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THENECK PARTI BONESANDJOINTSOFTHENECK MUSCLESOFTHENECK–SCM CAROTIDTRIANGLE ENDOCRINELAYEROFTHECERVICALVISCERA THENECK THENECK Theneckhasfourmajorcompartments,whichareenclosedbyan outermusculofascialcollar: • Thevertebralcompartmentcontainsthecervicalvertebraeand associatedposturalmuscles. • Thevisceralcompartmentcontainsimportantglands(thyroid, parathyroid,andthymus),andpartsoftherespiratoryand digesRvetractsthatpassbetweentheheadandthorax. • Thetwovascularcompartments,oneoneachside,containthe majorbloodvesselsandthevagusnerve. THENECK THENECK TheanteriorporRonoftheneckcontainsthemajorvisceral structuresbetweentheheadandthethorax: • pharynx • larynx • trachea • esophagus • thyroid andparathyroidglands THENECK–THECERVICALVERTEBRAE THENECK Theskeletonoftheneckisformedby: • thecervicalvertebrae, • hyoidbone, • manubriumofthesternum, • clavicles THENECK–THECERVICALVERTEBRAE THECERVICALVERTEBRAE Thesevencervicalvertebrae havetransverseforamina (forthevertebralarteriesto passthrough)withintheir transverseprocesses VERTEBRALARTERIES Thesevesselsenterthe foramentransversarium ofthe6thcervicalvertebra, emergingabovethe1st cervicalvertebratoenterthe suboccipitaltriangle ThemostdisRncRvefeatureofeachcervicalvertebrais theovalforamentransversarium(transverseforamen)inthe transverseprocess. THENECK–THECERVICALVERTEBRAE THECERVICALVERTEBRAE Thereare7cervicalvertebrae: • the4typicalcervicalvertebraeC3–C6 • the3atypicalcervicalvertebrae(C1,C2,andC7) ThefourtypicalcervicalvertebraeC3–C6havethefollowing characterisRcs: • Thevertebralbodyissmallandlongerfromsidetosidethan anteroposteriorly;thesuperiorsurfaceisconcave,andtheinferior surfaceisconvex. • Thevertebralforamenislargeandtriangular. • Thetransverseprocessesofallcervicalvertebrae(typicalor atypical)includeforaminatransversariaforthevertebralvessels (thevertebralveinsand,exceptforvertebraC7,thevertebral arteries). • Theirspinousprocessesareshortandbifid. THENECK–THECERVICALVERTEBRAE THECERVICALVERTEBRAE Thevertebralarteriesandtheiraccompanyingveinspassthrough thetransverseforamina,exceptthoseinC7,whichtransmit onlysmallaccessoryveins. Thefirst(C1,atlas), second(C2,axis)andseventh(C7,vertebraprominens)cervical vertebraeareatypical. VertebraeC3–C6arethetypicalcervicalvertebrae. THENECK–THECERVICALVERTEBRAE THECERVICALVERTEBRAE Therearethreeatypicalcervicalvertebrae(C1,C2,andC7): • TheC1vertebraoratlas:aring-like,kidney-shapedbonelackinga spinousprocessorbodyandconsisRngoftwolateralmasses connectedbyanteriorandposteriorarches.Itsconcavesuperior arRcularfacetsreceivetheoccipitalcondyles. • TheC2vertebraoraxis:apeg-likedens(odontoidprocess) projectssuperiorlyfromitsbody. • Thevertebraprominens(C7):so-namedbecauseofitslong spinousprocess,whichisnotbifid.Itstransverseprocessesare large,butitsforaminatransversariaaresmall. THENECK–THEHYOIDBONE THEHYOIDBONE ThehyoidisuniqueamongbonesforitsisolaPon fromtheremainderoftheskeleton. Itissuspendedfromthestyloidprocesses ofthetemporalbonesbythestylohyoidligaments andisfirmlyboundtothethyroidcarPlage. FuncRonally,thehyoid servesasana_achment foranteriorneck