Abnormal origin of the vertebral artery from the common carotid artery

An abnormal origin of the vertebral artery from the common carotid artery (VA-CC) may occur on the right or left side with different embryonic mechanisms. We describe a patient with a double developmental anomaly, a right VA-CC and a right aortic arch. The rotation of the aortic arch caused a 'twist' of the embryonic mechanisms of VA-CC and misdirected the differential diagnosis of the embryonic mechanisms at first glance. We discuss the pivotal points in differentiating the embryonic mechanisms of VA-CC.