984 



THE NERVE SYSTEM 



to the inner wall of the orbit. Here it passes through the anterior ethmoidal 

 foramen, and, entering the cavity of the cranium, traverses a shallow groove 

 on the front of the cribriform plate of the ethmoid bone, and passes down, through 

 the slit by the side of the crista galli, into the nose (Fig. 735), where it divides 

 into two branches, an internal and an external branch. The internal branch 

 (rami nasales mediates) supplies the mucous membrane near the fore part n thp 

 septum of the nose. The external branch (rami nasales laterales) descends in a 

 groove on the inner surface of the nasal bone, and supplies a few filaments to the 

 mucous membrane covering the fore part of the outer wall of the nares as far as 

 the inferior turbinate process; it then leaves the cavity of the nose, between the 

 lower border of the nasal bone and the upper lateral cartilage of the nose, and, 

 passing down beneath the Compressor nasi, supplies the integument of the ala 

 and the tip of the nose, joining with the facial nerve. 



The branches of the nasal nerve are the ganglionic, long ciliary, and infratrochlear. 



The ganglionic branch or the long root of the ciliary ganglion (radix longa ganglii 

 ciliaris) (Figs. 730 and 733) is a slender branch, about 1 to 2 cm. in length, which 

 usually arises from the nasal nerve, between the two heads of the External rectus 



Internal carotid artery 

 and carotid plexus. 



FIG. 733. Nerves of the orbit and ophthalmic ganglion, side view. 



muscle. It passes forward on the outer side of the optic nerve, and enters the 

 postero-superior angle of the ciliary ganglion, forming its long root. It is some- 

 times joined by a filament from the cavernous plexus of the sympathetic or from 

 the superior division of the oculomotor nerve. 



The long ciliary nerves (nn. ciliares longi), two or three in number, are given 

 off from the nasal as it crosses the optic nerve. They accompany the short ciliary 

 nerves (Figs. 730 and 733) from the ciliary ganglion, pierce the posterior part of 

 the sclera, and, running forward between it and the choroid, are distributed to 

 the Ciliary muscle, iris, and cornea. 



The infratrochlear branch (n. infratrochlearis) (Fig. 729) is given off just before 

 the nasal nerve passes through the anterior ethmoidal foramen. It runs forward 

 along the upper border of the Internal rectus muscle, and is joined, beneath 

 the pulley of the Superior oblique, by a filament from the supratrochlear nerve. 

 It then passes to the inner angle of the eve, and supplies the integument of the 

 eyelids and side of the nose, the conjunctiva, the lacrimal sac, and the caruncula 

 lacrimalis. 



