OPHTHALMIC ARTERY. 311 



Brandies. The cervical portion of the internal carotid gives off no 

 branches : from the other portions are derived the following : 



Tympanic, 



Anterior meningeal, 



Ophthalmic, 



Anterior cerebral, 



Middle cerebral, 



Posterior communicating, 



Choroidean. 



The Tympanic is a small branch which enters the tympanum through 

 a minute foramen in the carotid canal. 



The Anterior meningeal is distributed to the dura mater and Cas- 

 serian ganglion. 



The Ophthalmic artery arises from the cerebral portion of the inter- 

 nal carotid, and enters the orbit through the foramen opticum, imme- 

 diately to the outer side of the optic nerve. It then crosses the optic 

 nerve to the inner wall of the orbit, and runs along the lower border 

 of the superior oblique muscle, to the inner angle of the eye, where it 

 divides into two terminal branches, the frontal and nasal. 



Brandies. The branches of the ophthalmic artery may be arranged 

 into two groups: first, those distributed to the orbit and surrounding 

 parts ; and secondly, those which supply the muscles and globe of the 

 eye. They are 



First Group. Second Group. 



Lachrymal, Muscular, 



Supra-orbital, Anterior ciliary, 



Posterior ethmoidal, Ciliary short and long, 



Anterior ethmoidal, Centralis retinae. 



Palpebral, 



Frontal, 



Nasal. 



The Lachrymal is the first branch of the ophthalmic artery, and is 

 usually given off immediately before that artery enters the optic fora- 

 men. It follows the course of the lachrymal nerve, along the upper 

 border of the external rectus muscle, and is distributed to the lachrymal 

 gland. The small branches which escape from the gland supply the 

 conjunctiva and upper eyelid. The lachrymal artery gives off a malar 

 branch which passes through the malar bone into the temporal fossa 

 and inosculates with the deep temporal arteries, while some of its 

 branches become subcutaneous on the cheek and anastomose with the 

 transverse facial. 



The Supra-orbital artery follows the course of the frontal nerve, 

 resting on the levator palpebrse muscle ; it passes through the supra- 

 orbital foramen and divides into a superficial and deep branch, which 

 are distributed to the muscles and integument of the forehead and to 



