A pneumothorax is a collection of air outside the lung but within the pleural cavity. It occurs when air accumulates between the parietal and visceral pleurae inside the chest. The air accumulation can apply pressure on the lung and make it collapse. The degree of collapse determines the clinical presentation of pneumothorax. Air can enter the pleural space by two mechanisms, either by trauma causing communication through the chest wall or from the lung by rupture of the visceral pleura. A pneumothorax can be a complete lung collapse or a collapse of only a portion of the lung. Usually air escapes from the lung or gets sucked in through the chest wall and condition is called as Pneumothorax. Consult Dr. Harsh Vardhan Puri for collapsed lung or pneumothorax treatment in Delhi and Gurgaon, India.