Fallen lung sign: radiographic findings.

The term "fallen lung sign" refers to the collapsed lung in a dependent position, hanging on the hilum only by its vascular attachments. This is usually the result of the complete rupture of a bronchus. On chest radiograph, the diagnosis of bronchial tear is usually suspected with the persistence of a pneumothorax after chest tube insertion. An 8-year-old male patient had radiographic findings of persistence of right pneumothorax which was due to complete rupture of the right main bronchus, resulting in fallen lung.