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TheLarynx
Prof. Dr.Mohammed Hisham
Al-Muhtaseb
TheLarynx
• ExtendsfromthemiddleofC3
vertebratillthelevelofthe
lowerborderofC6
• ContinueasTrachea
• Aboveitopensintothe
laryngo-pharynx
• Suspendedfromthehyoid
boneaboveandattachedto
thetracheabelowby
membranesandligaments
Functions
• 1.actsasanopenvalveinrespiration
• 2.Actsasaclosedvalveindeglutition
• 3.Actsasapartiallyclosedvalveinthe
productionofvoice
• 4.Duringcoughitisfirstclosedandthen
opensuddenlytoreleasecompressedair
Parts
• 1.Cartilage
• 2.Mucosa
• 3.Ligaments
• 4.Muscles
Cartilage
• A.Single:
Epiglottis
Cricoid
Thyroid
B.Pairs:
Arytenoid
Cuneiform
Corniculate
Cricoidcartilage
• Themostinferiorofthelaryngeal
cartilages
• Completelyencirclestheairway
• Shapedlikea'signetring'
• Broadlaminaofcricoidcartilage
posterior
• Muchnarrowerarchofcricoid
cartilage circlinganteriorly.
Cricoidcartilage
• Posteriorsurfaceofthelaminahastwooval
depressionsseparatedbyaridge
• The esophagus isattachedtotheridge
• Depressionsareforattachmentoftheposterior
crico-arytenoidmuscles.
• Hastwoarticularfacets oneachside
• Onefacetisontheslopingsuperolateralsurface
andarticulateswiththebaseofanarytenoid
cartilage;
• Theotherfacetisonthelateralsurfacenearits
baseandisforarticulationwiththeinferior
hornofthethyroidcartilage
Thyroidcartilage
• Thelargestofthelaryngeal
cartilages
• Itisformedbyarightanda
leftlamina
• Widelyseparatedposteriorly,
butconvergeandjoin
anteriorly
• Posteriormarginofeach
laminaiselongatedtoforma
superiorhorn andaninferior
horn
Thyroidcartilage
• Mostsuperiorpointofthesiteoffusion
betweenthetwolaminaeisthelaryngeal
prominence ('Adam'sapple')
• Anglebetweenthetwolaminaeismoreacute
inmen(90°)thaninwomen(120°)
• Superiortothelaryngealprominence,the
superiorthyroidnotch separatesthetwo
laminae
• Superiorthyroidnotchandthelaryngeal
prominencearepalpable landmarksinthe
neck
• Lessdistinctinferiorthyroidnotch inthe
midlinealongthebaseofthethyroidcartilage.
Thyroidcartilage
• Themedialsurfaceoftheinferiorhornhasafacet
forarticulationwiththecricoidcartilage;
• Thesuperiorhornisconnectedbya ligamentto
theposteriorendofthegreaterhornofthehyoid
bone.
• Lateralsurfaceoflaminaismarkedbyaridge(the
obliqueline),whichcurvesanteriorlyfromthe
baseofthesuperiorhorntotheinferiormarginof
thelamina.
• Endsoftheobliquelineareexpandedtoform
superior andinferiorthyroidtubercles
• Theobliquelineisasiteofattachmentforthe
extrinsicmuscles ofthelarynx(sternothyroid,
thyrohyoid,andinferiorconstrictor).
Epiglottis
• Isa'leaf-shaped'cartilageattachedbyitsstem
totheangleofthethyroidcartilage
• Projectsposterosuperiorlyfromitsattachment
tothethyroidcartilage.
• Theattachmentisviathethyro-epiglottic
ligament inthemidlinebetweenthelaryngeal
prominenceandtheinferiorthyroidnotch
• Theuppermarginoftheepiglottisisbehind
thepharyngealpartofthetongue.
• Theinferiorhalfoftheposteriorsurfaceofthe
epiglottisisraisedslightlytoformanepiglottic
tubercle.
