar pulled mdially, like sid curtain. By thi means te nasal prt of the pharynx is closd off frm the orl part.

Cinical Ntes ngioedem of the vula (Quincke's Uula) The uvula has a core of oluntary muscle, he muscuus uvule, that s attachd to the posterio border of the har palate. Surrouning the muscle i the loose connectve tissu of the ubmucosa that is responsile for te great welling of this stucture scondary to angiodema.

Embryolgic Note Devlopment f the Paate n early etal lif, the naal and muth caviies are n communication, but later they beome sepaated by the develoment of the palae (Fig. 11-2). Te rimary plate, which caries the four incsor teet, is fored by the medial nsal proess. Poserior to the primy palate, the maxllary prcess on ach side sends meially a orizonta plate clled the paatal process; tese plats fuse t form th scondary alate and als unite wih the prmary palte and te developing nasal septum. The fusin takes place from the anteior to te posteror region. The primary and secondar palates later wil form the

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snell ard palae. Two folds grw posterorly fro the posterior edg of the alatal pocesses o create the soft paate, s that th uvula i the las structue to be ormed (Fig 11-82. The uion of te two fods of th soft paate occus during the eighth week. The two arts of he uvula fuse in he midlie during the 11th week. Te intervl betwee the priary palae and seondary plate is represened in th midline by the inciive foraen.

Ceft Palae Clet palate is commoly assocated wit cleft uper lip All degees of ceft palae occur nd are cused by ailure o the paatal proesses of the maxila to fus with eah other n the mline; i severe cases, these processes also ail to fse with he primry palate (premaxila) (Figs. 1-83 nd 11-84) The fist degre of seveity is cleft uvula and the second dgree is ununited palatal pocesses. The thir degree s ununitd palata proceses and a cleft on one side of the primary palte. This type is usually ssociate with unilateral ceft lip. The fourh degree of seveity, which is rare consist of ununted palatl proceses and a cleft o both ides of the primar palate. This typ is usualy assoiated wih bilateal cleft lip. A rre form y occur in which a bilateal cleft lip and ailure o the priary palae to fus with th palatal processes of the maxilla n each sde are pesent. A baby brn with severe left palte presets a dificult feding prblem, sice he or she is uable to suck effiently. uch a bay often eceives n the mouth some mlk, whih then s regurgtated though the nose or spirated into the lungs, eading to respiratry infecion. For this reaon, carefl artifiial feeing is rquired util the bby is stong enouh to undrgo surgery. Plaic surgey is recmmended sually btween 1 nd 2 yeas of age before mproper speech hbits have been acquired. P.78

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Figure 11-82 A. The formaton of he palate and te nasal eptum (cronal setion). B The different sges in te formaton of th palate.

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Figue 11-83 Differnt forms of cleft palate: left uvua (A), ceft soft and hard palate (B), total unilateral cleft palate an cleft l (C), toal bilatral cleft palate ad cleft ip (D), nd bilatral clef lip and jaw (E).

he Salivary Gland

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Paotid Glad The parotid land is the larget salivay gland nd is compoed mostly of serou acini. It lies n a deep hollow below the xternal uditory eatus, behind the amus of he mandile (Fig. 1185), and in frnt of the sternoclidomastod muscle The facial nerve divides te gland nto superfiial ad eep lobe. The parotid uct emeres from he anteror border of the gand and es frward ovr the laeral surace of te masseter. It enters the vestibul of the outh upo a small papilla pposite the upper econd mlar toot (ig. 11-7).

Figure 11-84 Cleft hard and soft palte. (Courtesy of . Chase.

Nerve Spply arasympahetic seretomotor supply rises frm the gossopharyngeal nerve. The nerves rech the gand via e tympanic branc, the leser petrsal nerv, the otic gangli, and th auricuotempora nerve.

Clinical Notes Parotid Duct Injry Te parotid duct, which is a comparatvely suprficial structure on the fce, may e damage in injuies to te face o may be inadvertntly cut uring sugical oprations on the fac. The dut is abut 2 in. (5 cm) lng and psses forrd acros the maseter abot a finerbreadth below th zygomatc arch. t then perces th buccinaor musce to entr the moth oppose the uper secon molar toth.

Cliical Nots Partid Saliary Glan and Lesons of the Facial Nerve

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snell Th parotid salivary gland cosists esentially of supeficial ad deep prts, and the impotant facal nerve lies in the interal betwen these arts. A enign paotid neopasm rarey, if eer, causs facial palsy. A malignan tumor of the paroid is usally highly invasve and qickly inolves th facial erve, casing unilateral fcial parlysis.

Partid Glan Infectins Te parotid gland may become cutely flamed a a resut of retograde bcterial nfection from the mouth vi the partid duc. The glad may alo become infected via the oodstrem, as in mumps. In both caes the gand is sollen; i is painul because the fascial capule deried from he investing laye of deep ervical fascia i strong nd limit the sweling of te gland. The swolen glenid proces, which extends edially ehind th temporoandibula t, is resposible for the pain experiened in acte parottis when eating.

Freys Syndroe Fre's syndrme is an interestng complcation tat someimes devlops after penetrating wouds of the parotid gland. Wn the patient eats, beads of perspration apear on he skin overing he paroid. This conditio is caused by damae to the auriculoemporal nd grea auriculr nerves. During te proces of healng, the parasymathetic ecretomtor fibers in th auriculotempora nerve row out and the distl end o the gret auricuar nerve Eventualy, thee fibers reach the sweat glnds in te facial skin. By this meas, a stmulus inended fo saliva roductio produce sweat scretion instead. P.788

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Figure 11-85 Parotd gland nd its rlations. A. Lateral surface of the gland and the couse of the parotid duct. B. orizonta section f the parotid glad.

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Subandibula Gland The sumandibular gland consists f a mixtre of seous and mucous acini. It lies beneth the lwer bordr of the body of te mandile (Fig. 1186) an is divied into superfical and deep parts by the mlohyoid uscle. Te deep prt of the gland lies beneah the muous membane of te mouth n the sie of th tongue. The submndibular duct emeges from the anteror end of the dep part o the glad and rus forward beneath the mucos membrae of th mouth. t opens nto the outh on a small ppilla, wich is situated at the sid of the renulum f the togue (Fig. 1-72).

Nerve Supply Parasympthetic scretomotr supply is from he facia nerve ia the corda tymani, and the submndibular ganglion The postganglioc fibers directly to the gland

Clinical Notes Submandiular Salvary Glad: Calculus Formation The sbmandibuar salivry gland is a comon site f calcuus formation. This condition is rar in the ther saliary glads. The resence f a tens swellin below te body o the mandible, whch is gratest beore or dring a mal and i reduced in size or absen between meals, is diagnostc of the conditio. Examiation of the floor of the muth will reveal asence f ejecton of sliva fro the oriice of the duct o the affcted glad. Frequently, th stone cn be palated in he duct, which lis below he mucous membran of the loor of he mouth

Elargemen of the ubmandibular Lymp Nodes an Swellin of the ubmandiblar Saliary Glan The submandibular lymph nodes re commoly enlared as a result o a pathoogic conition of the scal, face, axillary sinus, r mouth cvity. On of the ost commn causes of painfl enlargment of these noes is acte infection of th teeth. nlargemet of thee nodes should nt be confuse with pahologic welling f the sbmandibuar salivry gland

Subingual and The sublingual gland lies beneath th mucous embrane sublingul fold) f the flor of th mouth, lose to he frenuum of te tongue (Fg. 11-86). It hs both srous and mucous aini, wit the later predoinating. he sublingual ducts (8 to 0 in nuber) open into the mouth on the summt of the sublingua fold (Fig. 11-72.

Nerve Suply Parasympathetic secetomotor supply i from th facial nerve vi the chorda tympa, and t submandibular gaglion. ostganglonic fibrs directly o the gland.

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Cliical Nots Subingual Slivary Gand and yst Formtion The sblingual salivary gland, wich lies beneath he sublngual fod of the floor of the mout, opens nto the outh by numerous small duts. Blocage of oe of the ducts s believed to be he cause of cysts under th tongue.

The harynx The pharnx is siuated beind the asal cavties, the mouth, and the rynx (Fig. 11-87 and may be dividd into nasa, oral and laryneal part. The pharynx s funnel shaped, s upper wider end lying under the skull an its lowr, narro end becing contnous with the esopagus oposite th sixth crvical vrtebra. he pharynx has a musculomembranous all, whih is defcient anteriorly. Here, it is rplaced b the poterior oenings ito the nse (choaae), the opening into the mouth, ad the inet of th larynx. By means of the aditory tube, the mucous mmbrane i also continuous with that of the tympanic cavity.

Muscls of the Pharynx The mscles in the wall of the parynx consist o the superor, midde, and inerior costrictor muscles (Fig. 11-0A), whose fibes run in a somewht circulr directon, and he stylophayngeus and salpinopharyngus muscles, whoe fibers run in a somewhat longitudnal direcion. The three constrictr muscle extend round th pharyneal wall to be inserted int a fibros band o raphe tat extends from the pharygeal tubrcle on he basilr part o the ocipital bne of th skull dwn to th esophags. The three conrictor muscles oerlap each other s that th middle onstrict lies o the outide of te lower art of the superio constritor and the infeior consrictor lies outsid the lowr part o the midle consrictor (Fig 11-88). The lowr part o the infrior contrictor, which arses from the cricid cartilage, is clled th cicopharygeus musle (Fig. 1-88) The fiers of t cricophryngeus ass horiontally round th lowest and narrwest par of the harynx ad act as a sphincer. Kilian's dehiscence is te area o the poserior phayngeal wll betwen the uper proplsive part of the nferior onstrictr and th lower shincteri part, he cricoharyngeu. Te details of the origins, insertios, nerve supply, and actions of the haryngea muscles are sumarized in Table 11-10.

Interio of the harynx The phrynx is ivided ito three parts: te nasal parynx, te oral parynx, ad the layngeal parynx. P.79

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Figue 11-86 . Submndibular and sublingual salivary glands (lateral view. B. Cornal secton throuh the suerficial nd deep arts of he submadibular livary lands. C. Coronal ection (nterior o B) thrugh the ublingua salivar glands ad the duts of th submandbular savary glands.

Nasal Pharnx Ths lies abe the soft palate and behnd the naal cavites (Fig. 11-87. In the submucos of the oof is a collectin of lympoid tisse called the pharyngal tonsi (Fig. 1-89). The pharngeal ishmus is he openig in the floor between the oft palte and te posteror pharygeal wal. On the ateral wll is th 1471

snell openin of the audtory tub, the elevated ridge of which is called te ubal eleation (Fi. 11-89). The phayngeal rcess s a deprssion in the pharygeal wal behind he tubal elevation. The salpingoharyngea fold s a vertcal fold of mucous membrane covering the salpngopharyneus musce.

Oral Phaynx Tis lies ehind th oral caity (Fig. 1-87). The floo is formd by the posterio one thid of the tongue ad the iterval btween th tongue nd epiglttis. In the midline is the median glosoepiglotic fold (Fig. 11-7), an on each side the leral glosoepiglotic fold. The epression on each ide o the medan glossepiglotti fold is called te allecula (Fig. 1177). On the lateral all on ech side re the platoglosal and he palatpharyngel arches or folds and the alatine onsils etween tm (Fig. 11-9). Te palatoglossal arh is a fld of muous membrane covring the alatoglosus musce. The P.71

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inrval beteen the wo palatglossal rches is calld the oroaryngeal isthmu and marks the bounday betwee the mouth and parynx. Te palatpharyngal arch s a fold of mucou membran coverin the paatopharygeus musle. The ecess between the palatoglsal and palatophryngeal rches is occupied by the paline tonsl.

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Fgure 11-7 Sagttal secion throgh the nse, mout pharynx, and larnx to shw the subdivisions of the pharynx.

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Figur 11-88 The phaynx seen from behnd. A. Noe the thee constictor mucles and the posiion of te styloparyngeus muscles. B. The geater pat of the posterio wall of the pharnx has ben removd to diplay the nasal, orl, and lryngeal arts of he pharynx.

Table 11-10 Muscles of the Parynx

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Musce

Origin

Isertion

Neve Suppl

Action

Supeior consrictor

Medil pterygoid plate, pterygoid hamulu, pterygmand ibulr ligamet, mylohoid line of mandile

Pharyngel tuberce of ocital boe, raphe in midlie posteriorly

Paryngeal plexus

Aids oft palate in clong off nsal pharnx, propls bolus downward

Mddle contrictor

Lower part of tylohyoi ligamen, lesser and greaer cornu of hyoid bone

haryngea raphe

Pharyngeal plexs

Popels bous downwrd

Inferor constictor

Lamina of thyrod cartilge, cricid cartiage

Pharygeal rape

Pharyneal plexs

Proels bolu downwar

Cricophrynge us

Lowst fiber of infeior consrictor muscle

Stylophrynge us

Stylid proces of temporal bone

Sphinctr at lower end of harynx

Psterior order of thyroid

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Gossopharn geal neve

levates larynx duing swalowing

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cartilage

alpingoharyn geus

Audtory tub

Blds with alatopharyn geus

Pharngeal plxus

Elevates pharynx

Paatopharyg eus

Palatin aponeurosis

osterior border o thyroid cartilag

haryngea plexus

Elevtes wall of pharyx, pulls palatophryn geal rch medialy

Figure 11-8 Sagital secton of th head an neck, sowing th relations of the nasal caity, mouh, pharyx, and lrynx.

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Cinical Ntes he Lymphid Tissu of the harynx At te junctin of the mouth wih the orl part of the pharynx, an the nose with the nasal part of the pharynx, are colections f lymphod tissue of consierable cinical iportance The paatine tosils and the nasoharyngel tonsil are the ost impotant.

Tonsil and Toillitis The palatine tonsils reach thei maximum normal ze in arly childhood. After puberty, togeher with other lyhoid tisues in he body, they graually atrophy. The palatine tonsils re a comon site of infecion, proucing th charactristic se throat and pyrxia. The deep cerical lymh node situated beow and bhind the angle o the manible, whch drains lymph frm this ogan, is sually nlarged nd tende. Recurrnt attacs of tonillitis re best reated y tonsilectomy. fter tonsllectomy the extrnal paltine vei, which lis latera to the onsil, my be the source o troubleome posoperativ bleeding.

Quisy A peritonsillar abscess (quiny) is caused by spead of ifection rom the alatine nsil to the loose connective tissue outside he capsue (Fig. 11-0). The nasoharyngea tonsil r pharyneal tonsl consists of a collection of lymphid tissu beneath the epitelium of the roof of the nsal part of the pharynx. Like the alatine tonsil, i is larest in erly chilhood and starts t atrophy after pubrty.

Adenoid Excesive hypetrophy o the lymhoid tisue, usualy assocated wit infectin, cause the phayngeal tsils to become elarged; hey are hen commnly refered to as adenoids Marked hypertrophy blocks the postrior nasl openins and cases the patient to snore ludly at ight and to breate through the open mouth. Te close relationhip of th infecte lymphoi tissue o the auitory tue may be the caus of deafess and ecurrent otitis mdia. Adeoidectomy is the treatment of choice for hypertrophed adenods with nfection Te nasal art of the pharynx may be viewed cliically b a mirro ed through th mouth (Fig 1191).

Layngeal Parynx This lie behind he openig into te larynx (Fg. 11-87). The ateral wll is fomed by te thyroi cartilae and the thyrohyod membrane. The piiform fosa is depresson in th mucous embrane on each se of the laryngea inlet (Fig 11-88.

ensory Nrve Suppy of the Pharyngel Mucous Membrane 1477

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asal phrynx: he maxilary nerv (V2) Orl pharyn: The lossophayngeal nrve Laryeal pharnx (aound the entrance into the larynx): The intenal larygeal brach of the vagus nrve

Bloo Supply of the Phaynx Ascendin pharyngeal, tonsilar branches of fcial artries, an branches of maxilary and ingual ateries

Lymh Drainage of the harynx Direcly into he deep ervical ymph nod or indirecly via te retrophryngeal r paratrcheal noes into he deep cervical odes

Clinicl Notes Pirifrm Fossa and Foregn Bodie Te pirifom fossa is a recess of mucus membrane situaed on eiher side of the etrance o the larnx. It i bounded medially by the ayepiglottic folds nd laterlly by te thyroi cartilae. Clinically, it is imporant becase it is a common ite for the lodgng of shrp ingested bodies such as ish bone. The prsence of such a freign boy immeditely causs the paient to ag violetly. One the obect has become jamed, it s difficlt for the patient to remoe it witout a phsician's assistan.

Pharyneal Pouh Exmination of the ower par of the posterior urface f the inerior costritor muscle reveals a potntial gap betwee the upper obliue and te lower horizontl fibers (cricoharyngeu). his area is markd by a dmple in the linig mucou membran. It is believe that the functin of te cricoaryngeus is to pevent th entry f air ino the esphagus. Should te cricoparyngeus fail to relax duing swalowing, te interal pharngeal prssure may rise an force the mucosa and subucosa of the dimpe posterorly, to produce divertculum. Oce the dverticulm has ben formed it may radually enlarge and fill with foo with eah meal. Unable to expand posteriorly because of the rtebral column, i turns dwnward, sually o the lef side. he presnce of te pouch illed wih food cuses dificulty i swalling (dyspagia).

Cevical Tuberculous Osteomyeitis an the Phaynx Pus arisng from uberculois of th upper rvical vertebre is limted in font by the prevetebral ayer of eep fascia. A mdline swlling is formed ad bulges forward n the poterior wall of the pharnx. The us then racks lateraly and donward behind the carotid sheath to reach he posteior triagle. Here, the fascia, whch form a coverng to th muscul floor f the trangle, i weaker, and th abscess points ehind th sternoleidomasoid. Rarly, the bscess ay track downwar behind he prevetebral fscia to reach th superio and poterior mdiastin in the horax.

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snell It is imortant t distingish thi conditin from a abscess involvin the retopharyngal lymph nodes. Thes nodes lie in front of th prevertbral layr of fasia but ehind te fascia, which coers the oer surfae of the constritor muscles. Suh an absess usuly points on the posterio pharyngeal wall and, if untreate, rupturs into the pharygeal cavty. P.794

igure 1-90 Hrizontal section through the mout and the oral pharynx. Left, the ormal platine tnsil and its relaionships ight, the postion of peritosillar ascess. Nte the rlationshp of the abscess to the uperior constricor muscl and the caotid sheath. The openin into th larynx can also be seen elow an behind he tonge.

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Figure 11-91 A. Sagital secton throgh the nse, mouh, laryn, and parynx shwing th positio of the irror in posterior rhinoscopy. B. tructure seen in posterir rhinosopy.

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The Prcess of wallowing (Deglutition) Masticated food is ormed into a all or blus on te dorsm of the tongue nd volunarily puhed upward and bakward against te undrsurface of the ard palae. This is brougt about by the cotractio of the styloglosus musces on boh sides, which pll the oot of te tongue upward nd backwrd. The alatoglosus musles then squeez the bols backwrd into he pharyx. From this point onward the rocess o swalloing beomes a involunary act The nasl part o the phaynx is ow shut off fro the orl part o the phaynx by the elevaion of he sof palate, the puling forwrd of the posterio wall of the pharnx by th upper ibers of the supeior consrictor mscle, a the cotraction of the alatophayngeus mscles. Tis prevets the age of food and rink ino the naal cavites. The larnx and te laryngal part f the phrynx are pulled pward by the contrction o the styopharyngeus, salpngopharygeus, throhyoid, and palaopharyngs muscle. The man part f the laynx is tus elevated to th posterir surfac of the epiglottis, and th entranc into th larynx s closed The larngeal etrance is made smaller by the aproximation of the aryepilottic olds, an the aryenoid catilages are puled forwad by th contration of he aryeiglottic oblique arytenoi, and throaryteoid muscles.

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snell The blus moves downwa over te epiglotis, the closed ntrance nto the larynx, ad reache the lowr part o the pharnx as te result of the sccessive contracton of th superior, middle, and inerior costrictor muscles. Some of he food slides down the grove on ether sid of the ntrance nto the arynx, tat is, down throug the pirform fosae. Fnally, te lower art of the pharyngal wall the criharyneus muscle) relxes and the bolus enters te esophaus.

Paltine Tonils The palaine tonsls are to masses of lymphid tissu, each ocated i the depession o the latral wall of the oal part of the pharynx between the alatoglosal and alatophayngeal aches (Fig. 1-90) Each tsil is overed by mucous mmbrane, nd its fee media surface project into th pharynx The surfce is pited by nmerous sall opengs that lead int the tonsillar cryps. The onsil is covered n its laeral surace by a firous capule (Fig 11-90. The casule is eparated from the superior constricor muscl by loose areolar issue (Fig. 11-90 and the external palatin vein desends fro the sof palate n this issue to oin the haryngea venous lexus. Lteral to the supeior constrictor scle lie the stylglossus uscle, the loop of the facil arter, and th interna carotid artery. The tosil reaches its maximum size during arly childhood, but after uberty i diminises consierably i size.

Bood Suppy The tonsilla branch f the faial artey. The vins pierce the serior costrictor muscle ad te externl palatie, the pharyngea, or the facial veins.

Lymh Drainae of the Tonsil The uper deep cervical lymph noes, just below an behind he angle of the mandible

Wadeyer's ing of ymphoid Tssue The lymphoid tissue that surrounds the opening into the reiratory nd digesive systms forms a ring. he laterl part o the rig is fored by the palatine tonsils nd tubal tonsils lymphoid tissue round th opening of the aditory tbe in th lateral wall of the nasoharynx). The pharyngeal tonil in th roof of the nasoharynx orms the upper pat, and te lingua tonsil on the poterior trd of the tongue forms te lower art.

The Esophagu The sophagus is a musclar tube about 10 in. (25 cm) long extending from th pharynx to the tomach (Fi. 11-13 and 11-88). It begins at the leve of the ricoid crtilage, opposite the body of the ixth cerical verebra. It commence in the idline, ut as it descend through the neck it inclnes to te left side. Its further curse in he thora is descibed on age 128.

Reations i the Neck 1481

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Antriorly: The rachea; the recurent layngeal nrves asend one n each ide, in the grooe betwen the tchea an the esohagus (Fig 11-49). Posterioly: Th prevertbral layr of dee cervica fascia, the longs colli, and the ertebral column (Fig 11-49) Lateraly: O each sie lie th lobe of the thyrid gland and the arotid sheath (Fig. 1-49)

Bood Suppy in the Neck Th rteries of th esophags in the neck are derived rom the nferior hyroid arteries. he veins drain ino the inerior throid vein.

Lymph Drainage i the Nec The lymph vsels dran into te deep crvical lmph node.

erve Suply in th Neck The neres are drived frm the reurrent lryngeal nerves and from the sympatheic trun.

The Respiraory Systm in the Head and Neck The Nose Th nose cosists of the extenal nose and the asal cavty, both of which are divied by a eptum ino right nd left alves.

Eternal Nse The externa nose ha two ellptical oifices clled the notrils which a separated from ach other by the nasl septum (Fig. 11-2). Te latera margin, the ala nas, is runded an mobile. he framework of e external nose s made up above b the naal bones, the fronal procsses of he maxilae, and the nasal part of he frontl bone. elow, th framewok is fored of pltes of yaline crtilage Fi. 11-92). P.796

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Figue 11-92 Externl nose ad nasal septum. A. Latera view of bony and cartilagnous skeeton of xternal ose. B. Aterior vew of boy and catilaginos skeleton of external nos. C. Bon and carilaginou skeleton of nasal septum.

Blod Supply of the Eternal Nse The skin of the eternal nse is suplied by branches of the ohthalmic and the axillary arteries (see page 70). T skin of the ala nd the lwer part of the sptum are supplied by brances from he facia artery.

erve Suply of th External Nose The inratrochlar and eternal nsal branhes of te ophthlmic nere (CN V) and the nfraorbial branc of the maxillary nerve (CN V) (se ages 760 and 761.

Nasal Caity

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snell Te nasal avity exends fro the nosrils in ront to he posterio nasal aertures or choana behid, where the nose opens into the napharynx. The nasal estibule is the area of he nasal cavity ling just inside te nostri (ig. 11-9). The nasal caity is dvided ino rght and eft halvs by the naal septu (Fig. 11-92). he septu is made up of th sptal catilage the vertical plate of the ethmoid, and the vomer.

Wals of the Nasal Caity ach half of the nasal cavity has a floor, a roof, a lateral wl, and medial o septal all.

Floor The palaine procss of the maxilla and the orizontal plate o the paltine bone (ig. 11-9)

Roo The rof is narow and s formed anteriory beneat the brdge of te nose by the naal and frontal bnes, in he middle by the cribrifom plate f the etmoid, loated benath the nterior ranial ossa, an posterirly by te downwa sloping body of the sphenid (Fig. 1193).

Lateral Wall The lteral wll has three proectins of boe called the superir, middl, and inerior naal conche (Fig. -93). The spac below ech conch is calld a meatus. P.79

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Figure 11-93 A. Latera wall of the righ nasal cvity. B. Lateral wall of he right nasal caity; the superior middle, and infrior conhae have been parially reoved to how openngs of te paransal sinues and te nasolarimal du into the meati.

Shenoethmidal Recss Te sphenothmoidal recess i a small area aboe the suerior cocha. It eceives he openig of the phenoid ir sinus (Fig. 1193).

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Supeior Meats The superior meatus les below the supeior conca (Fig. 11-93). I receive the opeings of he posterio ethmoid sinuses.

Mddle Meaus Th middle eatus lis below he middl concha. It has a rounded welling alled th blla ethmidalis that is formed b the middle ethmoida air sinses, hich ope on its pper borer. A cuved openng, the hiaus semilnaris, lies jut below he bulla (Fg. 11-93). The nterior nd of th hiatus eads int a funne-shaped hannel called the inundibulu, which is continuous wth the frontal sinu. The maillary snus opns into the middle meatus hrough te hiatus smilunari.

Inferio Meatus The iferior matus lies below te inferior concha and recees the opening of the lower end of the nasolacimal duc, whi is guarded by a fold of mucous mebrane (Fig. 11-93.

Media Wall The medial wall is formed b the nasl septum The uppr part i formed y the vetical plte of th ethmoid and the omer (Fig. 1-92). The antrior par is formd by the septal crtilage. The septum rarely lies in the midlne, thus increasig the sie of one half of he nasal cavity nd decresing the size of he other

Mucou Membran of the asal Cavty he vestbule is ined wit modifie skin an has coase hair. The ara above he superor conch is line with olactory mucous mebrane an contains nerve endings sensitive to the recetion of smell. he lower part of he nasal cavity is lined wih respirtory muous membane. A lrge plexs of veis in the submucous connective tisse is preent in te respiratory regin. P.79

Function of Warm lood and Mucus of Mucous Mmbrane Th presenc of warm blood in the venus plexses servs to het up the inspired air as i enters he respiatory sytem. The presenc of mucu on the surfaces of the conchae trap foreig particls and organisms n the inspired air which ae then sallowed and destoyed by astric aid.

Nerv Supply f the Naal Cavit.

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snell Te olfactory nerves from th olfactory mucou membrane ascend through the cribriform plae of the ethmoid one to te olfacory bulbs (ig. 11-9). The nerves o ordinay sensaton are ranches f the opthalmic ivision V1) and he maxilary divsion (V2 of the rigemina nerve (Fig 11-94.

Blood upply to the Nasa Cavity The rterial upply to the nasa cavity is from branches of the maxillary atery, on of the terminal ranches of the external carotid arery. The most imprtant brnch is te sphenoalatine rtery (Fig. 11-95). The senopalatne arter anastomses with the septl branch of the uperior abial brnch of the facial artery in the region of the estibule The subucous veous plexus is drained by veins that accompan the arteries.

Lmph Drainage of te Nasal avity The lmph vessls drainng the vstibule nd in th submanibular ndes. The remainde of the asal cavty is drined by vessels at to the upper deep cervical odes.

Cinical Ntes xaminatin of the Nasal Caity Examinaton of th nasal cavity may be crried ou by inerting a speculum through the extrnal naes or by means of a mirror in the harynx. n the later case the choanae and the posteror border of the septum an be viualized (Fig. 11-91). It sould be remmbered tat the nsal septm is rarly situted in te midlin. A seveely deviated septum may inrfere wth drainage of th nose an the parnasal siuses.

Trauma t the Noe Frctures ivolving he nasal bones ar common. Blows diected frm the frnt may cuse one r both nsal bones to be dsplaced ownward nd inwar. Lateral fracture also ocur in whch one asal bon is drivn inward and the ther outard; the asal sepum is uually inolved.

Infection of the Nasal Cavity Infecion of e nasal avity ca spread n a varity of drections. The parnasal sinses are especially prone to infectin. Orgaisms may spread va the nasal part of the pharnx and the auditory tube to the mddle ear It is pssible for organiss to ascnd to th menings of the anterior cranial ossa, alng the seaths of the olfctory neves throgh the cribriform plate, an produce meningits.

Foreign Bodies in the Nose Foeign bodes in th nose ar common n childrn. The resence o the nasl septum and the xistence of the flded, shlflike onchae mke impacion and tention f balloos, peas, and smal toys rlatively easy.

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Nose Bleeding Epistaxs, or bleeding from th nose, i a frequnt condiion. The most comon cause is nose picking. The bleeing may e arteril or vens, and most episodes occur on the nteroinfrior porion of e septum and invlve the septal branches of the spheopalatin and facal vesses.

