Larynx The larynx is an organ that provides a protective sphincter at the inlet of the air passages and is responsible for voice production. It extends from C3-C6: *Posterior: the pharynx *Lateral: the lobes of the thyroid gland ; also on the lateral side of the larynx is the carotid sheath *ich contain 4 structures : common carotid artery, internal carotid artery (medial), internal jugular vein (lateral) and vagus nerve (CN X). *Anterior: the infrahyoid muscles : sternohyoid, sternothyroid, thyriohyoid and omohyoid ; and the deep cervical fascia. It opens above into the laryngeal part of the pharynx, and below is continuous with the trachea. --Mucous membrane: Larynx is lined by pseudo stratified ciliated columnar epithelium, with goblet cells (respiratory epithelium) Except the followings (they are covered by stratified squamous epithelium): 1-True vocal cords 2-Tip of epiglottis 3-Aryepiglottic fold --Skeleton of the larynx : A- Single cartilage : 1- Thyroid 2- Cricoid 3- Epiglottis B- Paired cartilages: 1- Arytenoid 2-Corniculate 3-Cuneiform Rudimentary *thyroid cartilage : from C4-C5, largest cartilage, and consists of two laminae of hyaline cartilage that meet in the midline in the prominent V angle (the so-called Adam s apple) called the laryngeal prominence and it s 120 degree in female and 90 degree in male. On the lateral side of the lamina there is an oblique line *hich extend from the superior horn to the inferior border of the lamina and is a : 1-origin of thyriohyoid and inferior pharyngeal constrictor muscles 2- insertion of the sternothyroid muscle Behind the posterior surface : -stylopharyngeus - salpingopharyngeus -platopharyngeus *hich are supplied by glossopharyngeal nerve ; they function to raise and lower the larynx.
* cricoid cartilage: inferior part of the larynx,, having a broad lamina behind and a shallow arch in front (anterolateral arch ). The cricoid cartilage lies below the thyroid cartilage, and on each side of the lateral surface is a facet for articulation with the inferior horn of the thyroid cartilage. Posteriorly, the lamina has on its upper border on each side a facet for articulation with the arytenoid cartilage. All these joints are synovial. *epiglottis : leaf like structure, Its stalk is attached to the back of the thyroid cartilage. Moves up and down so it acts as a safety valve for the larynx. *Arytenoid cartilages: pyramid shaped and located at the back of the larynx sitting on top of the cricoid ; has 3 surfaces : medial, posterior and anterolateral and a vocal process that projects forward and gives attachment to the vocal ligament. A muscular process that projects laterally gives attachment to the posterior and lateral cricoarytenoid muscles rotate when muscles contract and moves the vocal cords. *Corniculate cartilages: Two small conical-shaped cartilages articulate with the arytenoid cartilages, They give attachment to the aryepiglottic folds. *Cuneiform cartilages: These two small rod-shaped cartilages are found in the aryepiglottic folds and serve to strengthen them. -all cartilages are made of hyaline cartilage except for epiglottis and upper part of the arytenoids it has a yellow elastic cartilage which is more flexible. #abduction of arytenoids : it descends #adduction : ascends #rotation and gliding movement : for cricoarytenoid and cricothyroid joint. Membranes and ligaments of the Larynx Thyrohyoid membrane: from the upper margin of the thyroid cartilage ascending up behind the greater horn of the hyoid bone ( there is a bursa between hyoid bone and the membrane ). The membrane is pierced on each side by the superior laryngeal vessels and the internal laryngeal nerve, a branch of the superior laryngeal nerve. Cricotracheal ligament: This connects the cricoid cartilage to the first ring of the trachea. Quadrangular membrane( aryepiglottic fold ) : This extends from the edge of the epiglottis to the anterior margin of arytenoid cartilages ; it has a free superior edge aryepiglottic ligament and free inferior edge vestibular ligament (false vocal cord) Cricothyroid ligament (The conus elasticus is the lateral portion): The lower margin is attached to the upper border of the cricoid cartilage The superior margin of the ligament, instead of being attached to the thyroid cartilage, ascends on the medial
surface of the thyroid cartilage. Its upper free margin, composed almost entirely of elastic tissue, forms the important vocal ligament on each side. The vocal ligaments form the interior of the vocal folds (vocal cords). The anterior end of each vocal ligament is attached to the thyroid cartilage, and the posterior end is attached to the vocal process of the arytenoid cartilage. Muscles of the larynx Extrinsic Muscles These muscles move the larynx up and down during swallowing. Elevation: The digastric, the stylohyoid, the mylohyoid, the geniohyoid, the stylopharyngeus, the salpingopharyngeus, and the palatopharyngeus muscles Depression: The sternothyroid, the sternohyoid, and the omohyoid muscles. Intrinsic Muscles ***the doctor s words are highlighted in red Muscles Controlling the Laryngeal Inlet Oblique arytenoids: from the Muscular process of arytenoid cartilage to the Apex of opposite arytenoid cartilage. Nerve supply : Recurrent laryngeal nerve Action : Narrows the inlet by bringing the aryepiglottic folds together Thyroepiglottic : from the Medial surface of thyroid cartilage to the Lateral margin of epiglottis and aryepiglottic fold Action : Widens the inlet by pulling the aryepiglottic folds apart Muscles Controlling the Movements of the Vocal Folds (Cords) Cricothyroid : from the Side of cricoid cartilage to the Lower border and inferior cornu of thyroid cartilage Supply: External laryngeal nerve Action : Tenses vocal cords (forward rotation of the thyroid ). Thyroarytenoid (vocalis): from the Inner surface of thyroid cartilage to Arytenoid cartilage supply : Recurrent laryngeal nerve
Action : Relaxes vocal cords(pulls the thyroid posterior to it s vertical position ). Lateral cricoarytenoid : from the Upper border of cricoid cartilage to the Muscular process of arytenoid cartilage Action : Adducts the vocal cords by rotating arytenoid cartilage(medial rotation) Posterior cricoarytenoid: from the Back of cricoid cartilage to the Muscular process of arytenoid cartilage Action : Abducts the vocal cords by rotating arytenoid cartilage(lateral rotation ) Transverse arytenoids: from the Back and medial surface of arytenoid cartilageto the Back and medial surface of opposite arytenoid cartilage Action: Closes posterior part of rima glottidis by approximating arytenoid cartilages(adduction of the arytenoids) *rima-glottidis : space between the vocal cords. Movements of the Vocal Folds with Respiration - On quiet inspiration, the vocal folds are abducted and the rima glottidis is triangular in shape with the apex in front. -On expiration, the vocal folds are adducted, leaving a small gap between them. -On deep inspiration, the vocal folds are maximally abducted and the triangular shape of the glottis becomes a diamond shape because of the maximal lateral rotation of the arytenoid cartilages. -Bi-lateral paralysis leads to suffocation. Nerve Supply of the Larynx Sensory Nerves: Above the vocal cords: The internal laryngeal branch of the superior laryngeal branch of the vagus Below the 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 the external laryngeal branch of the superior laryngeal branch of the vagus. *superior laryngeal gives 2 branches : internal and external laryngeal Blood Supply of the Larynx: Upper half of the larynx: The superior laryngeal branch of the superior thyroid artery Lower half of the larynx: The inferior laryngeal branch of the inferior thyroid artery Lymph Drainage of the Larynx The lymph vessels drain into the deep cervical group of nodes. Done by : marah marahleh Ps : the sheet contain many info from the book, I tried to cover the subject to the best of my abilities sorry for any mis info.