CIRCULATORY A^^PARATUS. QI 



curves 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, Bifurcation of the internal carotid; 11, 11, Posterior- 

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

 anastomosis the two terminal branches ol the basilar trunk; 12, Middle cerebral 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 a?iastomostfjg b7'anches with, internal carotid. They are not 

 constant, and unite with cartoids at second curvature. 



Posterior cerebral are given oif 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 cere- 

 brum 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 co?nmuni- 

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

 brals. 



Posterior co^nmtinicating passes backward beside the pituitary 

 body and unites with the posterior cerebral. 



Middle cei'ebral 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 iiiternal 7naxillary. 



