THE OrHTHALMIC GANGLION. 537 



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. 



Uxiox OF THE G.4XGLI0X WITH XERVES : ITS ROOTS. — The posterior 

 border of the ganglion receives three nerves. One of these, the long roof, 

 a slender filament from the nasal branch of the ophthalmic trunk, joins 

 the upper part of this border. Another branch, the short root, much 

 thicker and shorter than the preceding, and sometimes divided into 

 two parts, is derived from the branch of the third nerve to the inferior 

 oblique muscle, and is connected with the lower part of the ganglion. 

 The third root is a very small nerve which emanates from the cavernous 

 plexus of the sympathetic, and reaches the ganglion with the long upper 

 root : these two nerves are sometimes conjoined before reaching the 

 ganglion. Other roots have been assigned to the ganglion. (Valentin, 

 in Miiller's Archiv. for 1840.) The ganglion is sometimes very small, 

 probably from the nerve cells being distributed along the nerves which 

 are connected with it. 



Branches of the ganglion. — From the fore part of the ganglion 

 arise ten or twelve delicate filaments — the short ct'liari/ nerves. These 

 nerves are disposed in two fasciculi, arising from the U]3per and lower 

 angles of the ganglion, and they run forwards, one set above, the other 

 below the optic nerve, the latter being the more numerous. They are 

 accompanied by filaments from the nasal nerve (long ciliary), with 

 which some are joined. Having entered the eyeball by apertures in the 

 back part of the sclerotic coat, the nerves are lodged in grooves on its 

 inner surface ; and at the ciliary muscle, which they pierce (some filaments 

 supplying it and the cornea), they turn inwards and ramify in the iris. 



II. SUPEEIOR MAXILLARY NERVE. 



The superior maxillary nerve, or second division of the fifth cranial 

 nerve, is intermediate in size between the ophthalmic and the inferior 

 maxillary trunks. 



It commences at the middle of the Gasserian ganglion, and, passing 

 horizontally forwards, soon leaves the skull by the foramen rotundum 

 of the sphenoid bone. The nerve then crosses the spheno-maxillary 

 fossa, and enters the infraorbital canal of the upper maxilla, by whicli 

 it is conducted to the face. After emerging from the infraorbital fora- 

 men, it terminates beneath the elevator of the upper lip in branches, 

 which spread out to the side of the nose, the eyelid, and the upper lip. 



Branches. — Near its origin a recurrent branch passes to the dura 

 mater and middle meningeal artery. In the s])heno-maxillary fossa a 

 temporo-malar branch ascends from the superior maxillary nerve to 

 the orbit, and two spheno-palatine branches descend to join Meckel's 

 ganglion. Whilst the nerve is in contact with the upper maxilla, it 

 furnishes two posterior dental branches on the tul^erosity of the bone, 

 and an anterior dental branch at the fore part. On the face are the 

 terminal branches already indicated. 



Orbital branch. — The orbital or temporo-malar branch, a small 

 cutaneous nerve, enters the orbit by the spheno-maxillary fissure, and 

 divides into two branches (temporal and malar), which pierce the malar 

 bone, and are distributed to the temple and the prominent part of the 

 cheek. 



