CEREBRAL ARTERIES. 



377 



-the ophthalmic artery at its origin from the internal carotid ; 1', the same artery con- 

 tinued on the upx^er and inner side of the orbit ; 2, lachrymal branch ; 3, central artery 

 of the retina ; 4, some of the ciliary arteries ; 5, 5, upper and lower muscular branches ; 

 0, supraorbital ; 7, 7', posterior and anterior ethmoidal arteries ; 8, palpebral ; 8', 8", 

 its superior and inferior divisions ; 9, frontal ; 10, nasal, communicating with the 

 angular of the facial. 



((/) The two jxiljh'hnil branches, sn2)erior and inferior-, arise near the front of 

 the orbit, usually together, but soon diverge, one Ipng above, the other below 

 the tendon of the orbicularis muscle at the inner angle of the eye ; they form 

 arches, one in each lid, which lie between the orbicularis muscle and tarsal car- 

 tilage, and send branches to the caruncula lachrymalis and the lachrymal sac. 



(A) The nasal branch courses forwards above the tendon of the orbicularis 

 muscle to the root of the nose, where it ramifies, mamtaining a free communi- 

 cation with the nasal and angular branches of the facial artery. 



(0 Thefraiital branch runs close to the preceding, but on reaching the margin 

 of the orbit turns upwards on the forehead, where it anastomoses with the supra- 

 orbital artery. 



2. Cevebval Arteries. — The terminal branches of tlie internal 



Fig. 254. — View of the Fig. 254. 



Distribution of the 

 Branches of the In- 

 ternal Carotid and 



Vertebral Arteries to 



the lower I'ARTS OF 



THE Brain (altered 

 from Hirschfeld and 

 LeveilliS). (A. T.) i 



On the left side of the 

 brain a portion of the 

 middle lobe of the cere- 

 brum has been removed so 

 as to open up the fissure of 

 Sylvius and expose the 

 convolutions of the island 

 of Reil ; and the left half 

 of the cerebellum has been 

 removed to show the lower 

 surface of the posterior 

 cerebral lobe. 1, placed 

 on the optic commissure, 

 points to the divided stem 

 of the left internal carotid 

 artei-y where its cerebral 

 distribution begins ; 2, 

 anterior cerebral branch, 

 exposed fully by the re- 

 moval of a portion of the 

 left optic nerve ; 2', placed 

 on the knee or anterior 

 bend of the corpus callo- 



sum between its two arteries ; x , placed on the lamina cinerea in front of the optic 

 commissure, marks the anterior communicating artery ; 3, middle cerebral artery, 

 passing into the fissure of Sylvius and distributing its branches over the convolutions of 

 the island of Reil and others beyond ; 4, placed between the infundibulum and the 

 corpora albicantia, points by a line to the left posterior communicating artery ; 5, basilar 

 artery ; 6, posterior cerebral artery, its distribution exposed on the left 'side by the 

 removal of half of the cerebellum ; 7, placed on the pons Varolii, points to the right 

 superior cerebellar artery ; 8, anterior inferior cerebellar artery ; between 7, and 8, one 

 of the largest of the transverse branches of the basilar artery ; 9, 9, right and left 

 vertebral arteries ; 10, posterior inferior cerebellar arteries ;, 11, anterior spinal arteries. 



