416 VESSELS OF THE CHOROID. 



Fig. 189.* 2d. The short ciliary arteries, 



which are very numerous : they pene- 

 trate the sclerotic coat near the optic 

 nerve, are spread upon the choroides, 

 and anastomose very frequently with 

 each other : in their progress for- 

 wards they penetrate from the exter- 

 nal to the internal surface of the 

 choroides, and supply the iris and 

 ciliary processes. 

 These are about twenty in number, at the place where 

 they divide to perforate the sclerotica ; but they originate from 

 the ophthalmic as three or four separate branches. 



3d. The anterior ciliary arteries , which are not very 

 numerous, penetrate the sclerotic coat just behind the margin of 

 the cornea. These are distributed among the branches of the 

 long ciliary arteries on the iris. 



The veins of the choroides are very peculiar : besides those 

 which accompany the arteries above described, there are seve- 

 ral veins which are situated more internally than the arteries 

 and nerves, and about the middle of the eye : their branches 

 are not arranged in the usual manner, but run from the main 

 trunk, nearly in a semicircular curve, are almost parallel to 

 each other, and very numerous ; from this arrangement of their 

 branches, they are called the Vasa Vorticosa. 



There are, according to Zinn, four or five of these larger 

 trunks, the branches of which are vorticose, or thrown into 

 whirls, so as to admit of their arising from the whole surface 

 of the choroid, in front, and behind, as well as upon the side of 

 the trunks. This arrangement, has an arborescent appearance, 

 and has been compared to the weeping willow. The vorticose 

 vessels, being somewhat like the graceful pendent branches of 

 the tree. 



* Fig. 189 is a representation of the vessels of the choroid coat and iris. 

 The long ciliary artery and vein are seen running straight to the iris in front. 

 The vasa vorticosa are seen upon either side. The short ciliary arteries are 

 not seen in this figure. 



