Right aortic arch with left aberrant subclavian artery and azygos continuation of IVC


The right aortic arch and aberrant left subclavian artery occurred as the result of an interruption of the dorsal segment of the left arch between the left common carotid and left subclavian arteries with regression of the right ductus arteriosus in the hypothetical double aortic arch.

Kommerell diverticulum occurs in some anomalies of the aortic arch system. It refers to the bulbous configuration of the origin of an aberrant left subclavian artery in the setting of a right sided-aortic arch. The prevalence of a right sided-aortic arch is <1%. 

Continuation of the suprarenal IVC as the azygos or hemiazygos vein is attributable to embryonic failure to form the right subcardinal–hepatic anastomosis. The continuation of the azygos as the IVC has a prevalence of 0.6%.