NASAL NERVE. OPHTHALMIC GANGLION. 599 



a. The branch to the ophthalmic ganglion (radix longa ganglii ciliaris), very slender, 

 and about half an inch long, arises generally between the heads of the external 

 rectus ; it lies on the outer side of the optic nerve, and enters the upper and back 

 part of the ophthalmic ganglion, constituting its long root. 



This small branch is sometimes joined by a filament from the cavernous plexus of 

 the sympathetic, or from the upper branch of the third nerve. 



b. The long ciliary nerves, two or three in number, are situated on the inner side 

 of the optic nerve ; they join one or more of the nerves from the ophthalmic ganglion 

 (short ciliary), and after perforating the sclerotic coat of the eye, are continued 

 between it and the choroid to the ciliary muscle, the cornea, and the iris. 



c. The infratrochlear branch runs forwards along the inner side of the orbit below 

 the superior oblique muscle, and receives near the pulley of that muscle a filament of 

 connection from the supratrochlear nerve. The branch is then continued below the 

 pulley to the inner angle of the eye, and ends in filaments which supply the orbicular 

 muscle of the lids, the caruncula, and the lachrymal sac, as well as the integument of 

 the eyelids and side of the nose. 



In the cavity of the nose the nasal nerve ends by dividing into the following 

 branches. 



d. The branch to the nasal septum extends to the lower part of the partition 

 between the nasal fossae, supplying the pituitary membrane near the fore part of the 

 septum. 



e. The superficial branch (externus seu lateralis), descends in a groove on the inner 

 surface of the nasal bone ; and after leaving the nasal cavity between that bone and 

 the lateral cartilage of the nose, it is directed downwards to the tip of the nose, 

 beneath the compressor naris muscle. While within the nasal fossa, this branch 

 gives two or three filaments to the fore part of its outer wall, which extend as far as 

 the lower spongy bone. The cutaneous part is joined by a filament of the facial 

 nerve. 



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

 function. It furnishes branches to the ball of the eye 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 ; and to the muscles a'bove the middle of the circumference of the 

 orbit. Some of the cutaneous and muscular filaments join branches of the 

 facial nerve, and the nerve itself communicates with the sympathetic. 



OPHTHALMIC GANGLION. 



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

 nerve : the ophthalmic ganglion with the first, Meckel's 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 sympathetic ; and the nerves thus joining the 

 ganglia are named their roots. 



The ophthalmic or lenticular ganglion (gang, semilunare, vel ciliare) serves 

 as a centre for the supply of nerves motor, sensory, and sympathetic to 

 the eyeball. It is a small reddish body, 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 sympathetic nerves ; while from its fore part proceed the 

 ciliary nerves to the eyeball. 



Union of the ganglion with nerves : its roots. The posterior border of the 

 ganglion receives three nerves. One of these, the long root, a slender 

 filament from the nasal branch of the ophthalmic trunk, joins the upper 

 part of this border. Another branch, the short root y much thicker and 

 shorter than the preceding, and sometimes divided into parts, is derived 



