Bilateral variation in the origin and course of the vertebral artery.

Understanding the great vessels of the aortic arch and their variations is important for both the endovascular interventionist and the diagnostic radiologist. An understanding of the variability of the vertebral artery remains most important in angiography and surgical procedures where an incomplete knowledge of anatomy can lead to serious implications. In the present case, a bilateral variation in the origin and course of vertebral artery was observed. The left vertebral artery took origin from the arch of aorta and entered the foramen transversarium of the fourth cervical vertebra. The right vertebral artery took origin from the right subclavian artery close to its origin and entered the foramen transversarium of the third cervical vertebra. The literature on the variations of the artery is studied and its clinical significance and ontogeny is discussed.