Superior Oblique Perspective of Dissected Cerebellum and Brainstem. The right cerebellar hemisphere and part of the right superior cerebellar peduncle have been dissected to demonstrate the middle cerebellar peduncle entering the white matter of the cerebellar hemisphere. The superior (anterior) medullary velum, a thin lamina of white matter stretching between the superior cerebellar peduncles, has been been removed to expose the floor of the fourth ventricle. (Image courtesy of AL Rhoton, Jr.)