1. ANATOMY & PHYSIOLOGY OF LARYNX
Done by :
Deem Hatim Al-Fandi
Alsafa Abdulaziz Al-Kulaib
Norah Abdulaziz Al-Musallam

2. INTRODUCTION :
The larynx lies in front of the hypopharynx opposite to the 3rd till 6th cervical vertebrae.
It moves vertically and in anteroposterior direction during swallowing and phonation.
It can also be passively moved from side to side producing a characteristic grating sensation called laryngeal crepitus

3. Larynx has three unpaired & three paired cartilages.
1. LARYNGEAL CARTILAGES
Larynx has three unpaired & three paired cartilages.

4. Paired : Unpaired: Cartilages of Larynx : Arytenoid Corniculate
cunieform
Unpaired:
Thyroid
Cricoid
Epiglottic

5. Unpaired Cartilages :
Thyroid: It is the largest of all.
Its two alae meet anteriorly forming an angle of 90° in males and 120° in females.
Vocal cord are attached to the middle of thyroid angle ,Most of laryngeal foreign bodies are arrested above the vocal cords.
Cricoid: It is the only cartilage forming a complete ring.
Epiglottis: it is a leaf- like , yellow elastic ,forming anterolateral wall of laryngeal inlet

6. paired Cartilages :
Arytenoid cartilages: Each arytenoid cartilage is pyramidal in shape. It has base which articulate with cricoid cartilage
Corniculate cartilages ( of Santorini) they are paired , each articulate with apex of arytenoid cartilage
Cuneiform cartilages (of Wrisberg). They are rod shaped.

7. Thyroid, cricoid and most of the arytenoid cartilages are hyaline cartilages whereas epiglottis, corniculate, cuneiform and tip of arytenoid near the corniculate cartilage are fibroelasticin nature .

8. 2. LARYNGEAL MUSCLES They are of two types:
intrinsic, which attach laryngeal cartilages to each other & extrinsic, which attach larynx to the surrounding structures.

9. Abductors: Posterior cricoarytenoid
Intrinsic muscles:
They may act on vocal cords or laryngeal inlet.
Acting on vocal cords:
Abductors: Posterior cricoarytenoid
Adductors: Lateral cricoarytenoid – Interarytenoid -Thyroarytenoid
Tensors: Cricothyroid -Vocalis
Acting on laryngeal inlet:
Openers of laryngeal inlet: Thyroepiglottic (the internal part of thyroarytenoid)
• Closers of laryngeal inlet: Interarytenoid (oblique part).

10. 3. LARYNGEAL MUCOUS MEMBRANE
Epithelium of the mucous membrane is ciliated columnar type except over
the vocal cords and upper part of the vestibule where it is striated squamous type.
There are NO mucous glands in the vocal folds. .

11. 4. LARYNGEAL NERVE SUPPLY
Motor & sensory

12. NERVE SUPPLY:
Motor:
All the muscles which moves the vocal cord are supplied by:
the recurrent laryngeal nerve except the cricothyroid muscle. (innervated by the superior laryngeal nerve).
Sensory:
Above the vocal cords, larynx is supplied by superior laryngeal nerve.
Below the vocal cords by recurrent laryngeal nerve.

14. The larynx of an infant differs considerably from that of an adult:
PAEDIATRIC LARYNX
The larynx of an infant differs considerably from that of an adult:
Position
Laryngeal cartilage
Thyroid cartilage
Size and diameter
Submucosal tissue

15. POSITION:
Infant’s larynx is positioned higher at the level of C3 or C4 at rest, and reaches C1 or C2 during swallowing.
With growth of the neck, larynx gradually descends to adult level; the vocal cords lying opposite C5.
This high position allows the epiglottis to meet soft palate and make a nasopharyngeal channel for nasal breathing during suckling.

16. LARYNGEAL & THYROID CARTILAGE
Laryngeal cartilages are soft and collapse easily.
Epiglottis is omega shaped .
Thyroid cartilage is flat.

17. SIZE AND DIAMETER
Small and conical
Diameter of cricoid cartilage is smaller than the size of glottis.
Making the subglottis the narrowest part.
SUBMUCOSAL TISSUE
Loose and easily undergo edematous change with trauma or inflammation leading to obstruction.

18. The larynx performs the following important functions:
PHYSIOLOGY O F LARYNX
The larynx performs the following important functions:
Protection of lower airways , Phonation, Respiration & Fixation of the chest.

19. 1. Protection of lower airways :
The larynx protects the Lower passages in three different ways:
Sphincter closure of laryngeal opening.
Cessation of respiration
Cough reflex.

20. 2. Phonation
Larynx is like a wind instrument ,Voice is produced by the
Following mechanism
(Aerodynamic myoelastic theory of voice Production)
Vocal cords are kept adducted.
Infraglottic air pressure is generated by the exhaled air
From the lungs due to contraction of thoracic and Abdominal muscles.
The air force open the cords and is released as small puffs which vibrate the vocal cords and produce sound is amplified by mouth and chest.

21. 3. Respiration
Larynx regulates flow of air in to the lungs.
vocal cords abduct during inspiration and adduct during expiration.

22. Reference:

23. Thanks!
Any questions?