专业英语 unit 15

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1、UnitFifteenNORMALANATOMYANDHISTOLOGYOFTHEORALMUCOSAANATOMYTheoralmucosamaybedividedintoareascorrespondingtotheanatomicconfigurationofthejawsandassociatedmusculature.Theseareasarethegingiva,buccalmucosa,labialmucosa,tongue,hardpalate,andsoftpalate.GingivaThegingivao

2、r"gums"referstothetissuesurroundingtheteethandcoveringthealveolarbone.Thegingivaltissueistightlymattedtotheperiosteumofthealveolarbone,anditcoversthatportionoftherootsoftheteeththatextendsbeyondthecrestofalveolartoothsocket.Thegingivaltissuefillstheinterproximalspa

3、cesbetweentheteethsothatusuallyspacesarenotseenbetweenteeththatarenormallyalignedinthedentalarch.Theportionofthegingivathatextendsbeyondthealveolarboneandattachestotheteethisreferredtoasthemarginalgingivaorfreegingivalmargin,becauseitisrelativelyunsupportedbyhardti

4、ssueandformsacontinuousbandalongtheroot-crownjunctionoftheteeth.Thegingivaltissueattachestothetoothsurfacejustbelowthegingivalmargin,sothatasulcusorgingivalcreviceaboutlto2mmindepthisnormallyfoundbeneaththegingivalmargin.Theexactnatureofthegingivalattachmenttotooth

5、hasnotbeenestablished,buttheattachmentisfirm,sothatgingivacannotbedetachedfromatoothunlessconsiderableforceisusedtotearthetissueorasurgicalknifeisusedtoseverthetissue.Thesurfaceofthemarginalgingivaissmooth;thatoftheattachedgingivaisstippled.Thegingivaltissueappears

6、alightpinkcolornormally.Beyondthegingivaandseparatedfromitbyacleardemarcationisthealveolarmucosa.Thelineofdemarcationofreferredtoasthemucogingivaljunction,andthealveolarmucosabeyondthisjunctionisloose,delicatetissuenotmatteddowntounderlyingbone.Numeroussmallbloodve

7、sselscanbeseenthroughthisdelicatemucosa.Thealveolarmucosaontheouterorbuccalaspectiscontinuouswiththemucousmembraneofthelipandcheek,andavestibuleortroughisformedwheretheyblendintooneanother.Thistroughisreferredtoasthemucobuccalfoldorvestibuleofthemouth.(方晓倩)Buccalan

8、dLabialMucosaThebuccalmucosaistheoralmucosaofthecheek;itcoversthebuccinatormuscle.Thebuccalmucousmembraneisfreelymovableandoverlieslooseconnectiv