Asymmetrical bilateral duplication of the extracranial vertebral arteries: Report of a unique case

Duplication of the vertebral arteries is a rare developmental anomaly. We report on an asymmetrical bilateral duplication of the extracranial vertebral arteries which was an incidental finding demonstrated by MR angiography in a patient evaluated for middle cerebral artery stroke and internal carotid stenosis. On the right side two separate origins of the vertebral artery arose directly from the subclavian artery, whereas on the left side one leg originated directly from the aortic arch and the other one from the left proximal subclavian artery. To the best of our knowledge, this is the first report on an asymmetrical bilateral duplication of the origins of the extracranial vertebral arteries. The possible embryologic mechanisms and the possible clinical importance of this previously unreported variant are reviewed.