What is the difference between a pneumothorax and a hemothorax?

Air leak, blood leak. A collapsed lung (pneumothorax) is due to an air leak from the inside of the lung through the covering of the lung, out into the space between the lung and the ribs. The site of the leak has some damage, which heals itself later. With a hemothorax, it is not air that is filling the chest cavity between the lung and the rib cage, but it is blood (the blood can come from any broken vein or artery.