The Mediastinum on a Plain Chest X-Ray

Radiographic analysis of the mediastinum is challenging. Excellent knowledge of mediasti­nal anatomy and borders between individual mediastinal structures and the adjacent lungs is necessary in order to make analysis findings helpful to clinicians. Chest radiography is the first-step imaging method for analysis of the mediastinum. On chest x-rays, the mediastinum can be compared to a white box whose important contents, except for the trachea, cannot be seen, with the exception of the areas where they shape their wrapping membrane, the mediastinal pleura. The air-water interface at the boundary between the mediastinal pleu­ra and adjacent lungs permits the contours of the mediastinum to be seen and evaluated. Abnormalities in the borders and shapes of mediastinal structures define pathological con­ditions in this part of the thoracic cavity and determine further diagnostic procedures.