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 by
omembranes and ligaments,membranes and ligaments,
omoved by musclesmoved by muscles
oFunctions: 1)Functions: 1) SoundSound
oproductionproduction
o2)2) Closure of RespiratoryClosure of Respiratory
oSystem - allows increase inSystem - allows increase in
oAbdominal PressureAbdominal Pressure
olarynxlarynx
otracheatrachea

Situated at the upper end of trachea
Opposite 3rd
– 6th
cervical vertebrae (men)
Higher in women and children
44 x 43 x 36 mm / 36 x 41 x 26 mm
Infants – 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 CARTILAGEA. THYROID CARTILAGE –– Shield shapedShield shaped
o- has Sup. & Inf. Horns from upper & lower edges- has Sup. & Inf. Horns from upper & lower edges
oLaryngealLaryngeal
oProminenceProminence
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 in
omalesmales

Laryngeal cartilages
THYROID CARTILAGE
Shield like , longest
Meet at midline – Thyroid notch ( angle 90 /120
degrees)
Fused anterior border – laryngeal prominence
Intrathyroid cartilage separates the 2 laminae in
childhood
Posteriorly the laminae diverge
Superior and inferior cornua

Superior cornu – long, narrow, curves upwards,
backwards and medially, lateral thyroid ligament
attached to tip
Inferior cornu – shorter, thicker, curves downwards &
medially, oval articular facet
Oblique 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 covered
Thyroepiglottic ligament, vestibular and vocal ligaments,
thyroarytenoid, thyroepiglottic & vocalis muscles
Superior border – thyrohyoid ligament
Inferior border – cricothyroid ligament

LARYNX: CARTILAGES
oB.B. CRICOIDCRICOID
ocompletecomplete
oring ofring of
ocartilage hascartilage has
onarrow Arch ant.,narrow Arch ant.,
obroad Lamina post.broad Lamina post.
oCricoid meansCricoid means
oSignet RingSignet Ring
oLamina ofLamina of
ocricoidcricoid
oArch ofArch of
ocricoidcricoid
oANT .VIEWANT .VIEW oPOST .VIEWPOST .VIEW

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

LARYNX: CARTILAGES
Arytenoid - 2
pyramidal shaped
cartilages above
lamina – have
synovial joints with
Cricoid permit
Swivel = Rotate
Sliding = Ab/Adduct
D. Corniculate -
nodules above
arytenoids in
aryepiglottic folds
E. Cuneiform - rod
shaped, above
corniculate cartilages
oCuneiformCuneiform
oCorniculateCorniculate
oArytenoidArytenoid

ARYTENOID CARTILAGES :-
Placed on upper & lateral border of lamina
Three sided pyramid
Vocal process – vocal fold
Muscular process – posterior & lateral cricoarytenoid
Anterolateral surface – vestibular ligament, vocalis &
lateral cricoarytenoid muscles
Medial surface – mucosa covered

Apex – articulates with corniculate cartilage
Posterior surface – covered by transverse arytenoid
Base – concave, articular facet
Synovial joint with lax capsular ligament
Rotatory and medial & lateral gliding movement.

CORNICULATE (Wrisberg) –
Small, conical
Elastic fibrocartilage
Synovial joint or fused with apices of arytenoid
Situated in the aryepiglottic fold
CUNEIFORM (Santorini) –
Small, elongated
Elastic fibrocartilage
Lateral to corniculate

LARYNX: CARTILAGES
oF. EPIGLOTTISF. EPIGLOTTIS
o- leaf shaped- leaf shaped
ocartilagecartilage
oposterior to rootposterior to root
oof tongueof tongue
o- connected to- connected to
obody of hyoidbody of hyoid
oand post side ofand post side of
othyroid cartilagethyroid cartilage
oPOST. VIEWPOST. VIEW

EPIGLOTTIS :-
Thin, leaf-like, elastic fibrocartilage
Projects upward behind tongue & hyoid
Narrow stalk attached below thyroid notch by
thyroepiglottic ligament
Upper part directed upwards & medially
Superior margin free
Sides attached to arytenoid catilage by aryepiglottic fold.
tubercle in the lower part of posterior surface

