Pneumothorax is a collection of air or gas in the pleural space of the lung, causing the lung to collapse. Pneumothorax may be the result of an open chest wound that permits the entrance of air, the rupture of an emphysematous vesicle on the surface of the lung, a severe bout of coughing, or it may occur spontaneously without evident cause.

The major types of pneumothorax are:

Open pneumothorax results when a penetrating chest wound enables air to rush in and cause the lungs to collapse.

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