Arytenoidcartilages
• Twoarytenoidcartilagesarepyramidshapedcartilageswiththreesurfaces
• Baseofarytenoidcartilage andanApex
ofarytenoidcartilage
• The base ofarytenoidcartilageis
concaveandarticulateswiththefaceton
thesuperolateralsurfaceofthecricoid
cartilage;
• Theapexofarytenoidcartilage
articulateswithacorniculatecartilage;
• Themedialsurface ofeachcartilage
facestheother;
Arytenoidcartilages
• Theanterolateralsurface hastwo
depressions,separatedbyaridge,for
muscle(vocalis) andligament
(vestibularligament) attachment.
• Theanteriorangleofthebaseof
arytenoidcartilageiselongatedintoa
vocalprocess towhichthevocal
ligament isattached
• Thelateralangleissimilarly
elongatedintoamuscularprocess for
attachmentoftheposteriorand
lateralcrico-arytenoidmuscles.
CorniculateandCuneiform
• Thecorniculatecartilagesaretwosmall
conicalcartilages
• Basesarticulatewiththeapicesofthe
arytenoidcartilages
• Theirapicesprojectposteromedially
towardseachother.
• TheCuneiform aretwosmallclubshapedcartilages
• Lieanteriortothecorniculatecartilages
• Suspendedinthepartofthefibroelastic
membranethatattachesthearytenoid
theepiglottis.
Ligaments
Extrinsicligaments
• Thyrohyoidmembrane
• Hyo-epiglotticligament
• Cricotrachealligament
Thyrohyoidmembrane
• Toughfibroelasticligamentthatspans
betweenthesuperiormarginofthe
thyroidcartilagebelowandthehyoid
bone
• Attachedtothethyroidlaminaeand
adjacentanteriormarginsofthe
superiorhorns
• Ascendsmedialtothegreaterhornsand
posteriortothebodyofthehyoidbone
toattachtothesuperiormarginsof
thesestructures.
• Anaperture inthelateralpartofthe
thyrohyoidmembraneoneachsideis
forthesuperiorlaryngealarteries,
nerves,andlymphatics
Thyrohyoidmembrane
• Theposteriorbordersofthe
thyrohyoidmembraneare
thickenedtoformthelateral
thyrohyoidligaments.
• Alsothickenedanteriorlyinthe
midlinetoformthemedian
thyrohyoidligament.
• Occasionally,thereisasmall
cartilage(triticealcartilage)in
eachlateralthyrohyoidligament.
Extrinsicligaments
• Cricotrachealligament runs
fromthelowerborderofthe
cricoidcartilagetothe
adjacentupperborderofthe
firsttrachealcartilage.
• Thehyo-epiglotticligament
extendsfromthemidlineof
theepiglottis,
anterosuperiorlytothebody
ofthehyoidbone.
Intrinsicligaments
• Thefibro-elasticmembraneoflarynxlinkstogether
thecartilagesandcompletesthearchitectural
frameworkofthelaryngealcavity
• Itiscomposedoftwoparts-alowercricothyroid
ligament andanupperquadrangularmembrane.
Cricothyroidligament
• Cricovocalmembraneorcricothyroidmembrane
• Attachedtothearchofcricoidcartilageandextends
superiorly
• Endinafreeuppermargin withinthespaceenclosed
bythethyroidcartilage
• Upperfreemarginattaches:
• Anteriorly tothethyroidcartilage;
• Posteriorly tothevocalprocesses ofthearytenoid
cartilages.
• Thefreemarginisthickenedtoformthevocal
ligament,whichisunderthevocalfold (true 'vocal
cord')ofthelarynx.
