Ophthalmic artery originating from basilar artery: a rare variant.

The basilar artery as the origin of the ophthalmic artery is extremely rare. A 48-year-old patient had undergone angiography for suspicion of a right middle cerebral artery aneurysm. No aneurysm was detected. Vertebral artery injections demonstrated the left ophthalmic artery originating from the basilar trunk. Current embryologic theories fall short in explaining this entity. Awareness of neuroanatomic variations is of paramount importance in diagnosis and treatment of vascular lesions of the brain.