musclesandapropto keeptheairwayopen. Thehyoidliesinthe anteriorpartoftheneck attheleveloftheC3 vertebra. THENECK–THEHYOIDBONE THEHYOIDBONE C3-levelofbodyofhyoid Thebodyofthehyoid Eachendofitsbodyisunitedtoagreaterhornthatprojects posterosuperiorlyandlaterallyfromthebody. EachlesserhornisasmallbonyprojecRon. FRACTUREOFHYOIDBONE Itoccursinpeoplewhoaremanuallystrangledbycompressionofthe throat.Thisresultsindepressionofthebodyofthehyoidontothe thyroidcarPlage.Inabilitytoelevatethehyoidandmoveitanteriorly beneaththetonguemakesswallowingandmaintenanceofthe separaRonofthealimentaryandrespiratorytractsdifficultandmay resultinaspiraPonpneumonia. THENECK–THEHYOIDBONE THEHYOIDBONE Thehyoidboneissuspendedfromthestyloidprocessesbythe stylohyoidligamentsandgivesa_achmentto • thesuprahyoidmusclesand • theinfrahyoidmuscles. Thesuprahyoidmusclesraisethehyoidbonetowardastabilized mandibleduringswallowing. Thesuprahyoidregioncontains4muscles: • Mylohyoid(V3) • Digastric(V3+VII) • Stylohyoid(VII) • Geniohyoid(C1-C2) THENECK–THEHYOIDBONE THEHYOIDBONE Theinfrahyoidmusclesdepressthehyoidboneandlarynxduring swallowingandvocalizaRon. Theinfrahyoidregioncontains4musclescommonlycalledstrap muscles: • Omohyoid INNERVATION: • Sternohyoid cervical • Sternothyroid plexus(C1–C3) • Thyrohyoid Theinfrahyoidmusclesareorganizedsothat: • sternohyoidandomohyoidliesuperficiallyand • sternothyroidandthyrohyoidliemoredeeply THENECK–THEHYOIDBONE THESUPRAHYOIDANDINFRAHYOIDREGIONS Thesuprahyoidregioncontains4muscles: • Mylohyoid(V3) • Digastric(V3+VII) • Stylohyoid(VII) • Geniohyoid(C1viahypoglossalnerve(CNXII)) Theinfrahyoidregioncontains4musclescommonlycalledstrap muscles: • Omohyoid cervical • Sternohyoid plexus(C1–C3) • Sternothyroid • Thyrohyoid THENECK–THEHYOIDBONE Digastric Mylohyoid Stylohyoid THEHYOIDMUSCLES Anteriorbelly:mylohyoidnerve,V3 Posteriorbelly:facialnerve,CNVII Mylohyoidnerve,V3 Facialnerve,CNVII Thecervicalplexus,composedoftheventralramiofC1-C4, innervatesmostoftheneckmusclesandprovidessensory innervaRontotheanteriorandlateralneck THENECK–THECERVICALPLEXUS THECERVICALPLEXUS Thecervicalplexus,composedoftheventralramiofC1-C4, innervatesmostoftheneckmusclesandprovidessensory innervaRontotheanteriorandlateralneck. The(spinal)accessorynerve(CNXI)exitsthejugularforamenand crossestheposteriortriangle, innervaRngtheSCMandtrapeziusmuscles THENECK–THECERVICALPLEXUS THECERVICALPLEXUS AddiRonalinnervaRonincludes: • Themylohyoidnerve(CNV3)innervatesthemylohyoidmuscle andanteriorbellyofthedigastricmusclebeneaththechin. • Thefacialnerve(CNVII)innervatestheplatysmamusclethrough itscervicalbranchandposteriorbellyofthedigastricmuscle. • Theglossopharyngealnerve(CNIX)suppliesthecaroRdbodyand sinus(visceralsensory). • Thevagusnerve(CNX)suppliesthelarynxthroughitssuperior andrecurrent(inferior)laryngealnerves. • Thehypoglossalnerve(CNXII)loopsthroughtheneckto innervatethetongue. THENECK–THEFACIAOFTHENECK THEFACIAOFTHENECK ThefasciaoftheneckismulRlayeredandenclosesthemuscles, glands,andneurovascularstructures. TherelaRonshipsbetweenthedifferentfasciallayersdeterminehow infecPonandcancerspreadintheneck. FACIAOFTHENECK • THECERVICALSUBCUTANEOUSTISSUE • THEPLATYSMA • THEDEEPCERVICALFASCIA • THEINVESTINGLAYEROFDEEPCERVICALFASCIA • THEPRETRACHEALLAYEROFDEEPCERVICALFASCIA • THEPREVERTEBRALLAYEROFDEEPCERVICALFASCIA THENECK–THEFACIAOFTHENECK THECERVICALSUBCUTANEOUSTISSUE Theneckissurroundedby thecervicalsubcutaneousPssue/thesuperficialcervicalfascia thatliesdeeptotheskinandinveststheplatysmamuscle. ThecervicalsubcutaneousPssue/thesuperficialcervicalfascia liesbetweenthedermisoftheskinandtheinvesRnglayerofdeep cervicalfascia Itcontainscutaneousnerves,bloodandlymphaRcvessels, superficiallymphnodes,andvariableamountsoffat. Anterolaterally,itcontainstheplatysma. Theplatysmacoverstheanterolateralaspectoftheneck. Itderivedfrommesenchymeinthe2ndpharyngealarchofthe embryo,issuppliedbycervicalbranchofthefacialnerve,CNVII FACIAOFTHENECK • THECERVICALSUBCUTANEOUSTISSUE • THEPLATYSMA • THEDEEPCERVICALFASCIA • THEINVESTINGLAYEROFDEEPCERVICALFASCIA • THEPRETRACHEALLAYEROFDEEPCERVICALFASCIA • THEPREVERTEBRALLAYEROFDEEPCERVICALFASCIA THENECK–THEFACIAOFTHENECK THEDEEPCERVICALFACIA Thedeepcervicalfasciaconsistsofthreefasciallayers(sheaths): • invesPng,whichsurroundsallstructuresintheneck • pretracheal,whichenclosesthevisceraoftheneck • prevertebral,whichsurroundsthevertebralcolumnandthedeep musclesassociatedwiththeback Thedeepcervicalfasciasubdividestheneckinto • vascular(caroPdsheath) • vertebral • visceralcompartments Thisarrangementallowsmovementbetweenadjacentstructuresand compartmentsandfacilitatesthesurgicalapproachtospecificareas. Theylimitthespreadofabscesses(collecRonsofpus)resulRngfrom infecRons. FACIAOFTHENECK • THECERVICALSUBCUTANEOUSTISSUE • THEPLATYSMA • THEDEEPCERVICALFASCIA • THEINVESTINGLAYEROFDEEPCERVICALFASCIA • THEPRETRACHEALLAYEROFDEEPCERVICALFASCIA • THEPREVERTEBRALLAYEROFDEEPCERVICALFASCIA THENECK–THEFACIAOFTHENECK THEINVESTINGLAYEROFTHEDEEPCERVICALFACIA Themostsuperficialdeepfasciallayer.Completelysurroundsthe enRreneckdeeptotheskinandsubcutaneousRssue. TheinvesPnglayerofcervicalfasciaencirclesallstructuresofthe neckbyinvesRngthesternocleidomastoidandtrapeziusmuscles,the fascialroofsoftheanteriorandposteriorcervicaltriangles,andthe paroRdandsubmandibularsalivaryglands. THENECK–THEFACIAOFTHENECK THEINVESTINGLAYEROFTHEDEEPCERVICALFACIA • A_achingposteriorlytotheligamentumnuchae andthespinousprocessoftheCVIIvertebra, • thisfasciallayersplitsasitpassesforwardtoenclosethetrapezius muscle, • reunitesintoasinglelayerasitformstheroofoftheposterior triangle, • splitsagaintosurroundthesternocleidomastoidmuscle, • andreunitesagaintojoinitstwinfromtheotherside. THENECK–THEFACIAOFTHENECK THEINVESTINGLAYEROFTHEDEEPCERVICALFACIA Superiorly,theinvesRng(orsuperficial)layerofdeepcervicalfascia a_achestothe: • Superiornuchallinesoftheoccipitalbone • Mastoidprocessesofthetemporalbones • ZygomaRcarches • Inferiorborderofthemandible • Hyoidbone • Spinousprocessesofthecervicalvertebrae Justinferiortoitsa_achmenttothemandible,thefasciasplitsto enclosethesubmandibulargland; Posteriortothemandible,itsplitstoformthefibrouscapsuleofthe paroRdgland. Inferiorly,theinvesRnglayerofdeepcervicalfasciaa_achestothe