و ما أوتيتم من العلم إلا قليلا Larynx Dr. Hassan Shaibah

The pharynx a musculofascial half-cylinder that links oral & nasal cavities in the head to the larynx & esophagus in the neck. The pharyngeal cavity is a common pathway for air and 'food'.

pharynx is subdivided into three regions, nasopharynx, oropharynx, laryngopharynx

Nasopharynx is behind the choanae of the nasal cavities and above the level of the soft palate. There is a large collection of lymphoid tissue (the pharyngeal tonsil) in the mucosa covering the roof of the nasopharynx. Enlargement of this tonsil, known then as adenoids, can occlude the nasopharynx so that breathing is only possible through the oral cavity in the pharynx that the air and food pathways the soft palate serves as a flap-valve which shuts off the mouth from the oropharynx

The larynx hollow musculoligamentous structure with a cartilaginous framework that caps the lower respiratory tract. The cavity is continuous below with the trachea, & above opens into pharynx immediately posterior & inferior to the tongue

The larynx is both a valve (or sphincter) to close the lower respiratory tract, and an instrument to produce sound. It is composed of: 3 large unpaired cartilages (cricoid, thyroid, and epiglottis). 3 pairs of smaller paied cartilages (arytenoid, corniculate, and cuneiform). a fibroelastic membrane and numerous intrinsic muscles.

The thyroid cartilage the largest one formed by right & left lamina, which are widely separated posteriorly, but converge and join anteriorly. They meet at laryngeal prominence ('Adam's apple'). more apparent in men than women.

The cricoid cartilage most inferior one completely encircles the airway It is shaped like a 'signet ring' Landmark for tracheostomy.

The cricoid cartilage has two articular facets on each side for articulation with other laryngeal cartilages. one facet posteriorly articulation with arytenoid cartilage Lateraly facet articulation with the thyroid cartilage.

Epiglottis a 'leaf-shaped' cartilage attached to the thyroid cartilage. The upper margin of the epiglottis is behind the pharyngeal part of the tongue. The sides are attached to the arytenoid cartilages by aryepiglottic folds

Arytenoid cartilages are pyramid-shaped cartilages with three surfaces, a base of arytenoid cartilage, an apex of arytenoid cartilage, vocal process, and muscular process Articulate with cricoid cartilage

Corniculate articulate with arytenoid cartilages & attach to aryepiglottic folds Cuneiform found the fold to give strength to it

The ligaments of the Larynx

Thyrohyoid membrane Connect thyroid cartilages with hyoid bone. Opening on in the lateral part of on each side for superior laryngeal arteries, nerves, Posteriorly thickened lateral thyrohyoid ligaments. thickened anteriorly form the median thyrohyoid ligament. Cricotracheal ligament connect cricoid to 1st ring to trachea

Quadrangular membrane: extends between epiglottis & arytenoid cartilages its inferior margin forms the vestibular ligament covered by vestibular fold (false vocal cord)

Cricothyroid ligament its lower margin is attached to cricoid cartilage Extend superiorly as a free margin within the thyroid cartilage It forms the important vocal ligament on each side. This ligament is covered by vocal folds (true vocal cords) The anterior end of each vocal ligament is attached to the thyroid cartilage, and the posterior end is attached to vocal process of the arytenoid cartilage.

Division into three major regions Two pairs of mucosal folds, the vestibular (pink) and vocal folds (white), which project medially from the lateral walls of the laryngeal cavity constrict it and divide it into three major regions the vestibule, a middle chamber the infraglottic cavity

Inlet of the Larynx opening is wider in front than behind Bounded by: in front by epiglottis laterally by the aryepiglottic fold posteriorly by arytenoid, corniculate and cuneiform cartilages.

The Piriform Fossa is a recess on either side of the fold & inlet It is bounded medially by aryepiglottic fold laterally by thyroid cartilage & thyrohyoid membrane

laryngoscope 2 triangularshaped opening: rima vestibuli between two adjacent vestibular folds rima glottidis between the two adjacent vocal folds).

muscles of the larynx cricothyroid muscles Vocalis Posterior cricoarytenoid Lateral cricoarytenoid Transverse arytenoid Thyro-arytenoid Oblique arytenoid

Actions on the vocal folds Tightens cricothyroid muscles Vocalis Abduct Posterior cricoarytenoid Adduct Thyro-arytenoid Transverse arytenoid Lateral cricoarytenoid

LARYNGEAL MUSCLES:

Cricothyroid muscles The fan-shaped cricothyroid muscles arch of the cricoid cartilage to the thyroid cartilage External branch of superior laryngeal nerve from the vagus nerve [X] Stretch the vocal cords

Thyro-arytenoid muscle Posterior cricoarytenoid Lateral cricoarytenoid Transverse arytenoid Oblique arytenoid Thyro-arytenoid Vocalis

Nerves Sensory Nerves: Above the vocal cords: internal laryngeal branch of the superior laryngeal branch of the vagus ●Below level of the vocal cords: The recurrent laryngeal nerve

Motor Nerves All the intrinsic muscles of the larynx except the cricothyroid muscle are supplied by the recurrent laryngeal nerve. The cricothyroid muscle is supplied by external laryngeal branch of the superior laryngeal branch of the vagus.

Superior laryngeal nerves The superior laryngeal nerves originate from the inferior vagal ganglia descend and divide into internal and external branches just above the level of the superior horn of the hyoid bone: the external branch (external laryngeal nerve) supplying the cricothyroid muscle; the internal branch (internal laryngeal nerve) penetrate the thyrohyoid membrane it is mainly sensory and supplies the laryngeal cavity down to the level of the vocal folds.

The recurrent laryngeal nerve sensation to the inferior half of the larynx Motor to intrinsic laryngeal musculature. (not CT)

BLOOD SUPPLY The superior laryngeal artery is a branch of the superior thyroid artery, derived from the external carotid artery The inferior laryngeal artery derived from the inferior thyroid artery, which originates from the thyrocervical trunk of the subclavian artery.