THE NASAL NERVE. 237 



they join one or more of the short ciliary branches from the ciliary ganglion, 

 and, after perforating the sclerotic coat of the eje, are distributed in the same 

 manner as those nerves. 



(c) The wfmtrochlear nerve runs forwards along the inner side of the orbit, 

 below the superior oblique muscle, and parallel to the supratrochlear nerve, from 

 which it receives, near the pulley of the oblique muscle, a filament of connection. 

 The nerve is then continued below the pulley to the inner angle of the eye, and 

 ends, in filaments which supply the conjunctiva, the caruncle, and the lachrymal sac, 

 as well as the integument of the upper eyelid and root of the nose (fig. 171, 22). 



(d) The internal or septal branch (fig. 144, 2) supplies the pituitary membrane 

 over the fore part of the septum, extending downwards nearly as far as the opening 

 of the nostril. 



(e) The external branch (fig. 160, 2), often represented by two or three filaments, 

 is distributed to the mucous membrane of the fore part of the outer wall of the nasal 

 fossa, including the anterior ends of the middle and lower turbinate bones. 



(/) The anterior or superficial branch (fig. 171, 24) issues between the nasal 

 bone and the upper lateral cartilage of the nose, and runs downwards under cover of 

 the compressor naris muscle to the tip of the nose, supplying the skin of the lower 

 part of the organ. 



Varieties. The nasal nerve occasionally (frequently, Krause) gives filaments to the 

 superior and internal recti muscles. A branch to the levator palpebrse superioris has also 

 been met with (Fasebeck). In one case filaments of communication passed from a small 

 gang-lion connected with the nasal nerve to the third and sixth nerves (Svitzer). In tvro 

 instances Testut observed absence of the inf ratrochlear branch, its place being supplied by 

 the supratrochlear nerve. Offsets from the nasal nerve, as it traverses the anterior internal 

 orbital canal, to the frontal sinus and ethmoidal cells are described by Meckel and Langen- 

 beck ; and a tpheno-ethmoidal (Luschka) or posterior ethmoidal (Krause) branch is said to pass 

 through the posterior internal orbital canal to the mucous membrane of the sphenoidal sinus 

 and posterior ethmoidal cells. 



SUMMARY. The first division of the fifth nerve is altogether sensory in function. 

 It furnishes branches to the dura mater ; to the eyeball and the lachrymal gland ; 

 to the mucous membrane of the nose and eyelids ; to the integument of the nose, 

 the upper eyelid, the forehead, and the upper part of the hairy scalp. It has com- 

 munications with the third, fourth, and sixth nerves, with numerous branches of the 

 facial, and with the sympathetic. 



Ciliary Ganglion. 



There are four small ganglia connected with the divisions of the fifth nerve : 

 the ciliary ganglion with the first, the spheno-palatine ganglion with the second, 

 and the otic and submaxillary ganglia with the third. These ganglia, besides 

 receiving branches from the sensory part of the fifth, are each connected with a 

 motor nerve from the third, the fifth, or the facial, and with twigs from the sympa- 

 thetic ; and the nerves thus joining the ganglia are named their roots. 



The ciliary, ophthalmic, or lenticular ganglion serves as a centre for the 

 supply of nerves motor, sensory, and sympathetic to the eyeball. It is a small 

 reddish body, compressed laterally and somewhat four-sided, and measures about 

 2 mm. from before back. It is situated at the back of the orbit, between the outer 

 rectus muscle and the optic nerve, and generally in contact with the ophthalmic 

 artery ; it is joined behind by branches from the fifth, the third, and the sympa- 

 thetic nerves ; while from its fore part proceed the short ciliary nerves to the 

 eyeball. The cells of the ganglion are of the multipolar variety. 



VOL. III. PT. 2. Q 



