Azygoesophageal recess.

Knowledge of the normal radiologic appearance and manifestations of disease in the azygoesophageal recess can facilitate the detection and diagnosis of intrathoracic disease. The azygoesophageal recess is located lateral or posterior to the esophagus and anterior to the spine. It extends from the anterior turn of the azygous vein to the aortic hiatus. The configuration of the azygoesophageal recess is normally a smooth arc convex to the left. Because the right lung extends into the recess, pathology in this region can often be detected radiographically and typically manifests as increased opacity and/or as a contour abnormality. In adults, convexity directed to the right and immediately below the level of the azygous vein on a frontal radiograph is abnormal and requires further evaluation.