CHAP, vii.] SPECIAL MUSCULAR MECHANISMS. 



1453 



isosceles triangle with the apex dipping beneath the cushion 

 of the epiglottis, the sides formed by the vocal cords, and the 

 base by the arytenoids with the membrane between them. In 

 a favourable view (Fig. 185) the vocal cords (v.c.) may be seen 

 to be attached to the processus vocales and the distinction between 

 the membranous and cartilaginous glottis observed. On the 

 outside of each vocal cord, separated from it by the mouth of the 

 corresponding ventricle of the larynx and reaching to the side of 

 the laryngeal aperture, may be seen the ventricular band (c. v. s). 

 By their white colour the vocal cords present a strong contrast to 

 the rest of the larynx. 



FIG. 186. THE LARYNX AS SEEN BY MEANS OF THE LAKYNGOSCOPE IN DIFFERENT 

 CONDITIONS OF THE GLOTTIS. (From Quain's Anatomy, after Czermak. ) 



A while singing a high note ; B in quiet breathing ; C during a deep inspiration. 

 The corresponding diagrammatic figures A', B', C", illustrate the changes in 

 position of the arytenoid cartilages, and the form of the rima vocalis and 

 rima respiratoria in the above three conditions. 



I the base of the tongue ; e the upper free part of the epiglottis ; e' the 

 tubercle or cushion of the epiglottis ; ph. part of the anterior wall of the 

 pharynx behind the larynx ; w swelling in the aryteno-epiglottidean fold 

 caused by the cartilage of Wrisberg ; s swelling caused by the cartilage of 

 Santorini ; a the summit of the arytenoid cartilage ; cv the vocal cords ; 

 cvs the ventricular bands ; tr the trachea with its rings ; 6 the two bronchi at 

 their commencement. 



