322 THE BLOODVESSELS OF THE EYE, BY TH. LEBER. 



the one on the median, the other on the temporal side. They 

 perforate the sclerotic very obliquely, so that the artery runs in 

 a canal, in the substance of the sclerotic, of as much as four 

 millimeters in length. 



3. The anterior ciliary arteries (arterice ciliares anteriores, 

 c). These are not direct branches of the ophthalmica, but pro- 

 ceed from the arteries of the four recti muscles. Generally 

 speaking, two arteries arise from each muscle, though as a rule 

 only one comes from the rectus externus. They pass from the 

 insertion of the tendons on to the sclerotic, run for the most 

 part, with many curves, towards the cornea, and after giving off 

 delicate superficial branches, penetrate the sclerotic with their 

 perforating branches rather obliquely, not far from the margin 

 of the cornea. 



b. The veins of the ciliary vascular system are 1. The 

 so-called vence vorticosce, h, of which there are usually four 

 trunks, that either open directly into the vena ophthalmica, 

 or into the muscular branches. They perforate the sclerotic 

 near the sequator of the bulb, just as obliquely as the long 

 ciliary arteries. One or more of them frequently divide before 

 their entrance into the sclerotic, in consequence of which the 

 number of perforating branches is increased to six, but seldom 

 more. 



During and just after their passage through the sclerotic, 

 again, divisions frequently occur; and thus, besides the four or 

 six larger ones, a variable number of smaller vessels pass into 

 the choroid. 



2. The small venulce ciliares posteriores breves (fig. 367, i\ 

 which, like the corresponding arteries, emerge from the sclerotic 

 in the neighbourhood of the optic nerves, but correspond only 

 to the scleral branches of the latter, and receive no branches 

 from the choroid. They are consequently much less numerous 

 and much smaller than the corresponding arteries. 



3. The vence ciliares anteriores. These, like the correspond- 

 ing arteries, are branches of the veins of the recti muscles, but 

 are smaller than the arteries, because the region in which their 

 perforating branches ramify is much more limited in extent. 



There are no veins that correspond in their course with poste- 

 rior long ciliary arteries. 



