ThoraxTianhuaPartsandregionsofthethoraxBoundariesSuperiorly－jugularnotch,sternoclavicularjoint,superiorborderofclavicle,acromion,spinousprocessesofC7Inferiorly－xiphoidprocess,costalarch,12thand11thribs,vertebraT12RegionsThoracicwallThoraciccavity

LandmarksofthoraxJugularnotchcorrespondswithT2inmale,theT3infemaleSternalanglecorrespondswithConnects2ndcostalcartilagelaterallylowerborderofT4bifurcationoftracheaintheadultbeginningofaorticarchwhichendsposteriorlyatthesamelevelesophagusiscrossedbytheleftmainbronchusLandmarksofthoraxXiphoidprocess－xiphisternalsynchondrosisliesoppositethebodyoftheT9ClavicleInferiorfossaofclavicleCoracoidprocessRibsandintercostalspacesCostalarch

Infrasternalangle

Xiphocostalangle劍肋角Mammarypapilla

ReferencelinesofthoraxAnteriormedianlineSternallineMidclavicularlineParasternallineReferencelinesofthoraxAnterioraxillaryline

MidaxillarylinePosterioraxillarylinePosteriormedianlineScpularlineIntroductionforthoraxThoracicwallDiaphragmThoraciccavityOrgansinthoraciccavityMediastinumPleura

Thoracicwall—Skin—Superficialfascia：—Deepfascia—Musclescoveringthethorax：Pectoralismajor,pectoralisminorSerratusanteriorlatissimusdorsi,atc.—Ribsandintercostalspaces:intercostalm.(p12-13)：3layersbloodvesselsandnerves—Endothoracicfascia—Costalpleura

LayersofthoracicwallSuperficialfascia

Superficiala.：Superficialv.Thoracoepigastricv.Lateralthoracicv.Superficialn.Supraclavicularn.Ant.andlateralcutaneousbranchesofintercostaln.—BreastThoracoepigastricv.Superficialv.Lateralthoracicv.Cutaneousn.Lateral

cutaneousbranchesofintercostaln.lateralcutaneousbranchesofintercostaln.Supraclavicularn.Locationof

femalebreast:—Lieinsuperficialfasciaoverthepectoralsmajorandpectoralfascia，

—Extendfrom3rdto7thribsvertically,andfromparasternallinetomidaxillarylinetransversally—locationofnipple:—female:4thor5thintercostalspaceonmidclavicularline—man:4thintercostalspaceonmidclavicularline—composition:skin,mammaryglandsadiposetissue—mammaryglands:

15~20lobesofmammaryglandwhich

radiatesoutfromthenipple

lactiferousducts→lactiferoussinuses→thesummitofthenipple

—suspensorylig.ofbreast：connectivetissueseptathatextendfromtheskintothedeepfasciaonthepectoralismajor,tosupportthemammaryglandsStructureofbreast:suspensorylig.ofbreastlymphaticdrainageofbreast:—Topectoralln.—Toapicalln.andsupraclavicularln.—Toparasternallymphnodes(alonginternalthoracicvessels)pulmonarymetastasisBreastcancerMusclescoveringthethorax：

Intercostalm.

:

3layersfromthesuperficialtothedeep：

Externalintercostalm.--externalintercostalmembraneInternalintercostalm.--internalintercostalmembraneInnermostintercostalm.

a.,v.,n.supplyingthoracicwall:—

pos.intercostala.andv.(9pairs)：

subcostala.andv.(1pairs):—internalthoracica.andv.:—

intercostaln.(11pairs),subcostaln.(1pairs)：fromsup.toinf.:v.-a.-n.goalongthecostalgrooves

theyaccompanyintercostaln.intheintercostalspace.

thea.arisefromthoracicaorta,

giveoffcollateralbranchesatthecostalanglesalongthesup.bordersofribs.

thev.

drainintoazygosv.ontheright,andhemiazygosv.oraccessoryhemiazygosv.ontheleftTheysupplylower9intercostalsspaces,breastandabdominalwall.Pos.intercostala.andv.(9pairs),

Subcostala.andv.(1pairs):hemiazygosv.accessoryhemiazygosv.

lieabout1cmawayfromlateralborderofsternum，

thea.arisesfromsubclaviana.，Giveoffant.intercostala.anddividesintomusculophrenic

a.andsup.epigastrica.atthe6thcostalcartilage

thev.drainsintoleftandrightbrachiocephalicv.Internalthoracica.andv.:

internalthoracica.andv.musculophrenica.sup.epigastrica.subclaviana.brachiocephalicv.ant.intercostala.

