BLOOD-VESSELS OF THE EYE 



671 



to the papilla optica, 

 at w h i c li point it 

 divides into two 

 branches, an inferior 

 and a superior branch, 

 which, by rapid dicho- 

 tomous division, radi- 

 ate from the optic 

 papilla to all parts of 

 the retinal surface, 

 thereby forming a 

 plexus of small ar- 

 teries within the 

 nerve fiber and gan- 

 glion cell layers. 

 From this plexus ca- 

 pillaries are distrib- 

 uted to all the cere- 

 bral layers of the re- 

 tina. No blood-vessels 

 are found within the 

 neuro-epithelial lay- 

 ers. The retinal ar- 

 teries, like those of 

 the brain, do not anas- 

 tomose with one an- 

 other; they are ter- 

 minal arteries. 



The retinal veins 

 follow a course exact- 

 ly similar to that of 



FIG. 566. SCHEMATIC REPRESENTATION OF THE INTRINSIC BLOOD-VESSELS OF 

 THE EYE. 



Arteries in outline, veins in solid black. A, choroid; a, central artery, and a lt vein 

 of the retina; B, conjunctiva; b, retinal arteries; 6,, retinal veins; c, c, short ciliary 

 arteries; d, long ciliary artery; e, e,, anterior ciliary arteries and veins; /, chorio- 

 capillaris; g, capillaries of the ciliary body; H, cornea; h, circulus major of the 

 iridal arteries; i, arteries, and i\, veins of the iris; k, circulus minor of the iridal 

 arteries; L, crystalline lens; I, venae vorticosse; m, anastomosis of ciliary and an- 

 terior ciliary veins; N, retina; n, canal of Schlemm; O, optic nerve; o, posterior 

 conjunctiva! artery, and o\ t vein; p, anterior conjunctival vessels; ?, vascular loops 

 at the margin of the cornea; R, internal rectus muscle; S, sheath of the optic nerve; 

 Sc, sclera. (After Leber.) 



