Anterior extrapleural line: superior extension

Anatomic sections of the superior aspect of the anterior mediastinum reveal that normal structures can cause indentations upon the adjacent lung. On lateral chest films, the soft-tissue density of the anterior superior mediastinal structures contrasts with that of the normal lung, revealing a normal, undulating configuration of the anterior superior mediastinum. We have termed this the "vascular incisura," analogous to the cardiac incisura of the left lung seen inferiorly. An appreciation of normal variations within this space is essential when evaluating pathologic alterations.