Pits on cartilage – mucous glands
Anterior surface – mucosa covered
Median and lateral glossoepiglottic fold
Hyoepiglottic ligament
Pre-epiglottic space – between epiglottis & thyrohyoid
membrane, fat filled space
Neonates & infants – omega shaped, long, floppy

The Glottis
oFigure 23.5a,Figure 23.5a,
b

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 larynx
Extrinsic ligaments –
Connect cartilages to hyoid and trachea
Thyrohyoid Membrane :-
Between upper border of thyroid & upper border of
posterior surface of body and greater cornu of hyoid
Fibroelastic tissue – condensed anteriorly to form median
thyrohyoid ligament & posteriorly lateral thyrohyoid
ligaments
Cartilago triticea – small nodule
Pierced by internal branch of superior laryngeal nerve &
superior laryngeal vessels

Intrinsic ligaments
Connect the cartilages to each other.
Internal framework
Quadrilateral Membrane :-
Border of epiglottis and arytenoid cartilage
Upper margin forms framework of aryepiglottic fold
Lower 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 ligament
Attached below to the upper border of cricoid cartilage
Above between midpoint of laryngeal prominence to
vocal process of arytenoid
Free upper border forms vocal ligament , framework of
vocal fold / true cord
Anteriorly thickened to form cricothyroid ligament

II. LIGAMENTS OF LARYNX
o1. Thyrohyoid Membrane1. Thyrohyoid Membrane
olinks larynx to hyoid;links larynx to hyoid;
oMedian ThyrohyoidMedian Thyrohyoid
oLigament - thickenedLigament - thickened
omidline partmidline part
o2. Cricothyroid Membrane2. Cricothyroid Membrane
olinks thyroid to cricoid;links thyroid to cricoid;
oMedian CricothyroidMedian Cricothyroid
oLigament - thickenedLigament - thickened
omidline partmidline part
o3. Cricotracheal ligament3. Cricotracheal ligament
olinks Cricoid to firstlinks Cricoid to first
otracheal cartilagetracheal cartilage
oMedianMedian
oThyrohyoidThyrohyoid
oLigamentLigament
oMedianMedian
oCricothyroidCricothyroid
oLigamentLigament

STRUCTURAL LIGAMENTS
oEpiglottisEpiglottis
o4. Quadrangular4. Quadrangular
oMembraneMembrane linkslinks
oArytenoidArytenoid
oTo epiglottisTo epiglottisoArytenoidArytenoid

oArytenoidArytenoid
ocartilagecartilage
oAryepiglotticAryepiglottic
oFolds - overlieFolds - overlie
oQuadrangularQuadrangular
omembranemembrane

o5. Thyroepiglottic5. Thyroepiglottic
oLigamentLigament
olinks epiglottis tolinks epiglottis to
othyroid cartilagethyroid cartilage
oNOSENOSE
oSUPERIORSUPERIOR
oVIEWVIEW
oABOVEABOVE
oLARYNXLARYNX

oLower freeLower free
oedge ofedge of
omembrane ismembrane is
oCalledCalled
oVestibularVestibular
oLigament; deepLigament; deep
oto Vestibularto Vestibular
o(False Vocal)(False Vocal)
oFoldsFolds
oCORONALCORONAL
oSECTIONSECTION
oTHROUGHTHROUGH
oLARYNXLARYNX
otracheatrachea

B. FUNCTIONAL LIGAMENTS
oFunctional ligaments:Functional ligaments:
oConus ElasticusConus Elasticus --
oVibrating lips that ariseVibrating lips that arise
ofrom entire upper edge offrom entire upper edge of
oarch of cricoidarch of cricoid
oAttach: ant. to Thyroid,Attach: ant. to Thyroid,
opost. to Arytenoidpost. to Arytenoid
oRima Glottidis -Rima Glottidis -
oOpening BetweenOpening Between
oVocal ligamentsVocal ligaments
oVocalVocal
oLigaments -Ligaments -
oUpper freeUpper free
oEdgesEdges
oDeep toDeep to
oVocalVocal
oFoldsFolds
oNOSENOSE

FUNCTIONAL LIGAMENTS
o(In Coronal Section)(In Coronal Section)
oConus ElasticusConus Elasticus
oFunctionsFunctions
o1) Sound Production – Vibrate1) Sound Production – Vibrate
olike lips of trumpet player;like lips of trumpet player;
o2) Close Rima Glottidis stops2) Close Rima Glottidis stops
ooutflow air, upward movement ofoutflow air, upward movement of
odiaphragm - when contractdiaphragm - when contract
oabdominal muscle pressureabdominal muscle pressure
oincreases 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. -
oTensesTenses
oVocal LigamentVocal Ligament
oIncreasing PitchIncreasing Pitch
oSlackSlack oTenseTense

Intrinsic muscles and extrinsic muscles
All 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=thyroepiglottic
5)closers of the laryngeal inlet=interarytenoid & aryepiglottic.