• Thecricothyroidligamentisalsothickenedanteriorly
toformamediancricothyroidligament
• Inemergencysituations,themediancricothyroid
ligamentcanbeperforatedtoestablishanairway
Quadrangularmembrane
• Runsbetweenthelateralmarginofthe
epiglottisandtheanterolateralsurfaceof
thearytenoidcartilage
• Attachedtothecorniculatecartilage
• Freeuppermarginandafreelower
margin
• Freelowermargin isthickenedtoform
thevestibularligament underthe
vestibularfold (false 'vocalcord')
Quadrangularmembrane
• Vestibularligamentis
separatedfromthevocal
ligamentbelowbyagap
• Whenviewedfromabovethe
vestibularligamentislateral
tothevocalligament
CartilageandLigaments
Laryngealjoints
Cricothyroidjoints
• Betweentheinferiorhornsofthethyroid
cartilageandthecricoidcartilage,are
synovial
• Surroundedbyacapsuleandisreinforced
byassociatedligaments
• Enablethethyroidcartilagetomove
forwardandtiltdownwards onthe
cricoidcartilage
• Forwardmovementanddownward
rotationofthethyroidcartilageeffectively
lengthensandputstensiononthevocal
ligaments
Crico-arytenoidjoints
• Betweenarticularfacetsonthe
superolateralsurfacesofthe
cricoidcartilageandthebasesof
thearytenoidcartilages
• Enablethearytenoidcartilagesto
slideawayortowardseachother
andtorotate
• Thevocalprocessespivoteither
towardsorawayfromthe
midline.
• Thesemovementsabductand
adductthevocalligaments
Cavityofthelarynx
Laryngealcavity
• Thecentralcavityofthelarynxis
tubularinshapeandislinedby
mucosa
• Supportisprovidedbythefibroelasticmembraneoflarynxandby
thecartilagestowhichitis
attached.
• Thesuperiorapertureofthecavity
(laryngealinlet) opensintothe
anterioraspectofthepharynxjust
belowandposteriortothetongue
• laryngealinletisoblique and
pointsposterosuperiorly
laryngealinlet
• Anteriorborderisformedby
mucosacoveringthesuperior
marginoftheepiglottis
• Lateralbordersareformedby
mucosalfolds(aryepiglotticfolds),
• Posteriorborderinthemidlineis
formedbyamucosalfoldthat
formsadepression(interarytenoid
notch)betweenthetwo
corniculatetubercles
• Aryepiglotticfolds
• Enclosethesuperiormargins
ofthequadrangular
membranesandadjacentsoft
tissues
• Twotuberclesonthemore
posterolateralmarginside
markthepositionsofthe
underlyingcuneiformand
corniculate cartilages;
Inferioropening
• Inferioropeningofthelaryngeal
cavityiscontinuouswiththe
lumenofthetrachea
• Completelyencircledbythecricoid
cartilage
• Horizontalinpositionunlikethe
laryngealinlet
• Theinferioropeningis
continuouslyopenwhereasthe
laryngealinletcanbeclosedby
downwardmovementofthe
epiglottis
Divisionintothreemajorregions
• Thevestibularandvocalfolds,
divideitintothreemajorregionsthevestibule,amiddlechamber,
andthe infraglotticcavity
• Thevestibule istheupper
chamberofthelaryngealcavity
betweenthelaryngealinletand
thevestibularfolds
• Vestibularfoldsenclosethe
vestibularligamentsand
associatedsofttissues;
Divisionintothreemajorregions
• Themiddlepart ofthelaryngeal
cavityisverythinandisbetween
thevestibularfoldsaboveandthe
vocalfoldsbelow
• Vocalfoldsenclosethevocal
ligamentsandrelatedsofttissues
below.
• Theinfraglotticspace isthemost
inferiorchamberandisbetween
thevocalfoldsandtheinferior
openingofthelarynx;
VocalFolds
• Consistof:
• Vocalligament
• Mucousmembrane(stratifiedsquamous)
• Vocalismuscle
• Nosubmucosa
• Nobloodvessels(whiteincolor)
• Oneachsideextendbetweenthevocal
processofthearytenoidandthebackofthe
anteriorlaminaofthyroid.
