The Throat and the Voice 



279 



These folds are the true vocal cords, by the movement of 

 which the voice is produced. 



Above them are other folds of mucous membrane called 

 the false vocal cords, which take no part in the production 

 of the voice. 



The arrangement of the true 

 vocal cords, projecting as they do 

 towards the middle line, reduces to 

 a mere chink the space between 

 the part 'of the larynx above them 

 and the part below them. This 

 constriction of the larynx is called 

 the glottis. 



- 436. The Mechanism of the Voice. 

 The mechanism of the voice may be 

 more easily understood by a study 

 of Fig. 151. We have here the 

 larynx, viewed from behind, with 

 all the soft parts in connection 

 with it. On looking down, the 

 folds forming the true vocal cords 

 are seen enclosing a V-shaped 

 aperture (the glottis), the narrow 

 part being in front. 



The form of this aperture may 

 be changed by the delicately 

 coordinate action of the muscles of the larynx. For 

 instance, the vocal cords may be brought so closely together 

 that the space becomes a mere slit. Air forced through 

 the slit will throw the edges of the folds into vibration, and 

 a sound will be produced (Figs. 153 and 154). 



The variations in the form of the opening will determine 

 the variations in the sound. If the various muscles of the 



FIG. 151. View of the Carti- 

 lages and Ligaments of the 

 Larynx. (Posterior view.) 



A, epiglottis; B, thyroid carti- 

 lage; C, arytenoid cartilage; 



D, ligament connecting lower 

 cornu of the thyroid with the 

 back of the cricoid cartilage; 



E, cricoid cartilage ; F, upper 

 ring of the trachea. 



