Which condition is characterized by air entering the pleural space as a complication of rib fractures?

The condition characterized by air entering the pleural space as a complication of rib fractures is pneumothorax. This occurs when a rib fracture punctures the pleura, allowing air from the lung or the external environment to enter the pleural cavity. This disrupts the negative pressure that normally keeps the lung inflated, leading to lung collapse on the affected side.

Pneumothorax can be a life-threatening situation, particularly if it is a tension pneumothorax, where the buildup of air creates increasing pressure on the lungs and mediastinum. The presence of rib fractures significantly increases the risk of developing pneumothorax as sharp bone fragments can directly injure the pleura.

In contrast, hemothorax involves the accumulation of blood in the pleural space, usually due to vascular injury, and is not specifically characterized by the presence of air. Flail chest is a condition related to multiple rib fractures causing a segment of the chest wall to move independently from the rest of the thoracic cage, often leading to respiratory issues but does not inherently denote air in the pleural space. Cardiac perforation relates to injury to the heart and is not directly associated with the pleural space.