Embryologic Ntes eveopment of the Nose Th roof of the nose is formd from te latera nasal rocesse from wich the ateral wlls also are formd, with he assitance of the maxilary procsses (Fig. 1-43) The anerior opnings of the nose begin as olfactor pits in the frotonasal rocess. ach olfatory pit is boundd medially by the medial nsal procss, lateally by he laterl nasal rocess, nd infeiorly by the maxilary pross. As these processes fue, the lfactory pits become deepe and for well-defined blind sacs, the openig into ech of wich is te nostri. The flor of th nose at first is very shot and cnsists o the medal nasal rocess and the anterior pt of the maxillay proces on each side. At this stae, the foors of he olfatory pit rupture so that he nasal cavities ommunicae with te develping mouh (Fig. 11-2). Meanwhile, he nasal septum i forming as a dowgrowth fom the meial nasa process (Fg. 11-82). Laer, the palatal prcesses o the maxlla gro mediall and fuse with ech other and with the nasa septum, thus comleting te floor f the nose. Each asal cavty thereore commnicates nteriorl with the exterio through the nostil and psteriorl through the choaa with he nasoparynx. In he early stages o developent, the nose is much-fattened tructure and gain its recgnizable form only after t facial developmnt is coplete.

Median Nasal Furow I median asal furow, the as septum is split separating the two halves of the nose (Fig. 1-96A.

Lateal Probocis n latera proboscs, a skin-covered process evelops, sually with a dimple at its lower end (Fig. 1196B). P.799

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Figure 1-94 A. Lateral all of nsal caviy showin sensory innervaton of muous membane. B. Nasal septum showing sensoy inneration of mucous mmbrane.

The Parnasal Siuses The paraasal sinses are avities ound in he interior of the maxilla, frontal, sphenoi and ethmoid bones (Fig. 11-97). Tey are lned with mucoperisteum an filled ith air; they comunicate with the nasal caity throgh relatvely smal apertues. The maxillar and sphnoidal snuses are present in a

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Dranage of ucus and Function of Paransal Sinues The mcus produced by the mucous membrane is moved into th nose by ciliary ction of the colunar cell. Drainae of the mucus i also achieved by the siphon action created dring th blowing of the ose. The function of the snuses is to act a resonatos to the voice; they also reduce te weight of the sull. Whe the apetures of the sinses are locked o they beome filld with fuid, the quality f the vice is mrkedly canged.

axillary Sinus The maxilary sins is pyrmidal in shape an located within te body of the maxilla behid the skn of the cheek (Fig. 11-97). The rof is fored by th floor o the orbt, and te floor s relate to the roots of the premlars and molar teth. The axillary sinus oens into the midde meatus of the nse throuh the hitus semiunaris Fi. 11-97).

Fronta Sinuses The two frontal sinuses are contained wihin the rontal bne (Fig. 1197). hey are eparated from eac other b a bony eptum. Ech sinus is roughly triangular, exnding upward above the medial end f the eebrow and backwar into the medial part of the roof of the orbi. .800

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Fiure 11-9 A. Laeral wal of nasa cavity howing te arteril supply of the mcous memrane. B. Nasal setum showng the aterial spply of the mucous membrane.

Each frontal inus opes into te middle meatus o the nos through the infudibulum Fi. 11-93).

Sphenoidal Sinuses

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snell The two sphenoidal sinuse lie within the bdy of th sphenoi bone (Fig. 11-97. Each snus open into the sphenoethmoidal cess aboe the suerior cocha.

Ethoid Sinues Th ethmoidl sinuse are antrior, middle, and posteror and tey are cntained ithin th ethmoid bone, beween the nose an the orbt (Fig. 11-7). Tey are eparated from the latter by a thin late of one so tat infecion can readily pread from the sinses into the orbi. The anerior siuses opn into te infundbulum; te middle sinuses pen into the midde meatu, on or bove the bulla ethmoidalis; and the posterio sinuses open ino the suerior metus. The vaious sinses and heir opeings int the nos are ummarized in Table 1-11.

Clnical Ntes Snusitis nd the Eaminatio of the ranasal Sinuses Ifection f the paanasal snuses is a common compliction of asal infctions. arely, te cause f maxillry sinuitis is etension rom an aical denal absces. The fontal, thmoidal and maxllary sinuses can be palpated clinilly for areas of tendernes. The fontal sius can b examine by presing the inger uward beneath the medial end of the sperior obital argin. Hre the floor of the fronal sinus is closst to th surfac. The ehmoidal inuses cn be palated by ressing he fingr medialy agains the medal wall f the orit. The axillary sinus cn be exained for tendernes by pressing the inger aginst the anterir wall of the maxilla below the infeior orbial margi; pressre over he infrarbital nrve may eveal inreased sensitivit. Direcing the bea of a flashlight either through te roof f the mth or trough the cheek n a darkned room will ofen enabe a phyician to determin whether the maxilary sinus is full of infammatory fluid raher than air. Thi method f transiluminatin is sile and effective. Radiologc examintion of he sinuss is als most hlpful in making a diagnosi. One should always compare the cliical findings of ach sins on the two side of the ody. Te fronta sinus is innervated by he supraorbital nerve, whih also pplies te skin o the forhead and scalp as far bac as the ertex. I is, theefore, nt surpriing that patients ith frotal sinitis have pain reerred ovr this aea. The axillary sinus i innervad by the infraorbital nerv and, in this cas, pain s referrd to the upper ja, includng the teeth. The fronal sinus drains ito the hatus semlunaris, via the infundiblum, close to the orifice f the mallary sius on te latera wall of the nose It is tus not uexpected to find hat a ptient wih fronta sinusits nearly always hs a maxilary sinsitis. he maxillary sinus is partiularly one to ifection ecause is drainge orifie throug the hiatus semilaris is badly plced near the roof of the sinus. In other wods, the inus has to fill p with luid befre it can effectively drai with th person in the upright position. The relatio of the pices of the root of the teeth in he maxila to th floor o the maxllary sius was aready emhasized.

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Fgure 11-96 A. Median nsal furrw in whih the naal septu has comletely slit, searating he two hlves of he nose. Note tha the extrnal nares are separated by a wide furrow. (Courtesy of L. Thmpson.) B. Latera proboscis. (Courtesy of R Chase.)

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Fgure 11-7 A. Te positin of the paranasa sinuses in relaton to th face. B. Coronal section hrough te nasal vity shwing the ethmoidal and the maxillar sinuses.

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Table 1111 Paanasal Snuses an Their Ste of Drinage Ino the Nosea Sinus

Sie of Dranage

Maxilary sinu

Middle meats throug hiatus emilunars

Frontal sinuses

Mddle meaus via ifundibulm

Sphenodal sinues

henoethoidal recess

Ethmodal sinues

Anterior roup

Infundiblum and nto midde meatus

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Mddle grop

Middle meatus n or aboe bulla thmoidals

Postrior grop

Suprior meas

Note that maxillary an sphenoial sinuss are prsent in udimentary form a birth, enlarge ppreciaby after the eighth year, and are fuly forme in adolscence.

Crossing of Air and Food Pathways in te Pharyn It is in the pharnx that the air ad food phways coss. Thi is made possible by the pesence o the sof palate, which srves as flap-vave. This flap shut off the mouth frm the oopharynx for exaple, durng the pocess of chewing ood so tat breahing may continu unaffeced. The completey raise soft paate can shut off the nasoharynx fom the oopharynx thus peventing food enering the nasopharynx in swallowing (see page 75). hen it i desirabe to direct the maimum amont of ai in and ut of te larynx the soft palate i raised o direct air throgh the muth rater than the narrow cavities of the nse. Such an arranement prmits th expectortion of ucus fro the resiratory ystem though th mouth. I also alows the aximum epiration f air through the mouth a in the se of wid instruents suc as the tumpet.

The Larnx The larynx is an orga that prvides a protective sphincer at th inlet o the air ages and is rsponsibl for voie prodution. It is situaed below the tonge and hyoid bone and betwee the geat bloo vessels of the nck and les at the level of the fouth, fift, and sith cervial verterae (Fig. 1-87). It opens above ino the laryngeal part of th pharynx and belw is cotinuous ith the rachea. The larynx is coveed in frot by the infrahyid strap muscles nd at th sides by the thyrid gland The ramework of the lrynx is ormed of cartilags that re held ogether ligaments and membranes, moved by muscles, nd line by mucos membrae.

Crtilages of the Lrynx 



Thyroid cartilage This is the lrgest catilage o the larnx (Fig. 1198) nd consts of to lamine of hyaine cartilage that meet in he midlne in th prominet V angl (the socalled Aam's appe). The posterio border xtends uward into a superior cornu and downard into an inferio cornu On the uter surace of ech lamin is an olique lie for th attachment of mucles. Crcoid carilage: This crtilage s formed of hyalie cartilage and sped like a signe ring, aving a road plate behind and a shalow arc in front (Fig. 1198). he cricod cartilge lies

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

  

elow the thyroid artilage and on ach side of the ateral surface is a facet or articlation with the inferior crnu of te thyroi cartilae. Posteiorly, te lamina has on ts upper border o each sie a face for artculation with the arytenod cartilge. All hese joits are snovial. Arytenid cartiages: There ar two aryenoid catilages, which ar small ad pyramid shaped nd locatd at the back of he laryn (Fig. 11-9). Thy articuate with the uppe border f the lamina of the cricoid cartilae. Each artilage has an apex above hat artiulates wth the sall cornculate crtilage, a ase blow that articulas with te lamina of the cicoid catilage, nd a vocal rocess that prjects foward and gives atachment o the voal ligamnt. A muscuar proces that projects lateraly gives ttachmen to the osterior and lateal cricoarytenoid muscles. Coriculate artilage: Two small coical-shaed cartiages artculate wth the aytenoid artilage (Fig. 11-9). The give atachment o the arepiglottc folds. Cueiform crtilages Thes two smal rod-shped cartlages are found in the aryepiglotti folds and serve strengten them Fi. 11-99). piglotti: Thi leaf-shped lamia of elastic cartage lies behind te root o the tongue (Fig. 11-98). Its stal is attahed to te back o the thyoid cartlage. Th sides of the eiglottis are attahed to te arytenid cartiages by he aryeglottic folds of ucous mebrane. Te upper dge of te epiglttis is ree. The covering of mucous membrane es frward oo the psterior surface of the tonue as th median glssoepiglttic fol; the epressio on each side of he fold s called the vallecua (Fig. 1-90). Laterall the mucus membrne e onto th wall of the pharnx as th lateral glossoepiglottic ld.

Membanes and Ligament of the arynx 

 

Thyrhyoid mebrane: This conects the upper magin of te thyroi cartilae to the hyoid boe (Fig. 11-8). I the midline it i thicken to form the median thyrohyod ligamen. Th membran is piered on eah side b the superior laryngeal vessels an the intnal laryngeal nere, a brach of th superio laryngel nerve (Fg. 11-80). Crcotrachel ligamet: This connects the cicoid ctilage o the fist ring f the trchea (Fig. 198) Quadranglar membrane: Tis extens betwee the epilottis ad the artenoid crtilages (Fg. 11-99). Its thickened inferior margin frms the vetibular gament, and th vestibuar ligamnts form the inteior of te estibula folds (Fig. 11-99). .803

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Fgure 1198 The larynx and its lgaments rom the font (A), from the lateral spect (B, and frm behind (C). D. Te left lmina of hyroid crtilage as been emoved t display the inteior of te larynx

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Figue 11-99 A. Musces of th larynx een from behind. B. Coronal section hrough te larynx C. Rima glottidi partialy open a in quie breathig. D. Rima glotidis ide opn as i deep reathig. . Mscles hat moe voca ligamnts.

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Cricthyroi ligamnt: The lwer magin is attachd to te uppe borde of the cricoid carilage Fig. 1-99). Te supeior magin of the liament, insted of bing attached to the thyrid carilage, ascend on th medial surface of the thyroid crtilag. Its pper fee marin, coposed lmost ntirel of elstic issue, forms he imprtant vocal ligamet n each side. he vocl ligaents frm the interir of the voal fols (vocl cords) (Fig. 11-99). The antrior ed of ech vocl ligaent is attachd to te thyrid catilage and te postrior ed is atached to the vocal roces of he aryenoid cartilage.

Inlet of the Larynx The inlet of the larynx looks backwar and uward ito the laryngal par of th pharyx (Fg. 11-8). The opening is widr in font thn behid and s bouned in ront b the piglotis, laerally by the aryeiglottc fold of mucus memrane, and posteriorly by the arytenoid artilaes wit the crniculte catilage. The uneifom cartlage les witin and strenghens te arypiglotic fol and produces a small elevation o the uper boder.

Te Piriform Fossa he pirform fssa is a recess on ither ide of the fod and nlet (Fig. 1-99). It is bounded mdially by the aryepilottic fold ad lateally b the tyroid artilae and he thyohyoid membrane.

Laryneal Fods Vestibula Fold The vestibular fold is a fixed fol on eah side of the larynx (Fig 11-98). t is frmed b mucous membrane coverig the estibuar ligament nd is vasculr and pink in olor.

Vocal Fold (ocal Crd) The vcal fod is a mobie old on each ide of the laynx an is cocerned with vice production. It is fored by ucous embran covering the vocal ligament and i avasular ad white n colo. Th voal fol moves with espiraion an its wite color is easily seen when viewed wit a larngoscoe Fig. 1199). The gap beween te voca folds is caled the rima glottiis or lottis (ig. 1199). The glotti is bonded i front by the vocal olds ad behid by te medal surace of the artenoid cartilages. he glotis is the arrowet part of the larynx and masures about .5 cm from frnt to back i the mle adut and ess in the feale. I childen the lower part o the lrynx wthin te cricid carilage s the arrowest part.

Cavty of the Laynx The caity of the laynx extends rom th inlet to the lower border of the cricoid carilage, where it is continuous wit the avity f the rachea It is divide into hree rgions:

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Te vetibule, which is situatd betwen the inlet nd the vestiblar fods The midde regin, hich i situated between the vestbular olds aove an the vcal fods belw The loer region which is sitated between the vocal folds abov and te lowe borde of th cricod cartlage blow

Sinu of the Larynx The sinu of th laryn is a mall rcess o each side of the arynx situate betwen the estibuar and vocal olds. t is lined with mucous membrane (Fig. 1-99).

Saccle of he Larnx he sacule o the lrynx i a divrticulm of mcous membrane that ascends from the sinu (Fig 11-99). he mucus secetion ubricaes the vocal ords.

Muscles of the Larynx The muscles of the laryx may e divied int two goups: xtrinsc and ntrinsc.

Extrnsic uscles Thee musces mov the lrynx u and dwn during swallowing. Note that many of these uscles are attached to the hyoid bone, hich i attaced to he thyoid catilage by the thyrohoid mmbrane. It fllows hat moements of the hyoid one ar accomanied by movments f the arynx.  

Eleation: Te digatric, he stylohyoi, the mylohyoid, the genioyoid, he stlopharyngeus the slpingoharyngeus, an the platophryngeu musces Depession: Te sterothyrod, the sternohyoid, and the omohyid musles

Intrisic Mucles Two muscles odify he larngeal nlet (Fig. 11-99):  

Narrowing the inlet: The obique aytenoi muscl Wiening he inlt: The throepigottic uscle

ive muscles ove the vocal folds cords) (Fig. 11-99):     

Tensing te voca cords Te cricthyroi muscl Relaxing he vocl cord: The thyoaryteoid (vcalis) muscle Adducting he vocl cord: The latral crcoarytnoid mscle Abdcting he vocl cord: The poserior ricoarytenoi muscl Approxiates te arytnoid crtilags: The trnsvers aryteoid mucle

The details of the origins, inertion, nerv suppl, and ction f the intrinsic muscles f the arynx re givn in Table 1-12.

Movments f the ocal Flds (Crds)

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snell The moveents o the vcal fods depnd on the movements of the arytenoid cartilage, whic rotate and slide up and down on the sloping soulder of the superir bordr of te cricid carilage. Te rima glottidis is opene by the contraction of the posteior crcoarytnoid, hich rtates he aryenoid cartilage and abducts the vocal process Fig. 11-99). Th elasic tisue in he capules f the ricoartenoid ts keeps he artenoid cartilges aprt so hat th posteior pat of te glottis is open. P.86

Tale 11-12 ntrinsc Muscles of the Laynx uscle

Origin

nsertion

Neve Suply

Acion

Muscle Contrlling he Larngeal Inlet

Obique aytenoid

Musculr process of arytenoid carilage

Apex o opposte aryenoid artilae

Recurrent laryngal nere

Narros the nlet b bringng the aryepilottic folds ogethe

Thyropiglotic

Medial surfac of throid crtilag

Lateal marin of piglotis and aryepilottic fold

Recrrent aryngel nerv

idens the inlet by pulling the arepiglotic fods apat

Muscls Contolling the Moements of the Vocal olds (Cords)

Cricthyroid

Sie of cicoid artilage

Lower border and inferior cornu f thyrid carilage

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External lryngeal nerve

Tenses vocal cords

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Throarytnoid (ocalis

Inner urface of thyoid catilage

Aryteoid catilage

Rcurren laryneal neve

Relaes vocl cord

ateral cricoaytenoi

Upper order f cricid carilage

Musculr procss of rytenod carilage

Recurrent aryngeal nere

Adducs the vocal ords b rotaing artenoid cartilge

Posterior cricoaytenoi

Back o cricod cartlage

Mucular rocess of aryenoid artilae

Reurrent laryngeal nerve

Abducs the ocal crds by rotatng aryenoid artilae

Trnsvers aryteoid

Back and medial surface of arytnoid crtilag

Bak and edial urface of oppsite arytenoid cartilage

Recurent lryngea nerve

Closes osterir part of rim glottdis by approxmating arytenoid cartilage

The rima lottidis is closed by ion of the laterl cricarytenid, whch rottes te arytnoid crtilag and dducts the voal proess (Fig. 1-99). The posteior pat of te glotis is arrowed when the artenoid cartilges ae draw togeter by contraction of the transverse arytenoid mscles. The voca folds are stetched by contraction of the cricothyroid musce (Fig. 11-00. The ocal folds are slackened by contrction f the vocalis a par of th thyrorytenod musce (Fi. 11-9).

Mvement of th Vocal Folds ith Respiration On quiet nspiraion, te voca folds are aducted and th rima lottids is tiangulr in sape wih the pex in front Fig. 1199). On expiration the ocal folds ar adduced, leving a small ap beteen thm (Fig. 11-9). On deep inspiraion, te vocal folds are maimally abducted and the triangular shape of th glotts becoes a damond shape ecause of the maxima laterl rotation of the arytenoid cartilags (Fi. 119).

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Shincteric Function of the Larynx Tere ar two shinctes in te laryx: one at the inlet and another a the rima glotidis. The phinctr at te inle is used only during swallowing. As the bolus f food is ed bakward etween the togue ad the ard paate, te laryx is plled u beneah the ack of the tngue. he inlt of te laryx is nrrowed by the action of the oblique arytenoid nd arypiglotic musles. Te epigottis is pulled bacward b the tngue ad servs as a cap ovr the aryngel inle. The bolus f food or flids, ten eners the esophgus by in over the epglotti or moing don the rooves on eiter sid of the laryneal inet, th pirifrm fossae. In coughng or neezin, the ima glttidis serves as a sphincter. Afer insiratio, the ocal flds ar adduced, an the uscles of expration are mae to cntract strongly. As a result, the intrahoraci pressre riss, and the voal fols are uddenl abduted. Te suddn reease f the ompresed air will oten dilodge foreig partiles or mucus rom th respiatory ract and carry the material up into the pharyn, wher the mterial is either swallowed or exectoraed. In the Valsalva aneuve, forced expiation akes pace aainst close glotts. In bdominl strining ssociaed wit micturition defecation, and paturition, air is often held temporarily in the respirtory tact by closing the rima glottidis After deep nspiraion th rima lottids is cosed. he musles of the anerior abdomial wal now cntract and te upwad moveent of the diphragm is prvented by the presece of ompresed air within the repiratoy tract. After a prolonged effort the prson oten reeases ome of the ar by mmentarly opeing th rima glottiis, producing a grunting ound.

Voic Prodution i the Lrynx The intermttent elease of expired ar betwen the adduced vocl fold resuls in teir viration and in the productin f sond. Th freuency, or pitch, o the sund is determned b changs in te lengh and ension of the vocal ligaments. The quality of th voice depend on th resontors aove th laryn, namey, the pharyx, mouh, and paranasal sinuses. The quality of the voce is controlled by the muscles of the oft plte, togue, foor of the muth, ceeks, ips, ad jaws Norma speec depens on te modficatin of te soun into ecogniable cnsonans and owels by the use of the togue, eeth, and lips. Vowel souns are sually P.807

purely oral wth the soft plate raised so that the ai is channeled throug the muth raher thn the ose.

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Figure 11-100 Digrams howing the atachmets and actions of the cricthyroi muscl. A. Riht latral viw of the laryx and he criothyrod musce. B. Interior iew of the laynx shwing te relaed right vocal ligaent. . Interir view of the larynx showing the ight vcal ligaent stetched as a result of the cricoid and aytenoi cartiages tlting ackwar by contraction o the cicothyoid mucles.

Speech involves the intermttent elease of expred ai betwen the dducte vocal folds Singing a not requies a mre prolonged release of the expird air between the adducted vocal folds. In whipering the vcal fods are adducted, but the arytenoid cartilages are searated the vibratins are given o a cnstant stream of expired air that es throug the psterio part of the rima gottidi.

Muous Membrane of the Larynx Te mucos membane of the laynx lines the cavit and s covered with cilited coumnar epitheium. n the ocal cords, howeve, wher the mucous embran is suject to repeted truma duing honatin, the mucous membrne is overed with sratifid squaous eithelim.

erve Spply o the Lrynx Sensoy Nervs  

Above the vocal cords: The internal laryngeal branch of the superior laryngeal brach of he vags Below the level of the vocal cors: The reurrent laryngal nere (Fi. 11-101)

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Mtor Neves ll the intrinsic muscles of the lrynx ecept te criothyrod musce are upplie by th recurent laryngeal nerve. The cricothroid muscle i supplied by he extrnal lryngea branc of the suprior lryngea branc of th vagus

Blood Supply of he Larnx  

Uppr half of the larynx Te supeior layngeal branch of the superior thyroid artery ower hlf of he larnx: The iferior laryngal brach of he infrior tyroid artery

Lymph Drainage f the Larynx The lymph vessels drain into the deep cervicl grou of noes.

Clincal Noes Leions of the Laryngeal Nerves The mucles o the lrynx ae innevated y the recurrnt larngeal erves, with te extion f the ricothroid muscle, which is suplied by the eternal laryngal nere. Bot these nerve are vlnerabe durig opertions n the hyroid gland because of the close relationship betwee them nd the arteris of te glan. The left rcurren laryneal neve may be invlved i a brochial r esohageal carcinma or n secodary metastatic deposits in the ediastnal lyph nods. The right nd lef recurent layngeal nerves may b damagd by mlignat invovement of the deep crvical lymph nodes. Sectio of th exteral larngeal nerve produces weakness of the voice ecause the voal fol canno be tesed. Te cricthyroi muscl is paralyzed (Fig 11-10). Unilateral complet sectin of te recurrent laryngel nerv results in the vocal old on the afected ide asuming he postion idway etween abducton and adduction. It lies just lateral to the idline Speec is no greaty affeted beause te othe vocal fold ompenstes to some etent ad move towar the afected vocal old (Fig. 1-102). Bilatral coplete ection of th recurent laryngea nerve reults in both vocal olds asuming the poition idway etween abducion an adducion. Beathin is imaired ecause the ria glotidis is partially closed, and spech is lost (Fig. 11-102). Unilatral patial sction f the recurrent larngeal erve resuts in a greater degree of aralyss of te abdutor mucles tan of the adductor muscle. The ffecte vocal fold asumes he addcted idline position (Fig. 11-02) This henomeon ha not ben expained atisfatorily It mut be asumed hat th abdutor mucles rceive greatr numbr of nrves tan the adductr musles, ad thus partia damag of th recurrent laryngeal nerve resuls in dmage t relatvely mre nere fibes to te abdutor mscles. Anothe possiility s that the neve fibers to he abdctor uscles are trveling in a more exposed position in the recurrnt layngeal nerve nd are therefre mor prone to be amaged.

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snell Bilateral partial section of the ecurret larygeal nrve resuls in blatera paralsis of the abuctor muscles and the drawing tgether of the vocal olds (Fig. 11-102). cute beathlesness dyspnea) and stridor follow, and ricothroidotmy or racheotomy i necesary.

Edema of he Larngeal ucous embran The mcous mmbrane of the larynx is losely atached to th underying sructurs by sbmucou connetive tssue. n the egion of the vocal fold, howeer, the mucos membane is firmly attached to the voal ligments. This fct is f clincal imortanc in caes of edema f the arynx. The acumulaton of issue luid cuses te mucos memrane aove th rima lottids to sell and encroach on the airway. In severe case, a crcothyridotom or trcheostmy may be necessary.

Laryngea Mirro and Lryngosope The interir of te laryx can e inspcted idirecty thrugh a aryngel mirrr d throgh the open mouth into the oral pharynx (Fig. 11-103). more atisfatory ethod s the irect ethod sing te larygoscop. The eck is brough forwrd on pillo and te head is fuly exteded at the atlantooccipital ts. The illumnated nstrumnt can then be inroduce into the larynx oer the back o the tngue (Fig. 11-103). The valleculae the priform fossae the eiglotts, and the aryepiglottic folds are clearly see. The wo eleations producd by he coriculat and cneifor cartiages an be ecognied. Within th laryx, the vestiblar fods and the voal fols can e seen The ormer re fixd, widly seprated, and reddish in colo; the atter move wth respiratin and re whie in clor. Wth quit breahing, he ria glotidis i trianular, ith th apex in frnt. Wih deep inspiation, the rima glotidis ssumes a diamond shape because of the lteral otatio of th aryteoid catilages. If he patient is aske to brathe deeply, the voal folds becoe widely abduted, and the nside of the trachea can be seen.

Impornt Anatomic Axes for Endotacheal Intubaion he uppr airwy has hree aes tha have to be brought into lignment if te glotis is o be vewed adequately through a laryngoscopeâ”the ais of he mouh, the axis o the parynx, and te axis of the tracea (Fig. 11104). The ollowig procdures re necssary: First he hea is extended at the atlanto-occiital jints. his brngs th axis f the mouth nto th corret posiion. Ten the neck i flexe at crvical verterae C4 to C7 y elevting te back of the head of the table, often with the help of a pillow. This brngs th axes f the pharynx and he trahea in line wth the axis o the muth.

Anatmy of the Visualization of the Voal Cors With the Layngose The atients head and nek are orrecty posiioned o tha the tree axs of te airwy (notd above) have been establihed ad the patient has asumed te “siffing€• postion. he larngoscoe is insertd into the paient's mouth, and th blade is correctly placed alongside the right mandiblar moar teeh. The blade an the be pssed oer the tongue and don into the esophagus. The tip of

1506

snell he blde mus be fuly insrted ito the esophaus (so that you kno where it is anatomcally) The bade shuld by now have moved toward the midline and fllowed the antomic urvatue on te postrior srface f the tongue Th larygoscopc blae is thn gently and slowly withrawn. he tip of the blade is kept unde diret visin at al times and is permitted to ris up out of te esopagus. emember that the tp of he blae is at first in te esophagus nd is, therefre, distal o the level of the vocal cords. Once the blade ip has left te esohagus, it is n the aryngel part of the pharyn (igs. 1-88 and 11-91), ad a vew of the glotis shuld immediately be apparent. This is the critial stae. If he glotis is not viualize, then the oprator s vieing th posteior suface o the eiglotts. Nw use our antomic nowlede. Wth the tip of the blade of the layngose appied to the psterio surfae of te epiglottis gentl lift p and elevate the eiglotts to epose te glotis. If the glttis i still not in view, do no panic gain ue your knowlege of natomy With he rigt free hand gasp th thyrid carilage to whih the ords ad the piglottis are atached) betwen fingr and humb ad appl firm ackwar, upwad, rigtward pressure (BRP). This maneuvr realgns te box f the larynx relative to te larygoscopc blad, and he visual axs of te opertor an the gottis hould mmediaely be seen.

Reflex Activity Secondary to Endorachea Intubtion Stimlation of the mucous membrae of the upper airway during the proces of inubatio may poduce ardiovscular change such as bradycardia and hypertension. These canges re larely mdiated throug the banches of the vagus nerves. P.808

P.809

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Fgure 1-101 A. Lteral iew of larynx showing the nterna and eternal laryngal brnches f the superior laryngeal branch of the vagus neve. B. he disributon of he terminal ranche of th interal and recurrnt layngeal nerves The lrynx i viewe from bove ad postriorly

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Figue 11-12 he postion o the vcal fods (cods) after damage to the external nd recrrent aryngel nervs.

P.80

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Fgure 1-103 Inspction f the ocal flds (crds) idirecty throgh a lryngea mirror (A) and throuh a layngose (B). Note th orienation f the structures foming the larygeal ilet.

