376 



JAMES ROLLIN SLONAKER 



of branches to the upper hd. to the tissues in the region of the 

 superior fornix, and to the cihary region. These cihary arteries 

 pierce the sclerotic in the region of the scleral plates (fig. 14). 

 The third branch of the external ophthalmic, the ophthahno- 

 temporal, is directed backward, around the posterior side of the 

 eye, to the region of the optic nerve. This artery is the main 

 source of the blood supply to the extrinsic muscles, Harder's 



Fig. 14 Enlarged view of a section through the scleral plates (Scl p), showing 

 the passage of a blood-vessel (Bv) directly through them. C, cornea; Ep; epi- 

 thelium of cornea; L, lid; Nm, nictitating membrane. 



gland, and the structures at the back of the eye. Figure 15 

 shows the distribution of the arteries over the posterior part of 

 the eye. The general course of the ophthalmotemporal artery 

 is inward and downward, passing under the external rectus, 

 posterior to the optic nerve. It bends around under the nerve 

 and ascends on the anterior side of it. Here it unites with one 

 of its branches which has run forward over the dorsal side of 

 the nerve and thus forms a complete ring around the optic 



