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pl. larynges [Gr. larynx, stem laryng-, wind pipe, larynx]
A tube composed of cartilage that begins at the pharynx and forms the initial segment of the respiratory tree, extending from the base of the tongue to the trachea. Its closing mechanisms prevent the aspiration of liquids and solids during swallowing and allow coughing and the production of vocalizations.
SYN: SEE: voice box
The framework of the larynx is composed of three single cartilages and three paired cartilages. The unpaired cartilages are: the cricoid cartilage, a thick cartilage ring on top of the trachea; the thyroid cartilage, a V-shaped cartilage that sits on the cricoid with the point of its V facing forward; and above this, the epiglottic cartilage, shaped like an upright paddle, with its handle held inside the front angle of the thyroid cartilage. The three smaller paired cartilages are: the arytenoids, the corniculates, and the cuneiforms. These nine cartilages are held together by membranes and ligaments, usually named by the structures that are interconnected; e.g., the cricothyroid membrane connects the front of the cricoid cartilage with the base of the thyroid cartilage in the midline.
The intrinsic muscles of the larynx (cricothyroid, posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, transverse and oblique arytenoids, and vocalis) alter the length and tension of the vocal cords and the size and shape of the opening between them (the rima glottis). The vagus nerve supplies motor and sensory innervation to the larynx; the cricothyroid muscle is innervated by the external laryngeal branch of the vagus, while the other intrinsic muscles are innervated by the recurrent laryngeal branch of the vagus.
The cavity within the larynx comprises three consecutive chambers. The first chamber, the vestibule of the larynx, is a tube between the pharynx and a pair of folds, the vestibular folds (false vocal cords), that protrude into the larynx. The second chamber, the ventricle of the larynx, is a short segment between the vestibular folds and the vocal folds; the ventricle has lateral recesses extending laterally under the vestibular folds. The third chamber, the infraglottic cavity (infraglottic larynx, subglottic space), is a tube between the vocal folds and the trachea.