The Trchea escripion Te trachea is a mobie cartlaginos and embranus tube (Fig. 11-05). It begins s a cotinuaton of he larnx at he lowr bordr of te crioid catilage at the level of the sixth cervica vertera. It desceds in he midline f the neck. In the thorax the trahea ens at he carina by diiding nto riht and left

1510

snell principal (main) bronchi at the leel of he stenal anle (oposite the disc between th fourt and ffth toracic vertebae). The firoelasic tub is ket patent by the preence o U-shped catilaginus bar (ring) of yalie cartilge emedded n its wall. The psterio free nds of the crtilae are onnected by mooth muscl, the trachalis muscle. The muous membrane of the tracha is lned with pseudostrtified ciliatd columnar epithelim and ontain many oblet cells nd tuular mucous lands.

Relations of the Trachea in the Nck (ig. 1149) 

nteriorly: Skin fasci, isthus of he thyoid glnd (in front f the econd, third, and furth rngs), nferio P.811

thyrod vein jugulr arch, thyroidea ia artry (if preset), and the eft brchiocehalic ein in childrn, overlapped by the sternothyroid and sternohoid mucles

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Figure 1-104 Anatomic axes for endotrcheal ntubation. . With te head in the neutral posiion, te axis of the mouth M), th axis of the trache (T), nd th axis f the pharyn (P) ae not aligned with one another. B. If te head is extended at the atlano-occiital oints, the axs of te mouth is crrectl place. If te back of the head i raise off te tabl with a pillow, ths flexng the cervicl vertbral clumn, the axes of the trachea an pharynx are rought in

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lin with he axi of th mouth

 

Poseriorly: ight ad left recurrent laryngeal nerves and th esophgus Laterally Lobes of the thyroid gand an the crotid heath nd conents

Te relaions o the tachea n the uperio mediatinum f the horax re desribed n pag 87.

Nerv Suppl of th Tracha he sensory nrve suply is from te vagi and th recurent layngeal nerves.

Blood Suply of the Trchea The pper to thirs is spplied by the inferior thyoid areries nd the lower hird i suppled by he brochial arteries.

Lymph rainag of th Tracha Into he pretrachea and pratraceal lyph nods and he dee cervial nods P.812

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Fiure 11105 The trachea nd the bronch.

Clinical Noes Midline Structures in he Nec The midine stucture in th neck hould be readily recognized as one s an eaminin finge down he nec from he chn to te suprsterna notch (for dtails, see page 83). The physicia commoly forets tht an elarged submenal lymh node may b cause by a atholoic conition nywher betwen the ip of he togue an the pint of the chn.

alpatin of te Tracea 1514

snell The trchea cn be radily elt beow the larynx. As i descnds, i becoms deeply placd and ay lie as much as 1.5 in. (4 cm) from the surface at he supasternl notc. Remeber tht in the adut it my measre as much as 1 in. (2.5 cm) in diameter but i a 3-ear-ol child it may measur only .5 in. in diaeter. he trahea i a mobile elastic tbe and is easly displaced y the enlargeent of adjacnt orgns or he presence of tumors. aso tha laterl dislacemet of te cervcal pat of te tracea may be caued by pathologic lesion in the thorax

ompromised Arway No medical emergency quite producs the rgency and nxiety of the comproised arway. he physician has to institute almost imediate treatmnt. Al technques o airwa managment rquire a detailed kowledg of antomy.

Cricotyroidoomy In criothyrodotomy a tub is inerted n the nterva betwen the cricoid cartilage ad the hyroid cartilge. Th tracha and larynx are stedied b extending te neck over a sandbag. A verical o transerse incisio is mae in te skin in the intervl betwen the cartilages (Fig. 1-106). Te inciion is made trough he folowing tructues: th skin, the sperfical fasia (beware of the aterior jugula veins which lie cose toether n eithr side of the midlin), the investng layr of eep cevica fascia, the pretraheal fscia (eparat the sernohyid mucles ad incie the ascia) and te larnx. Th laryn is inised hrough a horiontal incision through the cricothyroid ligamen and te tub insered.

Cmplicaions 



Esohageal perfortion: ecause the lwer ed of te pharnx and the bginnin of th esophgus li direcly beind th cricod cartlage, t is iperatie that the sclpel ncisio throuh the ricothyroid membrane not be carrid too ar poteriory. Thi is paticulaly imprtant n youn childen, in whom he cros diamter of the laynx is so smal. Hemorrhage: The small branches o the uperio thyrod artery that occasionally cross the frnt of he crcothyrid memrane t anastmose wth one anothe shoul be avided.

Trachestomy Trachostomy is rarly perormed and is limite to ptients with etensiv laryneal damage and infants wit severe airwa obstuction Becaue of te presnce of major ascula strucures caroti arteres and internl jugular vin), te thyrid glad, neres (rcurrent laryneal brnch of vagus nd vags nerv), the pleura caviies, ad the sophags, metculous attenton to natomi detai has o be oserved (Fig. 11-10). Th proceure is as folows:   

The thyrid and cricoi cartiages are identified and th neck s exteded to bring the trchea frward. A vertica midlie skin incisin is made from the region of the ricothroid mmbrane inferirly toard th supraternal notch. The incision is carried trough he suerficil fasca and he fibrs of he playsma muscle. The anerior jugula veins in the superfcial fscia ae avoied by aintaiing a midlin positon. 1515

snell   





The investng layr of dep cerical fscia i incisd. Te pretacheal muscles embedded in the retraceal facia ar split in the midlin two ingerbeadths superir to he stenal noch. he traheal rngs ar then alpabe in he midine or the ishmus o the tyroid land i visibe. If a hook is paced uder th lower border of the cricoi cartiage an tracton is applied upwad, the slack s take out o the eastic rachea this stops t from slippig from side t side. A decision is then made as to whther t ente the tachea throug the scond rng aboe the isthmus of the thyrid gland; thrugh th third fourt, or ffth rig by first dviding the vscular isthms of the thyroid glnd; or through the lower trachel ring below the thyroid sthmus. At te latter site, the trachea is receding rom th surfae of te neck and te pretacheal fasci contains the inferior thyroid veins and possibly the thyroidea im arter. he preferred site is throuh the econd ring o the rachea in the midlie, wit the thyroid isthmu retrated iferiory. A vrtical tracheal incision is made, and the trachostomy tube s inseted.

Coplicaions Most complictions esult rom no adequtely plpatin and ecognzing the thyoid, cicoid, and tacheal artilaes an not onfinig the incisin stritly to the midline. 

  

Hemorrhag: The nterio jugular vens loated in the uperfiial fascia cose to the mdline hould be avided. f the sthmus of the thyrod glan is trnsected, secre the anasomosin branches of the superior and inerior thyroi arteres that cross the idline on the isthmus. Nerve pralysi: The ecurrnt laryngeal nerves may be damaed as they acend the neck in th groove between the tracea and the esphagus. Pneumotorax: he cervical ome of the pleura ay be ierced This is espcially commo in cildren becaue of he high level of th pleura in the neck Esophaeal inury: Dmage t the esophaus, whch is ocated immeditely psterio to th trachea, occurs most commonly in infants; it ollows penetrtion o the small-diameter trachea by te poin of th scalpl blade.

Some Imporant Aiway Ditances Table 1-13 show some mportat distances betwen the ncisor teeth r nostils to anatoic lanmarks in the airway in the adult. These approximate figures are helful in deterining he corect placemen of an endotrcheal ube (se page 808). P.813

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Figure 1-106 The anatoy of cicothyoidotoy. A. A vertical inciion is made trough he ski and sperficial and deep cervical fasciae. B. Te cricthyroi membrane (ligament) is incsed though a horizntal ncisio close to the upper order f the ricoid cartilge. C. Isertio of th tube.

P.814

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Figure 1-107 Cross secion of the nek at te leve of th secon trachal rin. A vrtical incision is ade though the ring and te traceostomy tube is insrted. Table 1-13 Impotant Arway Dstance (Adul)a Aiway

Distance

Inisor teeth to the vcal cods

5.9 in. (5 cm)

Incisor teeth to the caina

7.9 in. (2 cm)

External naes to he carna

11.8 in (30 c)

a

Aerage figure given = 1– cm.

P.815

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Endocrine Glands in the Hed and eck Pitutary Gand (Hpophyss Cerebri) Loction ad Desciption Th pituiary glnd is small oval tructue attahed to the undersurface of the brain by he ifundiblum (Fig. 11-1 an 11-108) The gland is well protected by irtue f its ocation in th sella turcica of the sphnoid bne. Beause te hormones produced y the gland nfluene the ctivites of any oter endcrine lands, the hpophyss cereri i often referrd to as the aster endocrne gland. For this reason, it is vital o life Th pituiary glnd is ivided into an anterior obe or denohyophysi, and a osterior lobe, o neurohypophysis. The anterir lobe is subivided into te pars anteior (someimes clled te pars distais) an the ars intermedia, hich my be sparate by a left tat is remnat of a embryonic pouch. A projecion frm the ars anerior, the pars tueralis, etends p along he antrior ad lateal suraces o the ptuitar stalk.

Relatins   

 

Anteriorly Te spheoid sius (Fg. 1113) Posteriorl: The dorsum sellae, th basilr artey, and the pos Superorly: The diaphragma sellae, hich hs a cetral aerture that alows te age o the ifundiblum. Te diapragma ellae eparats the anterir lobe from te opti chiasa (Fig. 11108) Inferiory: he body of the spheoid, wth its sphenod air inuses ateraly: The caernous sinus nd its contents (Fg. 11-08)

Blood Suply The arteies ar derivd from the superior and iferior hypophyseal arteries, branches of th interal carotid atery. he veins dran into the intercavernous inuses

Functons of the Ptuitar Gland he pititary gland influences the activiies of many other ndocrie glans. The pituitary glnd is tself ontroled by he hyothalaus and the acivitie of th hypotalamus are moified y informatin receved alng numrous nrvous fferen pathwys fro diffrent prts of the cetral nrvous ystem nd by he plama levls of the ciculatig elecrolyte and hrmones]

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Figre 11-08 Coronl secton thrugh th body of the sphenoid bone, showing the pituitary gland and cavernus sinuses. Nte the position of he inernal arotid artery and th cranil nervs.

P.81

Embryoloic Nots Devlopmet of te Pitutary Gand The pituitry glad deveops from two source: a smll ecoderma divericulum (Rathk's pouh), whch gros superiorl from the rof of te stomdeum imediatly antrior t the bccophayngeal membrne, and a small ectdermal divertculum the nfundbulum), which grws infriorly from the flor of the diecephalon of he bran (Fig. 11-09. During the econd onth development Rathe's poch coes into contct with the anterio surface of the inundibulum, ad its connection with th oral pithelium elngates narros, and finaly disppears (Fig. 11-19) Rathk's pouh now is a vesicle that fattens itsel aroun the aterior and laeral srfaces of the infudibulu. The ells o the aterior wall of the vesicle prolierate nd form the pars anterior 1520

snell of the pituitry; fom the vesicl's uppr part there is a ellula extesion hat grws supriorly and arund th stalk of the infudibulu, formng the pars tuberlis The cells of the posterio wall f the esicle never evelop extensvely; hey fom the pars ntermedia Some of the cells ater igrate anterirly ino the pars anterior The avity f the vesicle is reduced to a narrow clft, whch may disapear ompletly. Meanwhie, the infunibulum has differentiated into the salk and pars nrvosa of he pititary gland Fig. 11-109).

Figure 1-109 The differnt stages in the deelopmet of the pititary land shown in sagital setions.

Pineal Glad Location ad Desciption Te pinel gland is a small one-shaped body that proects posterirly frm te postrior en of the roof of he thid ventricle of he brain (Fig. 11-13). Te pineal consits esentialy of roups of cels, the piealocyes suppoted by glial ells. The glnd has a rich blood supply and is innervated by postgaglioni sympahetic erve fbers.

Functions of the Pineal Gland

1521

snell The pinal glad can influece the activties of the pituiary gland, the ilets o Lanerhns of the pacreas, the parahyroid, the drenals, and the goads. The pineal secetions prodced by the pnealoctes, rach their target organs vi the bloodsteam or throug the crebrosinal fuid. Teir acions ae maily inhbitory and ether drectly inhibi the poductin of ormons or idirecty inhibit the secreion of relesing actors by th hypothalamu. .817

hyroid Gland Locatin and escripion The tyroid gland consists of rght and left lobes onnectd by a narrow isthmus (Fig. 11-110). It is a vscular organ surrounded b a sheath deried fro th petracheal layer of deep fascia The heath attaches the glnd to he laynx and the rachea Each lobe s pear shaped with ts apex being direced upard as far as the olique ine on the lmina o the tyroid cartilge; it base ies beow at he levl of te fourh or fifth racheal ring The isthmus exends across th mdlie in fron of te secod, thid, an furth tacheal rings (Fi. 11-10). A pramida lobe is ften resent and i projets upwrd from the isthmus, usualy to te left of the midline. A fibrous or P.81

musclar bad freqently connecs the yramidal lob to th hyoi bone if it is muscular, it is refered to as the levtor glanulae tyroideae (Fig 11-110).

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Figure 11-110 he blood supply and venous drainage of the thyroid glnd.

Reations of th Lobes 1523

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nterolterall: he sternothyroid, the superir bell of th omohoid, te sterohyoid, and he anterior border f the sternoleidomastoid (Fig. 11-4) Posterlateraly: The crotid heath with the common caroid artry, th intenal juular vein, ad the agus nrve (Fig. 1-49) edially: he larynx, the trache, the harynx, and the esohagus. Associted wih thse strctures are te cricthyroi musle and its nerve supply, the external lryngea nerve In th groov between the esophaus and the tachea is the recurrnt laryngeal nerve ig. 1-49).

The rounded posteror borer of ech loe is rlated posterorly t the sperior and inferior parathyroid glands Fig. 11-110) ad the anastomosis btween he suprior and infrior tyroid rteris.

Relatons of the Ishmus  

Anteriorly he sternothyoids, sternoyoids, anteror juglar vin, fascia, an skin osteriorly: The second third, ad fourh ring of te tracea

Th termnal brnches of the superor thyoid arteries anastoose alng its uppr borde.

Blod Suply The aterie to the thyroid gland are the supeior throid rtery, the inferior thyroi artey, and sometimes te thyrodea im. The arteries anasomose rofusely wit one nother over the suface of the land. he uperio thyrid artry a brnch of the eternal carotd artey, descends to the pper ole of each lobe, acompaned by the eterna laryngeal nerve (Fig 11-10). The infrior thyroid artery, a branh of the thyocervial truk, ascends bhind the glad to the leel of he crioid catilage It then turns medilly and downard to reach the posterio bordr of the glad. The recurrent laryngel nerv crosses ither n fron of or behind the atery, r it ay pas between its branches. The thyroiea ima, i presnt, may aris from he brahiocepalic artery or the arch of the arta. I ascens in front of the trachea o the sthmus (Fig 11-11). Th veins from the thyoid gand are the uperio thyrid, whch drans into the nternl jugular vein; the middle tyroid, which rains into te intenal jgula vein; and the infrior tyroid Fi. 11-10. The infeior throid vins of the to side anastomose with oe another as they dscend n font of the trache. hey drin ino the eft brchiocephalic vein in the thora.

Lymph Drainae The ymph fom the thyroi glan drains mainly laterally into the eep cevical ymph nodes. few ymph vssel desced to te paatrachal nods.

Neve Supply uperior, midle, an inferior cevical ympathetic gnglia

Funcions o the Tyrod Glan 1524

snell The thyroi hormoes, thyroxin and riiodohyronine, icrease the meabolic activty of most cells i the body. he paafollcular ells produce the hormone hyrocacitonin, whih lowes the leve of bood cacium.

Clinical Ntes Swelings of the Thyroid Gland nd Moement on Swalowing Th thyrid glad is ivested in a heath erive from the pretrachal fasia. Ths tethers th gland to th laryn and the trachea and exlains hy the thyrod glan follows the movemets of the larynx n swallowing This nformtion is impotant bcause ny pthologc neck swelling tha is pat of he thyroid gland wil move upward when the paient i asked to swllow.

The Thyroi Gland and th Airwa The cose reationsip beteen the tracea and the lobes of the thyroid land cmmonly results in pessure on the trachea in atients with patholgic enargemet of te thyrid.

Retrosernal oiter The attachent of the sternothyroid mscles o the thyroid cartlage efectivly bins down the thyroid land t the arynx nd limts upwrd expnsion f the land. here bing no limittion t downward exansion it is not ucommon for a pathologicaly enlarged tyroid land t exted downward bhind te stenum. A retrosernal goiter (any bnorma enlarement of the thyroi gland) can compress the trachea and cause dngeros dyspnea; it can lso case severe venous cmpression.

Thyrod Arteies an Important Nrves It should b ed hat th two main arteries supplyng the thyroi gland are clsely elated to imprtant erves that cn be damaged during thyroidectomy operatons. Te supeior tyroid rtery on eac side is relted to the eternal laryngeal neve, which spplies the cicothyoid muscle. he terinal brnches f the inferior throid artery n each side are related to the rcurren larngeal erve. Damage to the external layngeal nerve esults in an inabiity to tense he vocl folds and in hoarseness. For the resuls of amage o the ecurret larygeal nrve, se page 08

Thyridectoy and the Paathyrod Glads Th parathyroid glands are uually our in number and re cloely related o the osterior surace of the tyroid land. n parial throidectomy, the poserior art of the throid gland i left undisturbed so tha the arathyroid glads are not dmaged. The dvelopment of the iferior paratyroid lands s closly assciated with te thymus. Fo this eason t is nt uncommon fr the sugeon to find the iferior parathyroid glands in the superor mediastinm because tey hav been ulled down ito the thorax by the thymu. P.81

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Embrologic Notes Deelopmnt of the Throid Gand The thyroi gland begins to develop dring te thir week as an entodemal thickenig in the midine of the flor of the parynx etween the tuberculum impar and te coula (Fi. 11-11) Later this thickeing beomes a diverticulum that grows iferiory into the unerlying mesenchyme nd is alled the hyroglossal duct As developent cotinues, the uct elngates and is distal end becoms biloed. Son, the duct ecomes a sold cord of cels, an as a result of epthelial proliferatin, the bilobe terminal swllings expan to fom the thyroi gland he thyoid gland no migraes inferiory in the nec and asses ither anterior to, osterior to, or thrugh th developing body of the hoid boe. By he sevnth week, it reache its inal ositin in rlation to the laryn and trachea Meanwile, the solid cor conneting te thyroid glnd to the togue frgments and disappears. Th site f oriin of he thyoglossal duct on th tongu remans as pit called he foramen ccum. Th thyroid glad may now be divide into small median isthmus and two lage lteral obes (Fi. 11-111) In the ealiest tages, the thyroid gland onsist of a solid mass o cels. Latr, as a result of nvasio by surounding vacular esenchymal tissue, he mas becoms broken up nto pltes and cords and finall into small clustes of cells. y the thir mont, coloid strts to accumuate in the cnter o each cluster so that folicles are forme. The ibrou capsue and connecive tisue dvelop rom th surrounding mesenhyme. The ltimobanchial bodies (from the fifth phayngeal pouch) and nural crest cells are belived t be icorported ino the thyroid gland where they form th parfolliclar cels, whic produe cacitonin.

Agensis of the Tyroid Failure o develpment of the thyroi gland may ocur and is te commnest cuse of cretinism.

Incomplte Desent of the Thyroid he descent o the tyroid ay be arrested at ay poin betwen the base o the tngue ad the trache (Fig. 11-12). Lingual throid is te most common form of incoplete escent (Fig 11-11). The mass of tissue found just bneath he foramen ccum may be sufficietly lage to bstruct swallowing n the nfant.

Ectopi Thyrod Tissue ctopic thyrod tissue is occasioally fund in the horax n relaion to the tachea or brochi or even the esohagus. It is assumd that this hyroid tissue arise from ntoderal cels displaced during the frmatio of the larygotraceal tube or rom etodermal cells of te deveoping sophags

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Persistent Thyroglossal Duct Conitions related to a persistence f the hyroglssal duct usally appear n chilhood, in adoescenc, or i young adults.

Thyroglossl Cyst Cyss may ccur t any point long te thyoglossl trac (Fgs. 11-112 and 11-114). They occur most comonly i the region elow te hyoi bone. Such cys occupes the midlie and evelop as a esult of peristenc of a small amount of epihelium that ontinus to screte mucus. As the cyst nlarges, it s pron to infectio and s it shuld be removed surically Since remnants of he dut ofte traverse te body of the yoid bone, his my have to be excise also to preent reurrenc.

Tyroglossal Sinus (Fistula) Ocasionally, a thyroglossal cyst upture spontneousl, prodcing a sinus (Fig 11-11). Usuall, this is a rsult of an ifectio of a yst. Al remants o the tyroglosal dut shoud be removed surgiclly. P.20

Figur 11-111 Te different stages n the evelopent of the throid gand. A. Sagittl section of the

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togue sowing n entoermal hickenng beteen th tuberulum impar and the opula. B Sagital sction f the ongue showin the dvelopmnt of he thyroglosal duct. C. Saittal sectio of th tongue and neck shwing te path taken by the thyroid glan as it migrates infriorl. D. The fully develoed thyoid glnd as seen from in front Note he remins of the hyroglssal duct abve the isthms.

Figure 1-112 A throglosal cyst in te midline in the nek and thyrolossal fistua.

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Figure 11-13 Lingual hyroid. (Courtey of J. Radolph.)

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Figure 1-114 A tyroglssal cst. (Courtesy of L. Thompsn.)

Paratyroid Glands Locaion and Desciption The parathyrid glands ar ovoid bodie measuing about 6 mm lon in thir gretest diametr. The are our in number and ae closely rlated to the posterior boder of the tyroid land, lying withn its ascia capsule (Fg. 11-110). he to superior prathyrid glands are the mor constnt in ositio and le at the level of he midle of the poterior border of the thyrod glan. The two inferior parathroid glands usually le clos to th inferior poes of he throid gand. hey ma lie ithin he facial seath, mbedde in th thyrod subsance, r outside the fascal sheth. Sometimes they are foud some distane caudal to the throid gland, in assoiatio with he inferor thyoid veins, r they may even resde in the superir mediastinu in the thoax.

Blood Suppy Te artrial supply to the arathyroid gands i from the sperior and inferior thyroid arteies. Te venous dranage i into the sperior, midde, and inferior thyroid vens.

Lymph Drainage eep cervical and paatracheal lyph noes

Nerve Suppl Suprior r middle cerical sympathetic gnglia

unctios of the Parthyroid Glans Te chief cels prodce the parathyroi hormne whih stimlates osteocastic ctivity in bnes, hus moilizin the bone calcium nd inceasing the calcium evels n the blood. The arathroid hrmone also simulates the absorpion of dietary calcum frm the mall itestine ad the reabsoption f calcum in the proximal convouted tbules of the kidney It also strongly dminishes th reabsrption of phosphat in the proimal convolued tubules o the kidney. The scretion of the parthyroi hormoe is controled by he cacium lvels i the bood.

The Rot of te Neck Th root f the eck ca be deined a the aea of he nec imediately above the nlet ito the thorax (Fig. 1-16).

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Embryoogic Ntes Developent of the Paathyrod Glans The air of infeior paathyrod glands, known s paathyrod III, develop as the result f prolferatin of etoderml cell in th third pharyngea pouc on eah side As te thymc diveticulum on ech side grows inferioly in he neck, it pulls te inferior prathyroid wih it, so that it fnally omes t rest on the posteror surace of the ateral lobe of the hyroid gland near is lowe pole and becomes compltely eparae from the tmus (Fig. 11-15. The pair of superior parathyroid glnds, prathyrid IV, dvelop s a prliferaion of entodrmal clls in the forth phryngea pouc on eah side These loosen their onnecton wit the pharyngeal wal and ake up their inal psition on the posteror aspct of he laeral lbe of he thyoid glnd on ach sie, at bout te leve of te isthus (Fg. 11-115. In the eariest sages, ach glnd conists o a sold mass of cler cell, the chief cells. In late cildhoo, acidphilic cells, the xyphil cells, apear. he conective tissue and vacular upply re derved from the surrounding mesenchyme. It is beleved tat the parathroid hrmone s seceted erly in fetal ife by the chef cels, to egulat calcim metbolism The oxyphil cels are hought to be nonfunctionig chie cells.

Absnce an Hypopasia o the Prathyrid Glads Agenesis or incmplete develoment of the parathyroid gands has been demonsrated n indiiduals with idiopathic hypoparatyroidim.

Ectopic Prathyrid Glads The close relationship beteen th paratyroid II and the dvelopig thyms explins th frequnt finding of parathyroid tissue in the superir medistinum of the thorax (Fig. 11-11). If th paratyroid lands emain ttache to th thymu, they may be pulle inferorly ito the lower art of the neck or thoracic cavity. Moreover, this alo explins th variale position of the inferio parahyroid glands in reltion t the lower ples of the laeral lbes o the tyroid land. P.822

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Fgure 11-115 Parathyroid gland takin up teir final positions in the neck.

Muscles f the oot of the Nek Salenus Anterior Te scalnus anerior uscle Fig. 11-57) is a key muscle to the undersanding of the root of the neck an has een fuly described n page 743. I is deply plced an desceds alost veticall from he verebral column to the first ib. Beause he musle is n important andmark in the neck its rlation should be understod. see page 743

Sclenus Medius The calenu mediu lies ehind the sclenus nterio and extends from te tranverse rocess of the atlas and the transerse rocesss of the next five crvical vertebae (ig. 1157) downward an laterlly to be inserted into the upper surfac of th first rib bhind te grooe for he sublavian artery The mscle les beind th roots of the brachil plexs and he sublavian artery or a smmary f musces of he neck, their nerve suppl, and heir ation, ee Tale 11-.

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Subclavian Artery The right subclaian artry aries from the brachiocephali arter, behid the ight sernoclvicula t (Fig 11-57). It pases upward an laterlly as a genle cure behid the calenus antrior muscle, and at the ouer border of the fist rib it becmes the axilary atery. he lef subclavian rtery rises from the arch of th aorta in th thorax It acends to the root o the nck and then rches ateraly in a manner imilar to that of the right subclavian rtery (Fig. 1-57). The relatins and branches of the subclavian arteris have been dscribe on pae 751. P.83

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Figure 1-116 A. Cros secton of the head a shrt disance beneath the valt of he skull viewed from below. B. Cros sectin of te head at the level f the orpus allosu viewe from elow.

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Subclvian Vin Te sublavian vein bgins a the oter boder of the fist rib as a cntinuaion of the axillary vein (Fig. 11-57). At the medial border of the scalenus nterio it jons the internl juguar vei to fom the rachiocephalic vein.

The Thorcic Duct he thracic duct bgins i the abdomen at the upper end of the csterna chyli (see page 273). I enters the horax hrough the aortic oening n the diaphrgm and ascens throgh the posteror mediastinm, incining radualy to te lef. On raching the superior mediastinum, it is found in upwar alon the lft margin of he esophagus. At the root o the nck, it contiues to ascen along the let margin of te esophagus ntil i reaces the level f the ransvese proess of the seenth crvical vertebra. Here, it bends lateraly behid the arotid sheath (Fig 11-57). On reahing te medil bordr of te scalnus anerior, it turns downward and drains into the bginnin of th left brachiocephalic vein. It may, howver, ed in te termnal pat of te subcavian r intrnal jgular veins.

Clinicl Note Pleua and ung Inuries n the Root of the Neck Te cervcal doe of te pleua and he ape of th lung extend up into the root of the nek on ech sid. Coveed by he surapleual memrane, hey li behin the sbclavin artey. A enetraing wond aboe the edial nd of he claicle my invove the apex f the ung.

Radioraphic Anatoy Before studing th radigraphi appearance of the head ad neck, the tudent is ecouraged to examin photoraphs of secions f the ead and neck (Fis. 11-16 11-17, and 1-118).

adiogaphic ppearace of he Hea and Nck Rotine radiologic examination of th head nd nec concntrate mainl on th bony tructures beause te brain, musces, tndons, and neves blnd int a homgeneou mass Howevr, a few nomal sructurs withn the kull ecome alcifid in te adult, and the displacement of such structurs may ndirecly

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snell giv evidece of a pathlogic conditin. The pineal gland, for exmple, s calcfied i 50% f norml aduls. It ies in the midline. The fax cereri and the coroid lexuse also ecome alcifid freqently. The brain an be tudied indiretly by the injection of contrast edia ito the arteril systm leading to the brain (cerebra arterogram). The introduction of CT and MRI scan has povided physicans wih safe and acurate methods of studying the intracranial contents.

Raiographic Appearance of th Skull The rdiograhic apearancs of te skul as sen on sraight posteranterir views and ateral views an be tudied in Fiures 1-119, 11120, 11-21 and 1-122.

Cerbral Ateriogaphy The echniqe of crebral arteriograph can b used o detect abnrmalities of he cerbral ateries and loalizaton of space-ccupyig lesons suh as tumors, blood clots, or abscsses. Exampls of crebral arterigrams an be een in Figues 11-23, 11-124, 11-125, ad 11-26.

Cmputed Tomogrphy Scns CT is commony used for th detecion of intracanial lesions. It is safe and provides ccurat inforation. Exampls of C scans of the head can b seen n Figre 11-27.

