THE FIFTH, TRIGEMINAL, OR TRIFAOIAL NERVE 985 



The ophthalmic, lenticular, or ciliary ganglion (ganglion ciliare) is a small, quad- 

 rangular, 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 exposure by dissection some- 

 what difficult. 



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

 border. One, the long or sensor root (radix longa ganglii ciliaris}, is derived 

 from the nasal branch of the ophthalmic and joins its postero-superior angle. 

 The second, the short or motor root (radix brevis ganglii ciliaris}, is a short, thick 

 nerve, occasionally divided into two parts, which is derived from the branch of 

 the oculomotor to the Inferior oblique muscle, and is connected with the postero- 

 inferior angle of the ganglion. The third, the sympathetic root (radix sympa- 

 thetica ganglii ciliaris), is a slender filament from the cavernous plexus of the 

 sympathetic. This is frequently blended with the long root, although it some- 

 times passes to the ganglion separately. The ganglion occasionally receives a 

 filament of communication from the sphenopalatine ganglion. 



Its branches of distribution are the short ciliary nerves (nn. ciliares breves') (Figs. 

 730 and 733). 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 above and the other below the optic nerve, 

 and are accompanied by the long ciliary branches of the nasal nerve. They pierce 

 the sclera 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. One 

 small branch is said to penetrate the optic nerve with the arteria centralis retinae. 



The superior maxillary nerve (n. maxillaris) (Figs. 729 and 732), or second 

 division of the trigeminal, is a sensor 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 firmer in texture. It then crosses the 

 sphenomaxillary fossa (Fig. 67), inclines outward on the back of the maxilla, 

 and enters the orbit through the sphenomaxillary fissure; it traverses the infra - 

 orbital canal in the floor of the orbit, and appears upon the face at the infra- 

 orbital foramen. 1 At its termination the nerve lies beneath the Levator labii 

 superioris muscle, and divided into a leash of branches, which spread out upon 

 the side of the nose, the lower eyelid, and upper lip, joining with filaments of the 

 facial nerve. 



Branches of Distribution. The branches of this nerve may be divided into four 

 groups: (1) Those given off in the cranium. (2) Those given off in the spheno- 

 maxillary fossa. (3) Those in the infraorbital canal. (4) Those on the face. 



In the cranium .... Meningeal or dural. 



( Orbital or temporomalar. 

 Sphenomaxillary fossa j Sphenopalatine. 



^Posterior superior dental. 



Infraorbital canal I Diddle superior dental 



( Anterior superior dental. 

 ( Palpebral. 



On the face . j Nasal. 



(- Labial. 



1 After it enters the infraorbital canal the nerve is usually called the infraorbital (n. infraorbiialis) , and is 

 therefore, the terminal branch of the superior maxillary nerve (Fig. 737). 



