This case demonstrates a variant anatomy of the left vertebral artery. The origin is at the arch of aorta, instead of the typical origin from the left subclavian artery, and the artery enters the transverse foramina of the cervical vertebrae at the C4 level, rather than the typical C6 level.

The origin of the left vertebral artery is from the aortic arch in approximately 5% of people, and is more commonly variant than the right. If the left vertebral artery originates at the arch of aorta, it is then more likely to enter the transverse foramina of the cervical vertebrae at a level higher than C6 ¹.