Magnetc Resoance Iaging MRI is als commoly use for detection of intracranial lsions. MRI is absoluely sae to te patint, an becaue it povides better differentiation between gray and white atter n the rain, ts us can b more evealig than a CT san (Figs. 11-128, 11-129, and 11-13).

Surace Antomy Surface Landmaks of he Hea Nsion Te nasin is te deprssion n the idline at the root of the ose (ig. 11131).

Externl Occiital Potubernce This is a bony pominene in te midde of te squaous pat of te occiital bne (Fg. 11131. It ies in the midline at the junctio of th head and nec and gives atachment to the ligaentum uchae, which is a large ligament that runs dow the bck of the nec, connecting the skul to te spinus prcesses of the cervicl vertbrae. line oining the naion to the eternal occipial prouberane ove the sperior aspct of the hed would indcate te posiion of the uderlyig falx cerebri, the uperior sagittal sius, and the longitudial cerbral fissure, whch searates the right an left erebral hemipheres

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Verex Th vertex is te highst poit on he skul in he sagttal plane (Fig. 11-131).

Anerior Fontanlle In the baby, he antrior fntanelle lies between the two haves of the frntal bne in ront and the two parietal bones ehind Fig. 11-13). It is usually not papable fter 1 month. P.25

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Fiure 11117 A. Cros sectin of the head viewed from elow. B. Corona sectin of te head and the upper part of the eck.

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Figure 11-18 A. ross section of the head just below the level f the ard paate viwed from belw. B. Cross section of the nek at te leve of th sixth cervicl vertbra viwed frm belo.

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Figure 11-119 Posteroanerior radiogaph of the skll.

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Figue 11-10 ain fetures hat cn be sen in he poseroantrior radiograh of te skul in igure 1-119.

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Figue 11-11 Lateral radiogaph of the skll.

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Figure 11-122 ain fetures that cn be sen in the lateral rdiograh of te skull in igure 1-121.

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Figure 11-23 ateral interal cartid areriogram.

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Figur 11-12 Main features tat can be see in th arterogram n Figure 11-123

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Figure 11-125 Aneroposterior internl caroid artriogram.

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Figure 11-126 Man features that can be see in th arterogram n Figre 11-25

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Figure 11-27 xial (horizontal) cmputed tomogrphy scns of he skul. A. Th skull bones and th

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brain and the different parts of the laeral ventricls. . scan ade at a lowe level showin the hree canial ossae.

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Figre 11-128 Magnetic resnance maging of the skull A. Axal image of he brain shoing the diffrent prts of the lteral ventrile and the lateral ulcus f the cerebrl hemiphere. B. Coronal iage though the frontal lobe of the bran showng the anteior hon of te lateral ventricl. Note the iproved contrat btween the gry and hite matter compared with the comuted omograhy scns

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seen in Fgure 1-127.

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Figur 11-12 Mgnetic resonace imaging of the skull. . Corona image throug the ocipital lobes of the brain showing the osterir horn of the laterl ventricle nd the cerbellum. B. Saittal mage howing the diferent parts of the brain and th nasal and muth caities.

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Fgure 1-130 Axil (horzontal) magnetic reonance imagin showig the ontents of te orbital and cranial cavities. Nte that the eeballs the otic nrves, he optc chiama, and the xtraoclar mscles an be identiied.

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Poserior ontanele In the baby, the posterior fontanlle lis betwen the squamus par of th occiptal boe and the poterior border of th two parieta bones (Fig 11-13). t is uually losed y the nd of the frst yer.

Suprciliay Ridgs The suprciliary ridgs are wo proinent idges n the rontal bones bove te uppe margin of the orbit (Fig 11-13). Deep t these ridges on eiter sid of th midlie lie he frntal air sinuses.

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Sperior Nuchal Line The uperior nuchal line is a crved rdge tht runs laterlly frm the xterna occiptal prtuberace to he masoid pocess of the temporal bone. It gives attachment to the trapezus and sterncleidoastoid muscles.

Mastid Proess of the Teporal Bone Th mastod procss proects dwnward and forward from behind the ear (Figs. 1-131 and 11-14). It is undeveoped in the newborn child and grows only as the result of th pull f the ternoceidomastoid, as the child oves his or hr head. It cn be rcognized as a bony pojectin at te end f the second year.

Aurice and xterna Auditry Meaus These structures ie in ront o the mstoid rocess (Fig 11-27). The exernal uditor meatu is abut 1 i. (2.5 cm) log and orms a S-shped cuve. To examin the oter suface o the tmpanic membrane in the adlt wit an otscope, the tue may e straghtene by puling he aurcle upard an backward. In small hildre, the uricle is puled staight ack or downwad and ackwar.

Tympanic embran Th tympanic mebrane s normlly parly gay and is concave tward te meatus (Fg. 11-27) The most depressed part of the concavity is clled te umbo and is cause by th attacment o the hndle of the alleus on its medial surfae.

Zygomatic Arch The ygomatc arch extend forwad in font of the ar and ends n fron in th zygomatic bne (Fig. 1111) Above the zyomatic arch i the temporl foss, hich i fille with P.39

th temporalis muscle. Attached to the lower argin f the ygomatc arch is the masster mucle. ion of bot the tmporals and assete muscls (Fig. 11-85) can be fel by clnching the teeth.

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Figure 11-131 A. Righ side f the head sowing elatios of te midde menigeal atery and the brain to the surface of the skull. B Superor aspct and right ide of the nenatal kull. Note the posiions o the nterio and posterior fontanelles.

Sperfical Temoral Atery

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snell The pulsatons of the superficial temoral atery cn be elt as it croses th zygomtic arch, immediately in font of the aricle Fig. 11-131).

Pterio The pterion is the point where he greter wig of te sphenoid meets te anteoinferor ange of te parital bone. Lying 1.5 in. (4 cm) above the midpont of he zygmatic rch (ig. 11131), it s not marked by an eminenc or a epression, bu it is importnt becuse beeath i lies he anerior branch of the middle meningal artry. Above and ehind he extrnal uditor meatus, deep to the auricle, can be felt a smal deprssion, the uprametal P.40

triangle (Fig. 11-131) This is bouded behind by a line drawn verticlly upard frm the posteror marin of he extrnal aditory meatus above by the suprmeatal crest f the empora bone, and beow by the external auditory meats. The bony foor of the tiangle forms he latral wal of he mstoid ntrum.

emporomandibular Jont The teporomadibula t can be easily palpatd in front of the auricle (Fig. 1-131). ote tht as te mout is opned, te head of the mandible rotates and moves forward below the tbercle of the zygomatic arch.

Anteior Brder o the Rmus of the Mndible The nterio borde of th ramus can b felt eep to the msseter muscle The cronoid process of the mandble can be fet with the goved fnger iside te mout, and he pteygomanibular ligamet can be palpated as a tese ban on it media side.

osterior Borer of he Rams of te Mandble Te postrior brder o the rmus is overlaped abve by he partid glnd (Fig. 1185), but below t is esily flt thrugh th skin. The ouer surace of the rmus of the madible s coveed by he masseter uscle nd can be fel on dep palation hen ths musce is rlaxed.

Boy of he Manible The bdy of he mandible is best examind by hving oe finer insde the mouth nd anoher on the ouside. hus, i is pssible to exaine th mandile fro the smphysi menti in th midlne anteriorly, as far backard as the anle of he manible (Fig. 1-131).

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snell The pusation of te facial artry can be fel as it crosss the ower mrgin o the bdy of he mandible, at the anterior border of the maseter mscle (Fig. 11-135).

Anteior Boder of the Maseter The anteior boder of the maseter an be asily elt by clenching the teeth.

Paotid Dct The paroid dut runs forward from the paotid gand on fingebreadt below the zyomatic arch (Fig. 1-135). It can e rolld beneth the examinng finer at he antrior brder o the assete as it turns edially and opens into the mouth opposite the pper scond mlar toth (Fg. 11-2)

rbital Margin The orbital margi is formed b the frontal zygomatic, ad maxilary bnes (ig. 1118.

Supraorbial Noth I preset, the notch an be elt at the junction of the media and itermedate thrds of the uper marin of he orbt. It transmits the supraorbital nerve, wich ca be roled aginst the bone (Fig 1118).

Infraorbtal Foamen The infraorbital framen ies 5 m belo the lwer magin of the orit (Fig. 111), on a ine drwn dowward fom the supraobital otch t the iterval betwee the to lowe premoar teeh.

Infraorbtal Neve he infaorbitl nerv emergs from the foamen ad supplies the skin of the face.

Maxillary Air Sinus The maxllary ir sins is stuated within the maxillary bone and lies below the infraorbial formen on each sde (Fig. 1197)

Fronta Air Snus he frontal air sinu is siuated ithin he frotal boe and ies dep to te supeciliar ridge on each side (Fig. 11-97).

Surfae Landarks o the Neck Anterir Aspet

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snell In the miline anteriorly, the folloing stucture can b palpaed fro above downwad:  

    

Symphsis meti: The lwer magin can be flt whee the wo hales of the body of te mandble unite in the miline (Figs. 11-132 and 1-133). Sbmental triagle: This lies btween the symphysis menti nd the body o the hoid bone (Fi. 11-6). It is bounded anteriorly by the idline of the neck laterally by the anterior belly of the digastric mucle, and infeiorly y the ody of the hoid boe. The floor s formd by te myloyoid mscle. he sumental lymph odes ae locaed in his trangle. Body of the hyoid one: This lies oposite the thrd cerical vrtebra (Figs. 11-1 an 11-32) hyrohyid membrane: Thi fills in the interal beteen th hyoid bone ad the hyroid cartilge (Fg. 11-133. Upper border of the thyroid cartlage: Thi notchd struture les oppsite te fourh cervcal vetebra Figs. 11-13 and 11-132). Criothyrod ligaent: This sructure fills in th interval betwen the ricoid cartilge and the thyroid artilae (Fig. 11-133). Cricid carilage: An importnt lanmark i the nck (Fig. 11132, thi lies at the level f the ixth crvical verteba, at he juntion f the arynx ith th tracha, at he levl of te juncion of the pharynx with the esophagus, at th level of th middl cervial sypathetc gangion, ad at te leve where the inerior hyroid arter enter the tyroid land. .841

Fgure 1-132 Antrior vew of the head and neck of a 29-yar-old woman. Note hat the atlnto-ocipital ts and th cervial par of th verteral clumn ae partally etended for ful

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expoure of the font of the nck.

Figure 1-133 Surace antomy of the eck frm in font.

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Criotrachal ligment: Thi strucure fils in he intrval btween he crioid catilage and th first ring of the rachea (Fig. 11-98).

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Firs ring f the rachea Tis can be fel by getle papation just aove the isthmus of the throid gand. Istmus of the tyroid land: Thi lies n fron of th secon, thir, and ourth ings o the tachea (Figs 11-13 and 11-33) Infrior tyroid veins: The inferior thyroid vens lie in frot of te fift, sixt, and eventh rings f the trachea (Fig 11-11). Thyroidea ima arery: Whe preset, thi arter ascens in font of the trchea t the isthmus of the thyrod glan, from the brchiocehalic rtery Fig. 11-110). Jugula arch: Ths vein connecs the two anerior ugular veins just aove th supraternal notch (Fig. 11-13). Sprastenal noch: This an be elt beween te anteior ens of the clavicles Fig. 1-132). t is te supeior boder of the maubrium sterni and lis opposite the lower border of the body of the second thoracc vertbra.

I the adult te tracea may measur as muh as 1 in. (.5 cm) in diaeter, hereas in a baby it may be narrowr tha a pecil. I young children, the thymus gland may exend abve the supraternal notch s far s the sthmus of the thyroid glan, and the brchiocehalic rtery nd the left bachiohalic vein my protude aove th supraternal notch.

Psterio Aspec In the miline psterioly, th folloing stucture can b palpaed fro abov downward. The externa occiptal prtuberace lies i the mdline t the unctio of th head nd nec (Fig. 11-135). If the index finger is placed on the skin in the midlie, it an be rawn dwnward in the nucha groov. he firt spinus process to be fel is tht of te seventh crvical verteba (verebra pominen). Cervicl spins one o six re covered b the ligametum nuhae.

Lateral Apect Sernocleidomastoid Mscle On te side of the neck, he sternocledomastid can be papated hroughut its length as it es upward from te sterum and clavile to he masoid prcess (Figs. 11-134 and 11-135). The uscle can be made t stand out by asking the patient to approximat the er to te shoulder of the sae side and at the sae tim rotat the had so hat th face ooks uward tward te oppoite sde. If the moement is caried ou againt resitance, the mucle wll be elt to contract, and its anterior and posterior border will be defned. he sternocleidomastoid divdes th neck nto anerior and poterior trianges. Th anteior trangle f the eck is bounde by te body of the mandibe, the sternoleidomstoid, and th midline (Fig 1156). he poserior riangl is bonded b the aterior border of the trapezus, th sterncleidoastoid and te clavcle (ig. 1-56.

Trpeziu Muscl

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snell The anterir bordr of te trapezius muscle (Fig. 1-132) cn be flt by sking he patent to shrug he sholders. It will be seen to extend from the superior nuhal lie of te occiital bne, dwnward and foward t the posterior border of the lateral third of he claicle.

Fiure 11134 Anteior viw of te neck of a 27-year-old man. Note that the head has ben laterally rotated to the left at the atlantoxial jints ad at he joits of he cerical prt of he vertebral column

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Figure 11-35 Surfac anatoy of the neck from the latral asect.

Playsma Muscle The patysma can be seen as a sheet of uscle y askig the patien to clnch th jaws irmly. The muscle extends rom the body of the mandibe downard ovr the clavicle onto the anterior thoracc wall (Fi. 11-5).

Root o the Nck A the root of the nek are he suprastenal noch in the midline anterorly (ee pae 841) an the cavicle. Each clavice is sbcutanous thoughou its etire lngth ad can e easiy palpted (ig. 1-135). It

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snell rticulates at its latera extreity wih the cromio of the scapua. At he medal end of the clavice, the sternoclaviular jint can be identified.

Anterior riangl of th Neck Th isthms of te thyrid glad lies in front of the second, third, and fourth rings of the trachea (Fis. 11-32 nd 1-133). Th latral loes of the throid gand cn be plpated deep to the sternocleidoastoid muscls. Thi is mot easiy caried ou by sanding behind the seated patient and asking the patien to flx the neck frward nd so elax te overying mscles. The observer can then examine boh lobes simultaneouly wit the tps of he finers of both hands.

Carotd Sheath Te carotid shath, which contains the carotid arteris, th intenal juular ein, te vags nerv, and he dee cervical lymph noes, ca be mrked ot by a line ing the strnoclaicular t to a pint miway between the tip of the mastoi proces and he ange of the manible. t the evel o the uper boder of the throid artilae, the commn caroid artry bifurcate into the internal and eternal carotid artries (Fig 11-135). The pulsatios of tese arteries can be felt t this level. P.844

osteror Tringle o the Nck At th posteior trangle f the eck, te spial pat of te accessory nerve is relatvely sperfical as t emeres fro the psterio borde of te sterocleidmastoi and rns dowward ad backward t eneath the aterior border of the trapezius (ig. 11135. The course of this nerve may b indicted as follow: Draw a line from he ange of te mandble to the ti of th mastod process. Bisect this lie at rght anles an exten the second ine donward across the psterio trianle; th secon line ndicats the ourse f the nerve.

Roos and runks f the rachia Plexus The oots ad truns of te bracial plxus ocupy th lower anterior angle of the postrior tiangle (Fig. 11-14 ad 11-135. The upper limit f the lexus an be ndicated by a line drawn fom the cricod cartlage dwnward to the middle of the clavicle.

Third Pat of te Subcavian rtery The thid part of the subclaian artery also occupies te lowe anteror angle of te postrior tiangle (Fig. 11-14 ad 11-135. Its course may be indicated by a cured lin, whic e upwar from the sternoclavicular t for abut 0.5 in. (13 cm) nd the downwrd to the midle of the clvicle. It is ere, were th arter lies n the upper urface of the first rib, that its pulsatons ca be fet easily. The subcavian ein lis behid the lavicl and des not enter he nek.

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External Jgular ein The eternal jugula vein ies in the sperficial fasia dep to te platsma. I e downwrd from the region of the ngle f the andible to th middle of th clavile (Figs. 11-134 and 11-135). t perfrates he dee fascia just bove the clavcle an drain into he sublavian vein.

Salivary Gands The three large salivary gands cn be plpated The arotid gland ies beow the ear in the interval betwee the mndible and te anteior boder of the strnocledomastid musle (Fg. 11-5) The srface marking of the parotid duct is given on pge 787 The submanibular gland an be divide into superficial nd dee parts The sperfical par lies beneath the lower margin of the bdy of he manible (Fig. 11-86). The deep art of the submandibular gand, te submndibulr duct and te subingual gland an be alpate throuh the ucous embran coverng th floor of the mouth n the nterva betwen the ongue nd the lower jaw. Te submandibular duct opens into the mout on th side of the frenulum of the tongue (Fig. 172).

Clinica Problm Solvng Study the followin case istoris and elect he bes answe to th questons folowing them. An 8-year-old girl was taken to a pdiatriian beause hr mothr had oticed a smal painless swellin below and beind th angle of the jaw on the riht sid. On xaminaion, te sweling wa superficial, cool to touch, and showed no redess. Creful alpatin of te neck reveald two irm lups mated toether eneath the anerior order f the ight sernoclidomasoid muscle. xaminaion of the paatine onsils showed moderate hypertroph on bth sids with a few ustule exudig from the tosillar crypts on the right side. The patient id not have a pyrexa. 1. he folowing tatemets conerning this cse are consitent wth the patien having chroic cerical lmphadeitis except hich? a) Th lymph drains from te tonsl into the sperfical cerical lmph noes, whch whe enlared prouce a swellng below and behind the angle of he jaw () Tubeculous cervicl lympadenits is a chronic infection that can enter the tonsil and spread to the lymph nodes. (c) The investing layer of deep cervial fasia can limit he sprad of nfectin in te neck (d) Tberculus infction f a lyph nod commonly spread to oter nods in te grop and hey bcome mtted tgether. e) Tuerculos infection esults in th destuction of the node wth the formaton of us tha later erodes throgh the deep fscia, roducig a lage col absces beneth the skin.

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snell (f) econdary infetion o a col absces causs the bscess to brek throgh the skin to form a discharging sinus. View nswer 1. A. Te lymp drain from he tonil int the jgulodiastric member of the deep cervica lymph nodes. A 25-yea-old wman cmplainng of a swelling on the front of the nck and breathessnes visied her physician. On examiation, a small, soliary swelling f firm consistency as foud to te left of the midline of the neck below the throid crtilag of th laryn. The wellin was nt attahed to the sin but moved pward n swalowing. About weeks previosly th sweling had suddenly increased in siz and bcome tnder t touch follwing tis incease in size the patient bcame beathles. 2. The folowing statements concernig this case wuld sugest a diagnois of denoma of the thyroid glan except which a) The pretrcheal ayer o deep ervica fasci binds the throid gand to the laynx, wich moes upward on swalloing. () Each lobe f the thyroid gland s closly relted to the sies of he trahea. (c) The isthmus of the thyroid land ws foun to crss in ront o the tird, furth, nd fifth rins of te trachea. (d) Th sudde increse in he siz of the swelling can be explained by a hemorrhae into the adnoma. (e) Te sweling wa locatd superficia to th left ternotyroid uscle. (f) The brathlesness ws causd by the adenoma pressing on the trachea, partilly ocluding the lumen. Viw Answr 2. E. The throid gand lis deep to the sternothyroid muscls. A 70year-od man complaining f a sall panless swelling below his chn visied his physiian. On questioning, he said that he had first oticed the selling 4 monts earler and that i was gadually increasing n size Becase it ad not caused any dicomfor, he hd chosn to inore i. On xaminaion, a single small hard wellin could be palpatd in te subental riangl. It ws mobie on te deep tissue and not attched o the skin. 3. The following statements sugget that the had sweling wa a secndary alignat depoit in lymph node except which? (a The sbmenta lymph nodes re loated i the sbmental trianle just below the chn.

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snell (b) The submental lymph odes dain th tip f the tongue, the loor o the mouth in the reion of the frnulum of the tongue, the gums and incisr teet, the iddle hird o the ower lp, and the skn over the chin. (c) A small, hard-based carcinmatous ulcer as foud on te righ side f the ongue ear the tip. d) Th deep ervica group of lymh node beneah the ternoceidomstoid uscle eceive lymph rom th submental lymph nodes. (e) The submental ymph ndes li deep o the uperfiial pat of te submndibulr saliary glnd. Vie Answe 3. E. he subental ymph ndes ar not covered by the superfcial prts of the sumandiblar saivary lands. A 45-year-old man with extensiv maxilofacia injures aftr an atomobie accient wa brouht to the emergency department. Evaluatin of te airwy reveled prtial bstruction. Despite n obvius fratured andibl, an atempt was mae to mve the tongue forward from the posterior pharyneal wal by ushing the anles of the madible orward This aneuve faile to mve the tongue and i becam necessary to hold the togue foward irectl to pull it away frm the osterir pharngeal all. 4. The ost liely reson th physiian wa unabl to pul the ongue orward in thi patiet is wich? (a) Te hypolossal nerves were damaged on both sides of the neck. (b) Sasm o the syloglosus muscles (c) The mandibular origi of th geniolossus muscle was foating becaus of biateral fractues of the body of the mandble. (d) The prsence f a blod clo in th mouth () The esistace of he patent Vew Answer 4. C. The genioglssus mscles rise from th superor menal spines beind th symphsis meti of he manible. Hving pssed a larynoscope into patiet, the anesthtist vewed te follwing natomi strucures i order from te base of the tongue to the trachea. 5. Al the fllowin strucures wre corectly ecognied ext whih? (a) Te medin glosoepiglttic fld and the valleculae (b) The two lateral glossepiglotic fods (c) The upper edge of the epiglotis

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snell d) The aryepiglottic folds (e) The rounded swellings of the cuneifrm and corniclate crtilags (f The mbile vestibular folds g) The whitish vocal cords (folds with he rim glottdis View Answe 5. F. The vesibular folds f the arynx re fixd and eddish and th vocal folds are moile an whitih. A 17-yer-old oy was seen n the emergency department after eceivig a stb woun at th fron of th neck. The nife etrance wound was located on the lft sie of te neck just lteral o the ip of he greter cornu of the hyoid bone. During the physicl examnation the paient ws aske to potrude his togue, wich deiated o the eft. 6. The following statements would explai the pysical signs n this patien excep which? (a) he genioglosss muscles ar respnsible for potrudig the ongue. (b) he genioglosus musle is upplie by th glosspharyneal neve. c) Paalysis of the left gnioglosus mscle prmitte the rght geioglosus to ull the tonge forwrd and turne the tp to te left side. (d) The hypolossal nerve descens in te neck betwee the iternal carotid artery and the intrnal jgular ein. (e) At about the leel of he tip of the greater cornu of te hyoid bone he hypglossa nerve turns orward and cosses he intrnal ad extenal caotid ateries and th lingul artry to nter the tongue. (f) The pint of the knfe blae severed the left hypoglssal nrve. View Anser 6. B The gnioglosus mucle is supplied by the hypoglossa nerve 43-year-old woman was seen in te emerency dpartmet with a larg absces in te middle of the riht poserior riangl of th neck. The abcess ws red, hot, ad flutuant. The abcess sowed eidence that t was pointing and about to ruptre. Th physiian decided t incise the ascess nd insrt a rain. he patent reurned o the epartmnt for the drssings to be change 5 days late. She tated hat she felt uch better and that her nck was no loner paiful. Hwever, there as one thing hat sh could not understand. She could no loner raie her ight hnd aboe her ead t brush her har. . The following staements explai the sgns an sympoms in this cse, sugestin that the spinal pat of te ry erve hd been incise, excet whic? (a) T raise the had abov the head, it is ncessar for the trapzius mscle, ssiste by th serraus anerior, to conract and roate te scapla so hat th glenod caviy facs upwad.

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snell () The trapezius muscle is nnervaed by he spial par of th ry neve. (c) A the sinal prt of he accssory nerve crosses the posterior trianle of the nec, it i deepl place, beig coveed by he ski, the uperfiial facia, te inveting lyer o deep ervica fasca, and the lvator capula muscl. (d) The surfac markig of te spinl par of the ry nrve is as folows: Bsect a right angles a line ng the angle f the aw to he tip of the mastoi proces. Cotinue he secnd lin downwrd and backwad across the posterior triangle. (e) The knife penin the abscess had cu the or nerve View Answer 7. C. Th spina part f the accessry nere lies superfcial t the evator scapule muscle in the posterior triangle of th neck. A 35-year-old woma had a partil thyridectoy for he tretment f thyrtoxicois. Duing th opertion a ligatre slped of the rght superir thyroid rtery. To stop the hemorrage, te surgeon blndly gabbed for th arter with artery forcep. The peratin was ompletd withut furher inident. The fllowin mornig the atient spoke ith a usky vice. 8. he folowing tatemets about thi patint would explain the husky voice xcept hich? a) Laryngoscopic examinatin reveled tht the ight vcal cod was lack, ausing the hukiness of th voice (b The vocal cord is tensed by the ontracion of the crcothyrid musle. (c) Th cricohyroid muscle tilts back te cricid carilage nd puls forwrd the thyrod cartlage. (d) The cricothyroid muscle is inervate by th recurent layngeal nerve. (e) The suerior hyroid artery is closely related to the xterna laryngeal neve. View Aswer 8. D. The cricotyroid uscle s innrvated by the externl larygeal nrve, wich wa damagd in tis patient. A 46-ear-ol man ws see in th emergncy deartmen after being knocked down in a steet bawl. H had rceived a blow on the head wth an mpty bttle. n exainatio, the atient was coscious and had a lage douhlike swellig over the bak of te head that ws resticted o the rea ovr the occipial bon. The kin wa intac, and he sweling fuctuatd on palpaton. 9. The fllowin stateents cncernig this patien are crrect xcept hich? (a) The hmatoma althogh lare, did not etend frward o the rbital margin and dd not extend lateraly as far as the teporal ines.

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snell b) The hematoma was locate just eneath the picranial aponeurosis and as superficia to th perioteum o the ccipitl bone c) Th swellng did not ocupy th subcuaneous tissue of the scalp. (d) The hematoma s resticted o one kull bne and is sitated bneath he perosteum e) The edge of the wellin is liited b the atachmet of te peristeum o the sutura ligamnts. View Anser 9. B The hmatoma was loated dep to he perosteum of the occipital bone. A 17-ear-ol girl visite her dermatologist because of severe acn of th face. On exminatin, it as foud that a smal absces was resent on the side of the nose. he patient wa given antibitics and was warned not to press the abcess. 1. The following facts concrning his paient ephasiz why i is imortant to adeuately treat this conditio except which a) The skin aea between the eye, the uper lip and te side of the nose i a hazrdous rea to have an infetion o the sin. (b) The danger area is drained by the facial vein. () Inteferenc with boil y squezing o pricking it can lead to spread o the ifectio and tromboss of te facil vein (d) The facial vein cmmunictes wih the avernos sinus via the superior and inferior opthalmi veins (e) Cavernus sins throbosis an occur by he sprad of infection by he venus blod. (f) The blood in the faial vein is unable to sprad upwrd becuse of valves Vie Answe 10. F The fcial ad ophtalmic eins do not possess valves so that infeted blod fro the fce can spread to the cavernus sins. A 7-year-od boy ith rght-sied otitis media was treated with ntibioics. Te orgaisms id not respon to th treatent, and the infection spread to the mastoid atrum ad the astoid air cels. Th surgen decided to perfom a raical mstoid peration. Aftr the peratin, it as noiced tat the boy's ace wa distoted. 11. Th folowing signs nd symtoms suggest that the right facial nerve had ben damaed durng the operaton ext whih? (a) The moth was drawn pward o the ight. () He ws unabe to cose hi right eye.

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snell (c) Saliva tended to accmulate in his right cheek. (d) The saliva tended to drible frm the corner of his mouth. (e) Al the uscles of the right side o his fce wer paralzed. Viw Answer 11. A. The facial muscle on th left ide of the moth on ontraction pull the mouth upward and to the let becase the muscles on the right side were pralyze. 43-yar-ol woman visitd her hysicin compaining of sevre intrmittet pain on the right side f her ace. The pain was prcipitaed by xposin the rght sde of er fac to a raft o cold ir. Th pain as stabing i nature and lasted about 12 hours before finaly disapearin. When asked to poit out n her ace th area here te pain was exeriencd, th patiet mappd out the skin area over the righ side of the ower jaw extendin backwrd and upward over he sid of the head o the vertex 12. The folowing signs nd symtoms i this atient strongy suggst a dagnosi of trigeminal neurlgia ecept which? (a) The skn area where the patient eperienced the pan was nnervaed by he manibula divison of the trgemina nerve (b) Te stabing nature of the pan is caracteistic f the isease (c) The trigger mechanism, stiulatio of a area hat reeived ts senory inervatin from the trigeminal nerve, is characteristic of trieminal neuralia. (d) Eaminaton of he actons of the master and the emporais musles shwed evdence f weakess on the right side. e) The patien experienced hyperethesia in the distriution f the ight ariculoempora nerve View Aswer 12 D. Th motor portio of th trigeinal nrve is unaffected in patients with trigeminal nuralgi. 10-yer-old oy was playig darts with his frends. e bent down t pick p a falen dat whe anothr dart fell fom the dart bard an hit him on the side of his face. On examinatin in te emerency dpartmet a smll ski wound was found over the right parotid salivay glan. Then 6 monts late, the boy's other oticed that bfore maltime the by bega to swat prfusely on the facial skin lose t the ealed art wound. 13. he folowing tatemets can explain this phenomenon except which? (a) Th point of the dart hd entered th paroid salvary gand an damagd the arasymatheti secreomotor fiber to th gland (b) Te secrtomoto fiber to th parotd glad arise in te otic ganglin.

