Anatomy of larynx

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LARYNX IS SOUND GENERATOR; SOUNDS ARE EXTENSIVELY MODIFIED IN SPEECH AND SINGING BY RESONANCE OF PHARYNX, NASAL CAVITY, ORAL CAVITY

oLARYNXLARYNX

oCartilages connected byCartilages connected byomembranes and ligaments,membranes and ligaments,omoved by musclesmoved by musclesoFunctions: 1)Functions: 1) Sound Soundoproductionproductiono2) 2) Closure of RespiratoryClosure of RespiratoryoSystem - allows increase inSystem - allows increase inoAbdominal PressureAbdominal Pressure

olarynxlarynx

otracheatrachea


Situated at the upper end of tracheaOpposite 3rd – 6th cervical vertebrae (men)Higher in women and children44 x 43 x 36 mm / 36 x 41 x 26 mmInfants – smaller, narrow lumen, funnel-shaped, higher,

cartilages softer & collapse easily At puberty AP diameter in males doubles


The Anatomy of the Larynx

oFigure 23.4Figure 23.4opgmedicalworld.compgmedicalworld.com


I. LARYNX: CARTILAGES

oA. THYROID CARTILAGE A. THYROID CARTILAGE – – Shield shapedShield shapedo- has Sup. & Inf. Horns from upper & lower edges- has Sup. & Inf. Horns from upper & lower edges

oLaryngealLaryngealoProminenceProminence

oSup.Sup.oHornsHorns

oInf.Inf.oHornsHorns

o- - Inf. horns make synovial hinges joint with Cricoid Cartilage;Inf. horns make synovial hinges joint with Cricoid Cartilage;

o- Laryngeal Prominence = Adam’s Apple, more prominent in- Laryngeal Prominence = Adam’s Apple, more prominent inomalesmales


Laryngeal cartilages

THYROID CARTILAGEShield like , longestMeet at midline – Thyroid notch ( angle 90 /120 degrees)Fused anterior border – laryngeal prominenceIntrathyroid cartilage separates the 2 laminae in childhoodPosteriorly the laminae divergeSuperior and inferior cornua


Superior cornu – long, narrow, curves upwards, backwards and medially, lateral thyroid ligament attached to tipInferior cornu – shorter, thicker, curves downwards & medially, oval articular facetOblique line – from superior thyroid tubercle (anterior to root of superior horn ) to inferior thyroid tubercle (on lower border of lamina) > site of attachment of muscles


Inner aspect smooth, mucosa coveredThyroepiglottic ligament, vestibular and vocal ligaments, thyroarytenoid, thyroepiglottic & vocalis musclesSuperior border – thyrohyoid ligament

Inferior border – cricothyroid ligament



LARYNX: CARTILAGES

oB. B. CRICOIDCRICOIDocompletecompleteoring ofring ofocartilage hascartilage hasonarrow Arch ant.,narrow Arch ant.,obroad Lamina post.broad Lamina post.

oCricoid meansCricoid meansoSignet RingSignet Ring

oLamina ofLamina ofocricoidcricoid

oArch ofArch ofocricoidcricoid

oANT .VIEWANT .VIEW oPOST .VIEWPOST .VIEW


CRICOID CARTILAGE :-Only complete cartilaginous ring (signet)Forms most of the posterior wall of larynxBroad quadrilateral lamina posteriorly and narrow arch anteriorlyArticular facet for inferior cornu at junction of arch and laminaArticular facets for arytenoids on laminaVertical ridge on midline for attachment of longitudinal muscles of the oesophagus



LARYNX: CARTILAGESArytenoid - 2

pyramidal shapedcartilages abovelamina – havesynovial joints withCricoid permitSwivel = RotateSliding = Ab/AdductD. Corniculate -nodules abovearytenoids inaryepiglottic foldsE. Cuneiform - rodshaped, abovecorniculate cartilages

oCuneiformCuneiformoCorniculateCorniculate

oArytenoidArytenoid


ARYTENOID CARTILAGES :-Placed on upper & lateral border of laminaThree sided pyramid Vocal process – vocal foldMuscular process – posterior & lateral cricoarytenoidAnterolateral surface – vestibular ligament, vocalis & lateral cricoarytenoid musclesMedial surface – mucosa covered


Apex – articulates with corniculate cartilagePosterior surface – covered by transverse arytenoidBase – concave, articular facet Synovial joint with lax capsular ligamentRotatory and medial & lateral gliding movement.


