HEMOTHORAX

also spelled Haemothorax, collection of a bloody fluid in the pleural cavity, between the membrane lining the thoracic cage and the membrane covering the lung. Hemothorax may result from injury, especially when there has been damage to the larger blood vessels of the chest wall. In addition to blood, air may also be present in the pleural cavity (pneumothorax), in which case the condition is named hemopneumothorax. This may lead to occult bleeding, a type of internal hemorrhage in which large amounts of blood may be lost.