Pneumothorax
Pneumothorax (sometimes called "collapsed lung") is a health problem where air or gas is in the pleural space (the space between the lung and the pleura). The pleura is a slim membrane that covers the lungs. The two parts of the pleura usually touch. A hole might grow in the surface of the lung. Air then enters between the pleura and the lung. The lung will collapse. If enough air gets into the pleural space, it can also push against other organs or parts in the chest, like the heart or the aorta. Pneumothorax is a medical emergency.