Every day people across the country receive emergency medical treatment following a car accident. While some are diagnosed with minor injuries, others are not so fortunate as they have sustained an injury severe in nature. One such injury is a pneumothorax. Better known as a collapsed lung, it occurs when air fills the space between the chest wall and lungs. As air fills the space, it pushes on the outside of the lung causing it to collapse. Symptoms There are several symptoms of a collapsed lung including: Pain that radiates.