Download Anatomy & physiology of larynx

Anatomy &
Physiology of
Larynx
Dr. 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 Laryngoscopy
LEFT
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
C. Subglottis
3. Posterior commissure
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 Muscles
Primary 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
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