OCCLUSION OF THE POSTERIOR INFERIOR CEREBELLAR ARTERY

The posterior inferior cerebellar artery is usually described as the largest branch of the vertebral artery, and its course as passing obliquely backward around the medulla oblongata, at first between the roots of the hypoglossal nerve, then between the roots of the accessory and the vagus nerves, to end on the inferior surface of the cerebellum. In a recent study Bury and Stopford1have shown that there is considerable variability in the course of the artery; that in many cases, instead of passing directly backward after its origin from the vertebral, it forms a distinct loop, the convexity of which is toward the pons. The ascending limb of the loop usually passes upward in the posteriolateral sulcus, and in this position supplies small terminal branches to the medulla oblongata. Occlusion of the posterior inferior cerebellar artery produces a definite clinical syndrome, in spite of the variability in the course