Internal cerebral veins
The internal cerebral veins (deep cerebral veins) drain the deep parts of the hemisphere and are two in number; each internal cerebral vein is formed near the interventricular foramina by the union of the superior thalamostriate vein and the superior choroid vein. They run backward parallel with one another, between the layers of the tela chorioidea of the third ventricle, and beneath the splenium of the corpus callosum, where they unite to form a short trunk, the great cerebral vein of Galen; just before their union each receives the corresponding basal vein.