THE EYE. 



431 



the sclera near the optic nerve, and course forward 

 between the choroid and the sclera to the ciliary 

 body. It supplies blood to the ciliary muscles, the 

 ciliary processes, and the iris. The anterior ciliary 

 arteries lie close to the straight ocular muscles and 

 penetrate the sclera near the sclerocorneal junction. 

 They give off branches to the iris and the ciliary body, 

 anastomosing with branches from the long posterior 

 ciliary artery. Veins return the blood from these 

 regions and bear the same names as the arteries 

 they accompany. 



Ocular muscle. 



Sclera. 

 Choroid. 



Ciliary muscle. 

 Iris. 



Conjunc. cul-de-sac. 



Ant. chamber and 



aqueous humor. 



Crystalline lens. 



Posterior chamber. 



Angle of ant. chamber. 



Suspensory ligament 



of the lens. 



Retina. 



Optic 



nerve with 



central 



retinal 



artery. 

 Ocular 



muscle. 



Cornea. Vitreous chamber. 



Fig. 296. Vertical section through the eyeball and lids (Pyle). 



The retina is supplied with blood from a central 

 artery and vein that enter and leave the retina at the 

 optic papilla, or blind spot. Each divides into a 

 superior and inferior papillary artery and vein. The 

 latter again divide into two branches, making in all 

 four arteries and four veins known according to their 

 position as superior and inferior nasal, and superior 

 and inferior temporal vessels. Within the retina 



