596 



THE CRANIAL NERVES. 



The roots of the fifth nerve, after emerging from the surface of the 

 encephalon, are directed forwards, side by side, to the middle fossa of the 

 skull, through a recess in the dura mater on the summit of the petrous 

 part of the temporal bone. Here the larger root alters in appearance : its 



Fig- 404. Fig. 404. GENERAL PLAN 



OP THE BRANCHES OF 

 THE FIFTH PAIR (after 

 a sketch by Charles 

 Bell), i 



1, lesser root of the 

 fifth pair ; 2, greater 

 root passing forwards 

 into the Gasserian gang- 

 lion ; 3, placed on the 

 bone above the ophthal- 

 mic nerve, which is seen 

 dividing into the supra- 

 orbital, lachrymal, and 

 nasal branches, the latter 

 connected with the oph- 

 thalmic ganglion ; 4, 

 placed on the bone close 

 to the foramen rotundum, 

 marks the superior max- 

 illary 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 submaxillary nerve, 

 giving off the anterior auri- 

 cular and muscular bran- 

 ches, and continued by the 

 inferior dental to the lower 

 jaw, and by the gustatory 



to the tongue ; a, the submaxillary gland, the submaxillary ganglion placed above it in 

 connection with the gustatory nerve ; 6, the chorda tympaui ; 7, the facial nerve issuing 

 from the stylo-rnastoid foramen. 



fibres diverge a little, become reticulated, and enter the Gasserian ganglion. 

 The smaller root passes inside and beneath the ganglion, without its nerve- 

 fibres being incorporated in any way with it, and joins outside the skull the 

 lowest of the three trunks which issue from the ganglion. 



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

 occupies a depression on the upper part of the petrous portion of the 

 temporal bone, near the point, and is somewhat crescentic in form, the 

 convexity being turned forwards. On its inner side the ganglion is joined 

 by filaments from the carotid plexus of the sympathetic nerve, and, accord- 

 ing to some anatomists, it furnishes from its back part filaments to the 

 dura mater. 



From the fore part, or 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 upper maxillary nerve, is continued forwards 

 to the face, below the orbit ; and the third, the lower maxillary nerve, is 

 distributed chiefly to the external ear, the tongue, the lower teeth, and the 

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