lieinthecostalgroovebetweeninternalintercostalm.andinnermostintercostalm.intheintercostalspaces

then.aretheventralramiofthoracicn.，giveoffcollateralbranchesatthecostalanglesandrunalongthesup.bordersofribs

supplyintercostalm.andcorrespondingskin;m.andskinofabdominalwallIntercostaln.(11pairs),subcostaln.(1pairs)：pleuritisThoracocentesis

pleuraleffusion：pleuritis，cellinfiltratedifficult

breathing—Thesegmentalinnervationofant.ramiofthoracicn.

Segment

Supplythelevel

T2SternalangleT4NippleT6XiphoidprocessT8CostalarchT10UmbilicusT12areabetweenumbilicusandsymphysispubisDiaphragmliesbetweenthoraciccavityandabdominalcavity，attachestotheinferioraperturesofthoraxLocationof

diaphragm—centraltendon—3foramina:location,passingstuctures—aortichiatus:liesanteriortothebodyofT12betweentherightandleftcrus,transmitsaorta,thoracicduct

—esophagealhiatus:

isatlevelofT10,transmitsesophagusandvagusn.

—venacavalforamen:liesincentraltendonatlevelofT8transmitsinf.venacava12108featuresofdiaphragm:partsofdiaphragm:3lumberpartcostalpartsternalpartWeakareasofdiaphragm:functionsofdiaphragm:

takepartinrespirationandregulateintra-abdominalpressure—whendiaphragmContracts:

thedomemovingdownward,increasesthevolumeofthoraciccavitywhichresultsininspiration,atthesametimetheintra-abdominalpressureisincreasedtoassistindefecation,vomitingorchildbirth.—whendiaphragmRelax:thedomereturnstotheformerposition,reducesthevolumeofthethoraciccavity,resultinginexpiration.Pleura

Definitionofpleura

:

Visceralpleura：Parietalpleura:pleuralcavity:alittleserousfluidnegativepressurepleuralrecesses:

alayerof

smoothandglisteningserousmembranecomposedbysimplesquamousepitheliumandabitofconnectivetissue.Themembraneformaclosedsac.

Divisionofpleura:

Visceralpleura：AdherestolungContinuouswithparietalatrootoflung：Pulmonarylig.Parietalpleura:4parts

—Cupulaofpleura：extendsupintotheneck,overtheapexoflung,2.5cmabovethemedialthirdofclavicle—Costalpleura—Mediastinalpleura—Diaphragmaticpleurapleuralcavity:—Potentialspacebetweenvisceralandparietalpleura—Containsasmallamountofpleuralfluid—negativepressurepleuralrecesses:

—costodiaphragmaticrecesses—costomediastinalrecesses:theleftisgreater

—phrenicomediastinalrecessPleurarecessesPotentialspacesofpleuralcavitywhichlungsarenotoccupiedinquietrespirationCostodiaphragmaticrecesseslit-likespacebetweencostalanddiaphragmaticpleuraeoneachsideThelowestareaofpleuralcavityintowhichthelungsexpandduringdeepinspirationCostomediastinalrecessbetweenthemediastinalpleuralandcostalpleura,theleftsideisgreaterpleuralrecessescostodiaphragmaticrecessescostomediastinalrecessesReflectionsofparietalpleuraAnteriorborderofrightpleuraRunsdownbehindthesternoclavicularjoint,almostreachingthemidlinebehindthesternalangleContinuesdownwarduntilitreachesthe6thsternocostaljointAnteriorborderofleftpleuraHasasimilarcourse,butatlevelof4thcostalcartilageitdeviateslaterally,2.5cmapartfromtheleftmarginofsternumItthenturnsshaplydownwardtomidpointof6thcostalcartilageTwotrianglesTriangleofthymus胸腺三角Triangleofpericardium心包三角ReflectionsofparietalpleuraLowermarginsofpleuracrossthe8th,10th,and12thribsatthemidclavicularlines,themidaxillarylines,andthesidesofthevertebralcolumn,respectivelyAnt.marginsofparietalpleura:

