Two paired veins passing caudally near the midline and uniting to form the great cerebral vein WordNet 3.0 & Open English WordNet

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. Wikipedia