446 CRANIAL NERVES. 



with the aliments. Longet, moreover, found that small 

 quantities of food may be digested after section of these 

 nerves. 



Spinal Accessory. The eleventh cranial nerve arises 

 from the oblong medulla, just behind the pneumogastric, 

 and from the lateral aspect of the spinal cord, as far back- 

 ward as the sixth spinal nerves. It emerges from the 

 cranium with the ninth and tenth, and divides into two 

 branches, one of which joins the pneumogastric, and the 

 other is distributed to the muscles of the neck and shoulder. 

 It is essentially a motor nerve acting on the cervical 

 muscles, and, through its pneumogastric branch, on those of 

 the larynx. Its action on the larynx is to render tense the 

 vocal cords, in order to the production of voice. The fibres 

 of the branch rendered to the pneumogastric would seem 

 to incorporate themselves with those of the recurrent nerve, 

 and with it proceed to the larynx. Its control over the 

 voice is proved by the fact, that section of the branch given 

 to the pneumogastric produces instantaneous and complete 

 aphonia, though the latter nerve be uninjured. Bernard 

 has found that the fibres which preside over phonation 

 belong to the anterior roots of the nerve, being all in front 

 of the first cervical nerve. After division on both sides of 

 the roots derived from the spinal cord, the voice remained 

 perfect as before, whereas, when those in front of the first 

 spinal nerve were cut, the voice became at first hoarse, and 

 as soon as the connection with the oblong medulla was de- 

 stroyed, became completely lost. The same result followed 

 the division of the anterior roots, though those derived from 

 the cord were left intact. In some cases the subjects were 

 preserved for months, and even for years, during which the 

 condition of aphonia continued. If injured, they opened 

 their jaws as if to cry, but a somewhat hurried expiration 