(twoant.marginsabutoneachotheratthelevelofsternalangle,therightmargindescendvertically,theleftmargindeviatestotheleftanddescendspos.tothe5thand6thcostalcartilages)#marginsofpleuralcavity

parietalpleuralungs

:#

inf.marginsoflungsandpleuraatthelevelofxiphosternaljointthe10thribinthemid-axillarylineant.:laterally:

post.：atthelevelof12ththoracicvertebralspineapointlateraltothexiphosternaljointthe8thribinthemid-axillarylineatthelevelof10ththoracicvertebralspine

SurfacemarkingsoflowerborderofthelungandpleuraLowerborderMidclavicularlinesMidaxillarylinesScapularlineSidesofthevertebralcolumnLungs6thrib8thrib10thribT11Pleura8thrib10thrib11thribT12Thoracocentesis

Lungs

thelungofsmokerthelungofun-smokerlieonsideofmediastinuminthoraciccavity

locationof

lungs:

X-rayofthorax

is

a

half

cone-shapedelasticorgans—apexoflung：

projectsupwardintotheneckforapproximately2.5cmabovethemedial1/3ofclavicle—baseoflungordiaphragmaticsurface—costalsurface—medialsurface:

hilumoflung

rootoflung—inf.Margin—ant.margin:cardiacnotchofleftlunglingulaofleftlung—fissures:

oblique

horizontal(right)—2lobes：2lobesinleftlung:3lobesinrightlung:Generalfeaturesoflungs:sup.inf.middlesup.inf.medialsurface:

hilumoflung

structurespassingthroughhilumoflung

rootoflung：—principalbronchus

—pulmonaryA.andV.—bronchialA.andV.—N.，L.andLn.

LeftpulmonaryA.LeftPulmonaryV.Leftprincipalbronchus—Intrapulmonarystructures—bronchi—Branchesofpulmonarya.—Tributaryofpulmonaryv.Leftandrightpulmonarya.andv.pulmonarytrunk—bronchiala.andv.—LymphaticvesselsandLn.alvealiBranchesofpulmonarya.Tributaryofpulmonaryv.#Lymphdrainageoflung:Paratrachealln.SuperficiallymphvesselsdeeplymphvesselsBronchomediastinaltrunksTracheobronchialln.Pulmonaryln.Bronchopulmonaryln.BronchopulmonarysegmentsBronchopulmonarysegmentsaretheanatomic,functional,andsurgicalunitsofthelungs.Itispyramidalinshape,withitsapextowardthelungroot,tenineachlungIthasasegmentalbronchus,asegmentalartery,lymphvessels,andnerves.ThesegmentalveinslieintheconnectivetissuebetweenbronchopulmonarysegmentsBecauseitisastructuralunit,adiseasedsegmentcanberemovedsurgically.Bronchopulmonarysegments

MediastinumConceptofMediastinum：

Alloforgansbetweentheleftandrightmediastinalpleuraeiscalledmediastinum.Itextendsfromthesternuminfronttothevertebralcolumnbehind,andfromthethoracicinletabovetothediaphragmbelow.ContentsinMediastinum：

Thymusleftandrightphrenicn.，pericardiacophrenica.andv.Pericardiumandheartv.Superiorvenacava,leftandrightbrachiocephalicveins,azygosveinInferiorvenacavaAortaandbranches

Pulmonarytrunk,Pulmonarya.ArterialligamentandTriangleofductusarteriosusleftandrightvagusn.Trachea，leftandrightprincipalbronchiEsophagusThoracicsympathetictrunkThoracicductDivisionofmediastinum

andstructuresineachpartofmediastinumRootoflungPericardiumPhrenicn.&pericardiacophrenica.Leftvagusn.Leftrecurrentn.ThoracicaortaSympathetictrunkGreatersplanchnicn.AorticarchThoracicductLeftsubclaviana.Esophagus—visiblestructuresthroughpleuraontheleftsideofmediastinum—visiblestructuresthroughpleuraontheleftsideofmediastinum—visiblestructuresthroughpleuraontherightsideofmediastinumRootoflungPericardiumSup.venacavaPhrenicn.&pericardiacophrenica.Rightvagusn.Azygosv.SympathetictrunkEsophagusArchofazygosv.TracheaInferiorvenacava—visiblestructuresthroughpleuraontherightsideofmediastinumPericardiumPericardiumFibrouspericardium

纖維心包AttachedtocentraltendonofdiaphragminferiorlyBlendswithoutercoatofgreatvesselssuperiorlySerouspericardium

