THE CRANIAL NERVES 283 



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 

 maxilla, give off twigs to the fangs of the molar teeth, sup- 

 plying them with sensation. In the infra-orbital canal the 

 superior maxillary nerve gives off (a) the middle superior 

 dental, which runs downward 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 sup- 

 ply sensation to the regions indicated by their names. 



3. The Inferior Maxillary Branch after its exit from the 

 cranium is a mixed nerve, supplying motion to the muscles 

 of mastication as well as common sensation to the parts 

 presently to be noted, and special sense to a part of the 

 tongue. Its large or sensory root comes from the Gasserian 

 ganglion to be joined just beneath the base of the skull by 

 the small motor root which has passed -under the ganglion. 

 Almost immediately this common trunk divides into (a) 

 anterior and (b) posterior branches, but first gives off a re- 

 current meningeal branch and a branch to the internal ptcry- 

 goid muscle. 



(a) The anterior of the two divisions of the inferior max- 

 illary nerve receives nearly the whole of the motor root and 

 divides into branches which supply the muscles of mastica- 

 tion, excepting the internal pterygoid and the buccinator. 



(b) The posterior division, chiefly sensory, divides into 

 the auriculo-temporal, lingual and inferior dental branches. 

 The auriculo-temporal branch runs backward to a point in- 

 ternal to the neck of the condyle of the inferior maxilla, then 

 passing upward under the parotid gland divides into 

 ^branches, which are distributed to the external auditory 



