THE ARTERIES. 



Anterior Cerebral Artery. — This enters immediately above the optic 

 commissure, and proceeds inwards to unite, in the middle line, with the opposite 

 artery, forming with it a single vessel. This middle artery (or arteria corporis 



ARTERIES OF THE BRAIN. 



B, Medulla oblongata; p, pons Varolii; L, mastoid lobule; o, olfactory lobule; C, chiasma of the 

 optic nerves; m, mammillary or pisiform tubercle (corpus albicans); h, pituitary gland (three- 

 fourths have been excised). 1, 1, Cerebro-spinal arteries; 2, middle spinal artery; a, loxenge- 

 shaped anastomosis of the two cerebro-spinal arteries, from which result, in front — 4, the basilar 

 artery (usually the cerebro-spinal arteries arrive in the middle of the lozenge); 5, 5, posterior 

 cerebellar arteries ; 6, anterior ditto ; 7, internal carotid artery, with the sigmoid curve it makes 

 in the cavernous sinus ; 8, internal carotid on the sides of the pituitary gland ; 9, transverse 

 reticulated anastomosis thrown between the two internal carotids behind the pituitary gland ; 

 10, biiurcation of the internal carotid; 11, 11, posterior cerebral arteries anastomosing behind 

 the corpus albicans, receiving in the middle of this anastomosis the two terminal branches of the 

 basilar artery; 12, middle cerebral artery; 13, anterior cerebral artery; 14, posterior com- 

 municating artery. 



callosi) enters the longitudinal fissure of the brain by bending round the anterior 

 extremity of the corpus callosum, and, after a short course, divides into two 

 branches which pass from before to behind, one to the right, the other to the 



