LARYNX By Dr Musaed Al Fayez Larynx Specialized

LARYNX By Dr. Musaed Al Fayez

Larynx 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.

Cartilages of the Larynx Unpaired cartilages Epiglottis Thyroid cartilage Cricoid Paired cartilages Arytenoid Corniculate Cuneiform All cartilages are hyaline except the epiglottis (elastic)

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.

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

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.

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

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.

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.

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.

Muscles of the Larynx 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

Cricothyroid Muscle 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.

Posterior cricoarytenoid is the only abductor of the vocal cords.

Muscles acting on the arytenoids Posterior cricoarytenoids Lateral cricoarytenoid Interarytenoid muscles: Transverse & Oblique Thyroarytenoid muscle Aryepiglottic muscles

Thyroarytenoid & Vocalis Muscles

Action of Intrinsic Muscles

Innervation of Larynx 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

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.

Blood Supply of Larynx Superior laryngeal artery – branch of superior thyroid artery Inferior laryngeal artery – branch of inferior thyroid artery Veins accompany the arteries