Core Features Embryology of the salivary glands and their as sociated structures Detailed - PDF document

Chapter Anatomy,Function,andEvaluationoftheSalivaryGlands F. Christopher Holsinger and Dana T. Bui 1 Contents Introduction ..................................... DevelopmentalAnatomy ArterialSupply ................................. VenousDrainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LymphaticDrainage............................ ParapharyngealSpace ........................... SubmandibularGland LymphaticDrainage............................ SublingualGland ................................. MinorSalivaryGlands............................ Histology....................................... PhysiologyofSalivaryGlands theanteriorborderofthegland,ittravelsparalleltothezygoma,approximatelybelowit,ananterior rectionacrossthemassetermuscleItthenturnssharplytopiercethebuccinatormuscleandenterstheoralcavityoppositetheseconduppermolartoothNeuralAnatomyefacialnerveexitstheskullbaseviathesty lomastoidforamen,whichisslightlyposterolateraltothestyloidprocessandanteromedialtothemastoidprocessBeforeenteringtheposteriorportionoftheparotidgland,threemotorbranchesaregivenotoinnervatethepos teriorbellyofthedigastricmuscle,thestylohyoidmuscle,andthepostauricularmusclesemaintrunkofthefacialnervethenpassesthroughtheparotidglandand,atthe pes anserinus(Latin:goose’sfoot),dividesintothetemporofacialandlowercervico facialdivisionsapproximatelyfromthestylomas toidforameneupper temporofacial divisionformsthefrontal,temporal,zygomatic,andbuccalbrancheselower cervicofacial divisionformsthemarginalmandibu larandcervicalbranchesBranchesfromthemajorup perandlowerbranchesoenanastomosetocreatethediversenetworkofmidfacialbuccalbranchese temporal branchtraversesparalleltothesuper cialtemporalvesselsacrossthezygomatosupplythefrontalbellyoftheoccipitofrontalismuscle,theorbicu larisoculi,thecorrugatorsupercilii,andtheanteriorandsuperiorauricularmusclese zygomatic branchtravelsdirectlyovertheperiosteumofthezygomaticarchto nervatethezygomatic,orbital,andinfraorbitalmusclese buccal branchtravelswithStensen’sductanteriorlyoverthemassetermuscletosupplythebuccinator,upperlip,andnostrilmusclesBuccalbranchescaneitherarisefromtheuppertemporofacialorthelowercervicofacialdivisione marginal mandibular branchcoursesalongtheinferiorborderoftheparotidglandtoinnervatethelowerlipandchinmusclesItsupercialtothepos teriorfacialveinandretromandibularveinstheplaneofthedeepcervicalfasciadirectlybeneaththeplatysmamusclee cervical branchsuppliestheplatysmamuscleLikethemarginalmandibularbranch,itislocatedwithintheplaneofthedeepcervicalfasciadirectunderneaththeplatysmaSmallconnectionscanexistamongthetemporal, gomatic,andbuccalbranches,andanatomicvariationsfacialnervebranchingpatternsoccurcommonlyEach terminalbranchcanbelocateddistallyandtracedretro gradeacrosstheparotidglandtothemaintrunkofthefacialnerveefacialnervecanalsobeidentiedatthestylomastoidforamenbyperformingmastoidectomyidenticationbytheusuallandmarksisnotpossiblele   10,   23]....egreatauricularnerveissensorybranchofthecervicalplexus,particularlyandandinnervatestheposteriorportionofthepinnaandthelobuleenerveparallelstheexternaljugularveinalongthelateralsurfaceofthesternocleidomastoidmuscletothetailoftheparotidgland,whereitsplitsintoanteriorandposte riorbranchesegreatauricularnerveisoeninjuredduringparotidectomy,whichcanresultlong-termsen sorylossthelobuleHarvestingofthisnervecanbeusedforfacialnervegraingcertaincaseseauriculotemporalnerveisbranchoftheman dibularnerve,thethirdinferiorsubdivisionofthe tri geminalnerve Aerexitingtheforamenovale,thenervetraversessuperiorlytoinnervatetheskinandscalpimmediatelyanteriortotheearItscourserunsparalleltothesupercialtemporalvesselsandanteriortotheexter nalauditorycanalAutonomicNerveInnervationeglossopharyngealnerveprovidesvisceralsecretoryinnervationtotheparotidglandenervecarriespreganglionicparasympatheticbersfromtheinferiorsalivatorynucleusthemedullathroughthejugularforamen(FigDistaltotheinferiorgan