CHAP, xxxi.] VOCAL CHORDS. 435 



The Epiglottis is a remarkable valve-like cartilage in shape, 

 like the spout of a ewer. It seems to issue from the angle be- 

 tween the alse of the thyroid cartilage to which it is attached by 

 a stalk-like ligament. It projects above the root of the tongue, 

 and lies between that organ and the aperture of the larynx, like 

 a valve, which is pressed over the glottis when the tongue is re- 

 tracted. Its upper border is convex, and its posterior surface 

 is concave, transversely convex in its length. It is a smooth and 

 very flexible cartilage, covered by mucous membrane, but pene- 

 trated by holes and depressions, in which are lodged the numerous 

 mucous glands of the membrane that covers it. 



Such is the skeleton of the larynx : it hangs from the hyoid 

 bone, suspended by the thyro-hyoid ligament and muscles, and, 

 through the hyoid apparatus and some muscles, it is brought into 

 connexion with the lower jaw and the base of the cranium. 



Vocal Chords or Superior Thyro- Arytenoid Ligaments. The various 

 cartilages of the larynx are connected to each other by ligaments. 

 Of these the most important and interesting, as being the 

 essential part of the mechanism for producing vocal sounds, 

 are the bands of fibrous tissue which extend from the anterior 

 angle of the base of the arytenoid cartilages to the angle between 

 the wings of the thyroid. These are the thyro-arytenoid liga- 

 ments, or, in physiological language, the vocal chords. They are 

 bands of elastic ligament, extending between the points named 

 (t, v, fig. 212). They do not, in the quiescent state, lie parallel 

 to each other, but converge from behind forwards : their relative 

 position, as well as their tension, can be varied to a considerable 

 degree by reason of the mobility of the arytenoid cartilages. The 

 length of the vocal chords is greater in the adult male than in the 

 female being as 3 : 2. 



The elastic chordae vocales are connected by an expansion of 

 elastic tissue with the superior thyro-arytenoid ligaments, which 

 are small bands of the same tissue extending from the apices of 

 the arytenoid cartilages to the hollow angle of the thyroid, and 

 separated from the inferior by a space called the ventricle of the 

 larynx. These superior ligaments are likewise known as the false 

 chordae vocales. 



Much importance is attached by Lauth, Miiller, and others to 

 the fact, that many of the ligaments of the larynx are composed of 

 elastic tissue, and connected together by a fibrous expansion of a 

 similar structure. Lauth describes the elastic tissue of the larynx 



