452 



THE CRANIAL NERVES. 



Fig. 150. 



and the mucous membrane of the lachrymal sac. It also sends off 

 a small branch (nasal branch) which penetrates into the nasal pas- 

 sages and supplies the Schneiderian mucous membrane. It then 

 ernerges upon the face by the supra-orbital foramen, and is distri- 

 buted to the integument of the forehead and side of the head as far 

 back as the vertex. 



The second division of this nerve, or the superior maxillary, 

 passes out by the foramen rotundum, and runs along the longitu- 

 dinal canal in the floor of the orbit, giving off branches during its 

 passage to the teeth of the upper jaw and to the mucous membrane 

 of the antrum maxillare. It finally emerges upon the middle of the 

 face by the infra -orbital foramen, and is distributed to the integu- 

 ment of the lower eyelid, nose, cheek, and upper lip. 



The third, or inferior maxillary division of the fifth pair, which 

 is the largest of the three, leaves the cavity of the cranium by the 



foramen ovale. It comprises a con- 

 siderable portion of the large root 

 of the nerve, and all the fibres of 

 the small root. This division is 

 therefore a mixed nerve, containing 

 both motor and sensitive fibres, 

 while the two former are exclu- 

 sively sensitive. It is distributed, 

 accordingly, both to muscles and 

 to the sensitive surfaces. Soon after 

 emerging from the foramen ovale 

 it sends branches to the temporal 

 muscle, to the masseter, the bucci- 

 nator, and to the internal and ex- 

 ternal pterygoids; that is, to the 

 muscles which are particularly con- 

 cerned in the movements of the 

 lower jaw. It also sends sensitive 

 filaments to the integument of the 



temple, to that of a portion of the external ear and external audi- 

 tory meatus. The third division of the fifth pair, then passing 

 downward and forward, gives off a branch of considerable size, the 

 lingual branch, which is distributed to the mucous membrane of the 

 anterior two-thirds of the tongue, and which also sends filaments to 

 the arches of the palate and to the mucous membrane of the cheek. 



DISTRIBUTION OF FIFTH NERVE 

 CPOW THE FACE. a. Casserian ganglion. 

 1 Ophthalmic division. 2. Superior maxil- 

 lary division. 3. Inferior maxillary division. 