CORNICULATE (Wrisberg) – Small, conicalElastic fibrocartilageSynovial joint or fused with apices of arytenoidSituated in the aryepiglottic fold

CUNEIFORM (Santorini) –Small, elongatedElastic fibrocartilageLateral to corniculate



LARYNX: CARTILAGES

oF. EPIGLOTTISF. EPIGLOTTIS

o- leaf shaped- leaf shapedocartilagecartilageoposterior to rootposterior to rootoof tongueof tongueo- connected to- connected toobody of hyoidbody of hyoidoand post side ofand post side ofothyroid cartilagethyroid cartilage

oPOST. VIEWPOST. VIEW


EPIGLOTTIS :-Thin, leaf-like, elastic fibrocartilageProjects upward behind tongue & hyoidNarrow stalk attached below thyroid notch by thyroepiglottic ligamentUpper part directed upwards & mediallySuperior margin freeSides attached to arytenoid catilage by aryepiglottic fold.tubercle in the lower part of posterior surface


Pits on cartilage – mucous glandsAnterior surface – mucosa coveredMedian and lateral glossoepiglottic foldHyoepiglottic ligamentPre-epiglottic space – between epiglottis & thyrohyoid membrane, fat filled spaceNeonates & infants – omega shaped, long, floppy


The Glottis

oFigure 23.5a, Figure 23.5a, bb



Calcification – Elastic fibrocartilage – epiglottis, corniculate,

cuneiform & apices of arytenoid – not calcified Hyaline cartilage – calcification by late teens /

early twenties Thyroid – starts at inferior cornu, rim is calcified

leaving a translucent window till old age Calcification of posterior part of lamina &

arytenoid Arytenoid – body & muscular process – 4th

decade, vocal process not calcified


Ligaments of the larynxExtrinsic ligaments – Connect cartilages to hyoid and tracheaThyrohyoid Membrane :-

Between upper border of thyroid & upper border of posterior surface of body and greater cornu of hyoidFibroelastic tissue – condensed anteriorly to form median thyrohyoid ligament & posteriorly lateral thyrohyoid ligamentsCartilago triticea – small nodulePierced by internal branch of superior laryngeal nerve & superior laryngeal vessels


Intrinsic ligaments

Connect the cartilages to each other.Internal frameworkQuadrilateral Membrane :-

Border of epiglottis and arytenoid cartilageUpper margin forms framework of aryepiglottic foldLower margin – vestibular ligament which underlies the vestibular fold or false cords


Cricotracheal ligament – lower border of cricoid to 1st tracheal ring

Hyoepiglottic ligament – epiglottis to back of body of hyoid


Conus Elasticus:-Cricovocal ligamentAttached below to the upper border of cricoid cartilageAbove between midpoint of laryngeal prominence to vocal process of arytenoidFree upper border forms vocal ligament , framework of vocal fold / true cordAnteriorly thickened to form cricothyroid ligament


II. LIGAMENTS OF LARYNX

o1. Thyrohyoid Membrane1. Thyrohyoid Membraneolinks larynx to hyoid;links larynx to hyoid;oMedian ThyrohyoidMedian ThyrohyoidoLigament - thickenedLigament - thickenedomidline partmidline parto2. Cricothyroid Membrane2. Cricothyroid Membraneolinks thyroid to cricoid;links thyroid to cricoid;oMedian CricothyroidMedian CricothyroidoLigament - thickenedLigament - thickenedomidline partmidline parto3. Cricotracheal ligament3. Cricotracheal ligamentolinks Cricoid to firstlinks Cricoid to firstotracheal cartilagetracheal cartilage

oMedianMedianoThyrohyoidThyrohyoidoLigamentLigament

oMedianMedianoCricothyroidCricothyroidoLigamentLigament


STRUCTURAL LIGAMENTS

oEpiglottisEpiglottis

o4. Quadrangular4. QuadrangularoMembrane Membrane linkslinksoArytenoidArytenoidoTo epiglottisTo epiglottisoArytenoidArytenoid




oArytenoidArytenoidocartilagecartilage

oAryepiglotticAryepiglotticoFolds - overlieFolds - overlieoQuadrangularQuadrangularomembranemembrane



