Double aortic arch and tracheal stenosis.
A. There is leftward deviation of the trachea (arrow), but no narrowing of the lateral walls. B. Impressions by the right aortic arch and the more inferiorly located left arch cause a "reverse S" appearance of the esophagus on this AP view. C. On the lateral projection, narrowing of the AP dimension of the trachea occurs at the same level as a posterior esophageal impression.