Embryology

The aortic arch can be anatomically sub-divided by embryological origin and adjacent brachiocephalic arteries. The proximal arch from innominate artery to left common carotid artery derives from the aortic sac; the distal arch from left common carotid artery to the left subclavian artery derives from the fourth embryonic arch; and the isthmus from distal arch to juxtaductal region from sixth embryonic arch. In "Interrupted Aortic Arch" (IAA), the interruption may occur as a result of pathologically excessive apoptosis of branchial arches and loss of patency and/or continuity of the relevant arch segment.[1]