o5. Thyroepiglottic5. ThyroepiglotticoLigamentLigamentolinks epiglottis tolinks epiglottis toothyroid cartilagethyroid cartilage

oNOSENOSE

oSUPERIORSUPERIORoVIEWVIEWoABOVEABOVEoLARYNXLARYNX



oLower freeLower freeoedge ofedge ofoQuadrangularQuadrangularomembrane ismembrane isoCalledCalledoVestibularVestibularoLigament; deepLigament; deepoto Vestibularto Vestibularo(False Vocal)(False Vocal)oFoldsFolds

oCORONALCORONALoSECTIONSECTIONoTHROUGHTHROUGHoLARYNXLARYNX

otracheatrachea


B. FUNCTIONAL LIGAMENTS

oFunctional ligaments:Functional ligaments:oConus Elasticus Conus Elasticus --oVibrating lips that ariseVibrating lips that ariseofrom entire upper edge offrom entire upper edge ofoarch of cricoidarch of cricoidoAttach: ant. to Thyroid,Attach: ant. to Thyroid,opost. to Arytenoidpost. to Arytenoid

oRima Glottidis -Rima Glottidis -oOpening BetweenOpening BetweenoVocal ligamentsVocal ligaments

oVocalVocaloLigaments -Ligaments -oUpper freeUpper freeoEdgesEdgesoDeep toDeep tooVocalVocaloFoldsFolds

oNOSENOSE


FUNCTIONAL LIGAMENTS

o(In Coronal Section)(In Coronal Section)

oConus Elasticus Conus Elasticus oFunctionsFunctions

o1) Sound Production – Vibrate1) Sound Production – Vibrateolike lips of trumpet player;like lips of trumpet player;o2) Close Rima Glottidis stops2) Close Rima Glottidis stopsooutflow air, upward movement ofoutflow air, upward movement ofodiaphragm - when contractdiaphragm - when contractoabdominal muscle pressureabdominal muscle pressureoincreases in abdominal cavity;increases in abdominal cavity;ooccurs in childbirth, defecationoccurs in childbirth, defecation


III. MUSCLES OF LARYNX A. Extrinsic muscles (ex. hyoid muscles) {joins the larynx to other structures} – Move whole larynx as in swallowing 1) changes tension in vocal cords. 2)change in pitch:- increase in tension>> raises pitch.

B.intrinsic muscles { connecting the laryngeal cartilages} 1)decreased tension lowers pitch 2) open & close Rima Glottidis

o1) CRICOTHYROID M. -1) CRICOTHYROID M. -oTensesTensesoVocal LigamentVocal LigamentoIncreasing PitchIncreasing Pitch

oSlackSlack oTenseTense


Intrinsic muscles and extrinsic musclesAll the Intrinsic muscles of the larynx are paired except tranverse inter arytenoid

muscle.These are:1)abductors of vocal cords=posterior crico-arytenoid.2)adductors of vocal cords=lateral crico-

arytenoid,interarytenoid,thyroarytenoid,cricothyroid.3)tensors & adductors of vocal cords=cricothyroid,vocalis & thyro-arytenoid.4)openers of the laryngeal inlet=thyroepiglottic5)closers of the laryngeal inlet=interarytenoid & aryepiglottic.

Extrinsic musclesThese are divided into two groups:1)cervical muscles:A)suprahyoid muscles,which act as elevators of the larynxB)infrahyoid muscles(strap muscles),which acts as depressors of the larynx.2)pharyngeal muscles including the inferior constrictor muscle.opgmedicalworld.compgmedicalworld.com



MUSCLES OF LARYNX

o5) ARYEPIGLOTTIC5) ARYEPIGLOTTICoMUSCLEMUSCLEoPulls epiglottis downPulls epiglottis downoduringduringoswallowingswallowingo- Covers inlet to larynx- Covers inlet to larynxo- Not necessary in- Not necessary inoadult humansadult humans