 Extrinsic muscles
These are divided into two groups:
1)cervical muscles:
A)suprahyoid muscles,which act as elevators of the larynx
B)infrahyoid muscles(strap muscles),which acts as depressors of the larynx.
2)pharyngeal muscles including the inferior constrictor muscle.

MUSCLES OF LARYNX
o5) ARYEPIGLOTTIC5) ARYEPIGLOTTIC
oMUSCLEMUSCLE
oPulls epiglottis downPulls epiglottis down
oduringduring
oswallowingswallowing
o- Covers inlet to larynx- Covers inlet to larynx
o- Not necessary in- Not necessary in
oadult humansadult humans

MUSCLES OF LARYNX
o2)THYROARYTENOID2)THYROARYTENOID
oMUSCLE -MUSCLE -
oRelaxesRelaxes
oVocal LigamentsVocal Ligaments
oDecreases pitchDecreases pitch
oNOSENOSE

MUSCLES OF LARYNX
o5) ARYTENOID5) ARYTENOID
o(Transverse and(Transverse and
ooblique arytenoid) -oblique arytenoid) -
oAdduct vocal foldsAdduct vocal folds
o4) LATERAL CRICOARYTENOID4) LATERAL CRICOARYTENOID
o- Adduct- Adduct
ovocal foldsvocal folds
o3) POSTERIOR3) POSTERIOR
CRICOARYTENOIDCRICOARYTENOID
o–– AbductsAbducts
ovocal foldvocal fold
oAdduct closes rima glottidisAdduct closes rima glottidis
oAbduct opens rima glottidisAbduct opens rima glottidis
oArytenoidsArytenoids
oCan rotate/slideCan rotate/slideopgmedicalworld.compgmedicalworld.com

Cavity of the larynx
Divided by vestibular & vocal folds
into 3 compartments
oSuperior vestibule
oVentricle / sinus of the larynx
oSubglottic space

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

LARYNGEAL VENTRICLE
Laryngeal sinus
Elongated recess between vestibular & vocal folds
Opens through a narrow slit into middle segment of
larynx
From anterior part a pouch extends between vestibular
folds & inner surface of thyroid cartilage - saccule
Mucous 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
oARYEPIGLOTTICARYEPIGLOTTIC
oFOLDFOLD

LARYNGOSCOPE VIEW OF LARYNX
oAnt.Ant.
oTongueTongue
oVocal FoldsVocal Folds
o(true vocal(true vocal
ofolds)folds)
oPost.Post.
oVestibularVestibular
FoldsFolds
o(false vocal(false vocal
ofolds)folds)
oadducted whenadducted when
otalking or singingtalking or singing

Vestibular folds
Thick, pink folds of mucous membrane
Encloses the vestibular ligament
Anterior attachment is to angle of thyroid cartilage,
inferior to epiglottis
Posterior attachment to anterolateral surface of
arytenoid cartilage superior to vocal process

Vocal fold
Extends from the middle of angle of the thyroid cartilage
to vocal process of arytenoid cartilage
Layered structure – mucosa & muscle
Mucosa – epithelium : stratified squamous
Lamina propria – superficial, intermediate and deep
layers
Superficial – loose fibrous substance : Reinke’s space –
vibrates maximum during phonation

Intermediate layer – elastic fibres
Deep layer – collagenous fibres
Intermediate & deep layers form vocal
ligament
Deep to vocal ligament – vocalis muscle
Anterior and posterior macula flava protect
vocal fold from damage due to vibration

