Trauma to the chest wall causing the pleural cavity to communicate with the outside atmosphere can lead to pneumothorax, which can be categorized into closed pneumothorax, open pneumothorax and tension pneumothorax. 1. Closed pneumothorax: this type of intrathoracic pressure is lower than atmospheric pressure. Lung atrophy on the injured side can lead to impaired pulmonary ventilation and lung gas exchange. The mediastinum is displaced to the healthy side. Physical examination may reveal fullness of the chest on the injured side, decreased respiratory activity, and displacement of the trachea to the healthy side. 2. Open pneumothorax: outside air passes through the chest wall wound or soft tissue defect, and enters and leaves the pleural cavity freely with respiration, and the intrathoracic pressure is almost equal to atmospheric pressure. The mediastinum is displaced to the healthy side, further limiting the expansion of the healthy lung. Symptoms of mediastinal flutter may be present, which can cause severe circulatory dysfunction. Patients may have obvious dyspnea, cyanosis, jugular vein rage and other symptoms. 3. Tension pneumothorax: The most serious type of pneumothorax is the formation of a living flap at the injury, where the gas only goes in but not out, resulting in the intrathoracic pressure being higher than the atmospheric pressure. The patient’s respiratory and circulatory functions are seriously affected, with severe dyspnea, irritability, impaired consciousness, cyanosis, lowered blood pressure, rapid pulse, etc. Most of the patients have subcutaneous emphysema, and may have mediastinal emphysema. For patients with pneumothorax, they should go to a regular hospital immediately to avoid delay.