564 PHYSIOLOGY. 



THE ORGAN OF VOICE. 



The special organ of voice in man is that portion of the air- 

 passages called the larynx. It is a sort of hollow chamber which 

 extends from near the root of the tongue to the first ring of the 

 trachea. It is placed in the middle line of the neck, where it forms 

 a considerable projection, larger above than below. 



Although the larynx is the proper organ of voice, yet the lungs 

 and the moving parts of the thorax serve to propel the air through 

 this organ. The cavities above it, including the pharynx, mouth, and 

 nasal cavities, assist in modifying the vocal sounds. They are, there- 

 fore, adjunct organs of voice. 



Fig. 208. The Larynx as Seen with the Laryngoscope. (LANDOIS.) 



L., Tongue. E., Epiglottis. V., Vallecula. R., Glottis. L. v., True vocal 



cords. 8. M., Sinus Morgagni. L. v. s., False vocal cords. P., Position of 



pharynx. S., Cartilage of Santorini. W., Cartilage of Wrisberg. S.p., Sinus 

 pyriformis. 



Anatomy of the Larynx. The larynx consists of a cartilaginous 

 skeleton which constitutes its walls; also vocal cords; muscles which 

 move directly the cartilaginous pieces, and influence indirectly the 

 tension of the cords; and finally, a mucous membrane which lines 

 the internal cavity. 



CARTILAGES. The cartilages of the larynx are four in number: 

 two unlike and two alike. One of the former is inferior and exists 

 in the form of a signet-ring. It is the cricoid. This cartilage is 

 continuous with the rings of the trachea. Its narrower portion is 

 situated anteriorly ; its wider portion is placed posteriorly. It ar- 

 ticulates with the inferior cornua of the thyroid cartilage, forming 

 the crico-thyroid articulation. 



The other odd cartilage, the superior one, is called the thyroid. 

 It is composed of two quadrilateral laminae which meet in front 



