The presence of air in the retropharyngeal and cervical subcutaneous spaces of the neck in association with the acute onset of severe odynophagia and dysphagia is an uncommonly recognized initial feature of pneumomediastinum. Free air in the mediastinum extends into the neck via fascial planes. Spontaneous pneumomediastinum is a self-limited disorder that can be confused with Boerhaave's syndrome (spontaneous esophageal perforation), which is potentially fatal. The diagnosis is established radiologically.