Pneumothorax (pneumothorax: Greek pneuma air + th rax chest, chest) is the accumulation of air in the pleural cavity due to disruption of the integrity of the visceral, parietal or mediastinal pleura. When enough air accumulates in the pleural cavity, the lung parenchyma collapses and loses its respiratory function. Based on etiology, pneumothorax is classified into traumatic, spontaneous, diagnostic and therapeutic. When a pulmonary abscess breaks into the pleural cavity or the esophagus ruptures with the development of mediastenitis, pyopneumothorax occurs, i.e., accumulation of pus and air in the pleural cavity. Basically, with an open or closed injury to the chest with damage to the lungs, hemopneumothorax develops, i.e., accumulation of air and blood in the pleural cavity. In the case of accumulation of serous exudate in the pleural cavity along with air, hydropneumothorax is spoken of.