Imaging of the azygos lobe: normal anatomy and variations.

We describe the normal appearance of the azygos lobe on plain radiography and CT. Several findings are presented that, to our knowledge, have not been previously reported, such as the inferior prolongation of the fissure, the apparent intrapulmonary path of the right brachiocephalic vein and superior vena cava seen on the anteroposterior chest radiograph, and the visible fissure on the lateral chest radiograph.