Inferior Cerebellar Exposure. A, The vermis on the suboccipital surface is situated in a deep cleft, the posterior cerebellar incisura, which is located between the hemispheres. The cerebellomedullary fissure is located between the cerebellum and medulla. The PICA passes around the medulla, through the cerebellomedullary fissure, and supplies the suboccipital surface. (Image courtesy of AL Rhoton, Jr.)