Electrolarynx

the muscular and cartilaginous structure, lined with mucous membrane, situated at the top of the trachea and below the root of the tongue and the hyoid bone; it contains the vocal cords and is the source of the sound heard in speech. The larynx is part of the respiratory system; air passes through it traveling from the pharynx to the trachea on its way to the lungs and again returning to the exterior.

The larynx is composed of nine cartilages that are held together by muscles and ligament: the single thyroid, cricoid, and epiglottic cartilages and the paired arytenoid, corniculate, and cuneiform cartilages. (See also color plates.) The largest of these, the thyroid cartilage, forms the Adam's apple, which protrudes in the front of the neck. Two flexible vocal cords reach from the back to the front wall of the larynx and are manipulated by small muscles to produce sound. The epiglottis, a flap or lid at the base of the tongue, closes the larynx as it is lifted up during swallowing and so prevents passage of food or drink into the larynx and trachea.