The vocal cords are two fibrous elastic bands. Each is attached at one end to the apex of the arytenoid cartilage, and at the other end to the median ridge on the dorsal surface of the thyroid. Each supports a projecting fold of mucous membrane, the vibration of which causes the voice.
Muscles of the Larynx.
—1. Muscles moving the entire larynx.
A. Elevators. M. thyreohyoideus ([Fig. 96], p, [page 229]).—A flat band on the lateral side of the larynx.
Origin on the lateral part of the caudal border of the thyroid cartilage.
Insertion on the medial two-thirds of the caudal border of the caudal cornu of the hyoid.
Action.—Raises the larynx.
The stylohyoid ([Fig. 65], d, [page 109]) and the median and inferior constrictors ([Fig. 96], j and k) of the pharynx, already [described], have the same action.
B. Depressors.—The sternothyroid ([Fig. 65], g′), already described ([p. 141]).
2. Muscles which move the parts of the larynx one upon another.