manubrium,clavicles,andacromionsandspinesofthescapula. FACIAOFTHENECK • THECERVICALSUBCUTANEOUSTISSUE • THEPLATYSMA • THEDEEPCERVICALFASCIA • THEINVESTINGLAYEROFDEEPCERVICALFASCIA • THEPRETRACHEALLAYEROFDEEPCERVICALFASCIA • THEPREVERTEBRALLAYEROFDEEPCERVICALFASCIA THENECK–THEFACIAOFTHENECK THEPRETRACHEALLAYEROFDEEPCERVICALFASCIA Itislimitedtotheanteriorpartoftheneck.Itextendsinferiorly fromthehyoidintothethorax,whereitblendswiththefibrous pericardiumcoveringtheheart. Thepretracheallayeroffasciaincludesathinmuscularpart,which enclosestheinfrahyoidmuscles,andavisceralpart,whichencloses thethyroidgland,trachea,andesophagus ItisconRnuousposteriorlyandsuperiorlywith thebuccopharyngealfasciaofthepharynx. Thebuccopharyngealfasciaextendsfromthebaseoftheskulland envelopsthebuccinatormuscleandpharyngealconstrictors FACIAOFTHENECK • THECERVICALSUBCUTANEOUSTISSUE • THEPLATYSMA • THEDEEPCERVICALFASCIA • THEINVESTINGLAYEROFDEEPCERVICALFASCIA • THEPRETRACHEALLAYEROFDEEPCERVICALFASCIA • THEPREVERTEBRALLAYEROFDEEPCERVICAL FASCIA THENECK–THEFACIAOFTHENECK THEPREVERTEBRALLAYEROFDEEPCERVICALFASCIA Theprevertebrallayerofdeepcervicalfasciaformsatubularsheath forthevertebralcolumnandthemusclesassociatedwithit. Theprevertebrallayerofdeepfasciaisfixedtothecranialbase superiorly. Inferiorly,itblendswiththeendothoracicfasciaperipherally TheprevertebralfasciainananterolateralposiRonextendsfromthe anteriorandmiddlescalenemusclestosurroundthebrachialplexus andsubclavianarteryasthesestructurespassintotheaxilla. Thisfascialextensionistheaxillarysheath ThecaroPdsheathisacolumnoffasciathatsurroundsthecommon caroRdartery,theinternalcaroRdartery,theinternaljugularvein, andthevagusnerveasthesestructurespassthroughtheneck THENECK–THEFACIAOFTHENECK THEPREVERTEBRALLAYEROFDEEPCERVICALFASCIA ThecaroPdsheathcontainsthe: • CommonandinternalcaroRdarteries • Internaljugularvein • Vagusnerve(CNX) • Somedeepcervicallymphnodes • CaroRdsinusnerve • SympatheRcnervefibers(caroRdperiarterialplexuses) Theretropharyngealspaceisthelargestand mostimportantinterfascialspaceintheneck. TheretropharyngealspaceisapotenPalspacethatconsistsofloose connecRveRssuebetweenthevisceralpartoftheprevertebral layerofdeepcervicalfasciaandthebuccopharyngealfascia surroundingthepharynxsuperficially. SUPERFICIALSTRUCTURESOFTHENECK • • • • • • CERVICALREGIONS/TRIANGLESANDCONTENTS CUTANEOUSANDSUPERFICIALMUSCLESOFNECK ARTERIESINCERVICALREGION VEINSINCERVICALREGION NERVESINCERVICALREGION LYMPHNODESINCERVICALREGION THENECK–THECERVICALREGIONS THECERVICALTRIANGLES Theneckisdividedintofourmajorregionsbasedontheusually visibleand/orpalpablebordersofthelargeandrelaRvelysuperficial SCMandtrapeziusmuscles: • Sternocleidomastoidregion • Posteriorcervicalregion • Lateralcervicalregion(posteriortriangle) • Anteriorcervicalregion(anteriortriangle) Theneckisdividedinto: • Sternocleidomastoidregion • Posteriorcervicalregion • Lateralcervicalregion(posteriortriangle) • Anteriorcervicalregion(anteriortriangle) THENECK–THECERVICALREGIONS THECERVICALTRIANGLES Theneckisdividedinto: • Sternocleidomastoidregion • Posteriorcervicalregion • Lateralcervicalregion(posteriortriangle) • Anteriorcervicalregion(anteriortriangle) THENECK–THECERVICALREGIONS THESTERNOCLEIDOMASTOIDREGION TheSCMvisiblydivideseachsideoftheneckintotheanteriorand lateralcervicalregions(anteriorandposteriortriangles). MAINCONTENT: • • • • sternocleidomastoidmuscle superiorpartofexternaljugularvein greaterauricularnerve transversecervicalnerve Thetwoheads(clavicleandsternal)oftheSCMareseparated inferiorlybyaspace,visiblesuperficiallyasasmalltriangular depression,thelessersupraclavicularfossa. THENECK–THECERVICALREGIONS THESTERNOCLEIDOMASTOIDREGION MAINCONTENTOFTHELESSERSUPRACLAVICULARFOSSA • inferiorpartofinternaljugularvein Thesuperiora_achmentoftheSCMisthemastoidprocessofthe temporalboneandthesuperiornuchallineoftheoccipital bone. INNERVATIONOFtheSCMs: • Spinalaccessorynerve(CNXI,motor) • C2andC3nerves(painandpropriocepRon) THENECK–THECERVICALREGIONS THESTERNOCLEIDOMASTOIDREGION AcRngbilaterally,theSCMscanflextheneck. AcRngunilaterally,theSCMlaterallyflexestheneck(bendstheneck sideways)androtatestheheadsotheearapproachestheshoulder oftheipsilateral(same)sidewhilerotaRngtheheadsothatthechin isturnedtowardthecontralateral(opposite)sideandelevates. TotesttheSCM: theheadisturnedtotheoppositesideagainstresistance(hand againstchin). THENECK–THECERVICALREGIONS THEPOSTERIORCERVICALREGION BORDERSofthesuboccipitaltriangle: •ObliquuscapiRssuperior •ObliquuscapiRsinferior •RectuscapiRsposteriormajor MAINCONTENTS: • trapeziusmuscle • cutaneousbranchesofposteriorramiofcervicalspinalnerves suboccipitalregionortriangleliesdeeptosuperiorpartofthis region INNERVATIONOFTHETAPEZIUS: Spinalaccessoryn.alsoreceivessomebranchesfromC2andC3, thoughttobepropriocepRve Ifthetrapeziusisparalyzed,theshoulderdroops THENECK–THECERVICALREGIONS THELATERALCERVICALREGION Thelateralcervicalregion(posteriortriangle)isbounded: • anteriorlybytheposteriorborderoftheSCM • posteriorlybytheanteriorborderofthetrapezius • inferiorlybythemiddlethirdoftheclaviclebetweenthetrapezius andtheSCM • byanapex,wheretheSCMandtrapeziusmeetonthesuperior nuchallineoftheoccipitalbone • byaroof,formedbytheinvesRnglayerofdeepcervicalfascia • byafloor,formedbymusclescoveredbytheprevertebrallayerof deepcervicalfascia THENECK–THECERVICALREGIONS THELATERALCERVICALREGION Thelateralcervicalregionisdividedinto: • alargeOCCIPITALTRIANGLEsuperiorlyand • asmallOMOCLAVICULARTRIANGLEinferiorlybytheinferiorbelly oftheomohyoid TheOCCIPITALTRIANGLEissocalledbecausetheoccipitalartery appearsinitsapex.Themostimportantnervecrossingtheoccipital triangleisthespinalaccessorynerve(CNXI). MAINCONTENTSOFTHEOCCIPITALTRIANGLE: • partofexternaljugularvein(EJV) • posteriorbranchesofcervicalplexusofnerves • spinalaccessorynerve(CNXI) • trunksofbrachialplexus • cervicodorsaltrunk • cervicallymphnodes THENECK–THECERVICALREGIONS THELATERALCERVICALREGION MAINCONTENTSOFTHEOMOCLAVICULAR(SUBCLAVIAN)TRIANGLE: • • • • subclavianartery(thirdpart) partofsubclavianvein(someRmes) suprascapularartery supraclavicularlymphnodes TheinferiorpartoftheEJVcrossesthistrianglesuperficially; thesubclavianarteryliesdeepinit THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION