662 



TEXT-BOOK OF PHYSIOLOGY 



from which it takes its origin. The fibers of the muscle pass upward and 

 outward and in their course converge to be inserted into the external angle of 

 the arytenoid cartilage. The superior and more horizontally directed fibers 

 rotate the arytenoid around its vertical axis; the inferior and obliquely 

 directed fibers draw the cartilage downward and inward. As a result of the 

 action of the muscle in its entirety, the vocal process is turned upward and 

 outward, and as the vocal band is carried with it the glottis is widened 

 a condition necessary to the free entrance of air into the lungs (Fig. 278)' 

 Since the contraction of the crico-arytenoid has this result, it is generally 

 spoken of as the abductor or respiratory muscle. 





mh K the side of the 



From th ls point its fibers are directed upward and backward 



to be inserted into the external process of the arytendd Itfactfon is to 



f rWard ^ d ' * approximating 

 The thyro-arytenoid muscle arises from the inferior two-thirds of the 



is*5H^s^-*BgtSaa- 



