VEINS OF THE CEREBRUM. 21 



of the posterior cerebral and posterior communicating arteries 

 (Figs. 9 and 10). They supply the interpcduncular structures, 

 the peduncles and, after piercing the posterior perforated sub- 

 stance, the walls of the third ventricle and the medial parts of 

 the thalami. 



Postero-lateral Ganglionic Arteries. They rise, on either 

 side, from the posterior cerebral artery after it has wound around 

 the base of the peduncle (Fig. 10). They are distributed to the 

 posterior part of the thalamus; the geniculate, quadrigeminal and 

 pineal bodies; the quadrigeminal brachia and the pedunculus 

 cerebri. The superior cerebellar arteries send several branches 

 to the dorsum of the mid-brain, and complete the arterial supply 

 of the cerebrum. 



VEINS OF THE CEREBRUM. 



The Internal Veins of the Cerebrum. The veins of the cere- 

 brum (vents cerebri) are classed as internal and external. The 

 trunks of the internal veins are located largely in the chorioid 

 tela of the third ventricle, near the apex of which the internal 

 cerebral vein is formed: while at the base of this chorioid tela 

 the internal cerebral vein unites with its mate in forming the 

 great cerebral vein. 



The internal cerebral vein (v. cerebri interna) is formed by 

 the union of the chorioidal, the terminal and the vein of the sep- 

 tum pellucidum. It runs backward between the layers of the 

 chorioid tela of the third ventricle (Fig. 7), receiving several 

 small collaterals from the tela, from the pineal and quadrigeminal 

 bodies and the corpus callosum ; and, finally, it receives the basilar 

 vein from the inferior surface of the cerebral hemisphere. Under 

 the splenium of the corpus callosum it joins the internal cerebral 

 vein of the opposite side and forms the great cerebral vein. 



The great cerebral vein (v. cerebri magna, Galeni) is a short, 

 thick, median trunk, a half-inch long (Fig. i). At the posterior 

 border of the tentorial notch it is joined by the inferior sagittal 

 sinus and then continued as the sinus rectus. This short vein 

 receives collateral tributaries from the gyrus cinguli, from the 



