EIGHTH PAIR. 555 



(4.) SUBMAXILLARY GANGLION. 



The SUBMAXILLARY GANGLION (fig. 280) is of small size, circular in form, and 

 situated above tne deep portion of the submaxillary gland, near the posterior 

 border of the Mylo-hyoid muscle, being connected by filaments with the lower 

 border of the gustatory nerve. 



Branches of communication. This ganglion is connected with the gustatory 

 nerve by a few filaments which join it separately, at its fore and back part. It 

 also receives a branch from the chorda tympani, by which it communicates with 

 the facial ; and communicates with the sympathetic by filaments from the nervi 

 molles, surrounding the facial artery. 



Branches of distribution. These are five or six in number ; they arise from the 

 lower part of the ganglion, and supply the mucous membrane of the mouth and 

 Wharton's duct, some being lost in the submaxillary gland. According to Meckel, 

 a branch from this ganglion occasionally descends in front of the Hyo-glossus 

 muscle, and, after joining with one from the hypoglossal, passes to the Gemo- 

 hyo-glossus muscle. 



EIGHTH PAIR. 



The eighth pair consists of three nerves, the glosso-pharyngeal, pneumogastrie, 

 and spinal accessory. 



(1.) GLOSSO-PHARYNGEAL NERVE. 



The GLOSSO-PHARYNGEAL NERVE is distributed, as its name implies, to the 

 tongue and pharynx, being the nerve of . 



. i i j? J.T. Fie. 283. Origin of the Eighth Pair, their 



sensation to the mucous membrane ot the Ganglia and Communications. 



pharynx, fauces, and tonsil ; of motion, to 



the Pharyngeal muscles, and a special 



nerve of taste, in all the parts of the 



tongue to which it is distributed. It is 



the smallest of the three divisions of the 



eighth pair, and arises by three or four 



filaments, closely connected together, from 



the upper part of the medulla oblongata, 



immediately behind the olivary body. 



Its deep origin may be traced through 

 the fasciculi of the lateral tract, to a 



nucleus of gray matter at the lower part of the floor of the fourth ventricle, 

 external to the fasciculi teretes. From its superficial origin, it passes outwards 

 across the flocculus, and leaves the skull at the central part of the jugular foramen, 

 in a separate sheath of the dura mater and arachnoid, in front of the pneumogastric 

 and spinal accessory nerves. In its passage through the jugular foramen, it grooves 

 the lower border of the petrous portion of the temporal bone ; and, at its exit from 

 the skull, passes forwards between the jugular vein and internal carotid artery, 

 and descends in front of the latter vessel, and beneath the styloid process and the 

 muscles connected with it, to the lower border of the Stylo-pharyngeus. The nerve 

 now curves inwards, forming an arch on the side of the neck, lying upon the 

 Stylo-pharyngeus and the Middle constrictor of the pharynx, above the superior 

 laryngeal nerve. It*then passes beneath the Hyo-glossus, and is finally distributed 

 to the mucous membrane of the fauces, and base of the tongue, the mucous glands 

 of the mouth and tonsil. 



In passing through the jugular foramen, the nerve presents, in succession, two 

 gangliform enlargements. The superior one, the smaller, is called the jugular 

 ganglion ; the inferior and larger one, the petrous ganglion or the ganglion of 

 Andersch. 



The superior or jugular ganglion is situated in the upper part of the groove 

 in which the nerve is lodged during its passage through the jugular foramen. It 