Theanteriorcervicalregion(anteriortriangle)hasthefollowing: • ananteriorboundaryformedbythemedianlineoftheneck • aposteriorboundaryformedbytheanteriorborderoftheSCM • asuperiorboundaryformedbytheinferiorborderofthemandible • anapexlocatedatthejugularnotchinthemanubrium • aroofformedbysubcutaneousRssuecontainingtheplatysma • afloorformedbythepharynx,larynx,andthyroidgland THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION THEANTERIORCERVICALREGION(ANTERIORTRIANGLE): • submandibular(digastric)triangle • submentaltriangle • caroRdtriangle • muscular(omotracheal)triangle THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION THESUBMANDIBULAR(DIGASTRIC)TRIANGLE MAINCONTENTS: • submandibularglandalmostfillstriangle • submandibularlymphnodes • hypoglossalnerve • mylohyoidnerve • partsoffacialarteryandvein THESUBMENTALTRIANGLE MAINCONTENTS: • submentallymphnodesand • smallveinsthatunitetoformanteriorjugularvein THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION THECAROTIDTRIANGLE ThecaroRdtriangleisavascularareaboundedby: • thesuperiorbellyoftheomohyoid, • theposteriorbellyofthedigastric, • theanteriorborderoftheSCM TheneurovascularstructuresinthecaroRdtrianglearesurrounded bythecaroPdsheath: • thecaroPdarteriesmedially • theIJVlaterally • thevagusnerveposteriorly THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION THECAROTIDTRIANGLE MAINCONTENTS: • caroRdsheathcontainingcommoncaroRdarteryanditsbranches TheneurovascularstructuresinthecaroRdtrianglearesurrounded bythecaroPdsheath: • thecaroPdarteriesmedially • theIJVlaterally • thevagusnerveposteriorly THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION THECAROTIDTRIANGLE MAINCONTENTS: • caroRdsheathcontainingcommoncaroRdarteryanditsbranches • internaljugularveinanditstributaries • vagusnerve • externalcaroRdarteryandsomeofitsbranches • hypoglossalnerveandsuperiorrootofansacervicalis • spinalaccessorynerve(CNXI) • thyroidgland, • larynx,andpharynx • deepcervicallymphnodes • branchesofcervicalplexus THENECK–THECERVICALREGIONS THEANTERIORCERVICALREGION THECAROTIDTRIANGLE ThecaroRdtriangleisavascularareaboundedby: • thesuperiorbellyoftheomohyoid, • theposteriorbellyofthedigastric, • theanteriorborderoftheSCM THEMUSCULAR(OMOTRACHEAL)TRIANGLE MAINCONTENTS: • sternothyroidandsternohyoidmuscles • thyroidandparathyroidglands THENECK–THEMUSCLESOFTHENECK THECUTANEOUSANDSUPERFICIALMUSCLESOFNECK Platysma-cervicalbranchoffacialnerve(CNVII) Sternocleidomastoid(SCM)-spinalaccessorynerve(CNXI,motor); C2andC3nerves(painandpropriocepRon) Trapezius-spinalaccessorynerve(CNXI;motor);C2andC3nerves (painandpropriocepRon) THEMUSCLESINLATERALCERVICALREGION • • • • • spleniuscapiRs levatorscapulae anteriorscalene middlescalene posteriorscalene THENECK–THEMUSCLESOFTHENECK THEMUSCLESINANTERIORCERVICALREGION Thesuprahyoidregioncontains4muscles: • Mylohyoid-nervetomylohyoid,CNV3 • Digastric-anteriorbellyCNV3;posteriorbellyCNVII • Stylohyoid-CNVII • Geniohyoid–C1viahypoglossalnerveCNXII Theinfrahyoidregioncontains4musclescommonlycalledstrap muscles: • Omohyoid-C1–C3byabranchofansacervicalis • Sternohyoid-C1–C3byabranchofansacervicalis • Sternothyroid-C2andC3byabranchofansacervicalis • Thyrohyoid-C1viahypoglossalnerve(CNXII) THENECK–THEARTERIESOFTHENECK THELATERALCERVICALREGION Thearteriesinthelateralcervicalregioninclude: • thelateralbranchesofthethyrocervicaltrunk • thethirdpartofthesubclavianartery • partoftheoccipitalartery Thethirdpartofthesubclavianarterysuppliesbloodtotheupper limb.Itishiddenintheinferiorpartofthelateralcervicalregion, posterosuperiortothesubclavianvein. Thethirdpartofthearteryisthelongestandmostsuperficialpart. Itliesonthe1strib,anditspulsaRonscanbefeltbyapplyingdeep pressureintheomoclaviculartriangle. THENECK–THEARTERIESOFTHENECK THEANTERIORCERVICALREGION ThecommoncaroPdarterydividesinto: • theinternalcaroRdartery • theexternalcaroRdartery • C3-C4JUNCTION • SUPERIORBORDEROF THYROIDCARTILAGE ThecaroPdsinus,aslightdilaRonoftheproximalpartofthe internalcaroRdartery.Innervatedprincipallybythe glossopharyngealnerve(CNIX)throughthecaroRdsinusnerveas wellasbythevagusnerve(CNX),itisabaroreceptor (pressoreceptor)thatreactstochangesinarterialbloodpressure. ThecaroPdbody:asmall,reddishbrownovoidmassofRssueinlife thatliesonthemedial(deep)sideofthebifurcaRonofthecommon caroRdartery.SuppliedmainlybythecaroRdsinusnerve(CNIX)and byCNX,itisachemoreceptorthatmonitorsthelevelofoxygenin theblood THENECK–THEARTERIESOFTHENECK THEANTERIORCERVICALREGION Superiorly,thecommoncaroPdisreplaced bytheinternalcaroPdartery. TheinternalcaroPdarteryhasNOBRANCHESintheneck. TheexternalcaroRdhasseveral. TherightcommoncaroPdarterybeginsatthebifurcaRonofthe brachiocephalictrunk. Therightsubclavianarteryistheotherbranchofthisbrachiocephalic trunk. Fromthearchoftheaorta,theleccommoncaroPdarteryascends intotheneck. THENECK–THEARTERIESOFTHENECK THEANTERIORCERVICALREGION TheinternalcaroPdarteriesaredirectconRnuaRonsofthecommon caroRdssuperiortotheoriginoftheexternalcaroRdartery,atthe levelofthesuperiorborderofthethyroidcarRlage. C3-C4JUNCTION levelofupperborderof thyroidcarRlageand bifurcaRonofcommon caroRdartery. TheexternalcaroPdarteriessupplymoststructuresexternaltothe cranium.Theorbitandthepartoftheforeheadandscalpsupplied bythesupraorbitalarteryarethemajorexcepRons. THENECK–THEARTERIESOFTHENECK THEANTERIORCERVICALREGION TheexternalcaroPdarteries-sixarteriesarisefromtheexternal caroRdartery: • ascendingpharyngealartery • occipitalartery • posteriorauricularartery • superiorthyroidartery • lingualartery • facialartery • maxillaryartery(T) • superficialtemporala.(T) Theinferiorthyroid isabranchof thesubclavianartery. THENECK–THEARTERIESOFTHENECK THEANTERIORCERVICALREGION Theascendingpharyngealarterysendsbranchestothepharynx, prevertebralmuscles,middleear,andcranialmeninges. Theoccipitalarteryendsbydividingintonumerousbranchesinthe posteriorpartofthescalp. Theposteriorauriculararterysuppliestheadjacentmuscles;paroRdgland; facialnerve;andstructuresinthetemporalbone,auricle,andscalp. Thesuperiorthyroidarterygivesoffbranchestothyroidgland,the infrahyoidmusclesandtheSCMandgivesrisetothesuperiorlaryngeal artery,supplyingthelarynx. Thelingualarterydividesintothedeeplingualandsublingualarteries. TheexternalcaroPdarteriesisdividingintotwoterminalbranches: • themaxillaryartery • thesuperficialtemporalartery THENECK–THEARTERIESOFTHENECK THEANTERIORCERVICALREGION Thesubclavianartery: • rightfromthebrachiocephalictrunk • lecfromtheaorRcarch Thesubclavianarterysuppliesbloodtotheupperlimb. 