甲状腺解剖(英)

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1、ThyroidAnatomyQuintessence11ThyroidAnatomy13/13ThyroidAnatomy12/13Mostoftheanterolateralsurfaceoftheneckiscoveredbythethinplatysmamuscles,remnantsofthepanniculuscarnosusofmammals(watchadogshakeitscoat).Thismuscleisatthelevelofthesuperficialfasciaanditsun

2、dersideprovidesanexcellentplaneofdissectionexposingthedeepfasciaoftheneck.BecauseoftheinvertedV-shapedgapinthislayeranteriorly,dissectionofflapsinacollarincisionshouldbeginlaterally.ThyroidAnatomy11/13Thesternocleidomastoidmusclesflankthestrapsandcoverth

3、einternaljugularsandcarotidsheaths.Theyareenclosedinanencirclinggirdleofdeepcervicalfasciacalledtheinvestinglayer.Thislayercontinuesposteriorlytoenclosethetrapeziusmuscles(seeneckclinicalfolio).Theexternaljugularveinsdescendacrosstheposteriorportionsofth

4、esternocleidomastoidsandanteriorjugularveinsdescendalongthestrapsanteriorly.ThyroidAnatomy10/13Thethyroidiscoveredbythesternohyoidandsternothyroid(strap)muscles.Theseareenclosedinanintermediatelayerofdeepcervicalfascia(seeThryoidAnatomy:1)withthesternohy

5、oidsbeingapposedinthemidlineandtheunderlyingsternothyroidsbeingslightlymorelateral.Whenmobilizingthestrapsitisimportanttostayintheplanedeeptobothmuscles.Theomohyoidmusclesascenddiagonallyacrosstheupperpartofthestrapsandareautomaticallymobilizedwiththosem

6、uscles.ThyroidAnatomy9/13Venousdrainageofthethyroidrunswiththesuperiorlaryngealarteriesabove,passeslaterally(middlethyroidveins)directlyintotheinternaljugularveins,anddrainsinferiorlyintothebrachiocephalicveins.Thedominantlymphaticdrainageaccompaniesthev

7、esselswithinthelooseareolarcarotidsheaths.Theveinsformaplexusonthesurfaceoftheglandwithintheareolarthyroid(visceral)fascia.Remainingexternaltothiscapsuleprovidesarelativelybloodlessdissection.Entryintothecapsuleisabloodymess.ThyroidAnatomy4/13Twocommonva

8、riantsarethepresenceofapyramidallobeextendingupwardfromtheisthmusandathyroidimaarteryascendingfrombelow.Thepyramidallobeisaremnantofthetrackthethyroidfollowedinembryologiclifefromtheforamencecumatthebaseofthetongue,through