THE BRANCHES OF THE FIFTH NERVE. 729 



The ganjlionic is a slender branch, about half an inch in length, which usually 

 arises from the nasal, between the two heads of the External rectus. It passes 

 forward on the outer side of the optic nerve, and enters the postero-superior 

 angle of the ciliary ganglion, forming its superior or long root. It is sometimes 

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

 superior division of the third nerve. 



The long ciliary nerves, two or three in number, are given off from the nasal 

 as it crosses the optic nerve. They join the short ciliary nerves from the ciliary 

 ganglion, pierce the posterior part of the sclerotic, and, running forward between 

 it and the choroid, are distributed to the ciliary muscles, iris, and cornea. 



The infratrochlear branch 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, 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 eye, and supplies the integument of the eyelids and side of the nose, the 

 conjunctiva, lachrymal sac, and caruncula lachrymalis. 



The Ophthalmic Ganglion (Figs. 391, 394). 



Connected with the three divisions of the fifth nerve are four small ganglia. 

 With the first division is connected the ophthalmic ganglion ; with the second 

 division, the spheno-palatine or Mcckel's ganglion; and with the third, the otic 

 and submaxillary ganglia. All the four receive sensory filaments from the fifth, 

 and motor and sympathetic filaments from various sources ; these filaments are 

 called the roots of the ganglia. 



The Ophthalmic, Lenticular, or Ciliary Ganglion is a small, quadrangular, 

 flattened ganglion, of a reddish-gray color, and about the size of a pin's head, 

 situated at the back part of the orbit between the optic nerve and the External 

 rectus muscle, lying generally on the outer side of the ophthalmic artery. It is 

 enclosed in a quantity of loose fat, which makes its dissection somewhat difficult, 



Its branches of communication, or roots, are three, all of which enter its 

 posterior border. One, the long or sensory root, is derived from the nasal branch 

 of the ophthalmic and joins its superior angle. The second, the short or motor 

 root, is a short, thick nerve, occasionally divided into two parts, which is derived 

 from the branch of the third nerve to the Inferior oblique muscle, and is connected 

 with the inferior angle of the ganglion. The third, the sympathetic root, is a 

 slender filament from the cavernous plexus of the sympathetic. This is frequently 

 blended with the long root, though it sometimes passes to the ganglion separately. 

 According to Tiedemann, this ganglion receives a filament of communication from 

 the spheno-palatine ganglion. 



Its branches of distribution are the short ciliary nerves. These are delicate 

 filaments, from six to ten in number, which arise from the fore part of the ganglion 

 in two bundles, connected with its superior and inferior angles ; the lower bundle 

 is the larger. They run forward with the ciliary arteries in a wavy course, one 

 set aboveand the other below the optic nerve, and are accompanied by the long 

 ciliary nerves from the nasal. They pierce the sclerotic at the back part of the 

 globe, pass forward in delicate grooves on its inner surface, and are distributed to 

 the Ciliary muscle, iris, and cornea. Tiedemann has described one small branch 

 as penetrating the optic nerve with the arteria centralis retinae. 



The Superior Maxillary Nerve (Fig. 395). 



The Superior Maxillary (n. maxillaris), or second division of the fifth, is a sensory 

 nerve. It is intermediate, both in position and size, between the ophthalmic 

 and inferior maxillary. It commences at the middle of the Gasserian ganglion as 

 a flattened plexiform band, and, passing horizontally forward, it leaves the skull 

 through the foramen rotundum, where it becomes more cylindrical in form and 



