THE VOICX 



311 



broad part placed posteriorly (Fig. 73, E). At the top of the 

 ericoid cartilage are situated the two small arytenoid cartilages, 

 the right one of which is shown in Fig. 73, c. These latter 

 little organs are much more movable than the other two, and 

 are very important in the production of the voice. They have 

 a true ball-and-socket joint, and several small muscles which 

 contract and relax with as perfect regularity and accuracy as 

 any of the larger muscles of the body. 



6. The interior of the larynx is lined with a very sensitive 

 mucous membrane, which is much more 



closely adherent to the parts beneath 

 than is usually the case with membranes 

 of this description. The epiglottis (A), 

 consisting of a single leaf-shaped piece 

 of cartilage, is attached to the front part 

 of the larynx. It is elastic, easily moved, 

 and fits accurately over the entrance to 

 the air-passages below it. Its office is 

 to guard these delicate passages and the 

 lungs against the intrusion of food and 

 other foreign articles, when the act of 

 swallowing takes place. It also assists 

 in modifying the voice. 



7. The Vocal Cords. Within the 

 larynx, and stretched across it from the 

 thyroid cartilage in front to the ary- 

 tenoid cartilages behind, are placed the 

 two sets of folds called the vocal cords. t 



FIG. 73. SECTION OF THK 

 The Upper Of these, One On each Side, LARYNX AND TRACHBA 



are the false cords, which are compara- A > The Epiglottis 



,. , .c , i n -i_i mi. B, The Thyroid Cartilage 



tively fixed and inflexible. These are c , Arytenoid cartilage 

 not at all essential to the formation of Y<: nt c1 ' [., the Lar y nx 



; E, Cricoid Cartilage 



vocal sounds, for they have been injured, F, Right Vocal cord 



in those lower animals whose larynx H ' Ty 



resembles that of man, without materially affecting their 



characteristic cries. Below these, one on each side, are th 



ft. Lining of the interior of the larynx ? The epiglottis ? 



T. "WMr* are the vocal cords ? The false cords ? The true ori f 



