722 THE VASCULAR SYSTEMS 



The superior cerebral veins (yy. supercerebrales, vv. cerebri superiores), eight 

 to twelve in number on each side, return the blood from the convolutions on 

 the superior surface of the hemisphere; they pass forward and inward toward the 

 intercerebral fissure, where they receive the veins from the mesal surface of the 

 hemisphere; near their terminations they become invested with tubular sheaths 

 of the arachnoid, and open into the longitudinal sinus in the opposite direction 

 to the course of the current of the blood in the sinus. 



The inferior cerebral veins (vv. subcerebrales, vv. cerebri inferiores) ramify on 

 the lower part of the outer and on the under surfaces of the cerebral hemisphere. 

 Some, collecting tributaries from the under surface of the frontal lobes of the brain, 

 terminate in the cavernous sinus. One vein of large size, the middle cerebral 

 or superficial sylvian vein (v. cerebri media), commences on the under surface of 

 the temporal lobe, and, running along the sylvian fissure, opens into the cavernous 

 sinus. Another large vein, the great anastomotic vein of Trolard, connects the supe- 

 rior sagittal sinus with the cavernous sinus by becoming continuous above with 

 one of the superior cerebral veins and below by joining the middle cerebral vein. 

 A third, the posterior anastomotic vein connects the middle cerebral vein with the 

 lateral sinus by coursing over the temporal lobe. A fourth, the basilar vein 

 (v. basilis [Rosenthali]), is formed at the anterior perforated spot by the union 

 of (a) a small anterior cerebral vein, which accompanies the anterior cerebral artery 

 (6) the deep sylvian vein, which receives tributaries from the island of Reil (or 

 insula) and neighboring convolutions, and runs in the lower part of the sylvian 

 fissure; and (c) the inferior striate veins, which leave the corpus striatum through 

 the anterior perforated substance. The basilar vein passes backward around the 

 crus cerebri, and ends in the vein of Galen; it receives tributaries from the inter- 

 peduncular space, the descending horn of the lateral ventricle, the uncinate gyre, 

 and the mid-brain. Small inferior cerebral veins from the under surface of the 

 frontal lobe end in the cavernous sinus; others from the temporal lobe terminate 

 in the superior petrosal and lateral sinuses. 



The deep cerebral veins, or veins of Galen (venae Galeni, vv. cerebri internae] 

 (Fig. 723), are two in number. Each is formed by the union of two veins, the 

 vena corporis striati, and the choroid vein, on either side. They run backward, 

 parallel with each other, between the layers of the velum interpositum, and 

 beneath the splenium, and in the region of the pineal body unite to form a short 

 trunk, the vena magna Galeni (v. cerebri magna), which passes out of the brain at 

 the great transverse fissure, and ends in the anterior extremity of the straight sinus. 

 The two velar veins receive tributaries from the callosal region, from a portion of 

 the occipital lobe, and just before their union each vein receives the corresponding 

 basilar vein. Each vena magna Galeni also receives the superior cerebellar veins. 



The vena corporis striati on each side commences in the groove between the 

 corpus striatum and thalamus, receives numerous veins from both of these parts, 

 and unites behind the anterior pillars of the fornix, with the choroid vein to 

 form one of the venae Galeni. 



The choroid vein (v. choroidea) originates in the extreme end of the middle horn 

 of the lateral ventricle and runs along the whole length of the outer border of the 

 choroid plexus, receiving veins from the hippocampus, the fornix, and corpus 

 callosum, and unites, at the anterior extremity of the choroid plexus, with the 

 vein of the corpus striatum to form the vena Galeni of that side. 



The superficial cerebellar veins (Fig. 721) occupy the surface of the cerebellum, 

 and are disposed in two sets, superior and inferior. 



The superior superficial cerebellar veins (vv. supercerebellares, vv. cerebelli supe- 

 riores} pass partly forward and inward, across the superior vermis (prevermis), to 

 terminate in lateral branches which pass partly to the tentorial sinus and partly 

 outward to the lateral and superpetrosal sinuses. 



