To interpret mediastinal abnormalities, an understanding of the reflections produced by the various areas of lung in contact with the mediastinum is mandatory. In this prsentation many of the normal mediastinal reflections are reviewed and correlated with anatomic and CT demonstrations. Emphasis is placed on the similarities and dissimilarities of these reflections and their relationships to mediastinal structures or coronal mediastinal planes. Abnormal examples of these reflections are included, as well as the frequency with which the normal reflections may be seen.