MUSCLES OF LARYNX

o2)THYROARYTENOID2)THYROARYTENOIDoMUSCLE -MUSCLE -

oRelaxesRelaxesoVocal LigamentsVocal LigamentsoDecreases pitchDecreases pitch

oNOSENOSE


MUSCLES OF LARYNX

o5) ARYTENOID5) ARYTENOIDo(Transverse and(Transverse andooblique arytenoid) -oblique arytenoid) -oAdduct vocal foldsAdduct vocal foldso4) LATERAL CRICOARYTENOID4) LATERAL CRICOARYTENOIDo- Adduct- Adductovocal foldsvocal foldso3) POSTERIOR 3) POSTERIOR CRICOARYTENOIDCRICOARYTENOIDo– – AbductsAbductsovocal foldvocal fold

oAdduct closes rima glottidisAdduct closes rima glottidisoAbduct opens rima glottidisAbduct opens rima glottidis

oArytenoidsArytenoidsoCan rotate/slideCan rotate/slideopgmedicalworld.compgmedicalworld.com




Cavity of the larynx

Divided by vestibular & vocal folds into 3 compartments

oSuperior vestibuleoVentricle / sinus of the larynxoSubglottic space


Pre-epiglottic space (Space of Boyer) :-• Anterior – thyrohyoid ligament & hyoid • Posterior – epiglottis• Superior – hyoepiglottic ligament• Lateral – continuous with paraglottic spacePara-glottic space:-• Lateral – thyroid cartilage• Medial – conus elasticus & quadrangular membrane• Posterior – anterior reflection of PFS mucosa


LARYNGEAL VENTRICLELaryngeal sinusElongated recess between vestibular & vocal foldsOpens through a narrow slit into middle segment of larynxFrom anterior part a pouch extends between vestibular folds & inner surface of thyroid cartilage - sacculeMucous membrane lining the saccule contains numerous mucous glands


Respiratory System Organization

oFigure 15-4(a)Figure 15-4(a)

The Anatomy of the Larynx and Vocal Cords


LARYNGOSCOPE VIEW OF LARYNX

oTRUE VOCAL FOLDSTRUE VOCAL FOLDS

oFALSE VOCAL FOLDSFALSE VOCAL FOLDS

oARYEPIGLOTTICARYEPIGLOTTICoFOLDFOLD



LARYNGOSCOPE VIEW OF LARYNX

oAnt.Ant.oTongueTongue

oVocal FoldsVocal Foldso(true vocal(true vocalofolds)folds)


oPost.Post.

oVestibular Vestibular FoldsFoldso(false vocal(false vocalofolds)folds)

ovocal foldsvocal foldsoadducted whenadducted whenotalking or singingtalking or singing



Vestibular folds

Thick, pink folds of mucous membraneEncloses the vestibular ligamentAnterior attachment is to angle of thyroid cartilage, inferior to epiglottisPosterior attachment to anterolateral surface of arytenoid cartilage superior to vocal process


Vocal foldExtends from the middle of angle of the thyroid cartilage to vocal process of arytenoid cartilageLayered structure – mucosa & muscleMucosa – epithelium : stratified squamousLamina propria – superficial, intermediate and deep layers Superficial – loose fibrous substance : Reinke’s space – vibrates maximum during phonation


Intermediate layer – elastic fibresDeep layer – collagenous fibresIntermediate & deep layers form vocal ligamentDeep to vocal ligament – vocalis muscleAnterior and posterior macula flava protect vocal fold from damage due to vibration


TERMS ASSOCIATED WITH LARYNX

oVESTIBULE VESTIBULE - inlet above false- inlet above falseovocal foldsvocal folds

oVESTIBULAR (FALSE VOCAL)VESTIBULAR (FALSE VOCAL)oFOLDS FOLDS - overlie vestibular- overlie vestibularoligamentsligaments

oVENTRICLE VENTRICLE - area between true- area between trueoand false vocal folds; lateraland false vocal folds; lateraloextension is Laryngealextension is LaryngealoSinusSinus

oVOCAL (TRUE VOCAL) FOLDSVOCAL (TRUE VOCAL) FOLDSo- overlie vocal ligaments- overlie vocal ligaments

oNOSENOSE



oARYEPIGLOTTICARYEPIGLOTTIC

oFOLDS FOLDS - Overlie- OverlieoUpper Edge ofUpper Edge ofoQuadrangularQuadrangularomembranemembrane

oPiriformPiriformoRecess Recess - lateral- lateraloto laryngeal inletto laryngeal inlet



oVALLECULAEVALLECULAEo-depressions (2)-depressions (2)oBetween Med & LatBetween Med & LatoGlossoepiglotticGlossoepiglotticoFoldsFoldso-Food/objects-Food/objectsoLodge inLodge inoValleculaeValleculae

oValleculaVallecula

oMedialMedialoGlossoepiglotticGlossoepiglotticofoldfold oLateralLateral

oGlosso-Glosso-oEpiglotticEpiglottic


Mucous membranes of the larynxClosely attached over the posterior surface of the epiglottis, corniculate, cuneiform & vocal ligamentLoosely attached elsewhere – swollen Epithelium – squamous / ciliated columnar or transitionalNumerous mucous glands except at the vocal folds ( mucous from saccule )Few taste buds on posterior surface of epiglottis and AEF