glion,smallbranchof Jacobsen’s nervereen terstheskullthroughtheinferiortympaniccanaliculusandintothemiddleeartoformthe tympanic plexus epreganglionicbersthencoursealongasthelesserpetrosalnerveintothemiddlecranialfossaandouttheforamenovaletosynapsethe otic ganglionPostgan glionicparasympatheticbersexittheoticganglionbe neaththemandibularnervetojointheauriculotemporalnervetheinfratemporalfossaesebersinnervatetheparotidglandforthesecretionofsalivaPostgangli onicsympatheticbersinnervatesalivaryglands,sweatglands,andcutaneousbloodvesselsthroughtheexternalcarotidplexusfromthe superior cervical ganglionAce tylcholineservesastheneurotransmitterforbothpost ganglionicsympatheticandparasympatheticberss. . . . isphysiologiccoincidenceallowsforthedevelopmentof“gustatorysweating”(alsoknownasFrey’ssyndrome) 4 1 F.ChristopherHolsingerandDanaT.Bui followingparotidectomyy   26]. . . . Patientsdevelopsweat ingandushingoftheskinoverlyingtheparotidregionduringeatingduetoaberrantautonomicreinnervationofthesweatglandsbytheregeneratingparasympatheticbersfromanyresidualparotidglandFrey’ssyndromemayoccurasmanyasofpatientspostopera tivelyeriskforFrey’ssyndromecanbeminimizedrstbycompleteandmeticuloussupercialparotidectomySecond,bydevelopingskinapsofappropriatethick ness,exposedapocrineglandsoftheskinareprotectedfromingrowthandstimulationbytheseveredbranchesoftheauriculotemporalnerveandtheirparasympatheticstimulationduringmealserearenumerousnonsurgi calandsurgicaltreatmentsforpersistentFrey’ssyndromefollowingparotidectomy(seeChapterTreatmentofFrey’sSyndrome) ArterialSupplyebloodsupplytotheparotidglandisfrombranchesofthe external carotid arterywhichcoursessuperiorlyfromthecarotidbifurcationandparalleltothemandibleundertheposteriorbellyofthedigastricmuscleear terythentravelsmedialtotheparotidglandandsplitsintotwoterminalbranchese supercial temporal arteryrunssuperiorlyfromthesuperiorportionoftheparotidglandtothescalpwithinthesuperiorpretragalregione maxillary arteryleavesthemedialportionoftheparotidandsuppliestheinfratemporalfossaandthepterygopalatinefossaDuringradicalparotidectomy,thisvesselmustbecontrolledespeciallywhenmarginalorsegmentalmandibulectomyisrequirede transverse facial arterybranchesothesupercialtemporalarteryandrunsanteriorlybetweenthezygomaandparotidducttosupplytheparotidgland,parotidduct,andthemas setermuscle Fig. 1.2: Parasympatheticsupplytothemajorsalivaryglands 5 Anatomy,Function,andEvaluation Chapter oorofthemouthsubmucosalplaneBeneaththemandible,smallmotornervebranchesoandtrav elsposteriorlyfromthelingualnervetoinnervatethemylohyoidmuscleesebersareusuallysacricedduringsurgicalremovalofthesubmandibularglandParasympatheticbersarecarriedviathelingualnervetothesubmandibularganglion,andpostsynapticbersexitalongthecourseofthesubmandibularductto nervatetheglandehypoglossalnervesuppliesmotorinner vationtoallextrinsicandintrinsicmusclesofthetongueexceptforthepalatoglossusmuscleFromthehypoglos salcanalatthebaseoftheskull,thenerveispulled feriorlyduringembryonicdevelopmentdownintotheneckbytheoccipitalbranchoftheexternalcarotidar teryFromhere,thehypoglossalnervetravelsjustdeeptotheposteriorbellyofthedigastricmuscleandcommontendonuntilitreachesthesubmandibulartriangleHeredeepthetrianglecoveredbythinlayeroffasciaItslocationisanterior,deepandmedialrelativetothesubmandibularglandTypicallythenervehascloserelationshiptotheanteriorbellyofthedigastricmuscleItthenascendsanteriortothelingualnerveanditsgenudeeptothemylohyoidmuscleExtremecareshouldbetakentopreservethisimportantnerveduringheadandnecksurgeryArterialSupplyBoththesubmandibularandsublingualglandsaresup pliedbythe submentaland sublingual arteriesbranchesofthelingualandfacialarteriese facial arterythetor tuousbranchoftheexternalcarotidartery,isthemainarterialbloodsupplyofthesubmandibularglandItrunsmedialtotheposteriorbellyofthedigastricmuscleandthenhooksovertocoursesuperiorlydeeptotheglandearteryexitsatthesuperiorborderoftheglandandtheinferioraspectofthemandibleknownasthe facial notchItthenrunssuperiorlyandadjacenttotheinferiorbranchesofthefacialnerveintotheDuringsub