Arch of aorta with bi-carotid trunk, left subclavian artery, and retroesophageal right subclavian artery.

We report a case of left sided aortic arch with three branches - a bi-carotid trunk, left subclavian, artery and right subclavian artery. The anomalous right subclavian artery presented a retroesophageal course. A right non-recurrent laryngeal nerve was noticed. The embryonic development of this branching pattern is discussed.