ANGIOLOGY 217 



The palpebral plexus lies between the trunks of the trigeminus, 

 and supplies mainly the lower eyelid. 



The plexus muscularis extends to the fifth portion of the temporal 

 muscle. 



The plexus lacrimalis forms on the posterior, orbital wall on the 

 ramus ethmoidalis and supplies the lacrimal gland and the upper 

 eyelid. It anastomoses with branches from the facial artery. 



The ramus ciliaris posticus supplies the inferior rectus and the 

 external rectus muscle of the eyeball. It anastomoses with the 

 ophthalmica externa. 



The median meningeal artery passes through the foramen occupied 

 by the second branch of the trigeminal nerve. Passing into the 

 cranial cavity, it supplies the dura mater. Before passing into this 

 foramen, small branches are given off, which supply the skin and the 

 temporal muscle; and some branches anastomose with the superior 

 cervical and the ethmoidal arteries. 



4. The Cerebral Artery. Each cerebral artery enters the cranial 

 cavity through the canalis caroticus located in the sphenoid bone, 

 passes forward medially from the cochlea, dorsally from the Eusta- 

 chian tube, and passes through a small canal which opens on the 

 inner surface of the sella turcica. Originating in this foramen, the 

 sphenoid artery divides into two branches which anastomose with 

 the pterygoidean and the pterygo-pharyngeal artery and which 

 supply the upper jaw and the throat regions. 



The spheno-maxillaris artery supplies the gums. 



The right and the left cerebral arteries unite at the sella turcica. 

 After this union they divide again immediately and pass to the 

 base of the brain, where they give off twigs to the optic nerve, to 

 the optic chiasm, and where also is given off the arteria retinae 

 centralis. Passing posteriorly each cerebral artery gives off the 

 ramus posterior, and then passes to the side of the cerebellum. 



The basilar artery, a continuation of the anterior spinal artery, is 

 located ventrally and mesially to the cerebellum. Laterally and 

 inferiorly the basilar artery gives off the inferior cerebellar artery. 



The ramus anterior is given off from the cerebralis artery and 

 continues as the internal ophthalmic artery. The ramus anterior 

 also gives off the sylman artery, which supplies the sides of the cere- 

 brum and the middle brain. In the fissure between the hemi- 

 spheres and the optic thalamus is located the arteria cerebri profunda. 

 This artery passes along the median surface of the cerebrum and in 



