THE CRANIAL NERVES. 171 



the auditories, are distributed to the mucous membrane of 

 the pharynx, the posterior part of the tongue, and the 

 middle ear. 



The tenth pair (pneumogastric nerves or vagi), JT, arise 

 from the sides of the medulla oblongata. Each gives 

 branches to the pharynx, gullet and stomach, the larynx, 

 windpipe and lungs, and to the heart. The vagus runs 

 farther through the Body than any other cranial nerve. 



The eleventh pair (spinal accessory nerves), XI, do not 

 arise mainly from the brain but by a number of roots at- 

 tached to the lateral columns of the cervical portion of the 

 spinal cord, between the anterior and posterior roots of the 

 proper cervical spinal nerves. Each, however, runs into 

 the skull cavity alongside of the spinal cord and, getting a 

 few filaments from the medulla oblongata, passes out along 

 with the glossopharyngeal and pneumogastric nerves. Out- 

 side the skull it divides into two branches, one of which 

 joins the pneumogastric trunk, while the other is distrib- 

 uted to muscles about the shoulder. 



The twelfth pair of cranial nerves (liypoglossi)', XII, 

 arise from the sides of the medulla oblongata; they are 

 distributed mainly to the muscles of the tongue and the 

 hyoid bone. 



Deep Origins of the Cranial Nerves. The points re- 

 ferred to above, at which the various cranial nerves appear 

 on the surface of the brain, are known as their superficial 

 origins. From them the nerves can be traced for a less or 

 greater way in the substance of the brain until each is fol- 

 lowed to one or more masses of gray matter, which con- 

 stitute its proper starting-point and are known as its deep 

 origin. The deep origins of all except the first and second 

 and part of the eleventh lie in the medulla oblongata. 



The Ganglia and Communications of the Cranial 

 Nerves. Besides the Gasserian ganglion above- referred 

 to, many others are found in connection with the cranial 

 nerves. Thus for example there is one on each of the 

 main divisions of the trigeminal, two are found on each 

 pneumogastric and two in connection with the glosso- 

 pharyngeal. At these ganglia and elsewhere, the various 



