TRIFACIAL NERVE 



523 



tal branch of the superior maxillary nerve, passes through the lachrymal 

 gland, to which certain of its filaments are distributed, and its terminal 

 filaments go to the conjunctiva and to the integument of the upper 

 eyelid. 



The frontal branch, the largest of the three, divides into the supra- 

 trochlear and supraorbital nerves. The supratrochlear passes out of the 

 orbit between the supraorbital 

 foramen and the pulley of the 

 superior oblique muscle. It 

 sends in its course a long fila- 

 ment to the nasal branch and is 

 finally lost in the integument of 

 the forehead. The supraorbital 

 passes through the supraorbital 

 foramen, sends a few filaments 

 to the upper eyelid and sup- 

 plies the forehead, the anterior 

 and the median portions of the 

 scalp, the mucous membrane of 

 the frontal sinus and the peri- 

 cranium covering the frontal 

 and parietal bones. 



The nasal branch, before it 

 penetrates the orbit, gives off a 

 long filament to the ophthalmic 

 ganglion. It then gives off the 

 long ciliary nerves, which pass 

 to the ciliary muscle and iris. 

 Its trunk finally divides into the 

 external nasal, or infratrochle- 

 aris, and the internal nasal, or 

 ethmoidal. The irifratrochlearis 

 is distributed to the integument 

 of the forehead and nose, to the internal surface of the lower eyelid, the 

 lachrymal sac and the caruncula. The internal nasal is distributed to 

 the mucous membrane and also in part to the integument of the 

 nose. 



The superior maxillary division of the fifth passes out of the cranial 

 cavity by the foramen rotundum, traverses the infraorbital canal and 

 emerges on the face by the infraorbital foramen. Branches from this 

 nerve are given off in the spheno-maxillary fossa and the infraorbital 

 canal before it emerges upon the face. In the spheno-maxillary fossa, 



Fig. 127. Ophthalmic division of the fifth 



(Hirschfeld). 



I, ganglion of Gasser ; 2, ophthalmic division of the 

 fifth ; 3, lachrymal branch ; 4, frontal branch ; 5, ex- 

 ternal frontal ; 6, internal frontal ; 7, supratrochlear ; 

 8, nasal branch ; 9, external nasal ; 10, internal nasal ; 

 ii, anterior deep temporal nerve; 12, middle deep 

 temporal nerve; 13, posterior deep temporal nerve; 

 14, origin of the superficial temporal nerve ; 15, great 

 superficial petrous nerve. I to XII, roots of the 

 cranial nerves. 



