Anomalous variations of the origin and course of vertebral arteries in patients with retroesophageal right subclavian artery.

We present two rare cases of anomalous vertebral artery (VA) with retroesophageal right subclavian artery. One patient had a right VA arising from the right common carotid artery (CCA), and a left VA originating from the third branch off the aorta. Both VAs ascended anteriorly to the transverse foramen of C5 to C6 vertebra and entered the transverse foramen of C4. The other patient had a right VA arising from the right CCA and entering the transverse foramen of C5. The presence of anomalous variations of the origin and course of vertebral artery might have serious implications in angiographic and surgical procedures, and it is of great importance to be aware of such a possibility.