漿膜心包Viscerallayer(epicardium)ParietallayerPericardialcavityPotentialspacebetweenvisceralandparietallayersContainsfilmofpericardiumfluidasalubricanttofacilitatecardiacmovementsPericardiumsinus：Formedbyreflectionofserouspericardium

PericardiumsinusTransversesinusofpericardium

Lieposteriortoascendingaortaandpulmonarytrunk,anteriortosuperiorvenacavaandleftatrium.Obliquesinusofpericardium

Cul-de-sac,posteriortoheartBoundedbypulmonaryveinsoneithersideAnteriorinferiorsinusofpericardium

Heart—enclosedinthepericardiuminmiddlemediastinum—ant.toT5-8,pos.tosternalbodyandcostalcartilages2nd-6th—its1/3liesontherightsideofmedianlineits2/3ofitliesontheleftsideofmedianlineLocationofheart:externalfeatureofheart

cone-shapedorgan(1)cardiacbase:

—position:

facesupwards,backwardsandtotheright—formation:majorpart:leftatriumminorpart:rightatrium—connectedstructures:sup.venacavainf.venacavaleftandrightpulmonaryV.(2)cardiacapex:

—direction:directedforwards,downwardsandtotheleft—formation:leftventricle—surfaceprojection:lies

inthe5thintercostalspace,about

1~2cmmedialtotheleftmidclavicularline(3)2surfaces:

—sternocostalsurface:formation:majorpart:rightatriumrightventricleminorpart:

leftatriumleftventricle—diaphragmaticsurface:formation:majorpart:leftventricleminorpart:rightventricle(4)3borders:

—rightborder:formation:rightatriumstructure:

sulcusterminalis—leftborder:formation:leftatriumleftventricle—inf.border:formation:rightventriclecardiacapexstructure:cardiacapicalincisure(5)4grooves:

coronarygrooveant.interventriculargroovepost.interventriculargrooveinteratrialgroove(6)atrioventricularcrux—structurelayersofheart:3layers—fossaovalis

:thethinnestareaoftheinteratrialseptum—partsofinterventricularseptum:muscularpartmembranouspart:

thethinnestareaoftheinteratrialseptum—fiberousskeletonofheart:

—leftfibroustrigone—rightfibroustrigone（centralfibrousbody)—mitralring—tricuspidring—aorticvalvering—pulmonaryvalvering—membranouspartofinterventricularseptumwallstructuresofheartrightatrium—2parts:dividedbycristaterminalis—sinusvenarumcavarum:thewallissmooth—atriumproper:

rightauricle

pectinatem.—3inlets:

—orificeofsup.venacava—orificeofinf.venacava:valveofinf.venacava—orificeofcoronarysinus:valveofcoronarysinus—1outlet:rightatrioventricularorifice—fossaovalis:thethinnestareaoftheinteratrialseptuminterartrialseptaldefectThrombosisembolism—2parts:dividedbysupraventricularcrest—inflowtract:thewallisnotsmooth,

trabeculaecarneae

septomarginaltrabeculaetricuspidcomplex—outflowtract(conusarteriosus):thewallissmoothrightventricle—inlet—rightatrioventricularorifice:

tricuspidcomplex:

—ringoftricuspidvalve

—tricuspidvalve:attachedtoringoftricuspidvalveant.cusppos.cuspseptalcusp

—chordaetendineae

—papillarym.—outlet—orificeofpulmonarytrunk:

valveofpulmonarytrunk:location:attachedtoringofpulmonarytrunk

structures:nodulesofsemilunarvalve

thewallissmoothexceptforleftauricle—4inlets:orificesofpulmonaryV.—1outlet:leftatrioventricularorifice—leftauricle

leftatriumTheleftventriclewallis3-4foldthicherthantheright—2parts:dividedbyant.cuspofmitralvalveinflowtract:trabeculaecarneaemitralcomplexoutflowtract(aorticvestibule):thewallissmoothleftventricle—inlet—leftatrioventricularorifice:

mitralcomplex:—ringofmitralvalve—mitralvalve:attachedtoringofmitralvalveant.cusppos.cusp—chordaetendineae—papillarym.—outlet--aorticorifice:

aorticvalve:attachedtoringofaorticvalveleftsemilunarvalverightsemilunarvalvepos.semilunarvalve

aorticsinuses:left,right,pos.sinusesrheumaticheartdisease，valvestenosisorincompetenceConductingsystemcomposition:—sinuatrialnode：producecertainrhythmelectricalexcitationautonomously，≥100times/permin—internodaltract：transmitelectricalexcitation—atrioventricularnode—atrioventricularbundle—leftandrightbundlebranches—Purkinjefiberscardiacrhythmisdisorderartificialpacemakermetalleadrightcoronarya.:

