This radiograph demonstrates a right pneumothorax. Note the displacement of the heart to the left. A pneumothorax occurs with a penetrating chest injury, inflammation with rupture of a bronchus to the pleura, rupture of an emphysematous bulla, or positive pressure ventilation. The escape of air into the pleural space collapses the lung. The example seen here is a "tension" pneumothorax shifting the mediastinum, because a "ball-valve" air leak is increasing the air in the right chest cavity. A chest tube can be placed to re-expand the lung.