AUDITORY NERVE. EIGHTH PAIR. 615 



(b) The supramaxiUary branch, sometimes double, gives an offset over the side of 

 the maxilla to the angle of the mouth, and is then directed inwards, beneath the 

 depressor of the angle of the mouth, to the muscles and integument between the lip 

 and chin ; it joins with the labial branch of the lower dental nerve. 



(c) The inframaxillary branches (r. subcutanei colli), perforate the deep cervical 

 fascia, and, placed beneath the platysma muscle, form arches across the side of the 

 neck as low as the hyoid bone. Some branches join the superficial cervical nerve 

 beneath the platysma, others enter that muscle, and a few perforate it to end in the 

 integument. 



Summary. The facial nerve is the motor nerve of the face. It is 

 distributed to most of the muscles of the ear, and to the muscles of the 

 scalp ; to those of the mouth, nose, and eyelids ; aud to the cutaneous 

 muscle of the neck (platysma). It likewise supplies branches to the integu- 

 ment of the ear, to that of the side and back of the head, as well as to that 

 of the face and the upper part of the neck. 



This nerve is connected freely with the three divisions of the fifth nerve, 

 and with the submaxillary and spheno-palatine ganglia ; with the glosso- 

 pharyngeal and pneuino-gastric nerves : with the auditory, and with parts 

 of the sympathetic and the spinal nerves. 



AUDITORY NERVE. 



The auditory nerve, or portio mollis of the seventh pair, is the special nerve 

 of the organ of hearing, and is distributed exclusively to the internal ear. 



As the auditory nerve is inclined outwards from its connection with the 

 medulla oblongata to gain the internal auditory meatus, it is in contact 

 with the facial nerve, being only separated from it in part by a small artery 

 destined for the internal ear. Within the meatus the two nerves are con- 

 nected to each other by one or two small filaments. Finally the auditory 

 nerve bifurcates in the meatus : one division, piercing the anterior part of 

 the cribriform lamina, is distiibuted to the cochlea ; the other, piercing the 

 posterior half of the lamina, enters the vestibule of the internal ear. The 

 distribution of these branches will be described with the ear. 



EIGHTH PAIR OF NERVES. 



The eighth pair is composed of three distinct nerves the glosso-pharyn- 

 geal, pneumo-gastric, and spinal accessory, which leave the skull through the 

 anterior and inner division of the foramen lacerum posticum, to the inner 

 side and in front of the internal jugular vein. Two of these nerves, the 

 glosso-pharyngeal and pneumo-gastric, are attached to the medulla oblongata 

 in the same line, and resemble one another somewhat in their distribution, 

 for both are distributed to the first part of the alimentary canal. The other, 

 the spinal accessory, takes its origin chiefly from the spinal cord, and is 

 mainly distributed to muscles ; but it gives fibres to the first two nerves by 

 its communicating branch. 



GLOSSO-PHARYNGEAL NERVE. 



The glosso-pharyngeal nerve is destined, as the name implies, for the 

 tongue and pharynx. Directed outwards from its place of origin over the 

 flocculus to the foramen jngulare, it leaves the skull with the pneumo-gastric 

 and spinal- accessory nerves, but in a separate tube of dura mater. In passing 

 through the foramen, somewhat in front of the others, this nerve is 

 contained in a groove, or in a canal in the lower border of the petrous 



