1. By Dr. Musaed Al Fayez

2.  Specialized organ at the inlet of air passage.  Function :  1- Protective sphincter at the air passage.  2- Phonation.  3- Regulates passage of air in inspiration and expiration.  4- Opens & closes during swallowing, coughing & sneezing.

3.  Unpaired cartilages  Epiglottis  Thyroid cartilage  Cricoid  Paired cartilages  Arytenoid  Corniculate  Cuneiform  All cartilages are hyaline except the epiglottis (elastic)

4.  The framework of the larynx is made up of cartilages.  These cartilages are connected by joints, membranes & ligaments.  Moved by muscles.  Lined by mucous membranes.

5.  The Laryngeal cartilage are Nine  3 single & 3 Paired  Single:  Thyroid  Cricoid  Epiglottis.  Paired:  Arytenoids  Corniculate  Cuneiform.

6.  Thyroid Cartilage  It is the largest of the laryngeal cartilage.  Formed of 2 laminae, each has superior & inferior horn.  The angle between 2 laminae is 90 in male & 120 in female.  It has 2 notches superior & inferior at the meeting of its 2 laminae.

7.  Connection of the thyroid cartilage:  Superior: To hyoid bone by thyrohyoid membrane.  Inferior: To cricoid cartilage by the cricothyroid joint & cricothyroid membrane

8.  Epiglottis:  Leaf-shaped elastic cartilage.  Lies behind the root of the tongue.  Connected by its stalk to the back of the thyroid cartilage.  Its sides are connected to the arytenoid cartilage by aryepiglottic fold.  Its upper end is free. But its mucous membrane is connected to the back of tongue by 3 glossoepiglottic folds one median & 2 lateral.

9.  Cricoid cartilage:  Hyaline.  Ring shaped, having a narrow anterior arch and wide posterior lamina.  Connected superiorly to thyroid cartilage by cricothyroid joint and cricothyroid membrane.

10.  Arytenoid cartilage:  Paired hyaline cartilage.  Shaped like a 3- sided pyramid.  Its base sits on the superior surface of the cricoid lamina.  Apex: directed superiorly, supports the corniculate cartilage.  Muscular process directed laterally, gives attachment to 3 muscles:  Posterior & lateral cricoarytenoid.  And Thyroarytenoid.  Vocal process: directed forward and gives attachment to the vocal ligament.

11.  2 Major groups  Extrinsic Muscles: ( move the whole larynx)  Elevators: Digastric, stylohyoid, mylohyoid, geniohyoid, stylopharyngeus, salpingopharyngeus & palatopharyngeus.  Depressors: Sternothyroid, sternohyoid & omohyoid.  Intrinsic Muscles ( movement within larynx)  Control of laryngeal inlet  Control of rima glottidis  Control of length & tension of vocal cords  All intrinsic muscles lie inside the larynx cricothyroid

12.  Origin: Anterior part of arch of cricoid  Insertion: Inferior border & inf. Horn of thyroid  Causes flexion at cricothyroid joint  Lengthens & tightens the vocal ligament  Nerve supply: External laryngeal nerve of superior laryngeal of vagus.

13.  Posterior cricoarytenoid is the only abductor of the vocal cords.

14.  Posterior cricoarytenoids  Lateral cricoarytenoid  Interarytenoid muscles:  Transverse &  Oblique  Thyroarytenoid muscle  Aryepiglottic muscles

17.  MOTOR  All muscles of the larynx are supplied the recurrent laryngeal nerve EXCEPT  Cricothyroid – supplied by external laryngeal branch of superior laryngeal nerve.  SENSORY & SECRETOMOTOR  Above Vocal Cords: Internal laryngeal  Below Vocal Cords: Recurrent laryngeal

18.  The interior of the larynx  It is divided into 3 parts:  1- vestibule: between laryngeal inlet & vestibular fold.  2- Ventricle: a depression extending laterally between vestibular & vocal folds.  3- Infraglottic cavity: lies between the vocal fold & lower border of cricoid cartilage.  It is continuous with the trachea inferiorly.

19.  Superior laryngeal artery – branch of superior thyroid artery  Inferior laryngeal artery – branch of inferior thyroid artery  Veins accompany the arteries