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snell c) The preganlionic parasypathetc fibes originate in the superior salivatory nucleus f the acial nerve. (d) The ski over he parotid saivary land i innerated b the geat auicular nerve, which as also damaged by the dart. (e) On egenertion o the dmaged erves some of the parasympathetic neres to he parotid slivary gland had cossed ver an e the smpatheic secetomotr nervs to te swet glans in te distl end f the reat aricula nerve. f) The patient has Frey's yndrom. Viw Answr 13. . The ecretootor fbers to the arotid salivay glan origiate in the nferior salivatory ucleus of the glossoharyngal nere. A 6-year-old baseball playe was sruck o the rght sie of te head with a ball. The plyer fll to he grond but did no lose onsciosness. After esting for 1 hour ad then gettin up, h was seen to be confused ad irriable. Later, he stagered nd fel to th floor On qustionig, he as see to be drowsy and titching of the lower left half of his fae and eft am was oted. 4. A dagnosi of exradura hemorhage was mad based on the followng staements except which? (a) minor blow on the side of the hed can asily ractur the tin antroinfeior pat of te parital boe. (b) Th posteior brnch of the mddle mningea arter may be sectined at the sie of te fracure. (c) Artrial hmorrhae outsde the meningeal layer of the dura mater may occur. (d) A large lood cot outide th dura an exet presure on the loer end of the precentral gyrus. () The lwer en of th precetral gyrus or motor area supplies the faial mucles ad the uscles of the upper limb. View Answe 4. B. he antrior banch o the middle eningel artey may e sectoned at the ste of he frature. A 49year-od woma was ound on ophthalmoscopic exmination to hve eema of both otic dics (bilateral papilledema and cngestion of bth retnal vens. Th cause of th condiion wa found to be rapidy expading intracranial tumor. 1. The ollowig statments concerning ths patint are correc excep which () An itracranial tumor causes a ise in cerebrspinal fluid ressur. b) Th optic nerves are srrounded by heaths derivd from the pa mate, arachnoid ater, and dua matr. () The intracranial subaracnoid sace exends frward round he optc nerv for aout haf its ength. 1572

snell (d) he thi walls of the retinal vein will be compessed s the ein crsses the extesion o the ubaracnoid pace aound te opti nerve (e) Becaus both ubaracnoid etensions are continuous with the intracanial ubaracnoid sace, bth eye will exhibi papiledema nd conestion of the retinal veins. View Anwer 15. C. The intracanial ubaracnoid sace exends frward round he optc nerv as fa as th back f the yeball A 52-yea-old mn was eating his dnner in a seafood restaurant when he sudenly coked o a pice of ish. H gaspe that e had bone tuck i his troat. 16. Assuing tht the ish boe was tuck i the priform fossa, the folowing statemnts ae corrct ext whih? (a) The piriform fossae lie on either side o the etrance into te laryx. (b) Th mucou membrne linng the pirifom fosse is snsitiv and inervatd by te recurrent laryngeal nerve. (c The priform fossa is bounded laerally by the thyroi cartiage an the tyrohyod membane. () The piriform fosa is bunded medialy by te aryeiglottic fold. (e The priform fossa eads iferiorly into the esophagus. View nswer 16. B. he mucus memrane lning te piriorm fosa is nnervaed by he inernal aryngeal branch of he suprior lryngea nerve from te vags. P.45

P.846

P.847

Review Qestion Cmpletin Quesions

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snell Select the phase tht best completes each statment. 1. he levator palpebrae superoris mscle is innevated by the () facial nerve. (b) trochlar nere. (c) trigeminal nerve. (d) oculomotor nerve. (e) abducent nerve. Vew Answer 1. D. The smooth muscle fibers of the levato palperae sueriori are innervted by the sympathtic neves. Te greater part of the muscle is made up of strated mscle, hich rceives its inervation from the culomoor nere. Divsion o the oulomotr nerv cause sever ptosi. 2. The inferior oblique uscle f the ye is nnervaed by he (a abducnt nere. (b trigeinal nrve. (c) ocuomotor nerve. (d) fcial nrve. (e) troclear. View Answr 2. C 3. The lteral ectus uscle f the ye is innervated by the (a optic nerve. (b) trchlear nerve. (c) oculomotor nerve. (d facial nerve. (e) bducen nerve iew Aswer 3. E . The superior obliue musle of he eye is innrvated by the

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snell (a) trigeminal nerve. (b) trochear neve. c) abducent nerve. d) choda tymani neve. () oculomotor nerve. View Anwer 4. B 5 The orbicularis oculi muscle is nnervaed by he (a) facial nerve. (b) larimal erve. (c) maillary nerve. (d) nsociliry nere. (e) frontl nerv. View Aswer 5. A. The orbicuaris ouli mucle is a muscle of acial xpresson. 6. The mandiblar diision f the trigemnal neve leaves the skull hrough the (a) superio orbital fissure. (b) foamen rotundum. (c) oramen ovale. (d) jugular oramen (e) framen agnum. View Anwer 6. C. Bot the mtor an sensoy diviions o the mndibulr diviion of the tigeminl nerve leav the skull toether and quickly unte benath te foraen ovale. 7 The vgus neve leaes the skull through the (a) jugular foramen. (b occipital foramen. (c) inferior orbital fissue.

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snell (d) foraen rotndum. (e) foamen sinosum View Answer 7. A. The glossopharyngeal, agus, nd accssory crania part) nerves leave the skll through te juguar foramen; the sigmid sinus s thrugh th posteior pat of te same forame to beome th interal juular vein. 8. Th abducnt nerve leavs the kull trough he (a) oramen rotundum. (b jugulr foraen. (c) infeior orital fssure. (d) uperio orbitl fissre. (e) formen ovle. View Answer .D 9. The ophthalmic divisin of the trigemial nere leavs the kull trough he (a) nferio orbitl fissre. b) foamen oale. () foraen rotndum. (d) suerior rbital fissur. (e pteryopalatne formen. Vew Answer 9. . The ophthalmic diision f the trigeminal nrve leves te skull thrugh th superior orital fssure as its three erminal brachesâ€namely the acrima, fronal, and nasociliary nerves. 10. he maxllary ivisio of the trigminal erve laves te skul throuh the (a) forame spinoum. () foraen rotndum. (c) sperior orbita fissue. () foraen ovale. (e) jugulr foraen.

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snell View Answer 0. B 11. Th oculootor nrve leves the skul throuh the (a) infrior obital issure (b) forame rotundum. c) suprior obital issure (d) forame magnu. (e) foramen ovale View Anwer 11. C. The oculomtor neve pases thrugh th superor orbtal fisure a upper and lower diisions 12. The otic caal is n opening in he (a) lesser wing of the spenoid one. (b) ccipitl bone (c) petrous part of the tmporal bone. (d) fronta bone. e) squamous part of the temporal one. View Aswer 12. A 13 The crotid anal i located in the (a) frontal bone. (b) occiital bne. (c petros part of the temporal bon. () greater wig of te spheoid boe. e) parietal one. Vie Answe 3. C 14 The framen pinosum is located in the

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snell (a) sphenoid bone. (b) ccipitl bone (c) frontal bone. () petous pat of te tempral boe. (e) sqamous art of the teporal one. View Answer 14 A. The foramen spinosum is locaed in he greter wig of te spheoid bone; the middle eningel artey s throgh thi foramn into the mddle canial ossa fom the infratmporal fossa. 5. The hypoglossal canal is locatd in te a) sqamous art of the teporal one. (b) occiptal bne. (c) fronal bon. (d) phenoi bone. (e) paietal one. Vie Answer 15. B. The hypoglosal canal is stuated above he antrolateal boudary o the framen magnum. 16. The forame rotunum is ocated in the (a) leser wig of te spheoid boe. (b) frntal bne. (c petrous part of the tempoal bon. () occipital one. (e) greaer win of th sphenid bon. Viw Answr 16. . The oramen rotundm tranmits the maxillary division of th trigminal erve from th middle cranal fosa of te skul into he ptrygopaatine ossa. 17. The faial neve canl is lcated in the (a) tempral boe. (b) greate wing of the sphenoid bone

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snell () occiital bne. (d mastoid process. (e) lacrimal bone. View Answr 17. A 1. The forame magnu is loated i the (a) phenoi bone. (b) temporal bone. (c) paretal bne. (d) frontl bone (e) ocipita bone. iew Anwer 18. E. Th foramn magnm tranmits te medula oblngata, the spnal pat of he accssory nerve, and the right and left vertebral ateries 19. The genioglossus muscle _______ he tonue. (a) retracts (b) epresss (c) elevates d) protrudes (e) chages the shape of View Answer 9. D. Remembr that contration of the right gnioglosus mucle (for exaple) points te tip f the ongue to the patient's left. 20. he hyolossus muscle (a) canges he shae of he tongue. (b) elevates the tongue. (c) deresses the togue. d) protrudes the tongue.

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snell (e) retacts te tonge upwad and ackward. View Anwer 20. C 1. The styloglossus muscle (a) protruds the tongue (b) epresss the tongue. (c) retract the tngue uward ad backard. (d) change the sape of the togue. (e) levate the tngue. Vew Answer 21. 2. The palatoglossus muscle (a) depresses the tongue. (b) elevats the tongue. (c) canges he shae of te tonge. (d) reracts he tonue upwrd and backwad. (e) potrude the tngue. View Anwer 22. D Muliple-Coice Questions Slect te best answer for each quetion. 23. Te follwing uscles of the pharyx receve their moto innervation rom th pharngeal lexus ia the crania part f the ccessoy nerv excep whic? () Superior constrictor (b Palatopharyngeus (c) Styopharyneus (d) Middle cnstrictor (e) Salpingophryngeu

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snell View nswer 2. C 24. The folowing statemnts cocerning the tellat ganglon are correc excep which a) It is fored fro a fuson of he infrior crvical ganglin with the irst toracic ganglin. (b) It ha white and gry rami communicantes, which to spinal nervs. c) It s locaed behnd the verteral arery. (d) It lie in th interal beteen th transerse process of the seventh cervial vertebra ad the neck of the first rib. (e) The large anerior tuberce of he trnsvere procss of he fifh cerical vrtebra is an imporant urface landmark whe perfoming a stellte ganglion block. Vie Answe 24. E. The large anterior tuberce of te tranverse rocess of the sixth cervicl vertebra i an imortant surfac landmrk whe perfoming stellate ganglion block. 2. The ollowig statments oncernng the chord tympai are orrect except which? () It cntains parasympathetic posganglinic fiers. (b) It ontain specil sensry (tate) fibers. (c It jons the lingua nerve in the infratempoal fosa. (d It is a branch of the facial nere in te tempral boe. (e) It carries scretomotor fiers to the sumandiblar an subligual slivary glands. View Anser 25. A. It cntains parasypathetc pregnglionc fibes. 26 The followig statments oncernng the pituitry glad (hypophysis cerebri) are correc excep which (a) It is eparatd from the opic chiasma by the diaphraga selle. () The phenoi sinus is infrior to it. (c) It receives its arterial spply fom the internl caroid artry. d) It s suspnded from th floor of the third ventricle by the pars anteror. (e It is deeply placed within the slla tucica o the sull. Viw Answr

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snell 26. D The ptuitar is supended from he flor of te third ventrcle by the inundibuum. 2. The ollowig statments oncerning he subandibuar lymh node are crrect xcept which? (a) Thy drai into he dee cervial lymh node. (b) They drin the tip of the togue. (c) hey drin the skin o the forehead. (d) The are stuated on the superficial surface of the submanibular salivay glan. (e) Tey dran the ucous embran linin the ceek. View Answer 7. B. The lymph from the tip of te tonge drais into the sumental lymph odes. 28 The followig statments oncernng the cervicl part of the esophagus are correct excet whic? (a) The sesory nrve suply i the ecurret larygeal nerve. (b) The lymph rains nto th deep cervical lymph nodes. (c) It is the site of an importan porta–sysemic aastomois. (d) The lumen s narrwed at the juction with the pharynx. (e) It beins at the leel of he crioid catilage, opposite the body of the sixth crvica vertera. Vie Answer 28. C The iportan porta–systemic nastomsis is locate in th lower third of th esophgus whre it asses hrough the diphragm and eners te stomch (se page 245). 29. The ollowig statments oncernng the parotid salivary gland are correct excet which? (a) he facal nere s throgh it, dividing the gland into superficial and eep pats. (b) The secretomotor nerve supply is erived from te facil nerv. (c The parotid duct pierces the bucinator muscle and opns int the muth. (d) The external carotid artery ivids withn its ubstane to frm the superfcial tmpora and mxillar arteres. (e) Te retrmandiblar ven is frmed wthin i by th union of the superfcial tmpora vein nd the maxillry vei. Viw Answer 29. . The ecretootor nrve supply t the protid alivar gland is fro the nferio salivtory ncleus ia th glosspharyneal neve.

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snell 0. The followng staements concening te head and nek are orrect except which? (a) The astoid proces of th tempoal bon canno be papated n the ewborn () The eep cevical ymph ndes are situated i the nck alog a lie that extend from he midoint betwee the ip of he masoid prcess ad the ngle o the mndible down o the ternocavicular t. (c) The external jugular vein rus down the nek from the anle of he jaw to the middle of th clavile. () The arotid duct oens ino the mouth opposit the uper seond moar tooh. (e) Th anterior fntanele can e palated in a baby between the squamous part of the temporl bone, the parietl bone and te greaer win of th sphenid. (f) The root of the brachal pleus emrge ino the osterir triagle on the nek beteen th scaleus anerior nd scaenus mdius mscles. iew Anwer 30. E 1. The following fats concerning the togue ar corret except which? () The intrinsic muscles of the togue ar innerated b the hpoglosal nere. (b) Th taste buds o the vllate apillae are innervated by he glosopharyngeal erve. () The osterir thir of the tongue foms part of the anteror wall of te oral pharyx. d) Lymphoid issue is foud on he antrior tird of the dosum of the tongue. (e) On eiter sid of th frenuum of the tongue ar situated the openins of te submndibulr duct. View Answer 1. D. The lyphoid issue s found on the dorsum o the psterior thir of the tongue (ligual tnsil) here i forms part of the ring of lymphod tisue guading te entrnce ino the harynx 32. Which f the ollowig musces eleates te soft palate during swallowing? (a) Tensor veli platini (b) Palatglosss (c) Palatopharyngeus (d) Levatr veli palatii (e) Salpingopharyngeus Vew Answer

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snell 32. D 3. Which of the following muscles partialy insrts on the aricular disc of the temporoandibuar joit? () Medial ptrygoid (b) Anterio fiber of th tempoalis (c) assete (d) Poterior fibers of the temporalis (e) ateral pterygid View Answer 33. E 34. Assumig that the ptient's eyesight is normal in whch craial neve is there ikely o be a lesin when the diect an consesual lght relexes re absnt? (a) Trochlear nerve (b) Optic nerve (c) Abducent nerve (d) Oulomotor nerve (e) rigemial nere View nswer 34. D 35. A patint is nable to taste a pece of sugar laced n the nterio part f the ongue. Which cranial nerve is likely to have a lesion (a) Hpoglosal (b) Vagus (c Glosspharyneal () Facil (e) Maxillary division of he trieminal View Answer 35. D

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snell 3. On aking a patien to say “h,― he uvua is sen to e draw upwar to th right Which cranil nerv is liely to be damaged? () Left glossoharyngal (b) Righ hypogossal c) Left accessory (ranial part) (d) Right agus () Right trigminal Vew Anwer 36. C 37. Wen tesing th sensory inervatin of te face, it i imporant to rememer tha the skin o the tp of the nos is suplied by whih one f the followng neves? (a) Zygomati branc of th facial nerve () Maxillary division of th trigeinal nrve (c) Ophthalmic diision f the rigemial nere (d) Exernal asal banch o the facial erve (e) Buccal branch of the mandibular division of the trigemnal neve Vie Answe 37. . The xterna nasal nerve s a continuation of the anterior ethmoidal brach of he nasociliary branch of the ophthalmic ivisio of th trigminal erve. ead th case histories and select the bet answr to te quesion folowing them. An 18-year-ld womn wen to he physician because she had notice a swelling n the idline of he neck. She said she had first notced ths sweling 3 ears reviouly, and it ha gradully inreased in size. On hysica examnation a smal sweling wa found in the midlin of th neck; it mesured bout 05 in. 1.25 c) in dameter It wa situaed jus belo the bdy of he hyod bone, was soft and fluctuant, and move upward on swallowng. Nohing ese abnrmal ws discvered. 38. Th physician made the diagnois of hyroglssal cst basd on te follwing smptoms and signs except whch? (a) he sweling ws not hard. (b) Te sweling wa fluctant. (c) The swelling was located in te midlne of he nec.

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snell (d) It movd upwad on sallowig, whih indiated tat it as tetered t tissu assocated with th thyrod glan. () A throglosal cys is alays found below the hyoid one. View Answr 38. E. A throglosal cys occur most ommonl in th midlie of te neck below the hoid boe and bove te isthus of he thyoid gand. It should be emhasizd that it can occur anywhee alog the path o the hyrogossal tract, even as far uperioly as he foramen cecum of the tongue. As the cyst enarges t is pone to infecton so t shoud be emoved surgiclly. A 4-week-old baby boy was eamined by a pediatrician because of failure to gain eight and difficulty with feeding. The mother said tat the child as brest-fed and egerly ccepte the mlk whe it was manually expressed from te brest, bu obviosly wa havin diffiulty i suckig at te nippe. Th physiian caefully examind the aby an then ade a iagnoss and advise approriate reatmet. 39. he following statements about ths case are corect ecept wich? (a) The condition is often assoiated ith a left uper li. (b) The baby had a medin clef palat. c) The cleft in the palate involvd the ard paate bu not te soft palate or the uvula. d) The difficulty with the feedin was tat the cleft alate prevnted te chil from actively sucing mik from the beast. (e) urgica repair of a cleft palate should be undertaken at or before 18 monhs. View Answer 39. C. uring evelopent th palatl procsses o the mxilla row mdially and fue with each other ad the asal sptum; he fusion of the pocesse takes place rom anerior o postrior s that the uvla is the lat part of the palate to fuse, and this ocurs a about the 1th wee. If te peditricia had mde a mre thoough eaminaton in a good light, he or he woud have seen tat the cleft n the ard palate extended all the way posterorly t the tp of te uvul. Surical rpair o a clet palae must be undrtaken before the chld strts to speak. In th meantme, th child should be fed with te moter's milk with a pipette or spoon, after carefu manua expresion. Becaus of th risk f aspiation neumona, gret care must b taken to prvent te milk from puring own th throa into he larnx. P.848

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.850 Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

13. 12. The Back A 3-yea-old womn decidd to hel her neighbor move hi car, whch was stuck in snowdrift. Ater much pushing, the car woul not mov. It was decided o make oe lat effort and thi time te bak of the car was to be lited by is bumper. Sudenly the woman eperienc a shar, shootig pain i the lowr back. t the sae time she flt a dep, sharp pain dow the bac of the right leg. She tried t walk but her back fet “locked,― nd any atempt t mov intensiied the pain. On being questioed by he physician, the atient ointed t the lowr back a the sie of maximum pai and then ran he finger down the back of the thig and the outer sde of her right leg. On phsical eaminatio a decrese in te range f motin of the lumbosaral regin of the spine was noted. When askd to walk, she as relucant to pt her weght on te involed leg. The pain was mae worse y sittig and coghing. Eaminatio of the muscles f the lgs reveaed weakess in extension f the riht big te and slght weaness of he dorsilexors f the fot. The mscle refexes wer normal in both lower limbs. Slight sensry defict was prsent ovr the aterior art of te right eg and te dorsomdial aspct of th foot dwn to th big toe. Tensio on the lumbar scral nere roots as creted when the patint was i the supne positon. With the pelvs stabilized, te right eg was slowly raised by the heel, wit the kne extendd. The ptient experience severe ain down the leg elow the knee. Rdiographc and cmputed tmography (CT) exaination evealed nothig abnormal. A manetic reonance maging (RI) stud showed a hernited dis between the fourh and ffth lumbr vertebae, whic indicated that the nuclus pulpous was robably ressing n the fifth lumbar nerve root and would eplain th symptom and sigs. Lo back pn is a common coplaint n clinicl practie and my be cased by a wide spctrum of disease. The antomy of he regn is coplex, an many stuctures ave the otentia to caus pain. Only by aving a sound knowledge of the anatomy and the patologic rocess ivolving he area an the pysician dentify he cau and start treatment. P.852

hapter Ojectives  

Back injuries rage from simple muscular or ligamentous back strai to a caastrophi injury of the pinal cod or caua equina. utomobile accidets, motocycle accidents gunshot wounds, nd sport injuries are jut some of he comon cause of back injuries found in practic.

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Becaue of the anatomic configuration of this reion, unpotected ovement of the dmaged vrtebral olumn uring intial medcal care at the ite of te accidet can reult in irreversble injuy to th delicat spinal cord. ack pain provides the practicing physicia with a hallenge The phyician's ask is to identiy the lkely souce of th pain an the pahologic rocess ausing i. Th purpos of this chapter s to review the basic antomy of he verteral colun and rated sot nervou tissue structurs so tha the phyician wll feel easonabl confidet to institue the apropriat treatmet.

Basic natomy The bck, whih extend from te skull o the tp of the coccyx can be efined a the poterior srface o the truk. Supeimposed n the uper part f the poterior srface o the thoax are he scaplae and he muscls that onnect te scapule to the trunk.

The Vertebral Coumn The verebral coumn is e centrl bony pllar of he bod. It s the skull, pctoral irdle, uer limbs, and thracic cage and, y way of the pelic girdl, transmts body weight to the loer limbs. Within its caviy lie th spinal cord, th roots o the spnal nerves, and te coverng meninges, to wich the vertebral olumn gves gret protecion.

Compoition of the Vertbral Column The vetebral olumn (Fig. 12-1 and 12-2 is coposed of 33 vertbrae—7 cervica, 12 thoacic, 5 umbar, 5 sacral (fused t form te sacrum, and 4 coccygea (the lwer 3 ar commony fused). Becaue it is egmented and made up of vtebrae, oints, nd pads of fibroartilag called inervertebal discs, it i a flexble struture. Th intervetebral scs for about oe fourth the lenth of the column.

Genera Charactristics f a Vertbra Although verterae show regional differenes, they all possss a common pattern (Fig. 2-2). A typical vertbra cnsists o a roundd ody ateriorly and a vertbral arc postriorly. hese encose a spce calle the verteal foramen, though whih run th spinal ord and ts covengs. The vertebrl arch cnsists P.83

of a pair of cylindrical pedicles, whic form th sides o the arh, and a pair of lattene lminae which cmplete te arch psteriorly.

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Figure 121 Poserior viw of th skeleton showing the surace markings on te back.

Th vertebal arch ives ris to seve proceses: one pinous, wo transverse, and four aricular Fi. 122). The spinos proces, or spine, s directd posterorly fro the jution of the two aminae. he tranverse processes are direced latrally frm the juction of the lainae and the pedcles. Boh the sinous an transvese proceses sere as levrs and rceive atachments of muscls and liaments.

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snell Te articula processes re vertically rranged and consst of to superior and to inferior procsses. Thy arise rom the unction of the laminae ad the pdicles, nd thei articulr surfaes are overed wth hyalie cartlage. Th two suprior articular rocesse of one ertebra arch articulate with the two infrior aricular pocesses of the arch aboe, formig two syovial jonts. The pdicles ae notched on ther upper and lowe borders forming the superor and iferior rtebral notches. On eac side, te superior notch of one vertebra ad the inerior noch of an adjacent vertebr togethe form an iterverteral foraen. hese formina, in an articlated skleton, srve to tansmit te spina nerves and bloo vessels The antrior and posterior nerve oots of a spinal nerve unte with these foramina with ther coverigs of dra to fom the semental sinal neres. P.54

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Figure 12-2 A Lateral view of the verbral colmn. B. General features of different kinds f vertebae.

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Clinicl Notes Examnation o the Bac It s imporant that the whol area of the back and legs be examned and hat the oes be emoved. nequal lngth of te legs r diseas of the ip t can lea to abnomal curvtures of the verebral coumn. The patient hould be asked to walk up and down te examiation rom so tha the noral tiltig movemen of the elvis can be oberved. A one sid of the elvis is raised, coronal lumbar onvexity develops on the pposite ide, with a compenatory toracic cnvexity n the same side. When a prson assmes the itting psition, it will be noted hat the ormal lubar curvture becmes flatened, wth an inrease in the inteval betwen the lmbar spies. The noral range of movement of te differnt parts of the ertebral column sould be tested. n the cevical reion, fleion, exension, lateral otation, and lateal flexin are posible. Rmember that abot half o the movment refrred to s flexio is carried out at the alanto-ocipital jints. In flexion, the patint shoul be able to touc his or er chest with the chin, an in extesion he or she hould be able to ook diretly upwad. In laeral roation th patient should e able t place te chin narly in line with the sholder. Haf of laeral rottion occrs betwen the atas and te axis. n latera flexion the head can normally be tlted 45° to eac shoulde. It is importan that th shoulde is not aised wen this vement is being ested. In the toracic rgion th movemets are lmited b the prsence of the rib and stenum. Whn testin for roation, mke sure that th patient does not rotate the pelvi. In te lumbar region, lexion, extension, laterl rotaton, and ateral fexion ar possib. Flexin and exension ae fairl free. Lteral rotation, owever, s limited by the interlocing of the artiular prcesses. ateral flexion in the thoracic and lumbar egions i tested y asking the patint to slde, in trn, each hand down the lateral sie of the thigh.

Characteistics of a Typial Cervical Vertbra A tyical cerical verebra ha the folowing chracterisics (Fig. 2-3): 

   

Th transvrse procsses posess a foraen transersarium for he ae of the vertebrl artery and veis (note that the vertebrl artery es hrough te transvrse procsses C1 to 6 and not trough C7. The spnes are small an bifid. The boy is smal and brad from side to ide. he vertbral formen is lrge and riangula. Th superir articuar processes have facets hat face backward and upwrd; the inferior rocesses have fets that face dowward and forward

Charateristis of the Atypical ervical ertebrae The first, econd, ad sevent cervicl vertebae are aypical. 1592

snell The first ervical ertebra, or atlas (Fig. 12-3), does no possess a body o a spinos proces. It has an anterior and posteror arch. It has a lateral mass on ach side with artcular srfaces on its uper surfae for ariculatio with th occipitl condyes (atlant-occipitl ts and rticula surface on its ower suace for rticulaton with the axis (tlantoaxal t). Th scond cerical vetebra, or axis (Fg. 12-3), has peglik odontoid rocess that pojects fom the uperior urface o the bod (repreenting te body of the alas tha has fusd with the body f the axis). The sevent cervica vertebra, or vertebra pominens (Fig. 12-), is so namd becaus it has the longst spinos process, and th process is not bifid. he transerse proess is arge, bu the foamen tnsversaium is sall and transmit the vetebral vin or vens.

Chaacteristcs of a ypical Thoracic ertebra A typical thoracic vertebra has the following charactristics Fi. 12-2):      

The bod is medium size d heart shaped. The ertebral foramen s small nd circlar. Th spines re long and inclned dowward. Costl facet are preent on he sides of the bdies for articultion wit the heds of the ribs. Costal facets ae present on the tansverse rocesses fr articulation with the tubecles of the ribs (T11 ad 12 hae no faces on the transvere processe). Te superir articular proceses bear facets tha face bacward and aterally whereas he facets on the iferior aticular pocesses fce forwar and medilly. The inferior articula processs of the 12th vertebra face lterally, as do thse of te lumbar vertebrae

Characeristics of a Typial Lumbar Vertebr typical lumbar vetebra has the following charcteristis (Fig. 12-2):       

The boy is large and kidy shaped The edicles re strong and direted backrd. Te laminae are thick The vetebral framina ae trianular. he tranverse processes are long an slender The pinous pcesses ar short, lat, and uadrangulr and proect backard. The rticular surfas of the uperior articular processe face medally, an those of the infior articular prcesses fce lateraly.

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Figue 12-3 A. Typica cervica vertebra superior aspect. B. Atlas, or first ervical ertebra, uperior apect. C. xis, or econd crvical vrtebra, rom abov and behnd. D. eventh crvical vrtebra, superio aspect; the foramn transvrsarium forms a assage for the vrtebral ein but ot for te vertebal arter.

Note hat the umbar vrtebrae ave no cets fo articultion with ribs and o foramia in th transvese proceses.

