ORGANS OF SPEECH. 



85 



FIG. 45. 



hinged cover called the epiglottis. The interior of the 

 tube is lined with a continuation of the mucous mem- 

 brane of the mouth. 



The cartilages that 

 help form the larynx 

 are the thyroid in front, 

 the cricoid below and 

 behind, and the two 

 arytenoids above and 

 behind. These parts 

 are joined by ligaments 

 that allow some motion, 

 and by certain muscles 

 that somewhat change 

 their respective posi- 

 tions. The more im- 

 portant ligaments, and 

 the only ones that are 

 indispensable for the 

 formation of the voice, 

 are the inferior liga- 

 ments or vocal cords; 

 these are more or less 

 stretched, and closer 

 together or farther 

 apart, according to the 

 movements given by 

 the muscles of the 

 larynx to the different cartilages. The opening between 

 them through which the air passes is called the glottis. 

 During the production of vocal sound, the form of the 

 glottis is a narrow slit ; when at rest, the opening is 

 triangular. Above the vocal cords are two other liga- 



FRONT VIEW OP THE LARYNX. 1, hyoid 

 bone ; 2, greater cornu ; 3, small cornu ; 

 4, lateral thyro-hyoid ligament; 5, nod- 

 ular cartilage; 6, middle thyro-hyoid 

 ligament; 7, thyroid cartilage; 8, su- 

 perior horn ; 9, inferior horn ; 10, cricoid 

 cartilage ; 11, crico-thyroid ligament; 12, 

 crico-ary-thyroid ligament; 13, 14, first 

 and second rings of the trachea. 



