63 6 NERVOUS SYSTEM. 



anatomical point is of importance in view of some of the remote effects which follow 

 division of the fifth nerve through the ganglion in living animals. 



It will be necessary only to describe in a general way the numerous branches of dis- 

 tribution 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 the tentorium. 



From the convex border of the ganglion, the three great branches arise, which 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 ophthalmic and the superior 

 maxillary branch are derived entirely 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 receives filaments of communication from the sympathetic, 

 sends small branches to all of the motor nerves of the eyeball, and gives off a small recur- 

 rent branch which passes between 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 to the integu- 

 ment of the upper eyelid. 



FIG. 213. Superior maxillary division of the fifth. (Hirschfeld.) 



! ganglion of Gasser ; 2, lachrymal branch of the ophthalmic division ; 3. superior maxillary division of the fifth; 

 4, orbital branch; 5, lachrymo-palpebral filament; 6, malar branch; 7, temporal branch; 8, spheno- 

 palatine ganglion ; 9, Vidian nerve; 10. great superficial petrosal nerve; 11, facial nerve; 12, branch of the 

 Vidian nerve; 13, anterior and two posterior dental branches ; 14, branch to the mucous membrane of the 

 alveolar processes ; 15, terminal branches of the superior maxillary division; 16, branch of the facial. 



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 mucous membrane of the frontal sinus, and the pericranium covering the frontal and 

 parietal bones. 



The nasal branch, before it penetrates the orbit, gives off a long, delicate filament to 

 the ophthalmic ganglion, constituting its sensory root. It then gives off the long ciliary 



