What is the condition called when blood from damaged tissue enters the chest cavity?

• A. Pneumothorax
• B. Hemothorax
• C. Hemoperitoneum
• D. Pericardial effusion

Answer: (B)

When blood collects in the space around the lungs inside the chest, that condition is called a hemothorax. The chest cavity contains the pleural spaces around the lungs, and bleeding into that space causes the lung to be compressed, making breathing harder. This differs from pneumothorax, which is air in the same space causing lung collapse; from hemoperitoneum, which is blood in the abdominal cavity; and from pericardial effusion, which is fluid around the heart. In trauma or medical cases, recognizing a hemothorax guides imaging and treatments like drainage to remove the blood and allow the lung to re-expand.