Sacrum Te sacrum (g. 12-2) consiss of fiv rudimentary vertebae fused together form a edge-shapd bone, which is concave aneriorly. he upper order, or base, of he bone articulate with th fifth lubar vertbra. The arrow inerior brder artculates with the coccyx. aterally the sacum artiulates wh the tw iliac bons to for the sacriliac joits (see Fig 6-1). The anteior and upper margi of the irst sacrl vertera bulges forward s the poserior marin of the pelvic inet and is known as the

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snell sacral promontory. The acral proontory in the femal is of cosiderable obstetri importane and is sed when easurin the size of the pelvis. Te vertebrl foramia are preent and orm the saal canal. The laminae of the fifth sacral vertebra, ad sometis those f the fouth also, ail to met in the idline, orming th cral hiaus (see Fig. 68). he sacrl canal cntains te anterio and postrior root of the sacral an coccygea spinal nerves, th filum teminale, ad fibroftty mateial. It aso contans the lower part f the subrachnoid pace don as far s the loer border of the seond sacra vertebra. The anterior and poserior surfaces of the sarum each have four foramna on ea side fo the ae of the nterior ad posteror rami o the uppr four saral nervs.

occyx he coccx consists of four vrtebrae fused togther to orm a single, small triangulr bone tat articuates at i base wi the loer end of the sacru (Fig. 12-2). The first cocygeal vrtebra s uually no fused r is incmpletely used wit the secod vertebra. Knowedge of he precedng basic anatomy o the veebral coumn is iportant when interreting rdiograph and whe noting the preise site of bony athologic features relative o soft tssue injry. P.857

Imortant Vriations n the Verebrae The umber of cervical vertebrae is constat, but t seventh cervical ertebra my posses a cervical rib (se age 50). The toracic vetebrae my be incrased in umber by he additin of the first lmbar vertbra, whch may hve a rib. The ifth lumar vertbra may b incorpoated into the sacrm; this i usually incomplte and my be limted to on side. Te first acral vrtebra may reman partialy or cometely searate frm the sacrum and resemble a sxth lumbr verteb. A large extent of the postrior wall of the saral canal may be asent becae the lamnae and sines fail to develp. The cccyx, which usually consists of four fused vrtebrae, may hav three o five vetebrae. The first coccygeal vertebra may b separat. In thi conditin, the fee vertebra usualy projcts dowward and anteriorly from the apex of the sarum.

t of the ertebral Column Atlnto-Occiital Joits he atlanto-occiptal ts are snovial jints tht are frmed betwen the ocipital cndyles, wich are fund on eiher sid of the framen manum above and the acets on he superor surfces of te lateral masses o the atla below (Fig 12-4) They ar enclosed by a capule.

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Figue 12-4 Anterio view (A) and poserior viw (B) o the atlanto-occipial ts. Sagittl section (C) and osterior iew (D) o the atantoaxial ts. Nte that te posterir arch o the atla and the laminae nd spine f the axi have bee removed.

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Ligments 

Anterior atlanto-occiptal membrane: This is continuaion of th anterior longitudial ligamnt, which runs as a band don the anerior surace of t vertebrl column. The

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membane connets the aterior ach of the atlas to the aerior marin of th foramen magnum. Posteior atlano-occipitl membra: This membran is similr to the igamentum flavum (ee page 860) and onnects the posterior arch of the atlas to he postrior margn of the ramen manum.

Movement Flexn, extenson, and ateral flxion. No rotation i possibl.

Atlantoaxil ts The atlantoaxl ts are three synovial ts: ne is btween the odontoid proces and the anterior arch of the atla, and te other wo are beeen the ateral masses of te bones (Fi. 12-4). The jints are enclosed by capsules

Ligaents   



Apical lgament: This edian-plced structure onnects he apex f the odntoid process to the antrior margin of te forame magnum. Aar ligamnts: These le one on each side of the apicl ligamet and connect th odontid procss to th medial ides of the occiital conyles. Cruiate ligament: This ligment conssts of a ransverse part and verticl part. Te transerse par is attaced on eac side to he inner aspect of the lateal mass o the atla and binds the odotoid pross to th anterio arch of he atlas The vertial part rns from he posteror surfae of the body of he axis o the anerior magin of te forame magnum Mmbrana ectoria: This is an uward coninuation of the osterior longitudinal ligaent. I is attched aboe to the occipita bone jut within the formen magum. It cvers the posterir surfac of the odontoid process and the pical, aar, and ruciate gaments

Movements Tere can be extenive rotation of he atlas and thus of the had on te axis.

Joits of te Vertebal Colum Below te Axis Wih the eception f the fist two ervical vertebrae, the reainder the moile verebrae ariculate ith each other by means f cartilginous jints beteen their bodies ad by synovial ts between their articular procsses (Fig 12-5).

s Betwee Two Verebral Boies The uper and lwer surfaes of the bodies o adjace verterae are overed b thin pates of yaline crtilage Sandwiced betwen the plates of haline carilage is n intervtebral dic of firocartilae (Fig. 12-). The collagen fibers of the disc trongly unte the boies of th two verebrae. In the lower cerical regin, small synovial ts are present t the sids of the ntervertbral disc between e upper and lowr urfaces of the bdies of he verterae.

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Iterverteral Discs The ntervertbral disc are respnsible fo one fourh of the length of the verebral coumn (Fig 12-5) They ae thickes in the crvical an lumbar rgions, whre the mvements of the vetebral clumn are reatest. hey may e regardd as sei-elastic disc, which lie betwee the rigd bodies of adjacnt vertebrae (Fig. 12-5). Thei physica characeristics permit tem to seve as shck absorers when the lod on th vertebrl column is suddely incrased, a when one is juming fro a heigh. Their lasticit allows he rigid vertebre to mov one on the othe. Unfortunately, their reilience s gradualy lost ith advncing age. Each dis consist of a peipheral art, the anulus ibrosus, and a central pat, the ncleus pulposus (Fi. 12-5. The anulus fibrsus i composd of fibocartilge, in wich the ollagen ibers ar arrangd in cocentric layers or seets. Th collagn bundle oiquely between djacent vertebra bodies, and ther inclintion is eversed in alternate shets. The more peripheral fbers are strongly attache to the anterior and postrior lonitudinal ligamens of the vertebra column Te nucleus ulposus in cldren ad adolesents is n ovoid ass of glatinou materia contaiing a lage amoun of wate, a small number of collen fibers, ad a few artilage cells. It is norally undr pressue and stuated lightly earer to the poserior than to the anterior margin of the dsc. The uppr and loer surfaes of the bodies of adjacnt vertbrae tha abut ono the dic are cvered wih thin plates of hyaline cartilag. No diss are fond betwen the fist two crvical ertebrae or in te sacrum or coccx.

unction of the Iterverteral Diss The semluid naure of te nucles pulposs allows it to cange shae and prmits on verteba to roc forwar or backard on nother, s in flxion and extensio of the ertebral column. sudden ncrease n the copressio load on the vetebral clumn caues the smifluid ucleus plposus o become flatteed. The utward trust of he nucles is accmmodated by the resilience of th surrounding anuus fibrous. Someimes, th outwar thrust is too reat for the anuus fibrosus and i ruptres, allwing th nucleus pulposus to herniate and rotrude nto the vertebra canal, where it may pres on the pinal erve roos, the sinal nere, or een the pinal cord (see age 867). With advncing ag, the waer contnt of te nucleu pulposus diminshes and is replaed by fibrocartiage. Th collage fibers of the aulus degnerate ad, as a esult, te anulu cannot always contain he nucles pulposs under tress. I old ag the diss are tin and ess lastic, nd it is no longe possibl to distnguish the nuclus from he anulu.

Ligamnts Te anterior and poserior lgitudinl ligamets run s continous band down th anterir and poterior srfaces o the verebral coumn from the skul to the acrum (Fgs. 12-5 and 12-1). Te anterir ligamet is wid and is strongly attached to the font and sides of the vertbral bodes and t the

1598

snell intrvertebrl discs. The poserior liament is weak an narrow nd is atached t the poserior brders of P.89

the discs. These liaments hld the vrtebrae irmly toether bu at the same tim permit small aount of ovement o take pace betwen them.

Figre 12-5 A. t in the ervical, thoracic and lubar regins of t vertebrl column. B. Third lubar vertbra seen from above showin the reltionship between intervertebral disc and caud equina C. Sgittal ction trough three lumba vertebre showin ligamens and itervertbral diss. Note the relaionship etween te emergng spina nerve in an inerverteral foraen and he interertebral disc.

ts Btween wo Verebral Arhes 1599

snell The jonts beten two ertebral arches cnsist of synovia ts etween e superir and infrior artcular procsses of djacent vertebra (Fig. 125). The articular facets re coverd with haline crtilage, and the oints ar surrounded by a capsular ligament

Ligament 

Supaspinou ligament (Fig. 12-5): his run between the tips of adjacnt spines. P.80

  

Interspnous ligment (Fig 12-5) This conects adjcent spies. ntertranserse ligents: hese run between ajacent tansverse processes Ligmentum flvum (Fi 12-5) This cnnects the lainae of djacent vertebra.

In he cervicl region the suprspinous ad interspnous ligments are greatly tickened to form te strong liamentum nchae. The lattr extends from the spine of he sevenh cervica vertebr to the externa occipita protubrance of the skul, with ts anteror bordr being strongly attache to the ervical pines in between

Nerve Suply of Vetebral Jonts The joits betwee the vertbral bodis are inervated by the smal meningel branche of each spinal neve (Fig. 1-6). he nerve ises fro the spinl nerve a it exits from the intervertbral formen. It ten re-entrs the vetebral anal thrugh the intervertebral oramen ad supplies the meninges, ligaments, and intrvertebr discs. he ts between he articuar proceses are inervated by branchs from th posterir rami o the spinl nerves (Fig. 12-). It hould be oted that the s of any articula level reeive nerv fibers fom two ajacent spnal nerves.

Cuves of te Vertebrl Column Cuves in te Sagittal Plan In the fetus, th vertebral colum has one continus anterior concavity. s development poceeds, he lumboacral anle appars. Aftr birth, when the child beomes able to raise his or he head ad keep it poised o the vertbral colun, the crvical pa of the vertebral column becomes concve posterorly (Fig. 2-7). Toward te end of he first year, whe the chil begins o stand upright, he lumba part of he vertebral colun becomes concave osteriory. The deelopment f these secondary curves s largel cause by modiication in the sape of he intervrtebral iscs. In th adult in the standng positon (Fig. 127), he verteral colun therefre exhibts in te sagital plane the folowing rgional urves: crvical, osterio concaviy; thoraic, poserior cnvexity; lumbar, osterior concavit and sacal, posterior covexity. During the ater monts of pregncy, wit the incrase in ize and weght of te fetus, wmen ten to increae the poterior lmbar concvity in a

1600

snell attempt to presere their cnter of gavity. In old age, the intevertebral discs atrphy, reslting in a loss o heigh and a gradual return of he vertebral colmn to a ontinuos anterior concavity.

Curves n the Coroal Plane In ate childood, it i common o find th developmnt of mior latera curves n the tracic reion of th vertebra column. This is ormal and is usual caused by the pedominant use of one of the uppr limbs For exaple, rigt-handed persons ill ofte have a slight ight-sidd thoracc convexty. Slight compensatory cves are always present bove and below suh a curvture.

linical otes Abnormal Curves f the Vetebral Clumn Kyphosi is a exaggeration i the saittal cuvature pesent i the thoacic par of the vertebra column It can e caused by muscular weakess or b structual changs in th vertebrl bodie or by ntervertbral diss. In sikly adoescents for exaple, whee the mucle tone is poor, long hors of sudy or wrk over a low des can lea to a gently cured kyphois of te upper horacic egion. Te person is said o be âœround-souldere.― Crsh fractres or tberculos destrution of the vertbral bodes lead to acut angular kyphosis of the vertebral column. In the aed, osteopoosis (abnorma rarefacion of one) andor degenration o the inrvertebral discs leads to senile kyposis, involvin the cerical, thracic, ad lumbar regions of the column. ordosis is an xaggeraton in he sagital curvaure presnt in th lumbar egion. ordosis ay be cused by n increase in the weight f the abominal cntents, s with he gravi uterus or a large ovarin tumor, or it ma be causd by diease of he verteral colun such a spondylisthesis (see page 62). he possiility tt it is a postual compensation or a kyhosis in the thoacic regon or a isease o the hip t (ongenita disloction) mut not be overlookd. Scoliosis is a lteral dviation f the vetebral clumn. Ths is mos commonl found in the toracic rgion and may be cused by uscular r vertebral defects. Paraysis of muscles caused by poliomelitis can cause evere soliosis. The presnce of a congenitl hemivetebra ca cause coliosis Often soliosis s compenatory and may be cased by a hort leg or hip sease.

Moements o the Vertbral Colmn As has een seen in the revious ections, the vertebral clumn conists of everal eparate ertebra accuratly positoned one on the oher and separated b interverebral dics. The vrtebrae ae held n positio relativ to one aother by rong ligaents that severely imit the egree of movement ossible beween adjcent verbrae. Nertheless, the summtion of al these vements gves the vertebral olumn as whole a remarkabl degree o mobility The following mvements re possible: flexin, extenion, latel flexion rotation and cirumduction 

lexion is a forard moveent, and extnsion s a backard movemnt. Both re extensve in th cervical and lumba regions but restricted in the thorcic regin.

1601

snell   

Latera flexio is the bending of the boy to one or the oher sid. It is xtensiv in the cervical and lumbar regios but retricted n the thracic reion. Rottion s a twising of te vertebal colum. This i least etensive n the lubar regin. Circumuction is a cobination of all tese moveents.

The type an range of movemnts possble in ech regio of the olumn largely depnd on the thickness of the inervertebal disc and the shape an directin of the aticular pocesses. n the thracic reion, the rbs, the ctal cartiages, and he sternu severel restrict the range of movemet. P861

Fgure 12-6 The nnervatio of verteral ts. At any particular vertebral level, the oints reeive nere fibers from to adjacen spinal nves.

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Figure 12-7 Aâ“C. Curves of the vertebra column a differen ages. D. In the ault, the lower end of the sinal cord lies at te level o the loer borde of the body f the fist lumba verteba (top arrw), an the subaachnoid space ens at the lower brder of the bod of the econd sacal vertea (bottom

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arow).

P.82

The atlano-occipitl ts permit xtensive lexion ad extension of the head. The alantoaxil ts allow a wide rang of rotaion of th atlas an thus of he head o the axis Te vertebrl column is moved y numeros muscles many of which are attached irectly o the verebrae, wereas others, sch as the sterncleidomasoid and te abdominl wall mucles, are attachd to te skul or to he ribs r fascie. In he cervica region, flexin is produced by te longus cervicis, scalenus anterior and strnocleidomastoid muscles. Extensin is prouced by he postvertebral muscles (see page 86). Laeral flexon is prduced by he scalens anterir and meius and te trapezus and sternocleidmastoid mscles. Roation is roduced b the strnocleidoastoid o one sid and the splenius on the other sde. In he thoracic region rotaon is produced by he semispinalis ad rotators muscle, assisd by the oblique mscles of he anteroateral abominal wll. the lumba region flexio is produed by the rectus aominis ad the psas muscls. Extension i produce by the ostverteral musces. Lateral flexion is produce by the ostvertral mules, th quadratus lumboum, and the obique musles of te anteroateral adominal all. The psoas may also pla a part this movent. Rotation is roduced b the rotaores musles and te oblique uscles o the aerolaterl abdominal wall.

linical Ntes islocatins of th Vertebral olumn Dilocation without racture ocur only in the cevical rion becase the incination f the artcular proesses of he cervial verteae permits dislocaion to tae place wthout frcture of the procsses. In the thoracc and lumar regios, disloctions can occur oly if the verticall placed aticular pocesses ae fractued. Dslocatios commony occur etween te fourth and fift or fith and sixh cervical vertebre, where mobility s greates. In uniateral dilocations the inferor articuar proces of one vrtebra s forced orward ovr the antrior margn of the uperior rticular process o the vertbra below Because he articuar proceses normaly overlp, they bcome loced in the dislocate position The spial nerve on the sae side s usualy nipped in te interertebral foramen, producig severe ain. Fortnately, te large sze of te vertebral canal llows the spinal cod to escae damage n most cses.

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snell Bilateal cervial disloations ae almos always associated with evere inury to te spina cord. eath ocurs immdiately f the uper cervial vertbrae are involved because he respiatory mucles, incuding th diaphram (phreni nerves 3 to 5), re paralyed.

Fratures of he Vertebal Colum Factures f the Spious Procsses, Trasverse Pocesses, o Laminae Fractues of the spinous pocesses, transvers proceses, or amina are caued by direct injry or, n rare cass, by svere musclar actity.

nterior and Latal Compession Factures Aterior cmpressi fractues of th vertebrl bodies are usally caued by an xcessive lexion cmpression type of ijury an take plae at the ites of mximum moblity or at the juncion of te mobile nd fixed egions of the colum It is iteresting to note that the ody of a vertebra n such a racture i crushed, whereas he stron posterior longitudinal ligaent remans intac. The verebral arhes remai unbroke and the interverebral liaments emain intact so that vertbral dispacement d spinal ord injuy do not ocur. Whn injury auses exessive lteral fxion in ddition to excesive fleion, th lateral part of the body is also crushed.

Fracture Dislocatins Facture dilocatios are usally cased by a combintion of flexio and rottion tye of injury; the upper vrtebra i excessvely fleed and tisted on the lower vertebra. Here again, the ste is usally wher maximum mobility ccurs, as in the lmbar regin, or at he junctin of the obile and fixed reion of the column, as in the lower luar vertebrae. Becase the aricular rocesses ae fractued and the ligamens are ton, the vrtebrae nvolved ae unstabl, and the spinal cd is usualy severey damaged or seered, wih accompnying paaplegia

Verticl Compresion Fractres Vertical compressin fractures occur in the cevical and lumbar rgions, whre it is possible to fully traighten the verteal colum (Fig. 12-8). In te cervicl region, with te neck sraight, n excessve vertial forc applie from abve will cause the ring o the atls to be isrupte and the lateral asses t be dispaced latrally (Jeferson' fracture). If the neck is slihtly fleed, the ower cerical verebrae rmain in a straight line and the compression load is ansmittd to the lower vetebrae, ausing dsruption of the iterverteral disc and breaup of te vertebal body. Pieces o the verebral boy are commonly fored back into the spinal crd. It is ossible or nontrumatic cmpression fractus to ocur in severe cass of ostoporosis and for athologi fracturs to tae place. I the strightened lumbar rgion, an excessiv force rom belw can cae the vrtebral ody to reak up, with prorusion of fragmets posteiorly into the spinal canal 1605

snell

Factures of the Oontoid Process of the Axis ractures of the oontoid pocess ar relativly commo and reslt from alls or lows on he head Fg. 12-8). Excssive moility of the odontid fragmnt or ruture of he tranverse liament ca result n compression injry to th spinal cord.

Fractue of th Pedicle of the xis (Hanman's Frcture) Svere extnsion inury of the neck, such as ight occur in an automobie accidet or a fll, is te usual ause of angman's fractur. Sudden overextesion of he neck, as produed by the knot of a hangmn's rope beneath he chin, is the reason for he commo name. ecause te vertebal canal is enlared by th forward displacent of the verteral body of the ais, the pinal cod is rarly compessed (Fig. 12-8).

Spondylolistheis I spondyllisthesi, the boy of a ower lumar vertbra, usully the fifth, moves forwad on the body of he vertera belo and caries with it the wole of te upper ortion o the vetebral clumn. The essental defec is in te pedicls of the migratng vertebra. It is now geneally beleved tha, in thi condion, the pedicles are abnomally fomed and ccessory centers f ossifcation ae presen and fal to unie. The sine, lanae, and inerior aricular pocesses remain i positio, whereas the reainder f the vetebra, hving los the retraining influene of the inferior articulr proceses, slip forwar. Becaus the lainae are left bhind, the vertebal canal is not narrowed, but the nerve roos may be pressed on, causng low ackache nd sciatca. In svere cass the tunk becomes shorened, an the lowr ribs cntact the iliac crest. P.863

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Fgure 12- Dislocatios and factures of the vrtebral clumn. A Unilatral dislcation o the fifh or the sixth cevical vetebra. ote the orward dsplacemet of the inferior articula process over th superio articulr proces of the ertebra elow. B. Bilater disloction of the fifth or the ixth cervical vertbra. No that 5% of the vertebra body with has mved forwrd on th vertebr below. C. Flexio compresion–tpe fractre of th vertebrl body i the lumbar region. . Jeffrson's-tpe fractre of th atlas. E Fracturs of the odontoid process nd the peicles (hngman's racture) of the axs.

.864

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snell

Muscles of the Back The mscles of the back ay be diided int three goups:   

The superfiial musces conected wih the shulder gidle. The are described in Chater 9 The intemediate mscles involved with movments of the thoraic cage. They are describe with th thorax Chapter 2. Th dep muscle or postertebral muscles belongig to the vertebral clumn

Deep Mucles of the Back (Postverteral Muscls) In the standing position the lin of gravity (Fig. 129) psses through the odontoid process of the axs, behin the ceners of he hip jints, and in front of the kee and akle t. It folows that when the ody is in this posiion, the reater pa of its wight fals in frot of the ertebral olumn. It is, therfore, not surprisig to find that the ostvertebral muscles of the back are wel develod in humns. The pstural toe of thes muscle is the maor P.865

factor responsile for th maintennce of te normal curves of the verteral colum.

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Figure 129 A. Arangement of the dep muscles of the bck. B. Lteral viw of the skeleto showing the lin of gravty. Becase the greater art of he body eight les anteror to te vertebal colum, the eep muscls of the back are importan in maintainng the noral postral cures of th vertebrl column in the standing osition.

The deep musles of te back orm a brad, thick column of muscle tissue, hich ocies th hollow n each sde of th spinous processs of the vertebra column Fi. 12-9). They extend fom the scrum to he skull It must be realied that his comlicated muscle ass is cmposed of many separate mscles of varying length. Each indvidual uscle ma be regaded as a string, hich, when pulld on,

1609

snell cases one r severa verterae to b extende or rotaed on te verteba below. Because he origins and insrtions o the diferent goups of uscles ovrlap, enire regins of th vertebral column an be mde to moe smoothy. The spines ad transvrse procsses of he verterae sere as levrs that fcilitate the musle actios. The mscles of longest length li superfiially an run verically fom the sacrum to he rib angles, th transvese proceses, and the upper vertebra spines (Fg. 12-9). The scles of intermedate lenth run obliquely fom the tansverse processe to the spines. Th shortet and depest musle fiber run betwen the pines and between the tranverse prcesses o adjacen vertebre. Th deep mucles of he back ay be clssified follows

Superfcial Verically Rnning Mucles



Intermeiate Oblque Runnig Muscle



Deepest uscles  

Intespinales ntertranversarii

Knowlede of the detailed attachmets of th various muscles of the back has no practic value o a clinial profesional, and the attachment are theefore omtted in his text

Splenus The splenus is a etached art of te deep mscles of the back It consts of tw parts. he spleniu capitis arises from th lower part of t ligamenum nucha and the upper for thoraic spine and is nserted nto the uperior nuchal lin of the occipita bone an the mastid proces of the temporal bone. The spleius cervicis ha a similr origin but is iserted ito the tansverse processe of the pper cerical verebrae.

Neve Suppl Al the dep muscle of the ack are nnervate by the osterior rami of e spinal nerves.

Mucular Trangles o the Back 1610

snell

Aucultator Triangl The auscultaory triagle is te site o the bac where reath sonds may b most eaily hear with a tethoscoe. The oundarie are the latissims dorsi, the trapzius, an the medal bordr of the scapula.

Lmbar Tringle he lumba triangl is the ite wher pus may emerge from th abdominl wall. The bounaries ae the laissimus dorsi, te posteior borde of the xternal blique mscle of he abdomn, and the iliac crest.

Dep Fascia of the Bck (Thorcolumbar Fascia) Te lumbar part of he deep ascia is situated in the iterval btween th iliac cest and he 12th ib. It foms a strng aponurosis ad lateraly gives origin to the midde fibers of the ransverss and th upper fbers of he interal obliqu muscles of the bdominl wall (see page 15). Medially the lumar part of the dep fascia splits io three lamellae The poserior laella covrs the dep muscles of the back and is attaced to th lumbar pines. Te middle amella psses meially, t be attahed to the tips of the tranverse prcesses o the lubar vertbrae; it lies in ront of he deep mscles of the back and behnd the qadratus umborum. The anterior lamella e medially and is ttached o the anerior suface of te transvrse procsses of he lumbr vertbrae; it lies in ront of he quadrtus lumbrum muscle.

lood Suply of th Back Arteris 

  

I the cervicl region, branches arise from th occipitl artery a branc of the xternal carotid; from the ertebral artery, branch f the suclavian; and from the deep cervical artery, branch f the cotocervicl trunk. n the thorcic regin branhes aris from th posteror interostal arteries. In the lumba region branche arise fom the sbcostal nd lumba arterie. In the sacrl region branches arise from the iliolumbr and laeral sacal arteries, branhes of the interna iliac atery.

Veins he veins draining the strutures of the back form pleuses extnding alng the vrtebral olumn frm the skull to th coccyx.  

The external vertral venous plexu lies xternal and surounds te vertebal colum. The interal verteral venos plexus lies ithin the vertebral canal but outside the dua mater f the spnal cord (Fg. 12-10).

The exernal an interna vertebrl plexuss form a capacios venous network hose wals are thn and whse channls have incompetnt valve or are alveless They communicate through the foran

1611

snell magnu with th venous inuses wthin the skull. Free venou blood low may therefore take place between the skul, the nek, the thorax, P.866

th abdome, the pevis, and the vertbral plxuses, wth the drection f flow epending on the pessure dfference that exst at any given tim between the regios. This fct is of onsiderale clinial signiicance.

Figure 2-10 blique seion through the firt lumbar ertebra sowing the spinal rd and is coverin membrane. Note th relationship betwen the sinal nerv and symathetic tunk on ea side. Note also te importnt internl vertebl venous lexus.

1612

snell The iternal vrtebral lexus reeives trbutaries from the ertebrae y way of he basiverteral vein (Fig. 1210) an from the meninges ad spinal cord. The nternal plexus is rained by the intervetebral veins, wich utward wih the spial nerves through the intervrtebral oramina. ere, they are e by tribaries frm the extrnal verebral pleus and in turn dran into te vertbral, itercosta, lumba, and lteral sacral veins

Cinical Ntes Vertebral Venous Plexus nd Carcinoma of he Prostte Becaue the logitudina, thin-wlled, valveless ertebral venous plxus commnicates bove wit the intacranial venous inuses ad segmenally wit the veis of the thorax, adomen, ad pelvi, it is clinicaly imporant struture. Pevic venos blood nters not only th inferio vena ava, but also the vertebra venous plexus ad by thi route my also eter the skull. Th is espeially lkely to ccur if he intraabdomina pressur is incrased. Th internl vertebal venous plexus i not subect to eternal pessures when the intra-abominal pessure rses. A rise in prsure on the abdominal and pelvic vins woul tend to force th blood bckward ot of th abdominl and pevic caviies into the vein within te vertebral cana. The exstence o this veous plexs explais how crcinoma f the prstate may metastasize to the vertebl column and th cranial cavity. P.867

Lmph Draiage of te Back The dep lymph vessels ollow th veins ad drain into the eep cervical, poserior meiastinal lateral aortic, nd sacra nodes. The lymp vessels rom the kin of te neck dain into the cerical nods, those from the trunk abve the iliac crest drain ito the xillary odes, an those from below he leve of the iiac crets drai into th superfiial ingunal nodes (see pag 163)

Nere Supply of the Bck he skin nd muscls of the back are supplied n a segental maner by te posterir rami o the 31 airs of pinal nrves. Th posterio rami of the firs, sixth, seventh, nd eight cervicl nerves and the ourth an fifth lubar nervs supply the deep muscles f the bak and do not suppy the ski. The poterior rmus of e secon cervica nerve (he greater ccipital nerve) ascends over the back of te head ad supplis the skn of the scalp. The psterior ami run ownward nd laterlly and spply a and of sin at a ower levl than the intervetebral framen frm which hey emere. Consierable oerlap of kin area supplied occurs o that ction of a single nerve cases dimiished, but not totl, loss of sensaon. Each posterio ramus dvides into a media and a lateral bnch. For dermatoms of the ack, see Fiure 1-25.

Sinal Cor 1613

snell The pinal cod is a clindrica, grayis white tructure that begis above t the foamen magum, wher it is ontinuous with the medulla blongata f the brin. It trminates below i the adult at the level of he lower border o the firt lumbar vertebra (Fig. 12-7). In te young hild, it s relatvely loner and eds at th upper brder of te third umbar vrtebra. he spina cord in the cervial regio, where t gives rigin t the brhial pleus, and n the lower thoracc and lubar regins, whee it givs origin to the lubosacral plexus, as fusifrm enlagements clled cervical and lubar enlagements. Inferiorly, the spinal crd taper off int the conus medullari, fro the ape of whic a prologation of the pia ater, th flum termnale, descends o be attched to he back f the cocyx (Figs. 2-7, 12-1, and 1215). Te cord pssesses n the miline anteriorly a eep longtudinal issure, he anterior median fssure, and on te posteror surfae a shalow furrow the posteror media sulcus.

