RADIOLOGY: AORTA: Case# 29: DOUBLE AORTIC ARCH. 60 year old male with history of lymphoma who presents for routine follow-up CT. Two arches arise from the ascending aorta, one ascending on the right and the other on the left. The right arch is slightly higher than the left. The thoracic aorta descends on the right side. In double aortic arch, a single ascending aorta gives rise to two aortic arches. Each arch usually supplies the ipsialteral subclavian and carotid arteries. The arches surround the trachea and esophagus, often producing symptomatic compression. The right arch is usually larger and more cephalad in position. Portions of the left arch may be atretic making it difficult to distinguish this from right arch anomalies.