Subcutaneous Emphysema is best described as?

• A. Air in the pleural space
• B. Blood under the skin
• C. Air under skin causing crackling feel
• D. Fluid around the lungs

Answer: (C)

Subcutaneous emphysema occurs when air enters the subcutaneous tissues, typically after chest injury, surgery, or barotrauma. The hallmark sign is a crackling sensation under the skin (crepitus) when you palpate the chest, neck, or face as air disperses through tissue planes. This description matches air trapped under the skin producing that distinctive crackling feel.

This is distinct from air in the pleural space, which is pneumothorax and involves air between the lung and chest wall rather than under the skin. It’s also different from a subcutaneous hematoma, which is blood under the skin and feels like a bruise or lump without the crackling sensation. Likewise, fluid around the lungs (pleural effusion) involves fluid in the pleural space and presents with changes like decreased breath sounds and dullness to percussion, not a crackling skin sensation.