6. Histological types of laryngeal cartilages
(1) Elastic:
Epiglottis, corniculate, cuneiform & apex of arytenoid
Little or no calcification
(2) Hyaline:
Thyroid, cricoid & remaining arytenoid
Calcify as age advances
Ossification begins by 25 yr & is completed by 60 yr
7. 1. Thyrohyoid membrane:
2. Cricothyroid membrane:
cricothyrotomy
• Cricoid cartilage: only rigid &
complete ring among the
cartilages forming larynx and
trachea
15. Pediatric Larynx Vs Adult larynx
1. Subglottis is the narrowest part
2. Loose submucosal tissues (swell up
easily)
3. Positioned high (C3-C4)
4. Soft cartilages collapse easily
16. Subdivisions of larynx
A. Supraglottis: laryngeal
inlet to apex of ventricle
B. Glottis: apex of ventricle to
1cm below
C. Subglottis: lower glottic
border to lower cricoid
18. Intrinsic Muscles
A. Acting on vocal cords
Abduction → Posterior crico-arytenoid
Adduction → Lateral crico-arytenoid
Transverse arytenoid (inter-arytenoid)
Thyro-arytenoid
Tension + lengthening → Cricothyroid
Relaxation + shortening → Vocalis ( internal part of thyroarytenoid)
19. B. Acting on laryngeal inlet
Opener → Thyro-epiglottic (part of thyroarytenoid)
Closer → Inter-arytenoid (oblique part)
Ary-epiglottic(Posterior oblique part of interarytenoid)
20. Extrinsic laryngeal muscles
• Elevators of larynx
Primary elevators secondary elevators
• Stylo-pharyngeus • Mylohyoid
• Salpingo-pharyngeus • Stylohyoid
• Palato-pharyngeus • Geniohyoid
• Digastric
• Depressors of larynx (strap muscles of the neck)
Sternohyoid ,Sternothyroid , thyrohyoid ,Omohyoid
27. Nerve Supply
Superior Laryngeal Nerve (SLN):
• Internal: Sensory supply to supraglottis & glottis
• External: Motor supply to cricothyroid muscle
Recurrent Laryngeal Nerve(RLN):
• Sensory supply to subglottis
• Motor supply to all intrinsic muscles except cricothyroid
30. Functions of Larynx
1.Protection of lower airway: primary function
(i) Closure of larynx: three tier mechanism
(ii) Cough reflex
2.Phonation (voice production): secondary function
3.Respiration
4.Chest fixation by glottic closure: coughing,micturition,defecation