Roots f the Spnal Nerves Alng the wole lengh of the spinal crd are atached 31 pairs of spinal nrves by he anterio, or motor, roots and th psterior, or sensoy, roots (Figs. 1211, 12-1, 12-14 and 12-15). Each root is ttached o the cod by a sries of ootlets, which extend the hole lenth of th corresponding segent of te cord. ach postrior nere root pssesses posterior root gaglion, te cells f which give rise to periperal and central nerve fibrs. The spinl nerve oots pas lateraly from ech spina cord sement to he level of their respectie intervrtebral oramina, where they unite o form a spinal nere. Hee, the mtor and ensory fbers becme mixed so that a spinal nrve is ade up o a mixture of moto and senory fibes. Becaue of the disproportionate rowth in length o the vertbral colmn durin develoment compared to tat of th spinal ord, the ength o the ros increaes progrssively rom above downward (Fgs. 12-1 and 12-5). I the uppr cervica region he spina nerve rots are sort and un almot horizotally, bt the roos of the lumbar ad sacral nerves elow the level of he termiation of the cord (lower brder of te first lumbar vrtebra in the adul) form a vertical leash of nerves round the filum teminale. he lower nerve rots togeter are called th cuda equia (Figs. 12-11 and 12-15). After emergence rom the ntervertbral formen, eac spinal nerve immeiately dvides ino a larg aterior rmus a a smallr posterio ramus which cntain both motor ad sensor fibers.

Clincal Note Nerve Root Pn Spinal nerve roots ext from te vertebal cana through the intevertebra foramin. Each framen is ounded speriorly and infriorly b the pedicles, antriorly b the intrvertebr disc an the vertebral body, and posteriory by the articula process and jonts (Fig. 1-5). n the lubar regio, the lrgest foamen is etween th first ad second lumbar vrtebrae ad the sallest i between the fifth lumbar ad first sacral vetebra. One o the comications of osteorthritis of the ertebral column i the groh of osteophytes, which comonly enroach o the intervertebra foramin, causin pain alng the distributio of the segmenta

1614

snell nerve. he fifth lumbar sinal nere is the largest o the lubar spinl nerves and it xits from the vertbral colmn through the smllest inervertebal foramn. For ths reason it is te most ulnerabl Osteoarhritis a a cause of root ain is suggested b the paient's ae, its isidious nset, an a history of back pain of long durtion; th diagnoss is mad only whn all other causes have ben excludd. Fr exampl, a prolpsed dis usually occurs in a younger age gup and oten has n acute nset.

Herniated Intervertebral Discs The stucture ad functin of the interverebral dic is decribed o page 858. The reistance f these iscs to compressio forces is substntial, a seen, fr example, in circus acrobas who ca suppor four or more of heir coleagues o their soulders. Neverthess, the discs ar vulnerale to suden shocs, partiularly f the vetebral coumn is fexed and the dic is undrgoing egeneratve changs that rsult in erniatio of the ucleus plposus. The discs mot commony affectd are thse in ares where a mobile part of he colum s a relativey immobie part—hat is, the cervcothoracc junctin and the lumbosacal juncton. In tese ares, the pterior art of the anulus ibrosus uptures, and the nucleus lposus i forced osteriory like tothpaste ut of a ube. Ths is refrred to s a herniaton of th nucleus pulposus. Thi herniation can rsult eiter in a entral potrusion in the idline uder the osterior longitudnal ligaent of te vertebrae or i a laterl protruson at th side of the postrior ligment close to th intervertebral foamen (Fig. 2-16) The escape of te nucleu pulposus will prouce narrwing of he space between the vertbral bodes, whic may be vsible on radiograhs. Slackening o the anteior and osterior longitudnal ligaents resuts in anormal mbility o the verebral boies, proucing loal pain nd subsquent deelopment of osteorthritis Cevical dic herniaions are less ommon thn herniations in the lumbar region (Fig 12-34). The iscs mos susceptble to tis condiion are hose beteen the fifth an sixth o sixth and seventh vertebre. Lateral protruons cause pressure on a pinal nerve or its roots. Each spinl nerve merges bove the corresponding vertebra; thu, protruion of te disc etween te fifth nd sixth cervical vertebra can caue compression o the C6 spinal neve or it roots (Fig 12-16). Pain is felt ear the ower par of the ack of the neck a shoulde and alng the aea in th distribtion of he spina nerve ivolved. Central rotrusios may pres on the spinal crd and te anterir spina artery nd invole the vaious nere tracts of the sinal cor. Lubar disc herniatins ar more comon than cervical disc heriations Fg. 12-1). Te discs sually afected ae those etween te fourth and fifth lumbar vertebrae and beten the ffth lumbr verteba and th sacrum. In the umbar reion the oots of he cauda equina rn posteriorly over several interveebral discs (Fig. 1-16B). A laterl herniaion may ress on ne or tw roots ad often nvolves the nerve root gong to th intervetebral framen jut below. However, because C8 nerve roots exst and a eighth ervical vertebral body does not, th thoraci and lumar roots eit beow the vrtebra o the corespondin number. Thus, th L5 nerv root eits between the fifth lumb and first sacral vertebra. Moreovr, becase the nrve root move laerally a they pas toward their ext, the root correponding o that dsc space (L4 in te case o the L4 o 5 dis) is already too lateral o be presed on b the heriated dic. Hernation of the L4 t 5 disc sually gves rise to symptms referble to he L5 neve roots even thugh the 5 root eits betwen L5 an S1 verebrae. Te nucleu pulposu

1615

snell occasionlly hernates dirctly bakward, d if it s a larg herniaton, the hole caua equina may be ompresse, producing paraplegia. An initial eriod of back pai is usualy cause by the injury to the dis. The bak muscle show spsm, espeially on he side of the hrniation because of pressre on th spinal erve roo. As a onsequene, the vrtebral olumn shows a scolosis, wih its cocavity n the sie of the lesion. ain is rferred dwn the leg and foot in th distriution of the affeted nerv. Since he sensoy posterir roots most commonly prssed on re the ffth lumbr and th first acral, pin is usally felt down the back and lateral ide of te leg, adiating to the sle of th foot. This conditon is ofen calle ciatica. In sevre cases parestheia or acual sensry loss ay be prsent. Presure on he anteror motor roots cases musce weaknss. Invovement of the fifh lumbar motor rot producs weaknes of dorsiflexion of the nkle, whreas presure on he first sacral otor roo causes eakness f planta flexion and the ankle jek may b diminised or abent (Fig. 1-16). A larg, centraly place protruson may give rise to bilateral pain nd muscle weakness in bot legs. Acute retenion of rine may also occr. A crrelatio between the disc lesion, he nerve roots ivolved, he pain ermatome the musle weaknss, and he missig or diinished reflex is shown in Tale 12-1.

Diseas and the Interverebral Foramina The ntervertbral formina (Fig. 2-5) transmit the spina nerves nd the sall segmntal artries and veins, al of whih are emedded in reolar tssue. Eah foramen is boundd above and belo by the edicles of adjacen vertebre, in frnt by the lower prt of th vertebra body an by the nterverteral disc and beind by te articuar proceses and he t between hem. In his sitation, th spinal erve is ulnerabl and may e pressed on or irritated by diseae of the surroundig structres. Hernation of the intrvertebra disc, factures f the vetebral bdies, an osteoathritis nvolving he t of the articular processe or the oints beween the vertebral bodies cn all reult in pssure, tretchin, or edea of the emerging pinal neve. Such pressure ould gve rise to dermatomal pain, muscle wakness, nd diminhed or asent relexes.

arrowing f the Spnal Cana After about the fourh decade of life he spinal canal bcomes narrowed by ging. Oseoarthriic changes in the oints of the articular prcesses wth the formation o osteophtes, togher with degenertive chages in te intervertebral dscs and he formaon of lrge ostephytes between the vertebra bodies, an lead o narrowng of te spinal anal and intervertbral formina. In persons n whom te spinal canal wa originaly small signifcant stesis in te cauda equina aea can led to neuologic cmpressio. Symptom vary frm mild iscomfor in the lower back to sever pain raiating dwn the lg with he inabiity to wak.

Sacroilac t isease The saroiliac oint is escribed on page 29. The clinical aspects o this jont are rferred t again bcause dsease of this jont can cuse low ack pain and may b confuse with diease of the

1616

snell lumbacral jonts. Essntially, the sacoiliac jint is a sy-novil t hat has rregular elevatios on one articula surface that fi into corespondin depressons on te other rticular surface. It is a strong jint and is responsible for the tranfer of weight fr the vrtebral column to the hip bnes. The t is innervatd by the lower lmbar and sacral nrves so hat disese in th t my produc low bak pain ad sciatica. Th sacroilac t is inaccssible t clinical examination. Hoever, a mall are located just medal to an below te posteosuperio iliac sine is were the oint coms closes to the surface. In diseae of the lumbosacal regio, movements of the vertebrl column in any drection ause pai in the umbosacrl part of the coln. In sacroiliac isease, ain is etreme on rotation of the rtebral olumn and is worst at the end of frward flexion. The latter movement causes pin becaue the hamstring muscles hold the hi bones positio while te sacrum is rotatng forwad as the vertebra column is flexed. P.868

P.86

1617

snell

Figre 12-11 A. Lowr end of the spinl cord ad the cada equin. B. Setion thrugh the horacic art of te spinal cord showng the nterior nd posteior root of the pinal nerves and mninges. C. Transvrse secton throuh the spnal cord showing he menines and te posiion of te cerebrspinal

1618

snell

fuid.

P.870

1619

snell

Fgure 12-2 Poterior view of th spinal cord showng the oigins of he roots of the pinal neves and heir relationship o the diferent vrtebrae. On the ight, th laminae ave been removed o expose the righ half of the spial cord nd the nrve root

Blood Spply o the Spial Cord Te spinal cord recives its arterial supply fom three small, ongitudially runing arteies: the two postrior spial arteies and ne anterior spinal artery. The psterir spinal arteries, whih arise ither diectly or indirecty from the vertebrl arteris, run own the ide of te spinal cord, clse to the attachmets of th posteror spina nerve rots. The anerior spnal arteies, which aris from th vertebrl arteres, unite to form single rtery, wich runs down wihin the nterior edian fisure. The poserior an anterio spinal rteries re reinfrced by radcular areries which eter the ertebral canal though the intervertebral foramina. The veins of the spinal crd drain into the internal vertebra venous lexus.

Clnical Noes Snal Cor Ischemi The blood supply to th spinal ord is rprisingly meage, considring th importace of ths nervou tissue. The lonitudinaly runnin anterio and posterior spinal arteies are f small and varible diameter, and the reinorcing sgmental teries vary in number and in size. Ischemia of the sinal cor can easly follw minor amage to the arteial suppy as a rsult of egional anesthesa, pain block procedures, or aortic surgery.

Spinal Crd Injures The degree of spina cord inury at dfferent vertebral levels i largely governed by anatmic factrs. In te cervicl region, dislocation or fracture slocation is common, but te large ize of he verteral cana often rsults in the spinl cord ecaping svere inury. Howver, whe consideable dislacement occurs, he cord is sectioned and dath occus immediately. Repiration ceases i the leion occus above he segmetal orign of the phrenic erves (C, 4, and 5). In frcture diocations of the toracic rgion, dsplacemen is ofte consideable, an the smal size o the verebral canal esults i severe njury to the spinl cord. I fractur dislocaions of he lumba region, two anaomic facs aid the patient. First, te spinal cord in he adult extends only dow as far s the level of the lower boder of te first lumbar vrtebra. econd, te large ize of th vertebrl forame in thi region ives the oots of he cauda equina aple room Nerve injury may therefor be minial in ths region. Injur to the pinal cod can poduce patial or complete loss of unction t the leel of th lesion nd partil or complete los of funcion of aferent ad efferet nerve tracts below the lvel of te lesion

1620

snell The symtoms and signs of spinal sock and paraplega in flexion and extension are beyod the se of this book. For further informtion, a extbook f neurolgy shoul be conslted.

Reltionship of Spina Cord Sements t Vertebra Numbers Because he spina cord is shorter han the ertebral column, the spial cord sgments not correspond numericall with th vertebae that le at the same levl (Fig. 12-2). Te following list elps detrmine whh spinal segment s contigous with a given vertebral ody.

Verterae

Spinal Sgment

Cervcal

dd 1

Upper horacic

Add

Loer thorcic (T7 to 9)

Add 3

Tent thoracc

L1 and 2 cod segmens

Elevent thoracic

L3 nd 4 cor segment

Twelfth horacic

L5 crd segmet

First lubar

acral an coccygel cord sgments

P.81

Meninges of the Spinal Crd he spina cord, lke the bain, is urrounde by three meninges the dur mater, he arachoid mate, and th pia matr (Figs. 1-11, 12-4, an 1-15).

Dura Mater 1621

snell he dura ater is he most external embrane nd is a dense, srong, fibrous sheet that encloses th spinal ord and cauda equina (Figs. 2-10, 12-11, 12-14, and 12-5). I is contnuous abve throuh the foamen magum with the meningal laye of dura covering the brai. Inferirly, it nds on th filum erminale at the lvel of the lower rder of the second sacral vertebra (Fg. 12-7). The ural sheh lies loosely i the verebral caal and i separatd from te walls f the caal by the etradural space (epidura space). This conains looe areola tissue nd the iternal ertebral venous pexus. Th dura mater extend along ech nerve root an becomes continuos with cnnective tissue srroundin each spnal nere epineurim) at he interertebral foramen. The inne surface of the dra mater is separted from the aracnoid matr by the potentia sbdural sace.

Arachnoi Mater The arahnoid maer is a elicate impermeable membran coverig the spnal cord and lyin between the pia ater intrnally an the dua mater xternall (igs. 12-0 and 12-1). t is seprated frm the dua by the subdural space tha contain a thin film of issue flid. The rachnoid is separaed from he pia ater by wide spce, the subrachnoid space, which is filled wth cerebrosinal flud (Fig. 2-11). The arahnoid is continuos above through the framen manum with the arachnoid coring the brain. Iferiorly it ends on the flum terinale at the leve of the ower borer of th second cral vetebra (Fi. 12-7 and 12-15). Beteen the lvels of he conus medullars and th lower ed of the subaracnoid space lie the nerve rots of t cauda equina bahed in erebrospnal flui (igs. 12-1 and 12-5). Th arachnod mater s contined along the spinl nerve oots, forming smll lateral extensions of the subarahnoid spce.

Pia Mate The pa mater s a vasclar membane that closely overs th spinal ord (Figs. 2-10 ad 12-11) It is ontinuou above trough th foramen agnum with the pi coverin the brin; belo it fuse with th filum trminale. The pia ater is thickene on eithr side btween th nerve rots to frm the ligaentum deticulatu, whih es laterall to be atached t the dur. It is y this mans tha the spial cord s suspended in te middle of the dral sheah. The ia mater extends aong each nerve rot and beomes contnuous wih the cnnective tissue srroundin each spinal nerve (Fg. 12-11).

Cinical tes umbar Pucture (Sinal Tap Lumar punctre may b performd to witdraw a smple of cerebrosinal flud for exmination Fortunaely, the spinal cord termates belw at the level of the lowe border f the fist lumba vertera in th adult. In the ifant, it may reac as low s the thrd lumbr verteba.) The ubarachnid space extends own as far as the lower brder of he second sacral vertebra. he lower lumbar prt of te vertebal canal is thus ccupied y the suarachnoi space, hich cotains th cauda euina—tat is, th lumbar nd sacra nerve rots and the filum terminal. A neede introdced into he subarchnoid pace in his region usually pushes te nerve oots to ne side thout cusing daage.

1622

snell With the patint lying on the sde with he verteral colmn well lexed, te space tween aing aminae in the lumbar region is opened to a aximum (Fig 12-17. An imainary lie in the higest poins on the iliac crsts s over te fourth lumbar sine (Fig. 1-35). With a creful asptic tecnique and under loal anestesia, th lumbar puncture needle, fitted wit a style, is pased into he verteral canl above r below the fourth lumbar sine (Fig. 12-17). The neele will ass throgh the following natomic ructures before t enters the subaachnoid sace: ski, superfcial fasia, supraspinous igament, interspious ligament, ligentum flvum, arolar tisue (contining the internal vertebral venous plexus i the epdural space), dura mater, ad arachnid mater The deph to whih the nedle wil have to vares from in. (2. cm) or ess in a child o as muc as 4 in (10 cm) in obese adults. As the tylet is withdraw, a few drops of blod commoly escap. This uually indicates tat the pint of te needle is situated in on of the eins of he interal verteral plexs and ha not ye reached the subaachnoid pace. If the enteing needle should stimulat one of he nerve roots of the caud equina, the patint will experience a fleeting discfort in ne of th dermatoes, or a muscle ill twitch, dependng on wether a ensory o a motor root was impaled. If the needle is pushed to far aneriorly, it may ht the body of the third or fourth mbar vertebra (Fig. 12-17) The cerebropinal flid pressre can b measure by attching a manometer to the nedle. In the recubent postion, th normal pressure is about 60 to 15 mm H2O. I is inteesting o note tat the crebrospial fluid pressure normally fluctuats slightly with the heart beat and with eac phase o respiraon.

Anatom of “Not Getting In― If boe is encuntered, the neede should be withdawn as ar as th subcutaeous tissue, and he angle of inserion shou be chaged. The most comon bone ncounterd is the spinous rocess o the vetebra abve or beow the pth of inertion. f the needle is rected laterally rather thn in the midline, it may ht the laina or n articuar proces.

Anatomy f Compliations o Lumbar uncture 



Postlumbar puncture headache. Ths headace starts after th procedue and lasts 24 to 48 hours The case is a eak of crebrospial fluid through te dural uncture, and it sually fllows th use of wide-boe needle The lea reduces the volme of ceebrospinl fluid, which, in turn, cuses a dwnward displacement of the brain and stretchs the neve-sensiive meniges—a headache follows. The headche is rlieved b assumin the recmbent psition. sing smal-gauge tyletted needles nd avoidng multile dural holes reduce the incidence of headhe. Brin hernation Lumba punctur is conraindicaed in cases in wich intracranial pressue is significantly raised A large tumor, fr exampl, above he tentrium cerbelli with a high intracraial presure may result in a cauda displacement of he uncus through te tentoral notch or a dagerous dsplacemet of the medulla hrough te forame magnum, when th lumbar cerebrospnal fluid pressure is reducd.

Bock of he Subarchnoid Sace

1623

snell A block of the subachnoid space in the verebral cnal, which may b caused y a tumr of the spinl cord o the meinges, can be deected b compresing the ntenal jugular vein in the neck. Tis raiss the cerebrl venous pressure and inhiits the absrption o cerebropinal flid in th arachnoid grnulation, thus roducing a rise in the maometric eading f the cerebrospinal fuid prssure. I this rie fails o occur, the suarachnoi space i blocked and th patient is said o exhibi a posiive Quckenstedt's sign.

Caudal Aesthesia Solutons of nesthetis may be injected into the saral canl throug the sacal hatus. Te solutins pward in the oose cnnective tissue ad bathe he spinl nerves as they emerge from the dura sheath Caudal nesthesi is used in operations i the sacral regon, including anrectal surgery ad culdosopy. Obsetrician use ths method of nerv block t relieve the pain during te first and secnd stage of labr. Its avantage s that, istred by this method, the anesthetic does not affect he infan. The sacrl hiatus is palpted as a distinct depression in te midlin about 16 in. (4 cm) aboe the ti of the coccyx i the uper part f the cleft beteen the buttocks The hitus is tiangular or U saped and is bouned laterlly by te sacral cornua (Fi. 12-18). The size ad shape of the hiatus deend on te number of lamnae that fail to fuse in the midlne posteiorly. Te common arrangment is or the hatus to e forme by the onfusion of the ifth and sometims the fourth sacral verterae. With a careful septic tchnique and unde local nesthesi, the needle, fited wit a stylt, is pssed int the vetebral (acral) cnal thrugh the acral hiatus. The eedle pierces th skin an fascia and the sacrococygeal membrane that fills in the scral hitus (Fig. 12-18). The embrane s formed of dense fibrous tissue ad represnts the fused supraspinus and iterspinous ligamnts as wll as te ligametum flaum. A ditinct feling of €œgiveâ is fel when th ligamet is peetrated Not that he sacra canal s curved and folows the eneral curve of he sacrum (Fig. 1220). The anterior wal, formed by the fsion of he bodie of the sacral vertebrae is roug and rided. The posterio wall, ormed by the fuson of th laminae, is smooth. The verage stance etween te sacrl hiatus and the ower end of the sbarachnod space t the seond sacal vertbra is aout 2 i. (5 cm) in aduls. Not also tht the saral cana contains the dral sac (containng the cauda euina), hich is tethered to the coccyx by the film terminle; the acral ad coccygal nerve as the emerge rom the dural ac surronded by heir dual sheat; and th thin-waled vens of th interna vertebrl venous plexus. P.82

.873

1624

snell

Figre 12-1 Disection o the skll and te upper part of he cervial verteral coumn showing the rain in agittal ection ad the inact spinl cord n situ. ote the continuiy of the medulla oblongta and he spina cord t the foamen manum. Not also te roots f the crvical sinal nerves and the truns of the spinal nerves as they emerge through the dissected interverebral framina. Table 12-1 Summary o Importat Featues Found in Cervcal and Lumbosaral Root Syndroms

1625

snell

oot Injuy

Dermatme Pain

uscle Suplied

Moement Wakness Rflex Invlved

C5

Loer lateal aspec of uppe arm

Deltoid and iceps

Shouldr abducton, elbow flexio

Bceps

C6

Laterl aspect of foream

xtensor carpi raialis logus and revis

Wrst extesors

Brachioadialis

C7

Middle finge

Trieps and lexor capi radiais

Extensin of elbw and flxion of wrist

Trieps

C8

Medial apect of forearm

Fleor digitrum supeficialis and profndus

Finger flexon

Nne

L1

Goin

Iliopsoas

Hip flexion

Cremster

L2

nterior aspct of thgh

Ilopsoas, sartoriu, hip aductors

Hp flexion, hip aduction

Cremaster

L3

Medil aspect of knee

Ilopsoas, artorius quadris, hip dductors

Hip fleion, kne extensin, hip aduction

Patella

L4

Medial aspet of cal

Tiialis aterior, uadricep

oot invesion, kee extenion

Patella

L5

Lateral part of ower leg and

Extesor hallcis longs, extenor

Toe exension,

Nne

1626

snell

dorsum of oot

digitrum longs

nkle doriflexion

S1

ateral edge of fot

Gastrocnmius, soeus

Ankle pantar flxion

Ankle erk

S2

osterio part of thigh

Flexo digitom longu, flexor halluci longus

nkle platar flexon, toe lexion

Noe

P.84

1627

snell

Figre 12-14 Dissction of the back of the ad and nck. The reater prt of th occipital bone has been removed posing te perioseal laye of dura On the right sie a windw has be made in the dur below te transerse venus sinus to expos the cerbellum ad the meulla obongata in the poserior crnial fos. In the neck the dura and arachnoid have been incisd in te midlin to expoe the spnal cord and roolets of he cervial spina nerves. Note the cervical spinal erves leaving the vertebral canal enveloped n a menigeal sheth.

Cerebrspinal Fuid The cerebrospinal fluid is a clear, colorles fluid ormed manly by te horoid pexuses, withi the latral, thid, and furth venricles of the brai. The fuid circlates though the ventricular ystem and enters the ubarachnid space through he three foramina in the rof of th fourth ventricl (see pa 690) It circlates boh upwar over th surface of the crebral hmisphere and dowward arond the pinal cod. The sinal par of the ubarachnid space extends own as ar as the lower brder of e second sacral vertebra, here the arachnod fuses ith the ilum terinale (Fig. 12-7). Eventually, the fluid entes the blodstream by ig throug the arachnid villi into he dural venous sinuses, i particuar the superior sagittal vens sinus. In adition to removing waste prducts asociated ith neuonal activit, the ceebrospinl fluid rovides fluid mdium that surrouns the spnal cord This flid, togeher with the bony and ligmentous alls of he verteral cana, effectvely protects the spinal crd from rauma.

Clnical Noes Rlationsp of the Vertebral Body to the Spinal Nerve Since th fully dveloped ertebral body is intersegental in position each spnal nerv leaves he verteral canl throug the intervertebrl forame and is cosely reated to he intevertebra disc. Tis fact s of gret clinicl signifcance in cases with prolapse of an interverebral disc (Fig. 12-6) (se pge 867. .875

Embryoloic Notes Deveopment o the Verebral Coumn Early i developent, the embryon mesoder becomes differeniated ino three istinct egions: paaxial meoderm, itermediate mesodem, and laeral mesderm. The parxial mesderm is a column of tissue situated on eithe side of the midlne of th embryo, and at aout the ourth wek,

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snell it bemes divided into blocks o tissue alled somits. Eah somite becomes ifferentated int a ventrmedial prt (the sclrotome) and a orsolateal part (the dermatomyotome). The drmatomyoome now urther dfferentites into the myotome and the ermatome (Fig. 12-9) Th mesenchmal cell of the clerotom rapidly divide nd migrae medialy during the fourh week o developent and surround the notochod (Fig. 1-19). The caual half f each sclerotome now fuse with th cephalic half of the immediately scceeding sclerotoe to for the mesnchymal verebral boy (Figs. 2-19 and 12-20. Each ertebral body is hus an itersegmetal struture. Th notochod degenates comletely i the regon of the vertebral body, ut in th intervrtebral egion, i enlarge to form the nucleus pulposus of th iterverteral disc (Fig. 12-20). he surronding firocartile, the anuus fibrous, of the intevertebra disc is derived rom scleotomic msenchyme situated between adjacent vertebra bodies Fi. 12-20). Meanwhil, the meenchymal vertebra body gies rise o dorsa and latral outgowths on each sid. The dosal outgowths gro around the neurl tube btween th segmentl nerves to fuse ith their fellow of the pposite ide and orm the mesenchymal eural arh (Fig. 1-19). The lateal outgrowths between he myotoes to fom the meenchymal cotal procsses, or primordia of te ibs. Two enters o chondriication ppear in the midde of eah mesencymal vertebral body. Thes quickly fuse to orm a crtilagins centrum (ig. 12-1). A chondrifcation cnter fors in eac half of the mesechymal nural arc and sprads dorslly to fse behin the neual tube ith its fellow o the oppsite sid These cnters alo extend anteriory to fue with te cartilginous cntrum an laterally into te costal processs. The cndensed esenchyml or memranous vertebra has thus been conveted into a cartilagnous verebra. In the thorcic regin, each ostal process forms a cartilginous rib. The costal pocesses in the cevical reion reman short nd form he laterl and anerior bondaries f the foramn transvrsarium of ea vertebr. In the lumbar rgion, th costal rocess frms part of the ransvers process; in the sacral regon, the ostal prcesses use togeher to frm the laterl mass of the sacru. At about the ninth week of dvelopmen, primary ossificaon centes appear two for each centum and one for each alf of te neural rch (Fig. 1219). Te two ceters for e centru usually uite quicly, but th complete union of all the pimary ceners does ot occur util seveal years ter birt. Duing adolscence, econdary centers ppear in the carilage coering the uperior ad inferio ends of he vertebal body, and the epipyseal plaes are formed. A secondar center ao appears at the ti of each transverse process and at th tip of te spinou process. By the 25h year, al the secondary ceter have fued with te rest of the vertbra. The atlas and axis devep somewat diffeently. Te centru of the aas fuses with tht of th axis and beomes the part of he axis vrtebra kown as th odontoid pocess. This leavs only the neural arh for th atlas, wich grows anteriorly and fially fuses in the mline to rm the caracterisic ring hape of te atlas vrtebra. I the sacral egion, the bodis of the ndividul vertebrae are searated fom each ther in early le by inervertebal discs At abou the 18t year, the bodies tart to ecome unied by bon; this process

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snell stats cauday. Usuall by the 3th year ll the sacal verterae are uited. In te coccygeal region, segmenta fusion ao takes lace, and in later lfe the coccyx often fues with the sacrum.

Developent of te Curves f the Vetebral Colmn The ebryonic verteral column shows one continuous anterior (ventral concavy. Late, the sarovertebal angle develops At birh, the cevical, thracic, an lumbar egions sho one coninuous aterior (vntral) coavity. When the chid begins t raise hs or her ead, the ervical rve, whih is convx anterioly, deveops. Towad the end f the firt year, wen the cild stand up, the lumbar curve, which is conve anteriory, develps.

Development of the Muscles of the rtebral lumn The prevetebral an postvertbral muses develo from the segmentl myotome

Scolosis Soliosis rsults fro a congental hemivrtebra. A hemivertbra is csed by a ailure i developmt of one f the two ossificaion centes that apear in the centrum f the bod of each vertebr (Fig. 1221).

Spina Bifida In spna bifida, the spine and archs of one r more ajacent vrtebrae fal to deveop. The ondition ocurs most frequenty in the ower thorcic, lumar, and acral egions. eneath tis defec, the mennges and sinal cor may o may no be involved i varyig degree. This cndition s a resut of failure of the mesechyme, wich grows in btween th neural tube an the surace ectoderm, to form the vertebra arches in the ffected egion. Te types of spina bifida ae shown n Figurs 12-22 and 12-23. P.876

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Figue 12-5 Disection f the loer part f the bak includng a comlete lainectomy of the lmbar and sacral rgions of the vertbral colun. The eningeal sheath hs been inised and reflecte laterally exposing the ubarachnid space, the low end of he spina cord, ad the cada equia. Note he filum terminal surrouned by th anterior and posterior neve roots of the lmbar and sacral sinal neres formig the cauda equina.

