Anatomy & Physiology of

LarynxDr. Vishal Sharma

Larynx (anterior)

Larynx (posterior)

Larynx (posterior)

Larynx (lateral)

Larynx (superior)

Larynx (superior)

Larynx (sagittal section)

Larynx (sagittal section)

Larynx (coronal section)

Vocal fold

Vocal fold

Laryngeal Cartilages

3 single & 3 paired

Single Paired

Epiglottis Arytenoid

Thyroid Corniculate (Santorini)

Cricoid Cuneiform (Wrisberg)

Cartilages (anterior)

Laryngeal Cartilages

Cartilages (posterior)

Cartilages (posterior)

Cartilage Histology

Elastic: Epiglottis, corniculate, cuneiform &

apex of arytenoid. Little or no calcification.

Hyaline: Thyroid, cricoid & remaining arytenoid.

Calcify as age advances. Ossification begins by

25-30 yr & is completed by 60 yr.

Indirect Laryngoscopy

Flexible LaryngoscopyLEFT RIGHT

Laryngeal cavity

1. Laryngeal inlet

2. Laryngeal Vestibule

3. Laryngeal Ventricle

4. Rima glottis

5. Subglottis

Pediatric Larynx

• Conical in shape & subglottis is narrowest part

• Positioned high (C3-C4)

• Moves higher during swallowing allowing

simultaneous breathing & feeding

• Loose sub-mucosal tissues (swell up easily)

• Soft cartilages that collapse easily

Membranes & Ligaments

• Extrinsic:

connect thyroid cartilage & epiglottis with

hyoid bone; cricoid cartilage with trachea.

• Intrinsic:

connect cartilages of larynx to each other.

Extrinsic

• Thyrohyoid

membrane

• Hyoepiglottic

ligament

• Cricotracheal

ligament

Intrinsic

Intrinsic

Intrinsic

1. Quadrangular membrane

Ary-epiglottic ligament Vestibular ligament

2. Crico-vocal membrane

Vocal ligament Cricothyroid membrane

3. Thyro-epiglottic ligament

Oncological Divisions

A. Supraglottis: laryngeal

inlet to apex of ventricle

B. Glottis: apex of

ventricle to 10 mm below

C. Subglottis: lower glottic

border to lower cricoid

border

Subsites

A. Supraglottis: 1. Epiglottis 2. Aryepiglottic

folds 3. Ventricular bands 4. Laryngeal

Ventricle

B. Glottis: 1. True vocal cords 2. Anterior

commissure 3. Posterior commissure

C. Subglottis

Intrinsic Muscles

A. Acting on vocal cords

Abduction Posterior crico-arytenoideus

Adduction Lateral crico-arytenoideus

Transverse inter-arytenoideus

Thyro-arytenoideus externa

Tension + lengthening Cricothyroid

Relaxation + shortening Vocalis

Intrinsic Muscles

B. Acting on laryngeal inlet

Opener Thyro-epiglottic

Closer Oblique inter-arytenoideus

Ary-epiglottic

Extrinsic MusclesPrimary Elevators Secondary Elevators

Stylopharyngeus Mylohyoid

Salpingopharyngeus Stylohyoid

Palatopharyngeus Geniohyoid

Thyrohyoid Digastric

Depressors

Sternohyoid Sternothyroid Omohyoid

Posterior cricoarytenoid

Lateral cricoarytenoid

Transverse Inter-arytenoid

Cricothyroid

Thyroarytenoid externa + Vocalis

Oblique Inter-arytenoid

Spaces of Larynx

Reinke’s space

Pre-epiglottic space

Para-glottic space

Communications

Shape of Glottis

Shape of Glottis

Quiet Respiration Forced Inspiration

Inspiration

Shape of Glottis

Normal voice Whisper

Normal phonation

Whisper

Mucous Membrane

• Stratified squamous epithelium:

Epiglottis (anterior surface + upper half of

posterior surface), upper part of aryepiglottic

folds & vocal cords

• Pseudo-stratified ciliated columnar

(respiratory) epithelium:

Rest of laryngeal mucous membrane

Nerve Supply

Superior Laryngeal Nerve:

• Internal: sensation to supraglottis & glottis

• External: motor to cricothyroid muscle

Recurrent Laryngeal Nerve:

