234 



THE CKAN1AL NEBVE8. 



From the pons, the two roots are directed forwards beneath the anterior extremity 

 of the tentorium to the middle fossa of the base of the skull, and enter a recess in 

 the dura mater (cavum MecTceUi) over the summit of the petrous part of the temporal 

 bone. Here the large root becomes expanded, and its funiculi divide and unite so as 

 to form a plexiform network which is continued into the Gasserian ganglion. The 

 small root inclines downwards on the inner side of the large root, and then passes 

 outwards beneath the ganglion, without its fibres ? being incorporated in any way 

 with the latter, to join below the foramen ovale the lowest of the three trunks 

 issuing from the ganglion. 



The ganglion of the fifth nerve or Gasserian ganglion (ganglion semilunare) 

 occupies a depression on the upper surface of the petrous portion of the temporal 

 bone, near the apex, and is somewhat crescentic in form, the convexity being 

 turned forwards. It is flattened, and striated on the surface. Its internal part 



Fig. 154. GENERAL PLAN OF THE 



BRANCHES OF THE FIFTH PAIR. 



(After a sketch by Charles Bell.) ^ 



1, small root of the fifth nerve ; 2, 

 large root, passing forwards into the 

 (rasserian ganglion ; 3. placed on the 

 bone above the ophthalmic nerve, which 

 is dividing into the frontal, lachrymal, 

 and nasal branches, the latter connected 

 with the ciliary ganglion ; 4, placed on 

 the bone close to the foramen rotundum, 

 marks the superior maxillary division, 

 which is connected below with the 

 spheno-palatine ganglion, and passes 

 forwards to the infraorbital foramen ; 5, 

 placed on the bone over the foramen 

 ovale, marks the inferior maxillary nerve, 

 giving off the auriculo-temporal and 

 muscular branches, and continued by the 

 inferior dental to the lower jaw, and by 

 the lingual to the tongue ; a, submaxil- 

 lary gland, the submaxillary ganglion 

 placed above it in connection with the 

 lingual nerve ; 6, chorda tympani ; 7, 

 facial nerve, issuing from the stylo- 

 mastoid foramen. 



comes into close relation with the posterior extremity of the cavernous sinus and the 

 internal carotid artery. On its inner side the ganglion is joined by filaments from 

 the carotid plexus of the sympathetic nerve ; and, according to some anatomists, 

 it furnishes from its back part filaments to the dura mater. The cells of this 

 ganglion are similar to those found on the posterior roots of the spinal nerves. 



From the convex border of the Gasserian ganglion proceed the three large 

 divisions of the nerve. The highest (first or ophthalmic trunk) enters the orbit ; 

 the second, the superior maxillary nerve, is continued forwards to the face between 

 the orbit and mouth ; and the third, the inferior maxillary nerve, is distributed 

 chiefly to the external ear, the tongue, the lower teeth, the face below the mouth, 

 and the muscles of mastication. The first two trunks proceed exclusively from the 

 ganglion and are entirely sensory, while the third or inferior maxillary trunk, 

 derived principally from the ganglion, has associated with it also the whole of the 

 fibres of the motor root, and thus distributes both motor and sensory branches. 



