THE TRIGEMINUS. 529 



form, give off additional fibres in a peripheral direction. Thus the 

 branches of the fifth nerve beyond the ganglion contain, beside the fibres 

 derived from its sensitive root, others which have originated from the 

 ganglion itself. The motor root passes underneath the ganglion as a 

 distinct bundle, and neither gives to nor receives from it any nerve 

 fibres. At the anterior or convex border of the Gasserian ganglion, the 

 nerve separates into three nearly equal cylindrical bundles, namely, the 

 first, or ophthalmic; the second, or superior maxillary; and the third, 

 or inferior maxillary divisions of the fifth nerve. 



The ophthalmic division passes forward through the sphenoidal fis- 

 sure into the orbit of the eye, where it gives filaments to the ophthalmic 

 ganglion and to the ej^eball ; a nasal branch which supplies the integu- 

 ment and mucous membrane of the inner part of the eye, the mucous 

 membrane of the middle and inferior nasal passages, and the integument 

 of the root, wing, and tip of the nose; and a branch to the lachrymal 

 gland and the integument of the upper eyelid and adjacent region. It 

 then emerges from the cavity of the orbit by the supra-orbital notch, 

 and is distributed to the skin of the forehead and side of the head, as 

 far back as the vertex. 



The superior maxillary division passes out of the cranial cavity, by 

 the foramen rotundum, at the base of the skull, into the spheno-maxil- 

 lary fossa, where it gives a sensitive branch to the spheno-palatine gan- 

 glion of the sympathetic, thence into and through the longitudinal 

 canal in the floor of the orbit, giving off a branch which runs upward 

 and outward to terminate in the skin of the malar and temporal regions, 

 and numerous descending branches, which supply the teeth, gums, and 

 adjacent mucous membrane of the upper jaw, and, by a nasal filament, 

 the mucous membrane of the bottom of the nasal passages. The nerve 

 then emerges upon the face by the infra-orbital foramen, and is distri- 

 buted in abundant diverging branches to the integument of the lower 

 eyelid and the side of the nose, and to the skin and mucous membrane 

 of the upper lip. 



The inferior maxillary division leaves the anterior border of the 

 Gasserian ganglion at a different angle from the two others, passing 

 almost vertically downward through the foramen ovale. This division 

 receives all the fibres of the motor nerve root, which become more 

 or less intimately united to it during and after its passage through the 

 base of the skull. While the two other divisions of the fifth nerve are 

 therefore exclusively sensitive, the inferior maxillary division is a mixed 

 nerve, containing both motor and sensitive fibres. Its sensitive portion, 

 however, is still the most abundant, and all its motor branches are given 

 off a short distance below its point of exit from the skull. 



After emerging from the foramen ovale, this division of the fifth pair 

 supplies one or two filaments to the otic ganglion of the sympathetic, 

 which is situated near its inner surface, and passes downward toward 

 the inferior dental canal ; sending off, in the mean time, two sensitive 

 branches, namely, 1st, the buccinator branch (6), destined for the mucous 