mandibularglandresection,thearterymustbesacricedtwice,rstattheinferiorborderofthemandibleandagainjustsuperiortotheposteriorbellyofthedigastricmusclee lingual arterybranchesinferiortoorwiththefacialarteryotheexternalcarotidarteryItrunsdeeptothedigastricmusclealongthelateralsurfaceofthemiddleconstrictorandthencoursesanteriorandmedialtothehyoglossusmuscle VenousDrainageesubmandibularglandismainlydrainedbythe an - terior facial veinwhichiscloseapproximationtothefacialarteryasitrunsinferiorlyandposteriorlyfromthetotheinferioraspectofthemandibleBecauseitjustdeeptothemarginalmandibulardivisionofthefacialnerve,ligationandsuperiorretractionoftheanterior cialveincanhelppreservethisbranchofthefacialnerveduringsubmandibularglandsurgeryItformsextensiveanastomoseswiththeinfraorbitalandsuperiorophthal veinse common facial veinisformedbytheunionoftheanteriorandposteriorfacialveinsoverthemiddleaspectoftheglandecommonfacialveinthencourseslateraltotheglandandexitsthesubmandibulartriangletojointheinternaljugularveinLymphaticDrainageeprevascularandpostvascularlymphnodesdrainingthesubmandibularglandarelocatedbetweentheglandanditsfascia,butarenotembeddedtheglandulartis sueeycloseapproximationtothefacialarteryandveinatthesuperioraspectoftheglandandemptyintothedeepcervicalandjugularchainsesenodesarefrequentlyassociatedwithcancerstheoralcavity, peciallythebuccalmucosaandtheoorofthemouthus,whenligatingthefacialarteryanditsassociatedplexusofveins,greatercaremustbetakennotonlytore sectallassociatedlymphoadiposetissue,butalsotopre servethemarginalmandibularbranchofthefacialnerve,whichrunscloseproximitytothesestructures SublingualGland esmallestofthemajorsalivaryglandsisthesublingualgland,weighingConsistingmainlyofmucous narcells,itasatstructuresubmucosalplanewithintheanterioroorofthemouth,superiortothemy lohyoidmuscleanddeeptothesublingualfoldsoppositethelingualfrenulumum. . . . Lateraltoitarethemandibleandgenioglossusmuscleereisnotruefascialcapsulesurroundingthegland,whichisinsteadcoveredbyoralmucosaonitssuperioraspectSeveralducts of Rivinusfromthesuperiorportionofthesublingualglandeithersecretedirectlyintotheoorofmouth,oremptyinto Bartholin’s ductthatthencontinuesintoWharton’sduct 8 1 F.ChristopherHolsingerandDanaT.Bui Boththesympatheticandparasympatheticnervoussystemsinnervatethesublingualglandepresynapticparasympathetic(secretomotor)bersofthe facial nerve arecarriedbythechordatympaninervetosynapsethesubmandibularganglionPostganglionicbersthenexitthe submandibular ganglionandjointhelingualnervetosupplythesublingualglandSympatheticnervesinner vatingtheglandtravelfromthe cervical ganglionwiththefacialarteryy....Bloodissuppliedtothesublingualglandbythe sub - mental and sublingual arteriesbranchesofthelingualandfacialarteries,respectivelyevenousdrainageparallelsthecorrespondingarterialsupplyesublingualglandismainlydrainedbythesubmandibularlymphnodes Ranulasarecystsormucocelesofthesublingualgland,andtheycanexisteithersimplywithinthesublingualspaceorplungingposteriorlytothemylohyoidmuscleintothenecksimpleranulawillmostcommonlypres entasbluish,nontendermasstheoorofthemouthandmayeitherberetentioncystoranextravasationpseudocystplungingranulawillpresentasso,painlesscervicalmassandisalwaysanextravasationpseudocyst(seeChapterManagementofMucoceleandRanula) MinorSalivaryGlands Abouttominorsalivaryglands,rangingfromtolinetheoralcavityandorophar ynxegreatestnumberoftheseglandsarethelips,tongue,buccalmucosa,andpalate,althoughtheycanalsobefoundalongthetonsils,supraglottis,andparana salsinusesEachglandhassingleductwhichsecretes,directlyintotheoralcavity,salivawhichcanbeeitherse rous,mucous,ormixedPostganglionicparasympatheticinnervationarisesmainlyfromthe lingual nerveepalatinenerves,how ever,exitthesphenopalatinegangliontoinnervatethesuperiorpalatalglandseoralcavityregionitselfdeter minesthebloodsupplyandvenousandlymphaticdrain ageoftheglandsAnyofthesesitescanalsobethesourceofglandulartumors Histology Allglandsgeneralarederivedfromepithelialcellsandconsistof