Pneumomediastinum.

Pneumomediastinum, air within the mediastinum, is the manifestation of a variety of causes including those that are benign and some resulting in severe morbidity and even mortality. This article reviews the epidemiology, etiology, and pathophysiology of pneumomediastinum as an independent pathologic and physiologic entity, as well as reviews the workup and management of those patients who are diagnosed with pneumomediastinum.