646 



DISSECTION OF THE OKBIT. 



and in the 

 face. 



Lenticular 

 ganglion : 



situation ; 



connec- 

 tions. 



Three roots 

 long, 



short, 



and sym- 

 pathetic. 



Ciliary 

 branches to 

 eyeball. 



Ophthalmic 

 artery, 



in the orbit. 



Branches : 



general dis- 

 tribution. 



Branch to 

 retina. 



Ciliary 



arteries are 



posterior 



two named 

 long ciliary, 



Termination of the nasal nerve. After the nerve becomes 

 cutaneous on the side of the nose, it descends beneath the com- 

 pressor naris muscle, and ends in the integuments of the tip of 

 the nose. 



The OPHTHALMIC or LENTICULAR GANGLION (fig. 228, 3 ) is a small 

 reddish body, about the size of a pin's head, and in form nearly 

 square. It is placed at the hack of the orbit between the optic 

 nerve and the external rectus, and commonly on the outer side 

 of, and close to, the ophthalmic artery. By its posterior part the 

 ganglion has branches of communication with other nerves (its 

 roots) ; and from the anterior part proceed ciliary branches to the 

 eyeball. The ganglion receives roots from sensory, motor, and 

 sympathetic nerves. 



The branches of communication are three in number. One, the 

 long root ( 5 ), is the branch of the nasal nerve before noticed, which 

 joins the superior angle. A second branch of considerable thickness, 

 the short root ( 4 ), passes to the inferior angle from the branch of the 

 third nerve that supplies the inferior oblique muscle. And the 

 sympathetic root is derived from the cavernous plexus, either in union 

 with the long root, or as a distinct branch to the posterior border of 

 the ganglion. 



Branches. The short ciliary nerves (fig. 228), ten or twelve in 

 number, are collected into two bundles, which leave the upper and 

 lower angles at the front of the ganglion. In the upper bundle are 

 four or five, and in the lower, six or seven nerves. In their course 

 to the eyeball they lie along the outer and under parts of the optic 

 nerve, and communicate with the long ciliary branches of the nasal 

 nerve. 



The OPHTHALMIC ARTERY (fig. 229), a branch of the internal 

 carotid, enters the orbit through the optic foramen. At first the 

 vessel is below and to the outer side of the optic nerve, but it then 

 courses inwards over (or occasionally under) the nerve to the inner 

 side of the orbit, and finally perforates the palpebral fascia above the 

 internal tarsal ligament to end by dividing into frontal and nasal 

 branches. 



The BRANCHES of the artery are numerous, though inconsiderable 

 in size. They supply the structures within the orbit, and some 

 leave that cavity to be distributed to the lining membrane of the 

 cranium, to the interior and exterior of the nose, and to the adjoin- 

 ing part of the forehead. 



The central artery of the retina is a very small branch which pierces 

 the optic nerve about half an inch behind the eyeball. 



The ciliary branches are divided into anterior and posterior, which 

 enter the eyeball at the front and back : 



The posterior ciliary usually rise by two trunks inner and outer, 

 close to the optic foramen : they divide into a number of branches 

 (from ten to twenty) which run to the eyeball around the optic nerve, 

 and perforate the sclerotic coat at the posterior part Two of this set 

 (one on each side of the optic nerve), are named long ciliary and 



