282 THE NERVOUS SYSTEM 



cranium in the frontal and parietal regions, (c) The nasal 

 branch, crossing to the inner wall of the orbit, enters the anterior 

 ethmoidal foramen, passes thus into the cranium again, runs in a 

 groove on the cribriform plate of the ethmoid and finds exit into 

 the nose through a slit by the side of the crista galli. Here it 

 gives off branches which supply common sensation to the mucous 

 membrane of the fore part of the nose, and then running in a 

 groove on the posterior surface of the nasal bone, it leaves the 

 cavity at the lower border of that bone to supply the integument 

 of the ala and tip of the nose. From the nasal nerve pass fibers 

 to the ophthalmic ganglion and to the ciliary muscle, iris and 

 cornea. 



2. The Superior Maxillary Branch passes away from the 

 Gasserian ganglion and leaves the cranium by the foramen ro- 

 tundum. Crossing the spheno-maxillary fossa it enters the orbit 

 through the spheno-maxillary fissure and traverses the infra- 

 orbital canal to emerge upon the face at the infra-orbital foramen. 

 In the cranium it gives off a meningeal branch to supply the 

 neighboring dura mater. In the spheno-maxillary fossa it sup- 

 plies branches (a) to the integument over the temporal and post- 

 frontal regions and over the cheeks; (b) to the spheno-palatine 

 ganglion ; (c) the posterior superior dental branches (generally 

 two), which enter the posterior dental canals in the zygomatic 

 fossa, and, passing forward in the substance of the superior max- 

 illa, give off twigs to the fangs of the molar teeth, supplying them 

 with sensation. In the infra-orbital canal the superior maxillary 

 nerve gives off (a) the middle superior dental, which runs down- 

 ward and forward in the outer wall of the antrum to reach the 

 roots of the bicuspid teeth; (b) the anterior superior dental, 

 which likewise runs in the outer wall of the antrum to supply the 

 incisor and canine teeth. After its exit from the infra-orbital 

 canal the nerve divides into palpebral, nasal and labial 

 branches, which supply sensation to the regions indicated by 

 their names. 



