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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. .
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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 rimaglottidis • 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
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 • Veinsaccompany the arteries