parenchyma(thesecretoryunitandassociatedducts)and stroma(thesurroundingconnectivetissuethatpenetratesanddividestheglandintolobules)SecretoryproductsaresynthesizedintracellularlyandsubsequentlyreleasedfromsecretorygranulesbyvariousmechanismsGlandsareusuallyclassiedintotwomaingroups Endo - crine glandscontainnoducts,andthesecretoryproductsarereleaseddirectlyintothebloodstreamorlymphaticsystemIncontrast, exocrine glandssecretetheirproductsthroughductsystemthatconnectsthemtotheadjacentexternalorinternalepithelialsurfacesSalivaryglandsareclassiedasexocrineglandsthatsecretesalivathroughductsfromask-like,blind-endedsecretorystructurecalled the salivary acinus.eacinusitselfcanbedividedintothreemaintypes Serous acinisalivaryglandsareroughlysphericalandreleaseviaexocytosiswateryproteinsecretionthatisminimallyglycosylatedornonglycosylatedfromsecre tory(orzymogen)granuleseacinarcellscomprisingtheacinusarepyramidal,withbasallylocatednucleisur roundedbydensecytoplasmandsecretorygranulesthataremostabundanttheapex Mucinous acinistorevis cous,slimyglycoprotein mucinwithinsecretorygran ulesthatbecomehydratedwhenreleasedtoform mucus Mucinousacinarcellsarecommonlysimplecolumnarcellswithattened,basallysituatednucleiandwater-solu blegranulesthatmaketheintracellularcytoplasmappearclear Mixedor seromucous acinicontaincomponentsofbothtypes,butonetypeofsecretoryunitmaydominateMixedsecretoryunitsarecommonlyobservedasserous demilunes(orhalf-moons)cappingmucinousBetweentheepithelialcellsandbasallaminaoftheacinus,at myoepithelial cells(orbasketcells)formlat ticeworkandpossesscytoplasmiclamentsontheirbasaltoaidcontraction,andthusforcedsecretion,oftheacinusMyoepithelialcellsarealsoobservedaroundintercalatedducts,butheretheyaremorespindleshapedd....Electrolytemodicationandtransportationofsalivaarecarriedoutbythedierentsegmentsofthesalivarygland’sductsystem(Figerstsecretethroughsmallcanaliculiintotheintercalatedducts,whichturnemptyintostriatedductswithintheglan dularlobuleeintercalatedductiscomprisedofan regularmyoepithelialcelllayerlinedwithsquamousorlowcuboidalepitheliumBicarbonateissecretedintowhilechlorideisabsorbedfromtheacinarproductwithintheintercalatedductsegmentStriatedductshavedistin guishingbasalstriationsduetomembraneinvaginationandmitochondriaandarelinedbysimplecolumnar 9 Anatomy,Function,andEvaluation Chapter epitheliumeseductsareinvolvedwiththereabsorp tionofsodiumfromtheprimarysecretionandthecon comitantsecretionofpotassiumintotheproducteabundantpresenceofmitochondriaisnecessaryfortheducts’transportofbothwaterandelectrolytese nus,intercalatedduct,andstriatedductarecollectivelyknownassinglesecretoryunitcalled salivon n ....enextsegmentoftheductsystemismarkedbytheappearanceoftheinterlobularexcretoryductswithintheconnectivetissueoftheglandularseptaeeepithelialliningiscomprisedofsparsegobletcellsinterspersedamongthepseudostratiedcolumnarcellsAsthediam eteroftheductincreases,thecompositionoftheepithe lialliningtransitionstostratiedcolumnar,andthentononkeratinizedstratiedsquamouscells,withintheoralcavityy....earterialbloodowreceivedbythesalivaryglandsishighrelativetotheirweightandisoppositetheowofsalivawithintheductsystemeandductulesaresuppliedbyseparateparallelcapillarybedsehighpermeabilityofthesevesselspermitsrapidtransferofmoleculesacrosstheirbasementmembranesehighvolumeofsalivaproducedbythesalivaryglandsrelativetotheirweightispartlyduetothehighbloodowratethroughtheglandulartissueeserousthatmakeupthe parotid glandareroughlyspherical,andtheyarecomprisedofpyramidalepithelialcellssurroundedbydistinctbasementmem braneMerocrinesecretionbytheepithelialcellsreleasessecretorymixturecontainingamylase,lysozyme,anIgAsecretorypiece,andlactoferrinintothecentrallu menoftheacinusemainexcretoryductisalsoknownas Stensen’s ductandemptiesintotheoralcavityoppositetheseconduppermolartoothe submandibular glandisclassiedasmixedglandthatispredominantlyserouswithtubularema jorityofacinarcellsareserouswithverygranulareosino