Multilayered vibrator Cover – epithelium and superficial layer of lamina propriaTransition – intermediate & deep layerBody – vocalis muscleBlood vessels run parallel to the edge




V. NERVES OF LARYNX – Branches of VagusoA. Superior Laryngeal N.A. Superior Laryngeal N.

odivides to -divides to -o1. Internal Laryngeal N.1. Internal Laryngeal N.oGVA Sensory to LarynxGVA Sensory to LarynxoAboveAbove True Vocal FoldsTrue Vocal Folds

o2. External Laryngeal N.2. External Laryngeal N.oSVE Motor to CricothyroidSVE Motor to CricothyroidoB. Recurrent Laryngeal N.B. Recurrent Laryngeal N.

o- GVA Sensory to Larynx- GVA Sensory to LarynxoBelow Below True Vocal FoldsTrue Vocal Foldso- SVE motor to all other- SVE motor to all otheroMuscles of LarynxMuscles of LarynxoGVA=GENERAL VISCERAL AFFERENTGVA=GENERAL VISCERAL AFFERENToSVE=SPECIAL VISCERAL EFFERENTSVE=SPECIAL VISCERAL EFFERENT

oSUP. LARYNG. NSUP. LARYNG. N

oInt. Laryng. N.Int. Laryng. N.

oExt. Laryng. N.Ext. Laryng. N.

oRECURRENTRECURRENToLARYNG. N.LARYNG. N.



NERVES OF LARYNX(CONT.)



Nerve supply

Vagus – superior laryngeal nerve - Recurrent laryngeal nerve

Superior laryngeal arises from the inferior ganglion of the vagus + br. from superior cervical sympathetic ganglionAt level of greater horn of the hyoid divides into external & internal branchesExternal > cricothyroidInternal > pierces thyrohyoid membrane


Divides into upper & lower branches > pierces inferior constrictor > unites with ascending branch of recurrent laryngeal nerve ( Galen’s anastomosis )Recurrent laryngeal nerve –

Right – loops around right subclavian artery Left – Loops around the aortic arch & ligamentum

arteriosum Ascends in the tracheo-esophageal groove


Enters the larynx behind cricotracheal joint Divides into motor & sensory branch Motor – all intrinsic muscles of larynx except cricothyroid Sensory – below the level of vocal folds



VI. LARYNX - ARTERIAL SUPPLY

oSup. Laryngeal A.Sup. Laryngeal A.

ofrom Sup. Thyroidfrom Sup. ThyroidoarteryarteryoInf. Laryngeal A.Inf. Laryngeal A.

ofrom Inf. Thyroidfrom Inf. Thyroidoarteryartery


Blood supplyLaryngeal branch of superior thyroid (br. of external carotid)Laryngeal branch of inferior thyroid (br. of thyrocervical trunk of 1st part of subclavian)Cricothyroid branch of superior thyroidSuperior & middle thyroid vein, facial vein > internal jugularInferior thyroid vein > brachiocephalic veins


VII. LARYNX - LYMPHATICS

oSuperior DeepSuperior DeepoCervical NodesCervical NodesoLarynx above trueLarynx above trueovocal foldsvocal folds

oInferior DeepInferior DeepoCervical Nodes-Cervical Nodes-oLarynx below trueLarynx below trueovocal foldsvocal foldsoVII.VII.

oNote: Mucosa Tightly Attached to vocal foldsNote: Mucosa Tightly Attached to vocal foldsoAnaphylactic Shock Swell Vestibular folds --SuffocationAnaphylactic Shock Swell Vestibular folds --Suffocation


