Mechanics of voice production
Anatomy of Throat
The vocal apparatus of the larynx (the glottis) consists of a pair of true vocal cords that are lengthened, abducted and adducted by numerous muscles, thereby changing the tension of the cords and the amount of space between them. The musculature is innervated by two branches of the vagus nerve, the superior laryngeal and the recurrent laryngeal nerves (dominant supply).
During speech a column of air is passed through the adducted vocal cords, causing them to vibrate and produce sound that is shaped into articulated speech with the help of the oropharynx, tongue and lips. Any changes in the vocal cord or controlling structures may result in an abnormal voice production by interfering with cord movement, approximation or vibration (organic dysphonia). On the other hand dysphonia may still be present with normal anatomy (functional dysphonia).