The radiographic diagnosis of esophageal disease depends primarily upon the configuration of contrast material in the esophageal lumen. It has been pointed out (3) that large bulky tumors producing a considerable extraluminal mass can be visualized on the roentgenogram. It is less commonly recognized that minor variations in esophageal wall thickness can also be identified radiographically. Gladnikoff (2), in his classic monograph on the mediastinum, and more recently Cimmino (1), in an article entitled “Further Notes on the Esophageal Pleural Stripe,” have demonstrated the relationship of the esophagus to the medial margin of the lung. Little emphasis has been placed on utilizing this relationship as a means of evaluating changes in esophageal wall thickness, though Johnstone (4) did illustrate on radiographs esophageal thickening in diffuse spasm and diffuse muscle hypertrophy of the lower esophagus. Figure 1 is a diagram of the relationship of the lung margin to the esophagus and other bordering mediastinal structures. The radiographic demonstration of a line depends upon adjacent contrasting densities lying tangential to the x-ray beam. On the right side, particularly inferiorly, the relationship of the esophagus to the lung is such that minor degrees of rotation continue to produce a tangential interface. On the left, the lung extends to the esophagus as a lingular projection rather than nestling against it. The variation in position of the aorta also produces an inconstant relationship of the lung and esophagus on the left. Films should be obtained in the upright or prone position to prevent esophageal and pulmonary compression by gravitational shift of the heart posteriorly. The width of the pleural esophageal stripe is dependent upon the thickness of two pleural layers, adventitial tissue, including vessels, and the wall of the esophagus. The present study is limited to the evaluation of roentgenograms obtained in the frontal projection. We have accepted only those films on which the esophagus is projected over the spine and on which the right heart border, the aorta, and the paraspinal margins can be identified as distinct and separate structures. The width of the esophageal pleural stripe was measured in over 100 patients without known local disease. With the esophagus distended by barium, the mean measurement of the stripe is normally 3 mm., with maximum measurements as great as 5 mm. In the collapsed condition, with only sufficient barium to produce mucosal coating, the measurement may be as great as 7 mm. The stripe tends to be of uniform thickness, with smooth reflections at its ends, where the pleura loses contact with the esophagus. Carcinoma of the Esophagus The radiographic diagnosis of carcinoma of the esophagus is not ordinarily difficult. The luminal changes are usually characteristic.