Fig. 10
From: Classification and microsurgical treatment of foramen magnum meningioma
Four important triangles in operation (right side). a Triangle SOT: 1, oblique capitis superior; 2, oblique capitis inferior; 3, rectus capitis posterior major; 4, rectus capitis posterior minor; 5, vertebral artery. b Triangle VOT, V, point V3 segment of the vertebral artery entering the trouble side dura; O, opisthion; T, tubercula posterius. c Triangle JVV (triangle above the rectus capitis posterior minor): J, jugular foramen of the trouble side; V1, point V3 segment of the vertebral artery entering the trouble side dura; V2, the V3 segment of the vertebral artery enters the uninjured side of the dura. d Triangle TVV (triangle under the vertebral artery), T. inferior pole of a tumor; V1, point V3 segment of the vertebral artery entering the trouble side dura; V2, the V3 segment of the vertebral artery enters the uninjured side of the dura