Blunt traumatic rupture of a mainstem bronchus: spiral CT demonstration ofthe "fallen lung" sign

Tracheo-bronchial injuries occur in less than 1% of blunt chest trauma pati ents. Indirect signs, such as pneumomediastinum, pneumothorax, and/or subcu taneous emphysema, are revealed on admission plain films and chest CT surve y. In most instances, however, tracheobronchoscopy is mandatory in assessin g the definite diagnosis of tracheo-bronchial lesion. Occasionally, an abno rmal course of a mainstem bronchus or a "fallen lung" sign, featuring a col lapsed lung in a dependent position, hanging on the hilum only by its vascu lar attachments, may allow for CT diagnosis of a blunt traumatic bronchial injury.