—origin:rightaorticsinus—terminalbranches:pos.interventricularbranchpos.branchofleftventricle—supplyingregions:rightatriumandventriclepos.1/3ofinterventricularseptuminf.wallofleftventriclesinuatrialnodeandatrioventricularnodeCoronaryatherosclerosiscoronaryheartdiseasemyocardialinfarctionfattyplaquesthrombusleftcoronarya.:

—origin:leftaorticsinus—terminalbranches:ant.interventricularbranchcircumflexbranch—supplyingregions:leftatriumandventricleant.2/3ofinterventricularseptumant.wallofrightventriclesinuatrialnodeandatrioventricularnode

—coronarysinus:—location:liesincoronarygroovebetweenleftatriumandventricle—opening:rightatrium—tributaries:greatcardiacv.middlecardiacv.smallcardiacv.

—ant.v.ofrightventricle—smallestcardiacv.v.ofheart:interventionaltherapyexternalaspectoftheheartright

atriumandventricleSurfacemarkingsofheart

Rightborder－correspondstoalinerunningfromtheupperborderofrightthirdcostalcartilage±1.2cmfromthemarginofsternum,downwardstosixthsternocostaljointApex－inthefifthleftintercostalspace7~9cmfromthemidlineLeftborder－representedbyalinerunningfromapexupwardsandmediallytoapointonlowerborderofleftsecondcostalcartilage±1.2cmfromsternalmarginLowerborder－representedbyalinejointthelowerendofrightbordertoapexSurfaceAnatomyoftheHeartValves

Tricuspidvalveliesbehindtherighthalfofthesternumoppositesthefourthinterxostalspace.Mitralvalveliesbehindthelefthalfofthesternumoppositethefourthcostal

cartilage.Pulmonaryvalveliesbehindthemedialendofthethirdleftcostalcartilageandtheadjoiningpartofthesternum.Aorticvalveliesbehindthelefthalfofthesternumoppositethethirdintercostalsspace.VeinsSuperiorvenacavaleftandrightbrachiocephalicveinsAzygosv.Pulmornaryv.InferiorvenacavaBrachiocephalicv.：

FormedbyunionofinternaljugularandsubclavianveinsAngleofunionistermedvenousangleFormedbyunionofrightandleftbrachiocephalicv.Joinedbyazygosv.EntersrightatriumCollectsbloodfromveinsofupperhalfofbodySup.venacava—Formedbyunionofrightascendinglumbarv.andrightsubcostalv.—Ascendingalongtherightsideofvertebralcolumn—Drainsintosup.venacavabyarchofazygosv.aboverightlungrootatlevelofT4toT5—Receivesrightpos.intercostalv.andbronchial,esophagealandpericardialv.,hemiazygosv.andaccessoryhemiazygosv—Tributaries:hemiazygosv.

andaccessoryhemiazygosv.,whichreceivemostleftpos.intercostalv.andleftbronchialv.Azygosv.—3parts：

ascendingaorta：aorticarchdescendingaortathoracicaortaabdominalaorta

aorta—3branches：fromlefttoright:

—Leftsubclaviana.—Leftcommoncarotida.—Brachiocephalictrunk：—recepters:

—wallofAorticarch—baroreceptor

—Aorticglomera—chemoreceptoraorticarch—Anteriorlyandtotheleft：

—pleura,lung，

—phrenicn.,pericardiacophrenicvessels

—vagusn.—Posteriorlyandtotheright：

—trachea—esophagus—leftrecurrentn.—thoracicduct—deepcardiacplexus—Superiorly：

—threebranchesofaorta,—leftbrachiocephalicv.—thymus—Inferiorly：

—pulmonarya.,—arteriallig.,—leftrecurrentn.,—leftprincipalbronchus—superficialcardiacplexus—adjacentstructuresofaorticarch：

ThoracicaortaCourse

ContinuationofaorticarchatT4levelCoursesdownwardinposteriormediastinumonleftside,thenposteriortoesophagusPassesthroughaortichiatusofdiaphragmatlevelofT12vertebratoenterabdominalcavity

Parietalbranches

—pos.intercostalsa.（9pairs）—subcostala.

