1 — Pyramidal tract; 2 — Hypoglossal nerve [XII]; 3 — Inferior olive; 4 — Vagus nerve [X]; 5 — Anterior inferior cerebellar artery; 6 — Posterior inferior cerebellar artery; 7 — Fourth ventricle; 8 — Vascular plexus; 9 — Anterior spinal artery and Vertebral artery, medial branches; parame-
dian pontine branches
