Anatomic classification of the right aortic arch.

The term right aortic arch is used for an aorta that arches over the right bronchus. Right aortic arch was classified into two types by Felson et al, based on branching patterns, with a proposed embryological explanation, and into three types by Shuford et al. Other anatomical variants of right aortic arch were described later, including isolated left brachiocephalic artery and aberrant left brachiocephalic artery. We have classified right aortic arch anatomy into 10 variants, supported by radiological evidence, and with reference to possible embryology. This classification will help in understanding the morphological basis for the formation of different types of right aortic arch and the course of the recurrent laryngeal nerve in such cases.