（1pair）→lower9intercostalsspacesandupperpartofabdominalwall;—Sup.phrenica.

→thesup.surfaceofthediaphragm.Visceralbranches

—Bronchialbranches:1or2foreachlung—Esophagealbranches→—Pericardialbranches→MainbranchesofthoracicaortaRelationsofthoracicaortaAnteriorlyLeftrootoflungPericardiumEsophagusPosterior

Hemiazygosv.Accessoryhemiazygosv.

RightAzygosv.ThoracicductLeft－mediastinalpleuraPulmonarytrunkPulmonarytrunkLeftandrightpulmonarya.VagusnervesLeftvagusn.EnterthoracicinletbetweenleftcommoncarotidandleftsubclavianarteriesCrossestheleftsideoftheaorticarchwhereleftrecurrentlaryngealnervebranchesoffPassesposteriortoleftlungrootcontributingtothepulmonaryplexusDescendsontheanteriorsurfaceoftheesophagusandformsanterioresophagealplexusFormsanteriorvagaltrunkatesophagealhiatuswhereitleavesthoraxandpassesintoabdominalcavityRightvagusn.TravelsdownwardanteriortotherightsubclavianarteryandenterthoracicinletonrightsideoftracheaPassesposteriortorightlungrootcontributingtothepulmonaryplexusThenpassesontotheposteriorsurfaceofesophagusandformsposterioresophagealplexusFormsposteriorvagaltrunkatesophagealhiatuswhereitleavesthoraxandpassesintoabdominalcavityBoundariesPhrenicn.Leftvagusn.Leftpulmonarya.Contents—Arterialligament：ductusarteriosusinfetusarteriallig.6thmonthafterbirt—Leftrecurrentn.—Superficialcardiacplexuses

congenitalheartdisease：patentductusarteriosusTriangleofductusarteriosusTracheaandbronchiLocationoftrachealieanteriortoesophagusinneckandthoraciccavityfromthelevelofinf.borderofC6tosternalangle,whereitdividesintorightandleftprincipalbronchiTracheaFeaturesof

trachea:Wall

isformedbyincompleteringsofhyalinecartilagesforpatencyconnectedbysmoothmuscleandconnectivetissueBifurcationoftrachea：atthelevelofsternalangleCarinaoftrachea

氣管隆嵴—ridgeofcartilageatbifurcationRelationsoftracheaAnterior－manubriumosternum,remnantofthymus,leftbrachiocephalicv.,aorticarch,brachiocephalictrunk,leftcommoncarotida.andcardiacplexusPosterior－esophagusRight－rightlung,rightvagusn.,rightbrachiocephalicv.,superiorvenacava,archofazygosv.Left－aorticarch,leftcommoncarotidandsubclavianarteries,leftrecurrentlaryngealn.BronchiRightprincipalbronchuswider,shorter,moreverticalinpositionthantheleftAbout2.5cmlong,Leavestheextendlineofthemiddlelineoftracheaat22～25oangleForeignbodiesarethereforemorelikelytolodgeinthisbronchusoroneofitsbranchesLeftprincipalbronchusslenderer,longer,morehorizontalinpositionthantherightAbout5cmlong,leavestheextendlineofthemiddlelineoftracheaatabout35～36oangleforeignbodyintracheatracheascopetracheotomylodgeincarinaoftracheaEsophagusLocationofesophagusContinueswiththepharynxatthelevelofinf.borderofC6，passesdownfromthenecktothethoraciccavityposteriortothetracheafirstandthenpericardiumThenpassesinfrontofthethrocicaortaincontactwithparicardiumLeavesthroughesophagealhiatusofdiaphragmatT10vertebrallevelaccompaniedbyvagusnervesSurroudedbyplexusofvagibelowlevelofT4vertebra3portions:—cervicalpart—thoracicpart—abdominalpart1st:atthebeginningofesophagus,about15cmawayfromcentralincisorofmaxilla2nd:theportionacrossedbyleftbronchus,about25cmawayfromcentralincisorofmaxilla3ird:theportionpassingthroughtheesophagealhiatus,about40cmawayfrom

centralincisorofmaxilla3constrictionss:anteriorly:

ant.esophagealplexus

tracheabifurcationoftrac