philiccytoplasmOnlyapproximatelyofthearemucinous,withlarge,triangularacinarcellscontainingcentralnucleiandclearcytoplasmicmucinvacuolesrang ingemucinouscellsarecappedbydemilunes,whicharecrescent-shapedformationsofserouscellseintercalatedductsofthesubmandibularglandarelongerthanthoseoftheparotidgland,whilestriatedductsareshorterbycomparison Wharton’s ductservesasthemainexcretoryductandemptiesintotheoorofthemouthLikethesubmandibulargland,the sublingual gland hasmixedwithobservableserousdemiluneswithintheglandulartissueUnlikethesubmandibulargland,however,thesublingualglandispredominantly Fig. 1.4: Functionalhistologyofthesalivon 10 1 F.ChristopherHolsingerandDanaT.Bui trationswithinthecell,releasedfromeitherintracellular Ca storesorfromtheplasmaissecondmessengersignicantlyeectssalivaryvolumesecretionGlandu larsecretionissustainedby acetylcholinesteraseswhichinhibitthebreakdownofAChemuscarinicantago nist atropinehowever,decreasessalivationbycompetingwithAChforthesalivaryreceptorsiteesympatheticsupplytothesalivaryglandismainlyfromthethoracicspinalnervesofthesuperiorcervicalganglionLikeparasympatheticinnervation,myoepithe lialcellcontractionalsoresultsChangesbloodow,however,arebiphasic:vasoconstrictiondueto-adren ergicreceptoractivationisfollowedbyvasodilationduetobuildupofvasodilatormetabolitesBindingoftheneurotransmitter norepinephrineto-adrenergicrecep torresultsformationof3',5'-cyclicadenosinemono phosphatewhichthenleadstophosphorylationofvariousproteinsandactivationofdierentenzymesIncreasesresultincreasedsalivaryenzymeandmucuscontentWithinsaliva, concentrationsincreasewhileNa + concentrationsdecreasethepresenceofantidiuretichormone(ADH)oraldosteroneUnlikeotherdigestiveglands,however,thesetwohormonesnotaectsali varyglandsecretionrateAboutofsalivaissecretedbynormaladulteachdayDuringunstimulatedsalivation,ofsalivaiscon tributedbythesubmandibularglands,bytheparotid,andbythesublingualglandserelativeamountssuppliedbytheparotidandsubmandibularglands,how ever,areswitchedduringstimulation,wheretwothirdsofsecretionisthenfromtheparotidglandtotalow,isduetotheminorsalivaryglandsregardlessofstimulationepresenceoffoodthemouth,theactofchewing,andnauseaallstimulatesalivation,whilesleep,fatigue,dehydration,andfearinhibititSalivarysecretionratesarenotdependentonage,andowratesremainconstantdespitethedegenerationofacinarcellsduringtheagingprocessMedicationeectsorsystemicdis easearemorelikelytoberesponsibleforhypofunctionofsalivaryglandselderlypatients EvaluationoftheSalivaryGlands Symptomsindicativeofsalivaryglanddisordersare itednumberandgenerallynonspecicPatientsusu allycomplainofswelling,pain,xerostomia,foultaste,andsometimes sialorrheaorexcessivesalivationDespite theprevalenceofmoderntechnologytheidenticationofsalivaryglanddisorders,detailedhistoryandthor oughphysicalexaminationstillplaysignicantrolestheclinicaldiagnosisofthepatient,andgreatcareshouldbetakenduringtheseinitialstepsofevaluation HistoryWhentakingpatient’shistory,thepracticedskillsofattentivelisteningandpatiencearerequiredforsubse quentdiagnosisandpropertreatmentmostttingtothepatient’sexpectationsandneedsemedicalproleofthepatientcanprovidehelpfulcluestothecurrentcondi tionofthesalivaryglands,fordysfunctionoftheseglandsisoenassociatedwithcertainsystemicdisorderssuchasdiabetesmellitus,arteriosclerosis,hormonalimbalances,andneurologicdisordersEitherxerostomiaorsialorrhea,forinstance,maybeduetofactorsaectingthemedul larysalivarycenter,autonomicoutowpathway,salivaryglandfunctionitself,oruidandelectrolytebalanceefactorsofagegroupandgenderarealsoimpor tant,forseveraldiseasesareoenrelatedtoageorgendereautoimmunedisorderknownas Sjögren’s syndromeforexample,iscommonmenopausalwomen,while mumpsparotidswellingduetoparamyxoviralinfec tion,usuallyoccurschildrenbetweentheagesofandyearsDrughistoryofthepatientshouldalsobeconsidered,forsalivaryfunctionisoenaectedbydrugusageXe rostomiaisoenduetotheuseofdiureticsandotheran tihypertensivedrugsugs   18]....A   carefuldietaryandnutritionhistoryshouldbeob tainedPatientswhoaredehydratedchronicallyfrombu