Duplicate origin of the right vertebral artery in which both channels arose from the extreme proximal right subclavian artery: a case report.

Rarely, two channels of the right vertebral artery (VA) arise from the right subclavian artery (SA) and fuse at the level of the C5 or C4 transverse foramen, a variation of the artery termed duplicate origin. Usually, one channel arises from the normal position, and the second arises from the extreme proximal segment of the SA. We report a case of duplicate origin of the right VA in which both channels arose from the extreme proximal segment of the SA, which we diagnosed by computed tomography (CT) angiography. The smaller channel entered the C5 transverse foramen and the larger channel, the C4 transverse foramen, and they fused at the level of the C4. Careful scrutiny of CT angiographic source images is important to detect rare arterial variations, especially to identify the level at which the VA enters the transverse foramen.