TERMS ASSOCIATED WITH LARYNX
oVESTIBULEVESTIBULE - inlet above false- inlet above false
oVESTIBULAR (FALSE VOCAL)VESTIBULAR (FALSE VOCAL)
oFOLDSFOLDS - overlie vestibular- overlie vestibular
oligamentsligaments
oVENTRICLEVENTRICLE - area between true- area between true
oand false vocal folds; lateraland false vocal folds; lateral
oextension is Laryngealextension is Laryngeal
oSinusSinus
oVOCAL (TRUE VOCAL) FOLDSVOCAL (TRUE VOCAL) FOLDS
o- overlie vocal ligaments- overlie vocal ligaments
oNOSENOSE

oARYEPIGLOTTICARYEPIGLOTTIC
oFOLDSFOLDS - Overlie- Overlie
oUpper Edge ofUpper Edge of
omembranemembrane
oPiriformPiriform
oRecessRecess - lateral- lateral
oto laryngeal inletto laryngeal inlet

oVALLECULAEVALLECULAE
o-depressions (2)-depressions (2)
oBetween Med & LatBetween Med & Lat
oGlossoepiglotticGlossoepiglottic
oFoldsFolds
o-Food/objects-Food/objects
oLodge inLodge in
oValleculaeValleculae
oValleculaVallecula
oMedialMedial
oGlossoepiglotticGlossoepiglottic
ofoldfold oLateralLateral
oGlosso-Glosso-
oEpiglotticEpiglottic

Mucous membranes of the larynx
Closely attached over the posterior surface of the
epiglottis, corniculate, cuneiform & vocal ligament
Loosely attached elsewhere – swollen
Epithelium – squamous / ciliated columnar or transitional
Numerous 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 propria
Transition – intermediate & deep layer
Body – vocalis muscle
Blood vessels run parallel to the edge

V. NERVES OF LARYNX – Branches of Vagus
oA. 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 Larynx
oAboveAbove True Vocal FoldsTrue Vocal Folds
o2. External Laryngeal N.2. External Laryngeal N.
oSVE Motor to CricothyroidSVE Motor to Cricothyroid
oB. Recurrent Laryngeal N.B. Recurrent Laryngeal N.
o- GVA Sensory to Larynx- GVA Sensory to Larynx
oBelowBelow True Vocal FoldsTrue Vocal Folds
o- SVE motor to all other- SVE motor to all other
oMuscles of LarynxMuscles of Larynx
oGVA=GENERAL VISCERAL AFFERENTGVA=GENERAL VISCERAL AFFERENT
oSVE=SPECIAL VISCERAL EFFERENTSVE=SPECIAL VISCERAL EFFERENT
oSUP. LARYNG. NSUP. LARYNG. N
oInt. Laryng. N.Int. Laryng. N.
oExt. Laryng. N.Ext. Laryng. N.
oRECURRENTRECURRENT
oLARYNG. 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 ganglion
At level of greater horn of the hyoid divides into external
& internal branches
External > cricothyroid
Internal > 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. Thyroid
oarteryartery
oInf. Laryngeal A.Inf. Laryngeal A.
ofrom Inf. Thyroidfrom Inf. Thyroid
oarteryartery

Blood supply
Laryngeal 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 thyroid
Superior & middle thyroid vein, facial vein > internal
jugular
Inferior thyroid vein > brachiocephalic veins

VII. LARYNX - LYMPHATICS
oSuperior DeepSuperior Deep
oCervical NodesCervical Nodes
oLarynx above trueLarynx above true
oInferior DeepInferior Deep
oCervical Nodes-Cervical Nodes-
oLarynx below trueLarynx below true
oVII.VII.
oNote: Mucosa Tightly Attached to vocal foldsNote: Mucosa Tightly Attached to vocal folds
oAnaphylactic Shock Swell Vestibular folds --SuffocationAnaphylactic Shock Swell Vestibular folds --Suffocation

Lymphatic drainage
Separated by vocal fold into upper and lower group
Above vocal fold -> upper deep cervical nodes
Below vocal fold -> prelaryngeal, pretracheal & lower
deep cervical
Vocal folds firmly bound down to vocal ligament ->
relative absence of lymphatics

VIII. OBSTRUCTION OF LARYNX: TRACHEOTOMY
 open airway to lungs below obstructed larynx
oTracheotomyTracheotomy
o- cut between- cut between
o1st & 2nd or 2nd –1st & 2nd or 2nd –
o3rd Tracheal3rd Tracheal
ocartilagescartilages

