Changes in the right posterolateral tracheal band and the right retrotracheal recess are reliable parameters for evaluating pathology in the right superior mediastinum. We have measured the posterolateral tracheal band at the sternal notch and 2 cm below the sternal notch in computed tomograms. At the sternal notch, the average thickness was 8.4 ± 3.8 mm. At the level 2 cm below the sternal notch, the posterolateral band was 6.4 ± 1.8 mm. This represents measurements from 100 normal patients. Pathology in the lungs, pleura, esophagus, soft tissues, and other mediastinal structures can clearly affect the posterolateral tracheal band, causing abnormal contours and widening of the band.