• sensation to subglottis

• motor to all intrinsic muscles but cricothyroid

Blood Supply

Arterial supply:

• Laryngeal br. of superior & inferior thyroid

Venous drainage:

• Superior thyroid vein internal jugular vein

• Inferior thyroid vein innominate vein

Lymphatic Drainage

Supraglottis: via thyrohyoid membrane into upper

deep cervical nodes & thyroid gland

Subglottis: via cricothyroid membrane into

pretracheal + lower deep cervical nodes

Glottis: has no lymphatics

Functions of Larynx

1. Protection of lower airway

2. Phonation (voice production)

3. Passage of air into lungs for respiration

4. Chest fixation by glottic closure

Protection of lower airway

a. 3-level below-upward closure of:

vocal cords ventricular bands

aryepiglottic folds

b. Cessation of respiration: mediated by

glossopharyngeal nv & deglutition centre.

c. Cough reflex

Voice Production

1. Voice activating air reservoir in lungs:

affects voice intensity

2. Voice generation: affects voice pitch

3. Voice resonation: affects voice quality

4. Voice articulation: affects voice quality

Voice Production

Neuro-chronaxic theory (?)

• Vibration of vocal fold muscles due to impulses

generated from recurrent laryngeal nerves.

Speed is regulated by acoustic center in brain.

• Obsolete theory because:

• muscle contraction not so fast to produce vibrations

• even paralyzed vocal folds can produce phonation

• passive phonation occurs in excised larynges

Combined Aerodynamic & Myoelastic theory

Proposed by Jan Willem van den Berg in 1958

Vocal cords kept approximated Subglottic blast

of air opens vocal cords from below upwards &

causes their passive vibration, producing sound

Muscle tension + Bernoulli's effect closes vocal

cords below upwards Cycle repeated

Aerodynamic myoelastic theory (opening phase)

Aerodynamic myoelastic theory (closing phase)

Stroboscopic examination

Voice generation

High pitch = short, thin, tense, less

elastic vocal cords

Low pitch = long, bulky, relaxed, more

elastic vocal cords

Falsetto voice = tense vocal cords, only edge

of vocal fold vibrates & body is

relaxed,

with small phonatory gap

Falsetto voice

Vocal cord cross-section

Normal phonation

Falsetto voice

Glottis state in phonation

• Voiceless (full air stream)

• Breathy voice (murmur)

• Slack voice

• Modal voice: maximum vibration, sweet spot

• Stiff voice

• Creaky voice (restricted air stream)

• Glottalized (blocked air stream)

Glottis state in phonation

Vocal Registers

• Vocal fry register: lowest vocal register

• Modal voice register: commonly used for speaking

& singing

• Falsetto register: one octave higher than modal

voice register

• Whistle register: highest voice register. Used by

female singers

Musical notes & octaves

Guinness World records

Georgia Brown (2006):

• Highest vocal range from G2 to G10

• Highest vocal note (G10)

Adam Lopez (2002):

• Highest vocal note for male (C8)

Tim Storms (2002):

• lowest vocal note (8 Hz = two octaves below

lowest B on a piano)

Adam Lopez & Tim Storms

Voice resonation

• Oral & pharyngeal cavity S

• Nasal cavity M, N, Ng

In rhinolalia clausa:

• M, N & Ng are uttered as B, D & G respectively

In rhinolalia aperta:

• B, D & G are uttered as M, N & Ng

Organs of articulation

Places of articulation

Bilabial: both lips Labio-Dental: lips + teeth

Dental: teeth + tip of tongue

Alveolar: alveolus + tip of tongue

Palatal: hard palate + tongue blade

Retroflex: tongue tip + hard palate

Velar: tongue base + soft palate

Glottal: produced in glottis

Places of articulation

Sound production Bilabial P, B, M, W

Labio-Dental F, V; Dental T, D

Alveolar T, D, N, L, S, Z

Palatal Ch, Chh, J, Jh, Y

Retroflex R, T, Th, D, Dh

Velar K, Kh, G, Gh

Glottal H, ?, uh-oh

Chest fixation

Closure of glottis helps in raising intra-thoracic

& intra-abdominal pressure required for:

• Coughing Vomiting

• Defecation Micturition

• Climbing Weight-lifting

• Labour

Thank You