Subcutaneous emphysema is a sign of which injury?

• A. Chest injury
• B. Abdominal injury
• C. Head injury
• D. Limb injury

Answer: (A)

Subcutaneous emphysema is air trapped under the skin that results from air escaping from the lungs or airways due to trauma. This air escape most often points to chest injury because the lungs and major airways reside there; when the chest is damaged—such as with rib fractures or pneumothorax—air can leak into the mediastinum and then travel into the subcutaneous tissues, producing a crackling feel or visible swelling under the skin. This sign is not typically caused by injuries to the abdomen, head, or limbs, which don’t create the same airway or lung leak needed to produce subcutaneous air.