The accumulation of air in the pleural cavity is called pneumothorax. The incidence of traumatic pneumothorax is about 15% to 50% in blunt injuries and about 30% to 87.6% in penetrating injuries. In most cases, the air in the pneumothorax comes from the puncture of the lung by the broken ends of the rib fracture (the superficial one is called lung rupture, and the one that reaches the bronchioles is called lung laceration). It can also be caused by contusion and laceration of the bronchus or lung tissue caused by violence, or rupture of the bronchus or lung caused by a sharp increase in airway pressure. Sharp injuries or firearm injuries that penetrate the chest wall and injure the lungs, bronchi, trachea or esophagus can also cause pneumothorax, and most of them are hemothorax or purulent pneumothorax. Occasionally, closed or penetrating diaphragmatic rupture is accompanied by gastric rupture, causing purulent pneumothorax.