Lymphatic drainage

Separated by vocal fold into upper and lower groupAbove vocal fold -> upper deep cervical nodesBelow vocal fold -> prelaryngeal, pretracheal & lower

deep cervicalVocal folds firmly bound down to vocal ligament ->

relative absence of lymphatics


VIII. OBSTRUCTION OF LARYNX: TRACHEOTOMY open airway to lungs below obstructed larynx

oTracheotomyTracheotomyo- cut between- cut betweeno1st & 2nd or 2nd –1st & 2nd or 2nd –o3rd Tracheal3rd Trachealocartilagescartilages


BLEEDING IS PROBLEM: MIDLINE THYROID VEINS

o1) Sup. Thyroid vein1) Sup. Thyroid veinofollows arteryfollows artery

o2) Middle Thyroid2) Middle Thyroidovein- to Int Jugularvein- to Int Jugularo3) Inf. Thyroid vein3) Inf. Thyroid veinoBoth sides join atBoth sides join atomidline -> L.midline -> L.oBrachiocephalic VeinBrachiocephalic Vein


OBSTRUCTION OF LARYNX: CRICOTHYROTOMY

oCrico-Crico-oThyrotomyThyrotomyoLittle bleedingLittle bleeding

oCricothyroid MembraneCricothyroid MembraneoOBSTRUCTIONOBSTRUCTION


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onasal tractnasal tract

o(hard) palate(hard) palate

ooral tractoral tract

ovelum (soft palate)velum (soft palate)

ovelic portvelic port

otonguetongue

otongue tiptongue tip

opharynxpharynx

oglottisglottis(vocal folds and (vocal folds and

space between vocal cords)space between vocal cords)

ovocal folds (larynx)vocal folds (larynx)o= vocal cords= vocal cords

oalveolar ridgealveolar ridge

olipslips

oteethteeth

oThe Speech Production ApparatusThe Speech Production Apparatus (from Olive, p. 23)(from Olive, p. 23)

oAcoustic Phonetics: AnatomyAcoustic Phonetics: Anatomyo


Acoustic Phonetics: Anatomy

Breathing and Speech

• Duration of expiration in soft speech is 2.4 to 3.5 seconds; maximum value (singers, orators) is 15 to 20 seconds without distress.

• Louder voice requires inhaling more deeply after expiration; also deeper inhalation if followed by longer speech.

• More intense voicing requires greater lung pressure.

• Lung pressure relatively constant throughout an utterance.

• Emphasis in speech: greater tenseness in vocal folds yielding higher F0; greater lung pressure increases airflow (energy).


oAcoustic Phonetics: AnatomyAcoustic Phonetics: Anatomyo o

othe the false vocal foldsfalse vocal folds narrow the narrow the oglottis during swallowing, preventing glottis during swallowing, preventing opieces of food from getting into the pieces of food from getting into the otrachea. trachea.



oPhonationPhonationo

oPhonation is “conversion of potential energy of compressed airPhonation is “conversion of potential energy of compressed airointo kinetic energy of acoustic vibration.”into kinetic energy of acoustic vibration.”o oFor voiced speech:For voiced speech:o

o1.1. Buildup of Pressure: Buildup of Pressure:o air pressure from the lungs pushes against closed vocal foldsair pressure from the lungs pushes against closed vocal foldso so that Pso that Psubglottalsubglottal > P > Poraloral; buildup continues until; buildup continues until

o until Puntil Psubglottalsubglottal – P – Poraloral > elastic recoil force of vocal folds > elastic recoil force of vocal folds

o2.2. Release: Release:o vocal folds forced open by pressure difference;vocal folds forced open by pressure difference;o burst of compressed air hits air in vocal tract, causingburst of compressed air hits air in vocal tract, causingo acoustic shock wave moving along vocal tractacoustic shock wave moving along vocal tracto opgmedicalworld.compgmedicalworld.com

o Acoustic Phonetics: AnatomyAcoustic Phonetics: Anatomyo

o Implications:Implications:

