Fig 2. A and B, Axial multisection CT reference images. Arrowheads point to the vertebral artery of the right and left side. The transparent arrow shows the right subclavian artery. A, Anterior and posterior part of the left subclavian artery (white arrows). B, Origin of the left vertebral artery (white arrowheads) contralateral to the normal course of the right vertebral artery.