618 CRANIAL NERVES. 



OPHTHALMIC GANGLION. (Fig. 340.) 



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

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

 ated 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 inclosed 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 root, is derived from the nasal branch of the ophthalmic, 

 and joins its superior angle. Another branch, the short root, is a short thick 

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

 the third nerve or the Inferior Oblique muscle, and is connected with the in- 

 ferior angle of the ganglion. A third branch, the sympathetic root, is a slender 

 filament from the cavernous plexus of the sympathetic. This is occasionally 

 blended with the long root, and 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 ten to twelve in number, which arise from the fore part of the 

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

 upper bundle consisting of four filaments, and the lower of six or seven. They 

 run forwards with the ciliary arteries in a wavy course, one set above and the 

 other below the optic nerve, pierce the sclerotic at the back part of the globe, 

 pass forwards in delicate grooves on its inner surface, and are distributed to the 

 ciliary muscle and iris. A small filament is described by Tiedemann pene- 

 trating the optic nerve with the arteria centralis retina. 



SUPERIOR MAXILLARY NERVE. (Fig. 344.) 



The Superior Maxillary, 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 commence at the middle of the Casserian ganglion as a flattened 

 plexiform band, and passes forwards through the foramen rotundum, where it 

 becomes more cylindrical in form, and firmer in texture. It then crosses the 

 spheno-maxillary fossa, traverses the infraorbital canal in the floor of the orbit, 

 and appears upon the face at the infraorbital foramen. At its termination, the 

 nerve lies beneath the Levator Labii Superioris muscle, and divides 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. 



The branches of this nerve may be divided into three groups: 1. Those given 

 off in the spheno-maxillary fossa. 2. Those in the infraorbital canal. 3. Those 

 on the face. 



( Orbital. 



Spheno-maxillary fossa < Spheno-palatine. 



( Posterior dental. 

 Infraorbital canal . . Anterior dental. 



( Palpebral. 



On the face ....-< Nasal. 



( Labial. 



The orbital branch arises in the spheno-maxillary fossa, enters the orbit by 

 the spheno-maxillary fissure, and divides at the back of that cavity into two 

 branches, temporal and malar. 



The temporal branch runs in a groove along the outer wall of the orbit (in the 

 malar bone), receives a branch of communication from the lachrymal, and, 

 passing through a foramen in the malar bone, enters the temporal fossa. It 

 ascends between the bone and substance of the Temporal muscles, pierces this 