1.1. vocal folds do not open and close because of separate musclevocal folds do not open and close because of separate muscleo movementsmovements

o 2.2. opening and closing is automatic as long as the resting opening and closing is automatic as long as the resting positionposition

o of the vocal folds is (near) closure, and there is sufficient of the vocal folds is (near) closure, and there is sufficient o pressure buildup below vocal foldspressure buildup below vocal folds

o 3.3. Factors governing vocal fold vibration:Factors governing vocal fold vibration:o (a) position of vocal folds (degree of closeness between (a) position of vocal folds (degree of closeness between

folds)folds)o (b) elasticity of vocal folds, depending on position and(b) elasticity of vocal folds, depending on position ando degree of tensiondegree of tensiono (c) degree of pressure drop across vocal folds(c) degree of pressure drop across vocal foldsopgmedicalworld.compgmedicalworld.com


oTypes of phonation Types of phonation o

oquietquietobreathingbreathing

oforcedforcedoinhalationinhalation

onormalnormalophonationphonation

owhisperwhisper



oThe cycle of glottal vibrationThe cycle of glottal vibrationo

o1. folds at rest1. folds at rest o2. muscle2. muscleo contractioncontraction

o3. increase in3. increase ino pressurepressure

o4. forcing folds4. forcing foldso apartapart

o5. “explosion”5. “explosion”o openopen

o6. acoustic6. acoustico shockwaveshockwave

o8. folds close,8. folds close,o goto step goto step (3)(3)

o7. rebound toward7. rebound towardo closureclosure



oThe cycle of glottal vibrationThe cycle of glottal vibration

oclosure to opening, 0 to 2.1 closure to opening, 0 to 2.1 msecmsec

oopening to closure, 2.4 to 4.5 msecopening to closure, 2.4 to 4.5 msec

o((FF00 = 222 Hz) = 222 Hz)



oTypes of phonation Types of phonation o

ovoiceless, whisper, breathyvoiceless, whisper, breathy

ovoiced, creak, glottal stopvoiced, creak, glottal stop



oThe effects of nasalization on vowelsThe effects of nasalization on vowelso

oFigure 4-17. An example of theFigure 4-17. An example of theoeffects of vowel nasalization oneffects of vowel nasalization onothe vowel spectrum. The spectrumthe vowel spectrum. The spectrumoenvelopes of a normal [a] and a heavilyenvelopes of a normal [a] and a heavilyonasalized [a] were plotted… The firstnasalized [a] were plotted… The firstothree formants are labeled in the three formants are labeled in the onormal vowel. In the nasalized vowel,normal vowel. In the nasalized vowel,othere are three local reductions inthere are three local reductions inospectrum level, indicated by “z’s”;spectrum level, indicated by “z’s”;othese are the result of the additionthese are the result of the additionoof anti-resonant zeros to the vocalof anti-resonant zeros to the vocalotract response, due to a wide-opentract response, due to a wide-openovelar port.velar port.


o Acoustic Phonetics: AnatomyAcoustic Phonetics: Anatomyo

o The effects of nasalization on vowels The effects of nasalization on vowels

o Coupling of the oral and nasal tract introduces pole-zero pairsCoupling of the oral and nasal tract introduces pole-zero pairso (resonances & anti-resonances, occurring in pairs) in the spectrum.(resonances & anti-resonances, occurring in pairs) in the spectrum.o The amount of coupling affects the spacing between each poleThe amount of coupling affects the spacing between each poleo and its corresponding zero, as well as their frequency locations.and its corresponding zero, as well as their frequency locations.

1.1. The presence of a pole-zero pair increases the apparent bandwidth The presence of a pole-zero pair increases the apparent bandwidth of the neighboring formants.of the neighboring formants.

2.2. The presence of spectral zero below F1 tends to make the location The presence of spectral zero below F1 tends to make the location of F1 appear slightly higher (50-100 Hz) than it normally wouldof F1 appear slightly higher (50-100 Hz) than it normally would

3.3. If the zero is higher in frequency than its corresponding pole, the net If the zero is higher in frequency than its corresponding pole, the net effect is to reduce the amplitude of higher frequencieseffect is to reduce the amplitude of higher frequencies

o


Phonation

Adduction of vocal folds & adduction and medial rotation of arytenoids

Vocal folds are lengthenedChanges in length & tension control pitchTension in the vocal fold, decrease in subglottic air

pressure & sucking-in-effect of escaping air bring the vocal folds together


Air from subglottis released in small puffsVocal folds thinner at high pitchMucosal wave travels from inferior to superior surfaceSound produced is modified by resonating chambers above & below the larynx Converted to phonemes by articulation of pharynx, tongue, palate, teeth & lips


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Health & Medicine

Anatomy of larynx