Cerebellar vascular insults, in contrast to cerebral vascular occlusions, are rare. In this respect disease of the vessels of the cerebellum is almost as uncommon as disease of the vessels of the spinal cord. Of three hundred cases of cerebral vascular insults in which autopsy was performed, in only twenty was there evidence of involvement of the cerebellar vessels. The pathologic process in nine of these cases was confined to the superior cerebellar artery or its branches.
The nature of the vascular supply of the cerebellum explains the rarity of cerebellar occlusion. As is well known, the surface of the cerebellum, in contrast to that of the cerebrum, presents a more liberal anastomosis of the blood vessels. It should also be emphasized that the cerebral and cerebellar vessels are not end-arteries as was once stated by Cohnheim, Duret and others. As demonstrated by Pfeifer,1 Cobb2 and others, there