BLEEDING IS PROBLEM: MIDLINE THYROID VEINS
o1) Sup. Thyroid vein1) Sup. Thyroid vein
ofollows arteryfollows artery
o2) Middle Thyroid2) Middle Thyroid
ovein- to Int Jugularvein- to Int Jugular
o3) Inf. Thyroid vein3) Inf. Thyroid vein
oBoth sides join atBoth sides join at
omidline -> L.midline -> L.
oBrachiocephalic VeinBrachiocephalic Vein

OBSTRUCTION OF LARYNX: CRICOTHYROTOMY
oCrico-Crico-
oThyrotomyThyrotomy
oLittle bleedingLittle bleeding
oCricothyroid MembraneCricothyroid Membrane
oOBSTRUCTIONOBSTRUCTION

THANK
YOU
RAJESH MISHRARAJESH MISHRA

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: Anatomy
o

 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).

o
o
othethe false vocal foldsfalse vocal folds narrow thenarrow the
oglottis during swallowing, preventingglottis during swallowing, preventing
opieces of food from getting into thepieces of food from getting into the
otrachea.trachea.

o
oPhonationPhonation
o
oPhonation is “conversion of potential energy of compressed airPhonation is “conversion of potential energy of compressed air
ointo 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 folds
o 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, causing
o acoustic shock wave moving along vocal tractacoustic shock wave moving along vocal tract
o opgmedicalworld.compgmedicalworld.com

o Acoustic Phonetics: AnatomyAcoustic Phonetics: Anatomy
o
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 muscle
o movementsmovements
o 2.2. opening and closing is automatic as long as the resting positionopening and closing is automatic as long as the resting position
o of the vocal folds is (near) closure, and there is sufficientof 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 folds)(a) position of vocal folds (degree of closeness between folds)
o (b) elasticity of vocal folds, depending on position and(b) elasticity of vocal folds, depending on position and
o degree of tensiondegree of tension
o (c) degree of pressure drop across vocal folds(c) degree of pressure drop across vocal folds

o
oTypes of phonationTypes of phonation
o
oquietquiet
obreathingbreathing
oforcedforced
oinhalationinhalation
onormalnormal
ophonationphonation
owhisperwhisper

o
oThe cycle of glottal vibrationThe cycle of glottal vibration
o
o1. folds at rest1. folds at rest o2. muscle2. muscle
o contractioncontraction
o3. increase in3. increase in
o pressurepressure
o4. forcing folds4. forcing folds
o apartapart
o5. “explosion”5. “explosion”
o openopen
o6. acoustic6. acoustic
o shockwaveshockwave
o8. folds close,8. folds close,
o goto stepgoto step
(3)(3)
o7. rebound toward7. rebound toward
o closureclosure

o
oThe cycle of glottal vibrationThe cycle of glottal vibration
oclosure to opening, 0 to 2.1closure 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)

o
oTypes of phonationTypes of phonation
o
ovoiceless, whisper, breathyvoiceless, whisper, breathy
ovoiced, creak, glottal stopvoiced, creak, glottal stop

o
oThe effects of nasalization on vowelsThe effects of nasalization on vowels
o
oFigure 4-17. An example of theFigure 4-17. An example of the
oeffects of vowel nasalization oneffects of vowel nasalization on
othe vowel spectrum. The spectrumthe vowel spectrum. The spectrum
oenvelopes of a normal [a] and a heavilyenvelopes of a normal [a] and a heavily
onasalized [a] were plotted… The firstnasalized [a] were plotted… The first
othree formants are labeled in thethree 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 in
ospectrum level, indicated by “z’s”;spectrum level, indicated by “z’s”;
othese are the result of the additionthese are the result of the addition
oof anti-resonant zeros to the vocalof anti-resonant zeros to the vocal
otract response, due to a wide-opentract response, due to a wide-open
ovelar port.velar port.

o Acoustic Phonetics: AnatomyAcoustic Phonetics: Anatomy
o
o The effects of nasalization on vowelsThe 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 pairs
o (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 pole
o 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 bandwidthThe 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 locationThe 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 netIf 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 lengthened
Changes in length & tension control pitch
Tension 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 puffs
Vocal folds thinner at high pitch
Mucosal wave travels from inferior to superior surface
Sound 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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Anatomy of larynx

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