Pneumothorax is caused by the entry of air into the pleural cavity, leading to a series of changes. Pneumothorax can be divided into spontaneous and traumatic pneumothorax. Spontaneous pneumothorax occurs without trauma or other causes, while traumatic pneumothorax is caused by direct or indirect trauma to the pleura. Spontaneous pneumothorax can be further categorized into primary and secondary pneumothorax. Patients with primary spontaneous pneumothorax do not have underlying lung disease, whereas secondary pneumothorax is a complication of lung disease, commonly seen in chronic obstructive pulmonary disease. Traumatic pneumothorax includes iatrogenic pneumothorax, which occurs during diagnostic and therapeutic procedures.