Left Aortic Arch With Aberrant Right Subclavian Artery Etiology: congenitalUGI: posterior indentation on the esophagusClinical: usually asymptomatic but occasionally can have dysphagia lusora Cases of Left Aortic Arch With Aberrant Right Subclavian Artery AP (left) and lateral (right) images from an upper GI exam shows a left sided aortic arch and a posterior indentation on the esophagus.