1. medialpart 2. posteriorpart 3. lateralpart Thesubclavianartery–branches: 1. thyrocervicaltrunk a.inferiorthyroid b.ascendingcervical c.suprascapular 2.costocervicaltrunk THENECK–THEVEINSOFTHENECK THELATERALCERVICALREGION Theexternaljugularvein(EJV)beginsneartheangleofthemandible bytheunionoftheposteriordivisionoftheretromandibularvein withtheposteriorauricularvein. Theexternaljugularvein(EJV)descendstotheinferiorpartofthe lateralcervicalregionandterminatesinthesubclavianvein Thesubclavianveinuniteswiththeinternaljugularvein(IJV) toformthebrachiocephalicvein. MostveinsintheanteriorcervicalregionaretributariesoftheIJV, typicallythelargestveinintheneck. TheIJVdrainsbloodfromthebrain,anteriorface,cervicalviscera, anddeepmusclesoftheneck. THENECK–THEVEINSOFTHENECK THEANTERIORCERVICALREGION TheIJVcommencesatthejugularforamenintheposteriorcranial fossaasthedirectconRnuaRonofthesigmoidsinus FromadilaRonatitsorigin,thesuperiorbulboftheIJV,thevein descendsinthecaroRdsheath TheinferiorendoftheIJVdilatestoformtheinferiorbulboftheIJV. Thisbulbhasabicuspidvalvethatpermitsbloodtoflowtowardthe heartwhileprevenRngbackflowintothevein. THENECK–THEVISCERAOFTHENECK THETHYROIDGLAND Developmentofthethyroidglandbeginsinthefloorofthe embryonicpharynxatthesiteindicatedbyasmallpit,theforamen cecum,inthedorsumofthepostnataltongue. Thedevelopingglandrelocatesfromthetongueintotheneck, passinganteriortothehyoidandthyroidcarRlagestoreachitsfinal posiRonanterolateraltothesuperiorpartofthetrachea. DuringthisrelocaRon,thethyroidglandisa_achedtotheforamen cecumbythethyroglossalduct. THENECK–THEVISCERAOFTHENECK THETHYROIDGLAND Thethyroidglandliesdeeptothesternothyroidandsternohyoid muscles,locatedanteriorlyintheneckatthelevelofthe C5–T1vertebrae. Itconsistsprimarilyofrightandlellobes,anterolateraltothelarynx andtrachea. Thethyroidglandissurroundedbyathinfibrouscapsule Thehighlyvascularthyroidglandissuppliedbythesuperiorand inferiorthyroidarteries UsuallythefirstbranchesoftheexternalcaroRdarteries, thesuperiorthyroidarteriesdivideintoanteriorandposterior branchessupplyingmainlytheanterosuperioraspectofthegland. Theinferiorthyroidarteries,thelargestbranchesofthe thyrocervicaltrunksarisingfromthesubclavianarteries. THENECK–THEVISCERAOFTHENECK THETHYROIDGLAND ThelymphaRcvesselsofthethyroidglandrunintheinterlobular connecRveRssue ThevesselspassiniRallytoprelaryngeal,pretracheal,and paratracheallymphnodes. NERVESOFTHYROIDGLAND Thesefibersarevasomotor,notsecretomotor.Theycause constricRonofbloodvessels.EndocrinesecreRonfromthethyroid glandishormonallyregulatedbythepituitarygland. THENECK–THEVISCERAOFTHENECK THEPARATHYROIDGLANDS Thesmallfla_ened,ovalparathyroidglandsusuallylieexternalto thethyroidcapsuleonthemedialhalfoftheposteriorsurfaceof eachlobeofthethyroidgland,insideitssheath. Mostpeoplehavefourparathyroidglands.Approximately5%of peoplehavemore;somehaveonlytwoglands.
