Which condition involves blood in the chest cavity?

• A. Hemothorax
• B. Atelectasis
• C. Pneumothorax
• D. Pulmonary edema

Answer: (C)

Blood in the chest cavity means blood has collected in the pleural space, the thin gap between the lungs and the chest wall. This condition is called a hemothorax. It happens when chest trauma, surgery, or ruptured blood vessels spill blood into that space, and it can limit how well the lung can expand, causing shortness of breath.

This is different from a pneumothorax, which is air in the pleural space that can also cause lung collapse; atelectasis is collapse of lung tissue itself often from obstruction or compression; and pulmonary edema is fluid buildup inside the lungs rather than in the pleural space.