Radiogrphic Anaomy Radiogrphic Apparances f the Vertebral Column The views comonly usd are th anteropsterior nd the lateral. Examples of anteroosterior and lateal radioraphs of the verebral coumn can e seen i Figures 12-24, 12-2, 12-26, 2-27, 1228, 129.

Spina Subaracnoid Spac 1631

snell Th subaracnoid spae can be studied adiograpically y the inection o contras media ito the sbarachnod space y lumba punctur. Iodize oil has been used with success. This technique is rferred t as myelogrphy (Figs. 12-30 and 12-31). If the patient sitting in the uright poition, te oil snks to te lower imit of he subarchnoid sace at te level f the lwer bordr of the second scral verebra. By placing he patiet on a ilting tble, the oil can e made t gravitae gradualy to hgher levels of th vertebr column. A nomal myelgram wil show ponted latral projections at regular interva at the interverebral space levels. This appearance is caus by the opaque medium fillng the lteral etensions of the sbarachnod space round eah spinal nerve. Te presece of a umor or prolapsd intervrtebral isc may bstruct the movement of the oil fr one region to another whe the paent is tilted.

Comuted Tomgraphy ad Magnetc Resonace Imagig Studie Compute tomograhy (CT) nd magneic resonnce imagng (MRI are extnsively sed to dtect lesons of te vertebal colum, especlly those involving the soft tissue. CT scas can cocentrate on the intervertebral spaces and reveal the interverebral dic in trnsverse lices (Figs 12-32 and 12-33). The dsc has a higher dnsity thn the ceebrospinal fluid in the subarachnoi space ad the .877

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surrouning fat. Fragments of a herniated disc can b identifed beyond the boundaries of the anulus fibrosus.

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Figre 12-16 A, B. Posteri views o vertebral bodie in the ervical and lumbar regions showing the

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relaionship hat migh exist btween th herniatd nucleu pulposs and th spinal erve roos. Note that thee are eight cervial spin nerves but only seven cervical vetebrae. In the lumbar regi, for example, the emerging L4 nerve roots ass out aterally close to the pedcle of te fourth lumbar vrtebra ad are not relate to the interverebral dic betwee the fouth and fifth lumbr vertebae. C. osterolaeral heriation of the nuclus pulpous of th intervetebral isc betwen the fifth lumbar verteb and the first saral vertbra shoing presure on te S1 nerv root. D. An inervertebal disc tat has herniated ts nucles pulposs posterorly. E. Pressure on the L motor nrve root produces weakness of dorsiflexion o the anke; pressre on th S1 moto nerve oot prodces weakess of lantar fexion of the ankl t.

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Figre 12-17 Sagital secton throuh the lubar part of the vertebral clumn n flexin. Note hat the pines ad lamina are well separatd in thi positin, enablng one t introdue a lumbar punctue needle into the subarachnoid spa.

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igure 1218 A. he sacral hiatus. lack dot indicat the postion of mportant bony landmarks. B. osterior urface the lower end f the scrum and the coccyx showng the acrococcgeal memrane covring the sacral hatus. C. The durl sheath (thecal sac) arond the lower end of the spial cord and spinal nerves in the sacral canal; the lminae hae been rmoved. D Longituinal secion throgh the scrum showing the natomy o caudal nesthesia.

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Fgure 12-9 The stages i the foration of a thoracc vertebra.

MRI eaily defies the iterverteral disc on sagital secton and shows its relationship to th vertebrl body ad the psterior ongitudial ligamnt (Fig. 1234). he hernited fragent of te disc ad its reationshi to the ural sa can easly be deonstrate. The us of MRI s now largely replacing melograph or CT in this region.

Surace Anatmy The entire osterior aspect of the patnt shoul be examned from head to fot, and he arms hould hag loosel at the ide.

Midlne Strucures In the midline, the follwing strctures cn be palated fro above dwnward.

Externa Occipitl Protubrance 1637

snell The external ocipital otuberane lies a the juntion of he head nd neck Fi. 12-1. If the index finger is placed on the skin n the miline, it can be dawn downard from the protberance n the nucha groove

Cervica Vertebre The most proinent spnous proess that can be flt in th neck (Fig. 12-35) is tha of the sevent cervica vertebr (verteba prominns). Cervical spines oe to six are coveed by th lgamentum nuchae, a larg ligamen that rus down te back o the nec connectng the sull to te spinous processes of the cervical vertebra he transvese proceses are short ut easily palpable from the lateral ide in a thin nek. The anteior tubecle of te sixth ervical ransvers process (tubercl of Chassaignac) can be alpated edial to the strnocleidmastoid muscle, nd againt it the common crotid arery can e compresed. P.81

Figue 12-20 The formation of each mesenchymal vertebra body by the fusin of the caudal half

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of each sclertome wit the cepalic hal of the immediatly succeding sclrotome. ach vertbral bod is thus an intesegmenta structue. The cstal proesses grw out beeen adjcent myotomes. Alo shown s the clse relaionship hat exiss betwen each sinal nerve and each intervetebral dsc.

Toracic ad Lumbar Vertebra Th nuchal roove is continuos below ith a furow that uns down the midde of the back ove the tip of the spies of al the thoacic ad the uper four lumar verterae (Fig. 12-35. The mst promient spin is that of the frst thorcic vertbra; the others ay be eaily reconized when the trunk is ben forward

Sarum Te pines of the sacrm are fused wih each oher in te midlin to form the median acral cest. e crest an be fet beneat the ski in the ppermost part of he cleft between he buttoks.

Fgure 12-1 Poserior viw of a wman with scoliosi resultig from a ongenitl hemivetebra in the lowe thoracic region.

The sacral hiatus is stuated o the poserior asect of te lower nd of th sacrum, and her the extadural space (epidral spac) termintes. The hiatus les abou 2 in. ( cm) above the tip of the occyx an beneath the skin f the groove beteen the uttocks.

Cccyx

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snell Te inferir surfac and tip of the cccyx can be palpted in te groove between he buttoks about 1 in. (2.5 cm) behnd the nus (Fig. 1-1). he anteror surface of the coccyx cn be palated wit a glove finger n the anl canal.

Upper Lateral Part of the Torax The uper lateral part of the thrax is coered by he scapla and is associted musces. The capula lies posteror to th first o the seenth rib (igs. 12- and 12-3).

Scapula he medial order of the sapula forms a prominent ride, which ends aboe at the superior angle an below a the inferior angl (Fig. 12-5). Te superior angle an be palpated oposite the first thoracic spine, and the inferir angle can be palpated opposite he sevenh thoracc spine Fis. 12-1 and 12-35). he crest of the spin of the capula can be palpated and traced medialy to the medial brder of he scapla, whic it at the evel of he third thoacic spie (Figs. 121 and 12-5). P.882

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Figure 1-22 Dfferent types of ina bifia.

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Figure 12-23 A. Meningcele in he lumboacral reion. (Cortesy of L. Thompon.) B. Mningomyeocele in the uppe thoraci region. (Courtes of G. Aery.)

igure 1224 Ateroposerior raiograph f the uper cervical region of the ertebrl column with the patient' mouth oen to show the odontoid prcess of he axis.

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Fgure 12-5 Anteroposterr radioaph of he cervical region of the vrtebral olumn.

The acromio process of the sapula orms the lateral extremity of the spine of te scapul. It is ubcutaneous and esily locted.

Lower Lateral Part of the Back

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snell The lwer lateal part f the back is formed by th posteror aspec of the pper par of the ony pelvs (false pelvis) and its associated gluteal uscles.

Iiac Cress The iliac crsts are asily papable alng their entire lngth (Fig. 2-1). They lie at the level of the fourth lumbar sine and re used s a lanmark whe performig a lumbr punctue. Each rest end in fron at the anerior superior liac spie and behind at the posteior supeior ilia spine; the later lies beneath skin diple at the level o the secnd sacra verteba and th middle f the sacroiliac jint. The iliac tbercle is a prominence fel on the uter surace of te iliac est abou 2 in. 5 cm) poterior t the anterosuperio iliac sine. The iliac tuercle lies at the level of the fift lumbar pine.

Spinl Cord ad Subarahnoid Spce The spina cord in adult extends down to he level of the lwer bordr of the spine of the firs lumbar ertebra Fi. 12-7. In youg childrn, it ma extend o the thrd lumba spine. Te ubarachnid space, with its cerebropinal flid, exends dow to the ower borer of th second acral vetebra (Fig. 12-7) which les at the level of the posterosuperior iliac spine.

Symmety of the Back Observe he back s a whol and comare the wo sides with refrence to an imagiary line ing ownward rom P.885

the eternal ocipital rotuberace to th cleft btween th buttock.

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Figure 12-26 Latral radigraph of the cervcal regin of the vertebra column.

The posteror verteral muscuature which ainly cotrols th movemens of the vertebra column nd mainains the postural curves o the colmn, can e palpated. The uscles ae large nd lie o either ide of te spines of the vrtebrae (Fgs. 12-1, 12-9, and 12-35. They hould be examined with the flat of he hand. If they ehibit nrmal ton, they ae firm t the tou. A spasic muscl feels hrder thn normal; it is aso shortr than nrmal, whch produces a concvity of the vertbral colmn on th side of the muscular contrction. The cuves of te vertebal colum can be examied by inpecting he laterl contou of the back. Normally, the posteror surfae is conave in te cervicl region convex in the toracic rgion, an concave in the lmbar regon (Fig. 122). Te anterir surfac of the acrum an coccyx ogether have an anterior concavity. The lumbr region meets the sacrum at a sharp angle, the lumbosaral angl. Inspetion of he posteior surfce of th back, wih partiular refrence to the vertical alignment of he verteral spins, revels a sliht laterl curvatre in mot normal persons. Right-haded perons, espcially tose whos work inolves exreme and prolonge musculr effort usually exhibit lateral thoracic curve to the right; left-nded persons usually exhibt a lateal thoraic curve to the eft.

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Fgure 12-7 Antroposteror radioraph of he thoraic regio of the vertebral column.

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Figue 12-28 Anteroosterior radiograh of the lower thracic, lmbar, an sacral egions o the vertebral column.

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Figur 12-29 Lateral adiograp of the ower thoacic, lubar, and sacral rgions of the vertbral colmn.

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Fgure 12-30 Poseroanteror myeloram of te lumbar egion.

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igure 1-31 Man featurs that cn be seen in the melogram n igure 1230.

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Figure 1-32 Coputed toography can of te fourth lumbar vrtebra.

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Figure 1-33 omputed omography scan hrough te vertebal colum at the level of the intevertebra disc beween the fourth and fifth lumbar veebrae. he spine of L4 an the intrvertebrl forame on each side are shown. ote the oints beween the articular processe.

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Figur 12-34 Sagittl magnetc resonace imagig scan o the cerical part of the vertebra column. A herniaed disc etween the fifth and sixth vertebra is show. Note te positin of the spinal crd and is meningeal coveings relative to e herniaed disc. (Courtes of Pait)

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Figur 12-35 The back of a 27-ear-old an.

Clinial Problm Solvin Stud the folowing cse histories and select te best aswer to he questons follwing the. An 11-year-ld boy ws showig off in front of friends y diving into the shallow end of a swimming pool. Afr one prticular daring die, he sufaced quckly an climbed out of te pool, olding hs head btween hi hands. e said hat he hd hit th bottom of the pool with his head and now had severe ain in te root o the nec, which as made orse whe he trie to mov his nec. A lateal radiograph reveled that the rigt inferor artilar process of te fifth ervical ertebra was forced over th anterior margin of the right superor articlar procss of th sixth ervical ertebra, producing a unilateral dislcation wth nippig of th right sxth cervcal nerv.

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snell . The folowing smptoms an signs confirmed the diagnsis excet which? (a) The head wa rotated to the ght. (b) Thre was sasm of te deep nck muscls on the right sde of the neck, which were tender t touch. (c) he patiet complaned of svere pai in the egion of the back of the nek and riht shouler. (d) The slightest movement roduced evere pan in the right sith cervial dermaome. () The lage size f the vetebral cnal in te cervicl region permitte the spial cord o escape injury. iew Answr 1 A. The right inerior aricular pocess of the fift cervica vertebra was forced ove the antrior marin of th right uperior articular process f the sith cervial vertera, causng the had of th patient to be rtated to the left A 0-year-od coal mner was crouchin at the ine face when a lrge rock suddenly became islodged from the roof of he mine haft and struck hm on the upper prt of hi back. Te emergecy deparment phyician supected a displacment of he upper thoracic spines o the sixh thoracic spine. 2. The followin physica signs cnfirmed diagnoss of frcture dilocation between he fifth and sixt thoraci vertebre except which? (a) A laral radograph revealed ractures involving the superior artular proesses of the sixth thoracic vertebra and the inferio articulr proceses of th fifth horacic ertebra. () Considrable foward displacement of the bdy of th fifth toracic vertebra on the sixh thoracic verteba occurr. (c) The atient had signs and symptoms of spinal shock. (d) Th large sze of th vertebrl canal in the toracic rgion leaves plent of spac around he spina cord for bony diplacemen. (e) Th patient later shwed sign and symtoms of araplegi. Viw Answer 2. D. The vrtebral anal in he thoraic regio is smal and roud and lttle spae is arond the sinal cor for bony displaceent to ocur witout causng severe damage t the cor. A 66-yearold woma was sen in the emergenc departmnt complining of a burnin pain ovr the uper part of her rght arm. The pain had stared 2 day previously and hd progresively wrsened. hysical xaminatin reveald weaknes and wsting of the righ deltoid and bices brachi muscles The patient also had hyperesthesia in the sin over he lower part of he right deltoid and down the lateal side f the ar. Radiolgic examnation howed exensive sur formaion on te

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snell bodies of the fourth, ifth, and sixth cervical vrtebrae These igns and symptoms suggeste severe osteoartritis of the cervcal vertbral colmn. 3. This disase prodced the ollowing changes n the vetebrae ad relate structues excep which? (a) Repeated trauma ad aging ad resuted in dgeneratie changes at the aticulatig surfas of the fourth, fifth, and sixth ervical ertebrae (b) Extensive pur formtion reslted in arrowing of the iterverteral foramina with pressure on the nerv roots. (c The buring pain and hypeesthesia were caued by prssure on the thir and fouth cervial posteior root. d) The wakness ad wastin of the deltoid nd bicep brachii muscles ere causd by presure on he fifth and sixh cervicl anterior roots. (e) Moveents of he neck ntensifid the syptoms by exerting further ressure n the neve roots (f) Coughing or sneezng raise the pressure within the vertebral canal and sulted in furthe pressur on the roots. iew Answr 3. C. The burning pain and peresthia were caused by pressure on the ffth and ixth cerical poserior rots. A medial studet offere to mov a grand piano fo his lanlady. He had just finished his fina examintions in anatomy nd was i poor phsical shpe. He sruggled with the antique monstrosity and sudenly exerienced an acute pain in the back, which xtended own the ck and oter side of his lft leg. On examination in he emergncy depatment, h was foud to hav a sligt scoliois with he conveity on te right ide. The deep musles of he back n the let lumbar region flt firme than nomal. No evidence of muscl weaknes was preent, but the left ankle jerk was diminished. 4. he symptms and sgns of tis patiet strongy suggesed a diaosis of prolapsed intervetebral dsc excep which? (a) The pain as worst over the left lumar regio opposite the fifh lumbar spine. (b) The pain was accentuaed by coghing. (c) ith the atient spine, flxing the left hip t with the kne extendd caused a marked increase in the pin. (d) A lteral raiograph f the lubar vertbral colmn reveaed nothig abnormal. (e An MRI tudy revaled the presence of smal fragmens of the nucleus ulposus at had erniated outside he anulus in the disc betwen the ffth lumbr verteba and th sacrum. (f) The pai occurred in the dermatomes of the third and fourth lmbar segents on the left ide.

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snell View Answer 4. F. The pain occurred in the drmatomes of the ffth lumbr and first sacral segments on the left side . When erformin a lumbar punctue (spina tap) o an adul, the fllowing natomic acts hae to be aken int consideation exept whic? (a) With the patient n the laeral proe or upight siting posiion, the vertebra column hould be well fleed to sparate th spines nd laminae of adjacent vertebrae. (b) An imaginay line jining th anterio superio iliac sines pases over he fourt lumbar pine. (c) Te needle should be inserted above o below he fourt lumbar pine. () To entr the suarachnoi space, he neede will pss throuh the skn, supercial faia, suprspinous ligament interspnous ligment, liamentum lavum, aeolar tisue (cotaining he interal verteral venos plexus, dura mter, and arachnod mater. (e) The pinal cod ends blow in te adult t the leel of th lower brder of he first lumbar vrtebra. (f) ith the atient i the latral pron positio, the ormal ceebrospinl fluid ressure s about 20 mm H2O View Anwer 5. B. An imaginar line joning the highest oints of the ilia crests asses ovr the forth lumbr spine. A 22-year-old studet was diving he from a party an crashed his car ead on ito a brik wall. On examiation in the emerency deprtment, e was fond to hae a frature discation of the seenth thoacic vertebra, with signs and sympms of svere damage to the spinal cord. 6. On recovry from pinal shck he wa found t have th followig signs nd symptms excep which? (a) He had uper moto neuron aralysis of his lft leg. b) He ha a band f cutaneus hypeesthesia extendin around he abdomnal wall on the left side t the lvel of te umbilicus that was cause by the rritatio of the cord immediately bove the site of the lesion. (c) On te right ide, totl analgesia, termoaneshesia, and partial loss of tactile ense of he skin f the adominal wall below the leve of the mbilicus involvin the whoe of th right lg were pesent. d) Fractre disloation of the seveth thoracic vertbra woul result n severe damage t the sevnth thorcic segent of te spinal cord. (e The unequal sensry and mtor losss on the two side indicat a left emisectin of the spinal crd. View Answer

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snell 6. D Fracture dislocation of he 7th toracic vrtebra wuld result in sevre damag to the 10th thocic segment of the spinal ord. 45-yearold woma visited her physicia because of a low back pai of 3 moths' durtion. Se was oterwise vry fit. n examintion of er back, nothing abnormal as discoered. Th physicin then listened t her chet, examned her hyroid gand, and finally xamined oth breats. A large, hard mass was found in the left breast. 7 The folowing fcts supprted the diagnosi of carnoma of he left reast wih secondries in he verteral colun excep which? a) The lmp in th breast as painlss and te patien had notced it while showring 6 mnths preiously. (b) everal lrge, har, pectorl lymph odes wer found i the lef axilla. (c) A lteral raiogrph of the umbar vrtebral colmn showe extensie metastses in te bodies of the econd an third lmbar verebrae. d) The ump was situated in the per out quadran of the eft breat and wa fixed t surrouning tisses. (e) Alhough th cancer ad sprea by the ymph vesels, no vidence f spread via the bloodstrem was prsent. Viw Answer 7. E. The carcinoma f the let breast was in a advance stage ad had sread by ay of th lymph vssels to the axilary lymp nodes ad by th bloodsteam to the bodies of the second and hird lubar vertbrae. Crcinoma f the throid, brnchus, beast, kiney, and prostate tend to metastasze via te bloodsream to ones. A 75-yar-old woman was dusting the top o a high oset whie balancd on a cair. She lost he balance and fell to the foor, cathing her right lubar regin on th edge of the chai . The folowing satements about ths patien are corect excet which? (a) Exmination of the bck revead a larg bruised area in the righ lumbar egion, wich was xtremely tender to touch. (b Anteropsterior nd lateral radiogaphs excude the resence f a fracture, especially o a transverse proess. (c) A 4-hour secimen o urine sould be xamined or blood to exclue or conirm injuy to the right kiney. (d) Careful exanation the erector spinae muscles or quaratus luborum mucle may eveal exreme tederness nd thereore injuy to thee muscle. (e) A lumbar puncture (spinal ap) shoud always be perfomed in bck injures to exlude damge to th spinal ord.

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snell Viw Answer 8. . A lumbr punctue (spina tap) is not requred in cses of smple trama to th back. P.89

P.86

Reviw Questins Competion Qustions Select the phrae that bst compltes each statemen. 1. The haracterstic feaure of te second cervical vertebra is its a) absen body. (b) odotoid procss. ) hearthaped body. () massiv body. (e) trifid spinous process. View Aner 1. B 2. Te sevent cervica vertebr is charcterized by havin (a) the longest spinous process. (b) a large foramen transversarim. c) a heat-shaped body. (d) a massive body. (e) an odontid proces. View Aswer 2. A 3. The sixt thoracic vertebra is charcterized by

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snell (a) its heart-shped body. (b) ts bifid spinous rocess. (c) its massiv body. (d) haing the uperior rticular processe face meially an those o the infrior artcular prcess face laterally. (e) its thick laina. View nswer 3. A 4 The chaacteristc featur of the irst cerical verebra is ts (a) oontoid pocess. (b) masive body (c) bsent body. (d) long spious procss. e) absen foramen transverarium. Vew Answe 4. C. Durin developent the entrum o the atls fuses ith that of the ais to fom the oontoid pocess of the axis 5 The chaacteristc featur of the ifth lumar vertera is it (a) heat-shaped body. (b) rouned verteral foraen. c) small pedicles (d) assive bdy. (e) short nd thick transvere proces. View Aswer 5. D. Te pedicls are lage and te transvrse procsses are long and slender; the vertbral formen is tiangular 6 The caua equina consists of (a) a bundle of posterior roots of lmbar, saral, and coccygeal spinal nerves. b) the flum termnale.

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snell (c) a bndle of nterior nd posteior root of lumbr, sacra, and cocygeal spinal neres. () a bunde of lumar, sacrl, and cccygeal pinal neves and he filum terminale. (e) bundle f anterir and poterior rots of lmbar, saral, and coccygea spinal erves an the film terminle. Vie Answer 6. E 7. The spinal crd in the adult es inferiorly at the level of the (a L5 verbra. b) L3 vetebra. (c) S2 t 3 verterae. d) T12 vertebra. (e) L1 vertebra Vew Answe 7. E 8. Heriation o the intrvertebrl disc btween th fifth ad sixth cervical ertebrae will copress th (a fourth ervical erve roo. (b sixth crvical nrve root (c) fifth cevical neve root. (d) seventh nd eighth cervical nerve roots. (e) seenth cerical nerve root. Vew Answer 8. B (see Fig. 12-16 9. Th subaracnoid spae ends iferiorly in the ault at te level f (a) th coccyx. (b) te lower order of L1. (c) S2 t 3. (d) S5. (e) the promontoy of the sacrum.

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snell iew Answr 9C Multile-Choic Questions Selct the bst answ for eac question. 0. The fllowing tatement concernng an inervertebal disc re corret except which? (a) The nucleus ulposus s most lkely to erniate n an antrolatera direction. (b) The disc are the thickest in the lmbar regon. (c) Te atlantaxial jont posseses no disc. (d) The discs ply a majo role in the deveopment o the curatures o the verebral coumn. e) Durin aging, he fluid within te nucleu pulposu is replced by fbrocartiage. View Aswer 10. A. he nucles pulposs is mos likely o herniae in a psterolatral diretion. 1. The folowing satements concernng the vrtebral column ae correc except hich? (a) Throghout ife, the marrow of the verteral bods has a emopoietc functin. ) The iernal vertebral venous plxus proides a path for the ag of malinant cels from te prostae to the cranial avity. () The vetebral atery ascnds the eck throgh the framen trnsversarum of al the cerical verebrae. (d) Injection f an anethetic ito the sacral canl can be used to lock pai and senation frm the cevix, vagina, and perineum during cildbirth. (e) Te atlantaxial jont permis rotatin of the head on he verteral colun. iew Answr 1. C. Te vertebal artery ascends through he foramen transvrsarium f the uper six ervical ertebrae; only the vertebr vein pases thrugh the mall formen transversariu of the eventh crvical vertebra. 12. The first ervical ertebra atlas) hs all th followig anatomc featurs except which? (a) Laeral mases (b) Inferior articul facets (c) Aterior ach (d Spinous process

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snell (e) Superior artcular faets View nswer 12. D. The atla does no have a pine but exhibits a posterior tuberce on its posteri arch. Read the case history nd selec the bes answer to the qestions ollowing it. An 8-year-od girl was taken to a pedatrician because er mother was concerned about a laeral curature of the chil's spine which she had noticed since her dghter was 5 months old. The girl ws otherwise perfectly healty and ative. 13. Th pediatrcian perormed a horough hysical xaminatin and found the following xcept whch? (a) Both legs wee of equ length (b On staning, the heights f the ilac crest were th same on each sid. (c) Te left soulder ws lower han the right. (d) Te vertebal colum in the idthoracc region showed a sharp cuve conve to the ight. (e) Ther were getle compnsatory urves o the verebral coumn abov and belw the shrp curve in the idthoracc region, with coexities to the right. View Aswer 13. E The comensatory curves o the verebral coumn abov and belw a shap curve onvex to the righ would hve their convexites to th left. he pediarician prformed urther cinical eaminatios and orered a rdiographc examintion of he verteral colun. 14. The followin statemets about this patient are correct ecept whih? (a) he anteroposterior radiogrph of th midthoacic regon reveaed a wede-shaped vertebra at the lvel of T and fuion of te left ffth and ixth rib. (b) Flexion f the vertebral column showd that te sharp urved ara was riid. (c) The child had a cngenital hemiverbra at the level of T5 with compenstory cures above and bel that defect. (d) Te conditon is cased by a failure in develpment of one of te three ssificaton centes that apear in the centum of th body of each verbra. () Since he child had no smptoms and the compensatoy curves are well balanced no specal treatent is avised. iew Answr

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snell 1. D. Nomally, te centru has onl two ossfication centers nd not three as sated. A emivertera in th thoraci region ften is associate with apasia or usion of adjacent ribs. P.897

.898 Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

14. Appendix - Useful Anatomic Data of Clinical Significance

Repiratoy System Tale I Iportan Airwa Distaces (Adult) Aiway

Distances (approx.)

ncisor teeth to the vocal cords

.9 in. (15 cm

ncisor teeth to the carina

7.9 in. (20 cm

External nares t the crina

118 in. (30 cm)

Average figures given ± 1€“2 cm

Table II Imprtant ata Cocernin the Tacheaa

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Length approx)

Diameer (approx.)

Aults

4.5 i. (11. cm)

1 in (2.5 m)

Infats

16–2 in. (4€“5 cm

s smal as 3 mb

a

Extesion o the had and neck, s when maintaning an airway in a aneshetize patiet, may stretch the trachea and increase ts length by 25%. I the ault, te caria may escend by as uch a 3 cm n deep inspiation. At the carina the rght brnchus leaves the trchea a an agle of 25° fom the vertical and the left bronhus leves th tracha at n angl of 45° from the vetical. In chidren yunger han 3 ears, both bronchi arise from te tracea at qual agles. b As children grow, the diamter in millimters crrespods appoximatly to heir ae in yars.

Digetive System Table II Lenghs and Capaciies Regio

Legths (approx.)

apacites (aprox.)

Esophagus

1 in. (5 cm)

—

Stomacha

Lesser curvatue 4.8–5.6 in. (12–14 cm)

1500 L

Dodenu

10 in. (2 cm)

—

Jejunm

8 ft. (2.4 m)

—

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Ileum

12 ft. (.7 m)

—

Appedix

3–5 n. (8â“13 cm

€”

Ascendig colo

5 in. (1 cm)

—

Transvrse coon

15 in (38 c)

—

Dscending coln

0 in. 25 cm)

—

Sigoid coon

10–1 in. (5–38 cm)

—

Rectum

5 in. (1 cm)

—

Anal anal

1.5 in. (4 cm)

€”

Gallblader

2.8â€3.9 in (7–0 cm)

3–50 L

ystic uct

1.5 in. (3.8 cm)

—

Bile dct

in. ( cm)

—

a

he cured couse takn by a nasogastric ube frm the ardiac orific to the pylors is uually onger, 6–10 in. (15–25 cm).

Urinry Sysem

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Tabl IV Legths ad Capaities Organ

Lengths (appox.)

Capacity (approx.)

Ureter

10 in. (25 cm)

—

Blader

—

00 mL

Mae urethra

8 in. (20 cm

â€

Penil

in. 15.7 c)

—

Membranous

0.5 i. (1.2 cm)

—

Prostaic

125 in. (3 cm)

â€

1.5 in. (38 cm)

â€

Fmale uethra

Reproductve Sysem Tabe V Diension

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Orga

Dimensios (appox.)

Mae

Tesis

2 à 1 in. (5 × 2.5 cm)

Vas deerens

18 in. (45 cm)

Peis (erct)

6 in. (15 cm)

emale

Ovary

1.5 × .75 in (4 × 2 cm)

Utrine tbe

4 in. (1 cm)

Uteru

3 × 2 à 1 in. (8 × × 2. cm)

Vaina

3 n. (8 m)

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igure 1 Criticl time in th maturtion o the hman feus durng whih mutant genes, drugs, or environmenta factos may lter normal developmnt of specifc strutures.

Caution: Some letters were intendedly removed from the document because It was created by TRIAL version of Softany CHM to PDF converter. To get rid of this, please purchase the product.

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