Common origins of carotid and subclavian arterial systems: report of a rare aortic arch variant.

An aberrant right subclavian artery (aSA) arising from the proximal descending aorta is one of the most common anomalies of the aortic arch. We present our experience with an asymptomatic atypical aSA variant found during routine anatomic dissection. This aortic arch variant had two branches, the first being a bicarotid trunk and the second being a common trunk for both subclavian arteries. The right subclavian artery traveled behind the esophagus to reach the right upper extremity, thus forming an incomplete vascular ring around the trachea and the esophagus. The literature has been silent about the existence of this exact aSA variation. A plausible embryologic explanation is provided. An aSA is rarely symptomatic, but when symptoms do occur and intervention is warranted, it is important for surgeons and radiologists alike to be aware of the vascular anomalies that may potentially coexist with this entity. The surgical and endovascular options associated with this unique vascular anomaly are also discussed.