Figure 3 :Anterior intradural foramen magnum meningioma developed below the vertebral artery. (a) Preoperative view on axial T1-weighted MRI with gadolimium administration. The tumor (T) inserts on both sides of the midline (dotted line). The left vertebral artery (LVA) passes above the tumor. (B-E Operative views. (b) View just after the dura opening. (c) The tumor is developed below the vertebral artery. (d) The lower cranial nerves are identified at the superior aspect of the tumor. (e) Final view. White arrow indicates a feeding vessel that has been divided. Black arrow shows the right PICA. Bl: blade. C1 PR: C1 posterior rootlets. Cer: cerebellum. DL: dentate ligament. LVA: left vertebral artery. N: neuraxis. T: tumor. IX: glosso-pharyngeal nerve. X: vagal nerve. XI: accessory nerve. XII: hypoglossal nerve. Modified with permission.