186 NERVOUS SYS'LEM. 



the numerous branches of distribution of the fifth nerve, 

 remembering that it is the great sensitive nerve of the 

 face. 



At the ganglion of Gasser, from its anterior and external 

 portion, are given off a few small and unimportant branches 

 to the dura mater and tentorium. 



From the convex border of the ganglion, the three great 

 branches arise that have given to the nerve the name of 

 trifacial or trigeminal. These are: 1, the ophthalmic; 2, 

 the superior maxillary ; 3, the inferior maxillary. The oph- 

 thalmic and the superior maxillary branch are derived en- 

 tirely from the sensory root. The inferior maxillary branch 

 joins with the motor root and forms a mixed nerve. 



The ophthalmic branch, the first division of the fifth, is 

 the smallest of the three. Before it enters the orbit, it re- 

 ceives filaments of communication from the sympathetic, 

 sends small branches to all of the motor nerves of the eye- 

 ball, and gives off a small recurrent branch which passes be- 

 tween the layers of the tentorium. 



Just before the ophthalmic branch enters the orbit by 

 the sphenoidal fissure, it divides into three branches ; the 

 lachrymal, frontal, and nasal. 



The lachrymal, the smallest of the three, sends a branch 

 to the orbital branch of the superior maxillary nerve, passes 

 through the lachrymal gland, to which certain of its fila- 

 ments are distributed, and its terminal filaments go to the 

 conjunctiva and the integument of the upper eyelid. 



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

 the supra-trochlear and supra-orbital nerves. The supra- 

 trochlear passes out of the orbit between the supra-orbital 

 foramen and the pulley of the superior oblique muscle. It 

 sends in its course a long, delicate filament to the nasal 

 branch, and is finally lost in the integument of the forehead. 

 The supra-orbital passes through the supra-orbital foramen, 

 sends a few filaments to the upper eyelid, and supplies the 

 forehead, the anterior and median portions of the scalp, the 



