消化内科进展

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1、ThyroidAnatomy13#ThyroidAnatomy13/13ThyroidAnatomy12/13Mostoftheanterolateralsurfaceoftheneckiscoveredbythethinplatysmamuscles,remnantsofthepanniculuscarnosusofmammals(watchadogshakeitscoat).Thismuscleisatthelevelofthesuperficialfasciaanditsundersideprovidesanexcellentplaneo

2、fdissectionexposingthedeepfasciaoftheneck.BecauseoftheinvertedV-shapedgapinthislayeranteriorly,dissectionofflapsinacollarincisionshouldbeginlaterally.ThyroidAnatomy11/13Thesternocleidomastoidmusclesflankthestrapsandcovertheinternaljugularsandcarotidsheaths.Theyareenclosedina

3、nencirclinggirdleofdeepcervicalfasciacalledtheinvestinglayer.Thislayercontinuesposteriorlytoenclosethetrapeziusmuscles(seeneckclinicalfolio).Theexternaljugularveinsdescendacrosstheposteriorportionsofthesternocleidomastoidsandanteriorjugularveinsdescendalongthestrapsanteriorl

4、y.ThyroidAnatomy10/13Thethyroidiscoveredbythesternohyoidandsternothyroid(strap)muscles.Theseareenclosedinanintermediatelayerofdeepcervicalfascia(seeThryoidAnatomy:1)withthesternohyoidsbeingapposedinthemidlineandtheunderlyingsternothyroidsbeingslightlymorelateral.Whenmobilizi

5、ngthestrapsitisimportanttostayintheplanedeeptobothmuscles.Theomohyoidmusclesascenddiagonallyacrosstheupperpartofthestrapsandareautomaticallymobilizedwiththosemuscles.ThyroidAnatomy9/13Venousdrainageofthethyroidrunswiththesuperiorlaryngealarteriesabove,passeslaterally(middlet

6、hyroidveins)directlyintotheinternaljugularveins,anddrainsinferiorlyintothebrachiocephalicveins.Thedominantlymphaticdrainageaccompaniesthevesselswithinthelooseareolarcarotidsheaths.Theveinsformaplexusonthesurfaceoftheglandwithintheareolarthyroid(visceral)fascia.Remainingexter

7、naltothiscapsuleprovidesarelativelybloodlessdissection.Entryintothecapsuleisabloodymess.ThyroidAnatomy4/13Twocommonvariantsarethepresenceofapyramidallobeextendingupwardfromtheisthmusandathyroidimaarteryascendingfrombelow.Thepyramidallobeisaremnantofthetrackthethyroidfollowed

8、inembryologiclifefromtheforamencecumatthebaseofthetongue,throughthesiteofth