• Longerinmalewhichcausethedifferenceof
thepitchofthevoicebetweengenders
Vestibularfolds
• Falsevocalcords
• Vestibularfoldsenclosethe
vestibularligamentsand
associatedsofttissues
• Vascularised(redincolor)
• Fixedandnotmovableunlike
thevocalcord
• Superiortothevocalcord
Laryngealventriclesandsaccules
• Oneachside,themucosaofthe
middlecavitybulgeslaterallythrough
thegapbetweenthevestibularand
vocalligamentstoproducealaryngeal
ventricle
• Tubularextensionofeachventricle
(laryngealsaccule)projects
anterosuperiorlybetweenthe
vestibularfoldandthyroidcartilage
• Withinthewallsoftheselaryngeal
sacculesarenumerousmucousglands.
• Mucus secretedintothesaccules
lubricatesthevocalfolds.
Rimavestibuliandrimaglottidis
• Rimavestibuli isatriangular-shaped
openingbetweenthetwoadjacent
vestibularfolds attheentrancetothe
middlechamber
• Apexoftheopeningisanteriorandits
baseisposterior
• TheRimaglottidisisformedbythevocal
folds(truevocalcords) andadjacent
mucosa-coveredpartsofthearytenoid
cartilages
Rimavestibuliandrimaglottidis
• Rimaglottidisopeningseparatesthe
middlechamberabovefromthe
infraglotticcavity
• Thebaseofitisformedbythefoldof
mucosa(interarytenoidfold)atthe
bottomoftheinterarytenoidnotch
• Rimaglottisisthenarrowestpartof
thelaryngealcavity
• Boththerimaglottidisandtherima
vestibulicanbeopenedandclosedby
movementofthearytenoidcartilages
andassociatedmembranes.
Muscles
Intrinsicmuscles
• Adjusttensioninthevocalligaments,
• Openandclosetherimaglottidis,
• Controltheinnerdimensionsofthevestibule,
• Closetherimavestibuli
Cricothyroidmuscles
• Fan-shapedmuscles
• Attachedtotheanterolateralsurfaces
ofthecricoidcartilageandexpand
superiorlyandposteriorlytoattachto
thethyroidcartilage
• Eachmusclehasanobliquepartanda
straightpart:
• Theobliquepart runsinaposterior
directionfromthearchofthecricoid
totheinferiorhornofthethyroid
cartilage
• Thestraightpart runsmorevertically
fromthearchofthecricoidtothe
posteroinferiormarginofthethyroid
lamina
Cricothyroidmuscles
• Pullthethyroidcartilageforwardand
rotate itdownrelativetothecricoid
cartilage
• TheseactionsTensesvocalcords
• Aretheonlyintrinsicmusclesinnervated
bythesuperiorlaryngealbranches ofthe
vagusnerves
• Allotherintrinsicmusclesareinnervated
bytherecurrentlaryngealbranches of
thevagusnerves
Posteriorcrico-arytenoidmuscles
• Thereisarightandaleftposterior
crico-arytenoid
• Thefibersofeachmuscleoriginate
fromtheBackofcricoidcartilage,
andrunsuperiorlyandlaterallyto
themuscularprocessesofthe
arytenoidcartilage
• Abductsthevocalcords by
rotatingarytenoidcartilage
• Innervatedbytherecurrent
laryngealbranchesofthevagus
nerves
Lateralcrico-arytenoidmuscles
• Muscleoneachsideoriginates
fromtheUpperborderofcricoid
cartilage,andrunsposteriorlyand
superiorlytoinsertonthe
muscularprocessofthearytenoid
• Adductsthevocalcords by
internallyrotatingarytenoid
cartilage
• Innervatedbytherecurrent
laryngeal
Transversearytenoid
• OriginatesfromBackand
medialsurfaceofarytenoid
cartilageandinsertinthe
Backandmedialsurfaceof
oppositearytenoidcartilage
• Closesposteriorpartofrima
glottidis byapproximating
arytenoidcartilages
• Recurrentlaryngealnerve
Thyroarytenoid(vocalis)
• FromtheInnersurfaceof
thyroidcartilagetothe
Arytenoidcartilage
• Relaxesvocalcords
• Recurrentlaryngealnerve
Obliquearytenoid
• FromtheMuscularprocess
ofarytenoidcartilagetothe
Apexofoppositearytenoid
cartilage
• Narrowstheinlet by
bringingthearyepiglottic
foldstogether
• Recurrentlaryngealnerve
Thyroepiglottic(aryepiglotticmuscles)
• FromtheMedialsurfaceof
thyroidcartilagetothe
Lateralmarginofepiglottis
andaryepiglotticfold
• Widenstheinlet bypulling
thearyepiglotticfoldsapart
• Recurrentlaryngealnerve
Extrinsicmuscles
•
•
•
•
•
Elevatorsofthelarynx:
1.Digastricmuscle
2.Stylohyoid
3.Myelohyoid
4.Geniohyoid
• Thelarynxmovesupinswallowingbythesemusclesassistedby:
• Stylopharngeus,Salpingo-pharngeus,AndPalatopharngeus.
