554 



CRANIAL NERYES. 



mater, contained in, a groove in the anterior surface of the petrous portion of the 

 temporal bone, enters the hiatus Fallopii, and, being continued through it, into 

 the aquseductus Fallopii, joins the gangliform enlargement on the facial nerve. 

 Properly speaking, this nerve passes from the facial to the spheno-palatine 

 ganglion, forming its motor root. 



The carotid branch is shorter but larger than the petrosal, of a reddish-gray 

 color, and soft in texture. It crosses the foramen lacerum, surrounded by .the 

 cartilaginous substance which fills in that aperture, and enters the carotid canal, 

 on the outer side of the carotid artery, to join the carotid plexus. 



The Pharyngeal nerve (ptery go-palatine) is a small branch arising from the back 

 part of the ganglion, occasionally springing from the Vidian nerve. It passes 

 through the ptery go-palatine canal with the ptery go-palatine artery, and is dis- 

 tributed to the lining membrane of the pharynx, behind the Eustachian tube. 



(3.) OTIC OR ARNOLD'S GANGLION. 



The OTIC GANGLION (Arnold's) is a small, oval-shaped, flattened ganglion of a 

 reddish-gray color, situated immediately below the foramen ovale, on the inner 

 surface of the inferior maxillary nerve, and round the origin of the internal 

 pterygoid nerve (fig. 282). It is in relation, externally, with the trunk of the infe- 

 rior maxillary nerve, at the point where the motor root joins the sensory portion ; 

 internally, with the cartilaginous part of the Eustachian tube, and the origin of 

 the Tensor palati muscle ; behind it, is the middle meningeal artery. 



Fig. 282. The Otic Ganglion and its Branches. 



Branches of communication. This ganglion is connected with the inferior 

 maxillary nerve, and its internal pterygoid branch, by two or three short, delicate 

 filaments, and also with the auriculo-temporal nerve ; from the former, it obtains 

 its motor, from the latter, its sensory root; its communication with the sympathetic 

 being effected by a filament from the plexus surrounding the middle meningeal 

 artery. This ganglion also communicates with the glosso-pharyngeal and facial 

 nerves, through the small petrosal nerve continued from the tympanic plexus. 



Its branches of distribution are a filament to the Tensor tympani, and one to the 

 Tensor palati. The former passes backwards, on the outer side of the Eustachian 

 tube ; the latter arises from the ganglion, near the origin of the internal pterygoid 

 nerve, and passes forwards. 



