internal cerebral veins internal cerebral veins the internal cerebral veins are two veins included in the group of deep cerebral veins that drain the deep parts of the hemispheres; each internal cerebral vein is formed near the interventricular foramina by the union of the superior thalamostriate vein and the superior choroid vein. internal cerebral veinscoronal section of lateral and third ventricles.velum interpositum. (internal cerebral veins labeled as velar veins.)detailsdrains togreat cerebral veinarterycerebral arteriesidentifierslatinvenae internae cerebrita98a12.3.06.028ta24923fma70876anatomical terminology 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.