•
•
•
•
Depressorsofthelarynx:
1.Sternothyroid
2.Sternohyoid
3.Omohyoid
MusclesandCavity
Functionofthe
larynx
Respiration
• Duringquietrespiration,the
laryngealinlet,vestibule,rima
vestibuli,andrimaglottidisare
open
• Duringforcedinspirationthe
arytenoidcartilagesarerotated
laterally,mainlybytheactionof
theposteriorcrico-arytenoid
muscles.
• Asaresult,thevocalfoldsare
abducted,andtherimaglottidis
widens intoarhomboidshape,
effectivelyincreasesthediameter
ofthelaryngealairway.
Phonation
• Whenphonating,thearytenoid
cartilagesandvocalfoldsare
adducted andairisforcedthrough
theclosedrimaglottidis
• Thisactioncausesthevocalfolds
tovibrate againsteachotherand
producesounds
• Canthenbemodifiedbytheupper
partsoftheairwayandoralcavity
• Tension inthevocalfoldscanbe
adjustedbythevocalisand
cricothyroidmuscles.
Effortclosure
• Effortclosureofthelarynxoccurs
whenairisretainedinthethoracic
cavitytostabilizethetrunk
• Forexampleduringheavylifting,
oraspartofthemechanismfor
increasingintra-abdominal
pressure
• Therimaglottidisiscompletely
closed,asistherimavestibuliand
lowerpartsofthevestibule
• Theresultistocompletelyand
forcefullyshuttheairway.
Swallowing
• Duringswallowing,therimaglottidis,therima
vestibuli,andvestibuleareclosed andthe
laryngealinletisnarrowed
• Thelarynxmovesupandforward
• Thisactioncausestheepiglottis toswing
downward toeffectivelynarroworclosethe
laryngealinlet
• Theupandforwardmovementofthelarynx
alsoopenstheesophagus
• Alltheseactionstogetherpreventsolidsand
liquidsfromentryintotheairway
BloodSupply
Arteries
• Themajorbloodsupplytothe
larynxisbythesuperiorand
inferiorlaryngealarteries
• Thesuperiorlaryngealartery
originatesfromthesuperior
thyroidbranchoftheexternal
carotidartery,
• Accompaniestheinternalbranch
ofthesuperiorlaryngealnerve
throughthethyrohyoidmembrane
toreachthelarynx.
Arteries
• Theinferiorlaryngealartery
originatesfromtheinferiorthyroid
branchofthethyrocervicaltrunk
ofthesubclavianartery
• Togetherwiththerecurrent
laryngealnerve,ascendsinthe
groovebetweentheesophagus
andtrachea
• Itentersthelarynxbypassing
deeptothemarginoftheinferior
constrictormuscleofthepharynx;
Veins
• Veinsdrainingthelarynx
accompanythearteries:
• Superiorlaryngealveins
drainintosuperiorthyroid
veins,whichinturndrain
intotheinternaljugular
veins
• Inferiorlaryngealveins drain
intoinferiorthyroidveins,
whichdrainintotheleft
brachiocephalicveins.
