Which injury is a collection of blood in the pleural space that compresses the lung?

• A. Pulmonary contusion
• B. Hemothorax
• C. Open pneumothorax
• D. Rib injury

Answer: (B)

A hemothorax is a collection of blood in the pleural space that compresses the lung. When blood accumulates in the pleural cavity, it pushes on the lung and prevents full expansion, leading to reduced breath sounds on the affected side, dullness to percussion, and respiratory distress. Large amounts can also cause shock from blood loss.

Pulmonary contusion, by contrast, is bleeding within the lung tissue itself rather than into the pleural space, so the primary issue is damage to the lung parenchyma and gas exchange. An open pneumothorax involves air entering the pleural space through a chest wall wound, not blood, and is characterized by a sucking chest wound and hyperresonant percussion. A rib injury is a bone fracture and pain that can limit breathing but does not describe a collection of blood in the pleural space.