Duplicate origin of left vertebral artery.

A verified case of duplicate origin of the left vertebral artery in association with a large aneurysm arising from the aortic arch immediately distal to the left subclavian artery is presented. An anomalous left vertebral artery arises directly from the aortic arch between the left common carotid and subclavian arteries, and joins with the normal left vertebral artery in the transverse foramen of the fifth cervical vertebra.