Truncus bicaroticus with aberrant right subclavian artery and origin of right vertebral from right common carotid artery.

We describe a rare constellation of variant anatomy of the aortic arch branches, seen on a magnetic resonance angiographic examination during the course of investigation for recent onset memory loss in a 52-year-old patient. There was a common origin of both the common carotid arteries (CCA), the common trunk being the first major branch of the aortic arch, the right vertebral artery arising from the right CCA and the right subclavian artery arising as the last branch of the arch. In isolation, the three components of this constellation have been reported with different frequencies, but as per the authors' knowledge, this entire constellation has been rarely reported. We review the literature and propose an embryological mechanism for this variant anatomy.