limiaoranorexiaorduringchemotherapyareatriskforparotitisSwellingandpainduringmealsfollowedbyreductionsymptomsaermealsmayindicatepartialductalstenosisXerostomiaisdebilitatingconsequenceofradiationtherapytotheheadandneckandhistoryofpriorradia tionshouldbesoughtPhysicalExaminationesuperciallocationofthesalivaryglandsallowsthor oughinspectionandpalpationforcompletephysicalexaminationInitialinspectioninvolvesthecareful aminationoftheheadandneckregions,bothintraorally 13 Anatomy,Function,andEvaluation Chapter andextraorally,andshouldbecarriedoutsystematicwaysoastonotmissanycrucialsignsDuringtheinitial extraoral inspectionthepatientshouldstandthreetofourfeetawayanddirectlyfacingfrontoftheexaminereexaminershouldinspectsymmetry,color,possiblepulsationanddischargingof nusesonbothofthepatientEnlargementofmajororminorsalivaryglands,mostcommonlytheparotidorsubmandibular,mayoccurononeorboth Parotitis typicallypresentsaspreauricularswelling,butmaynotbevisibledeeptheparotidtailorwithinthesubstanceofthegland Submandibular swellingpresentsjustmedialandinferiortotheangleofthemandibleSalivaryglandswellingcangenerallybedierentiatedfromthoseoflym phaticoriginasbeingsingle,larger,andsmoother,butthetwotypesareoeneasilyconfusedSignicantneurologicdecitsshouldbeexaminedaswellFacialnerveparalysisconjunctionwithparotidmass,forexample,shouldremindusof malignantparotidneoplasm,althoughitdoesoccurrarelywithbenignneoplasmsaswellInadditiontosignsofpossibleasymmetry,discolor ation,orpulsation, intraoral inspectionalsoincludesas sessmentoftheductoricesandpossibleobstructionseproperlightingwithheadlightshouldalwaysbeusedwheninspectingwithintheoralcavityandpharynxeopeningsofStensen’sandWharton’sductscanbe spectedintraorallyoppositetheseconduppermolarandattherootofthetongue,respectivelyDryingothemu cosaaroundtheductswithanairblowerandthenpress ingonthecorrespondingglandswillallowtheexaminertoassesstheoworlackofowofsalivaSialolithiasiscansometimesbefoundbycarefulintraoralpalpationDentalhygieneandthepresenceofperiodontaldiseaseshouldalsobenotedsincedecientoralmaintenanceismajorpredisposingfactortovariousinfectiousdiseasesSize,consistency,andotherqualitiesofthesalivaryglandsandassociatedmassescanbeevaluatedthroughextraoralandintraoralpalpationBimanualassessmentshouldbeperformedwheneverpossiblewiththepalmaraspectofthengertipsDuring extraoral palpationoftheandneck,thepatient’sheadisinclinedforwardtomaximallyexposetheparotidandsubmandibularglandregionseexaminermaystandfrontoforbehindthepatientItshouldbenotedthatobservablesalivaryorlymphaticglandswell ingsnotrisewithswallowing,whileswellingsassoci atedwiththethyroidglandandlarynxelevateFinally,bimanualpalpation(extraoralwithonehand,introralwiththeother)mustbeperformedtoexam - inetheparotidandsubmandibularglandsOneortwoglovedngersshouldbeinsertedwithintheoralcavitytopalpatetheglandsandmainexcretoryductsinternally,whileusingtheotherhandtoexternallysupporttheheadandneckByrollingthehandsovertheglandsbothinter nallyandexternally,subtlemasslesionscanbeidentiedInthesubmandibulargland,lymphnodesextrinsictotheglandcanoenbedistinguishedfrompathologywithintheglanditselfusingthistechniqueeneckshouldthenalsobecarefullyexaminedforlymphadenopathyFinally,carefulsurveyofminorsalivaryglandtis sueshouldbeperformed,especiallytheanteriorlabial,buccal,andposteriorpalatalmucosaIncreasedsalivationfromtheductoricesduetopressureexternallyappliedtotheglandsmayindicateinammationn   18]. . . . Finally,rareclinicalentities,suchashemangiomasandothervas cularanomalies,maybeidentiedbyauscultation RadiologicandEndoscopicExaminationoftheSalivaryGlands Althoughthoroughhistoryandcompletephysical aminationarecrucialstepsthediagnosisandeven tualtreatmentofanysalivaryglanddisorder,patientsoccasionallyprovidelittlemorethanvaguecomplaintsofpainand/orswellingForpatientswiththeseunclearsymptomsandnophysicalsigns,radiographicdiagnosticstudies,suchassialography,plain-lmradiography,com