colloquial term for the radiographic appearance of the left superior intercostal or accessory hemiazygos vein as a bump on the aortic knob.
a·or·tic nip·ple
(ā-ōr'tik nip'ĕl) A colloquial term for the radiographic appearance of the left superior intercostal or accessory hemiazygos vein as a bump on the aortic knob.