A, The superior sagittal sinus is connected through the torcular herophili with the transverse sinuses. The right transverse sinus is slightly larger than the left. The veins arising along the posterior part of the hemisphere are directed for-ward and join the superior sagittal sinus well above the torcular herophili, leaving a void along the medial occipital lobe where there are no bridging veins emptying into the sinus. B, The tentorium has been elevated to show the veins from the cerebellum forming bridging veins that enter the sinuses in the lower margin of the tentorium. On the left side, a large vein (yellow arrow) passes from the superior surface of the cerebellar hemisphere to enter a tentorial sinus. On the right side, a large bridging vein from the suboccipital cerebellar surface (red arrow) turns forward on the superior surface and empties into a tentorial sinus in front of the torcular herophili. C, View below the tentorium. The vein of Galen empties into the straight sinus. A large superior vermian vein empties into the vein of Galen. The right basal and the right and left anterior calcarine veins are exposed. The left basal vein is hidden in front of the left superior cerebellar artery. D, The tentorium has been removed, while preserving the straight sinus and the tentorial edge. The vein of Galen and its tributaries are exposed in the quadrigeminal cistern. Both basal veins are exposed. Large anterior calcarine veins drain the calcarine sulcus and adjacent part of the atrium. The branches of the posterior cerebral artery course in the upper part of the quadrigeminal cistern and the branches of the superior cerebellar artery course in the lower part. (Images courtesy of AL Rhoton, Jr.)