putedtomography,andmagneticresonanceimaging,canplayimportantroleclarifyingtheetiologyofsuchnonspecicsymptomsForpatientswithknowndisease,imagingcanassisttreatmentselectionandplanningisnalsectionwillprovidebriefintroductiontothesevarioustechniques,whichwillthenbecoveredgreaterdetailsubsequentchaptersSialographyreliesontheinjectionofcontrastmediumintoglandularductssothatthepathwayofsalivaryowcanbevisualizedbyplain-lmradiographsCorrect posureandpositioningisachievedbytakingpreliminaryplainradiographspriortotheinjectionofradiopaquemediumum. . . . emostcommonindicationforsialogra phyisthepresenceofsalivarycalculus,whichis positofmostlycalciumsaltsthatcanblockowofsa livaandcausepain,swelling,andinammationorleadtoinfectionPatientswithcalculiusuallycomplainofrecurrentandacuteonsetofpainandswellingduringeatingOen,sialographicexaminationisunnecessarythepreliminaryradiographsdetectthecalculusbefore - 14 1 F.ChristopherHolsingerandDanaT.Bui handOtherindicationsforsialographyincludegradualorchronicglandularenlargement(whichcanbeduetosarcoidosis,infection,sialosis,Sjögren’ssyndrome,be nignlymphoepitheliallesion,orneoplasm),clinicallypalpablemassoneoftheglandularregions(possibletumor,cyst,orfocalinammation),recurrentsialadeni tis,ordrynessofthemouthAlthoughconventionalsialographycanbeclinicallyusefulthediagnosisandthedeterminationoftreat mentforvarioussalivarydisorders,itseectivenessre mainsarguablewhileitsrateofusageishighlyvariablele   30]. . . . ismethodshouldnotbeperformedwhenthepatienthasanacutesalivaryglandinfection,hasknownsensitivitytoiodine-containingcompounds,orisan ticipatingthyroidfunctiontestsus,othermethodsofradiographicdiagnosisarecurrentlypreferredandhavelargelyreplacedsialographicexaminationComputedtomographyisnowmorewidelyusedtoassesstheparotidandsubmandibularglandse vantageofimagingisthetwo-dimensionalviewofthesalivaryglands,whichcanelucidaterelationshipstoadja centvitalstructuresaswellastoassessthedrainingcervi callymphaticseparotidglandhaslowattenuationduetoitshighfatcontentandisthereforeeasilydiscerniblebyscanningesubmandibularglandhaslowerfatcontentandhigherdensitycomparedtotheparotidglandandthushasmuchhigherattenuation,althoughextrin andintrinsicmassdierentiationiseasiertoevaluateAlthoughstonescanbeidentied,salivaryglandinam mationisnotgenerallyanindicationforWhileisoenutilizedasprimaryscreeningtoolforthedetec tionofparotidandsubmandibularglandabnormalities,dicultcases,higher-sensitivityapproachusingbothandsialography(CT-sialography)canbeusedd. . . . Dierencesbetweenintrinsicandextrinsicparotidglandmasses,however,areoendiculttoassessespeciallywhenpresenttheparapharyngealspaceace....Magneticresonanceimagingismoreoenusedforassessmentofparapharyngealspaceabnormalitiesprovidesbettercontrastresolution,exposesthepa tienttolessharmfulradiation,andyieldsdetailedimagesonseveraldierentplaneswithoutpatientrepositioningistechniquethereforeispreferredtheevaluationofparapharyngealspacemasses,especiallydiscriminatingbetweendeeplobeparotidtumorsandotherpathology,suchasschwannomaand/orglomusvagalehowever,isinferiortoscanningforthedetectionofcalcicationsandearlyboneerosionChronicinammationofthesali varyglandsandcalculiarenotindicationsfor Sialendoscopyisminimallyinvasivetechniquethatinspectsthesalivaryglandsusingnarrow-diameter,rigidberopticendoscopeses. . . . Endoscopicvisualizationofductalandglandularpathologyprovidesanexcellental ternativetotheindirectdiagnostictechniquesdescribedaboveAssuch,sialendoscopyhasopenedupnewfron tierforbothevaluationandtreatmentofsalivaryglanddiseasee. . . . Lacrimalprobesareusedtogentlydilatetheductaloriceandthentheendoscopeisintroduced directvisualizationDuringlavageoftheglandularductofinterest,directinspectionoftheductandhilumoftheglandisperformedus,onesetting,atthetimeofdiagnosis,treatmentandtherapyforbenignlesionscanbeperformed(seeChapterSialendoscopy)roughCO -laserpapillotomy,sialolithectomycanbeeasilyperformedd. . . . Pharmacotherapyandlaser-ablationcanalsobeperformedSialendoscopyhasalsobeenshowntohavesignicantlylowcomplicationrateandisgener allywell-toleratedd. . . . isrelativelynewtechniquehasshownmuchpromisethediagnosisandtreatmentofchronicobstructivesialadenitis(COS),sialolithiasis,andotherobstructivediseasesofthesalivaryglands