Vocal Cords

About the Vocal Cords

The vocal cords, more precisely called the vocal folds, are two infoldings of mucous membrane stretched across the larynx from the thyroid cartilage at the front to the arytenoid cartilages at the back. The opening between them is the rima glottidis, and together they form the glottis. Each fold has a layered structure: a surface epithelium, a loose gel like superficial layer known as Reinke space, the vocal ligament, and the vocalis portion of the thyroarytenoid muscle. During speech, air from the lungs sets the loose outer cover vibrating in a rippling mucosal wave, producing sound. Pitch rises as the folds are stretched and thinned, mainly by the cricothyroid muscle, and loudness increases with air pressure from the lungs. The folds are typically longer and thicker in adult males, giving a lower voice. Above them lie the vestibular or false vocal folds, which have a mainly protective role. Most laryngeal muscles are supplied by the recurrent laryngeal nerve, a branch of the vagus, so damage to it can paralyze a fold and cause hoarseness. Laryngitis, vocal nodules from repeated strain, polyps, Reinke edema associated with smoking, and laryngeal cancer commonly affect the vocal folds.