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. 1. Introduction Anatomical variation is defined as the normal flexibility in the topography and morphology of body structures [1]. Many or most variations are totally benign; some are errors of embryologic developmental timing or persistence of normally obliterated structures [2]. 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. This has become more important in the era of carotid artery stents, vertebral artery stents, and therapeutic options for intercranial interventions [3]. In angiographic and anatomic postmortem examinations, abnormal vertebral artery origins are incidental findings because, in most cases, they are clinically asymptomatic; nonetheless, these abnormalities are of diagnostic importance either prior to vascular surgery in the neck region or in cases of intravascular disease such as arteriovenous malformations or cerebral aneurysms, thrombosis, occlusion, arterial dissection, and potentially atherosclerosis [1, 4, 5]. The vertebral artery arises from the superior aspect of the subclavian artery, passes through the foramina of all cervical transverse processes except the seventh, curves medially behind the lateral mass of atlas, and then enters the cranium via the foramen magnum. At the lower pontine border, it joins its fellow to form the basilar artery. Occasionally, it may enter the bone at fifth, fourth, or seventh cervical transverse foramen [6]. An abnormal origin of the
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