TakeHomeMessages  SalivaryglanddevelopmentistheresultofbranchingmorphogenesisMolecularbiologyisbeginningtounravelsignalingpathways plicatedbothcraniofacialdevelopmentandsalivaryglandhistogenesis,includingthesonichedgehog(Shh)andthebroblastgrowthfactorfamily  Humansalivaisnotonlyimportantforlubrica tiontheoralcavity,butplayscrucialroledigestiveandprotectiveprocesses  Bothvisualinspectionwithoptimallightingandbimanualpalpationiscrucialtheprecisephys icalexaminationofthemajorandminorsalivaryglands  Sialendoscopyisnovelmodalityfordiagnosticevaluationaswellastherapeuticinterventionfordisordersofthesalivaryglands 15 Anatomy,Function,andEvaluation Chapter References AreyDevelopmentalanatomy;textbookandlaboratorymanualofembryologyRevised7thedSaunders,IncPhiladelphia BerneldBanerjeeCohnDependenceofsalivaryepithelialmorphologyandbranchingmorphogen esisuponmucopolysaccharide-protein(proteoglycan)attheepithelialsurfaceCellBiol BhattacharyyaVarvaresAnomalousrelation shipofthefacialnerveandtheretromandibularvein:casereportOralMaxillofacSurg CarrauJohnsonJT,MyersManagementoftumorsoftheparapharyngealspaceOncology(WillistonPark)discussion DavisRA,AnsonBJ,BudingeralSurgicalanatomyofthefacialnerveandparotidglandbaseduponstudyofcervicofacialhalvesSurgGynecolObstet Frommerehumanaccessoryparotidgland:itsincidence,nature,andsignicanceOralSurgOralMedOralPathol Garatea-CrelgoJ,Gay-EscodaBermejoB,alMorphologicalstudyoftheparotidlymphnodesCranio maxillofacSurg Gibsoneprenatalhumansubmandibulargland:histological,histochemicalandultrastructuralstudyAnatAnz GraamansvonAkkerHistoryandphysi calexaminationIn:Graamans(ed)DiagnosisofSali varyGlandDisordersKluwerAcademicPublishers,Dor drecht,Germany,pp GrantAnAtlasofAnatomy,SixthednWilliamsWilkins,Baltimore HollinsheadAnatomyforSurgeons:VolumeeHeadandNeck,irdedLippincottCompany, Philadelphia JaskollT,MelnickSubmandibularglandmor phogenesis:stage-specicexpressionofTGF-alpha/EGF,IGF,TGF-beta,TNF,andIL-6signaltransductionnor malembryonicandthephenotypiceectsofTGF-beta2,TGF-beta3,andEGF-rnullmutationsAnatRec JaskollT,LeoT,WitcherD,alSonichedgehogsignalingplaysanessentialroleduringembryonicsalivaryglandepithelialbranchingmorphogenesisDevDyn Johnsesalivaryglands:anatomyembryol ogyOtolaryngolClinNorthAm Johnson(ed)SecretionElsevier,Amsterdam JunqueriaCarneiroBasicHistology:TextAt lasTenthednMcGraw-Hill,NewYork KontisTC,JohnsAnatomyandPhysiologyoftheSalivaryGlandsIn:Bailey(ed)HeadandNeckSurgeryOtolaryngologyLippincottWilliamsWilkins, Philadelphia MasonD,ChisholmSalivaryGlandsHealthandDiseaseSaunders,London MyersConleyGustatorysweatingaerradicalneckdissectionArchOtolaryngol NahlieliO,BaruchinSialoendoscopy:threeyears’experienceasdiagnosticandtreatmentmodalityOralMaxillofacSurgdiscussion NahlieliO,BaruchinLong-termexperiencewithendoscopicdiagnosisandtreatmentofsalivaryglandinammatorydiseasesLaryngoscope OrabiRiadO’ReganStylomandibu lartenotomythetranscervicalremovaloflargebenignparapharyngealtumoursBrOralMaxillofacSurg PogrelSchmidtB,AmmarerelationshipofthebuccalbranchofthefacialnervetotheparotidductOralMaxillofacSurg QuinnJrSymposium:managementoftumorsoftheparotidglandDiagnosisofparotidglandswellingLaryngoscope RabinovWeberRadiologyoftheSalivaryGlandsHallMedicalPublishers,Boston RoarkDT,SessionsRB,AlfordBRFrey’ssyndrome-technicalremedyAnnOtolRhinolLaryngol SomBillerecombinedcomputerizedtomography-sialogramtechniquetodierentiatedeeplobeparotidtumorsfromextraparotidpharyngomaxillaryspacetumorsAnnOtolRhinolLaryngol UeharaLocalizationofFGF-6andFGFR-4dur ingprenatalandearlypostnataldevelopmentofthemousesublingualglandOralSci WoodburneRT,BurkelEssentialsofHumanAnatomy,EighthednOxfordUniversityPress,NewYork, Oxford YuneSialographyanddacrocystographyIn:MillerR,Skucas(eds)RadiographiccontrastagentsUni versityParkPress,Baltimore,pp ZieglerHedemarkBrevikB,alEndos copyasminimalinvasiveroutinetreatmentforsialolithia sisActaOdontolScand 16 1 F.ChristopherHolsingerandDanaT.Bui