Lymphatics
• Lymphaticsdrainregionsaboveandbelowthevocalfolds:
• Thoseabovethevocalfoldsfollowthesuperiorlaryngeal
arteryandterminateindeepcervicalnodes
• Thosebelowthevocalfoldsdrainintodeepnodes
associatedwiththeinferiorthyroidartery
• Orwithnodesassociatedwiththefrontofthecricothyroid
ligamentoruppertrachea.
Innervations
Superiorlaryngealnerves
• Thesuperiorlaryngealnerves
originatefromtheinferiorvagalganglia
highintheneck
• Theydescendmedialtotheinternal
carotidarteryanddivideintointernal
andexternalbranches abovethehyoid
bone
• Theexternalbranch(external
laryngealnerve)descendsalongthe
lateralwallofthepharynxtosupply
theinferiorconstrictorofthepharynx
andendsbysupplyingthecricothyroid
muscle;
Superiorlaryngealnerves
• Theinternallaryngealnerve
passesanteroinferiorlyto
penetratethethyrohyoid
membrane
• Internalnerveismainly
sensory andsuppliesthe
laryngealcavitydowntothe
levelofthevocalfolds.
Recurrentlaryngealnerves
• Therecurrentlaryngeal
nervesare:
• Sensorytothelaryngeal
cavitybelowthelevelofthe
vocalfolds;
• Motortoallintrinsicmuscles
ofthelarynxexceptforthe
cricothyroid.
Recurrentlaryngealnerves
• Theleft recurrentlaryngealnerve
originatesinthe thoraxwhereas
theright recurrentlaryngealnerve
originatesintherootoftheneck
• Bothnervesgenerallyascendin
theneckinthegroovebetween
theesophagusandtrachea
• Enterthelarynxdeeptothe
marginoftheinferiorconstrictor
Relationsofthelarynx
• Oneachside:
• Carotidsheath(contents),and
laterallobeofthethyroidgland
• Posterior:
• Pharynxandtherightrecurrent
laryngealnerve
• Anterior:
• Skin,fasciaanditscontents,4
infra-hyoidmuscles
Clinicalnotes
Thyroidoctomy
• Sectioningoftheexternallaryngeal nervemight
happeninthyroidoctomy
• Duetothecloserelationshipbetweentheexternal
laryngealnerveandthesuperiorthyroidartery.
• Producesweaknessinvoice sincethevocalcords
cannotbetensed(criciothyroidM.).
SectionoftheRecurrentlaryngeal
nerve
• 1.Unilateralcompletesection:
• Onevocalfold(ontheaffected
side)inthepositionmidway
betweenabductedand
adducted
• Speechnotgreatlyaffectedas
theothervocalcord
compensatefortheaction.
SectionoftheRecurrentlaryngeal
nerve
• 2.Bilateralcomplete
section:
• Bothvocalfoldsinposition
midwaybetweenabducted
andadducted
• Breathingisimpairedsince
therimaglottisispartially
closeandspeechislost
SectionoftheRecurrentlaryngeal
nerve
• 3.Unilateralpartialsection:
• Thisresultsinagreaterdegreeof
paralysisoftheabductormuscles
thanoftheadductor.
• Thereforetheaffectedcordisin
theadductedmidlineposition
• Hoarsenessofthevoice(theother
vocalfoldcompensatestheaction)
SectionoftheRecurrentlaryngeal
nerve
• 4.Bilateralpartialsection:
• Thisresultsinbilateralparalysisofthe
abductormuscles
• Thereforethevocalfoldsare
adductedtogetherinthemidline
• Acutebreathlessness(Dyspnea)and
stridorfollow
• Leadtosuffocationsotracheostmyis
necessary
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