CIRCULATORY APPARATUS. 91 



terior ditto; 7, Internal carotid artery, with the two curves it makes in the caver- 

 nous 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; io,Bifurcation of ithe internal carotid; n, n, Posterior-cerebral 

 arteries anastomosing behind the pisiform tubercle, receiving in the middle of 

 this anastomosis the two terminal branches of the basilar trunk; 12, Middle cere- 

 bral artery; 13, Anterior cerebral artery; 14, Posterior communicating artery. 



Posterior cerebellar, to lateral and posterior borders of cerebel- 

 lum. 



Anterior cerebellar, two or three in number. To anterior por- 

 tion of cerebellum. 



Two anastomosing branches with internal carotid.. They are not 

 constant, and unite with carotids at second curvature. 



Posterior cerebral are given off from the basilar terminal branches, 

 pass outward and enter Bichat's fissure, where they terminate 

 in the choroid plexus or on the surfaces of the cerebrum and 

 cerebellum. 



Median spinal artery passes along the inferior fissure of the 

 cord from its beginning to its end. ' It receives branches from 

 the vertebral, intercostal, lumbar and sacral arteries, and supplies 

 the cord and its membranes. 



INTERNAL CAROTID. 



Passes up to base of skull through occipito-temporo-sphenoidal 

 opening, enters the cavernous sinus, has two curves develop in its 

 course; in the second, anastomosing with the basilar. They com- 

 municate with each other by a transverse branch, pass forward 

 and bifurcate behind the optic tract, into the posterior communi- 

 cating and the common trunk of the anterior and middle cere- 

 brals. 



Posterior communicating passes backward beside the pituitary 

 body and unites with the posterior cerebral. 



Middle cerebral passes outward into Sylvian fissure, and supplies 

 the brain structure. 



Anterior cerebral passes above optic commissure, unites with 

 its fellow, curves around the corpus callosum, runs backward 

 and supplies the brain structure. It anastomoses with post- 

 cerebral and ophthalmic. 



EXTERNAL CAROTID. 



Passes forward and upward to great branch of hyoid, then^ as- 

 cends to neck of condyle of lower jaw, where it bifurcates into 

 the superficial temporal and internal maxillary. 



