10 Chest Wall Visual Changes Associated With Respiratory and Cardiac Conditions

6. Subcutaneous Emphysema - Air in Soft Tissues

Subcutaneous emphysema presents as a distinctive visual and palpable change in the chest wall, characterized by the abnormal presence of air within the subcutaneous tissues, creating a characteristic swollen, puffy appearance of the affected areas. This condition typically manifests as visible swelling and distension of the neck, chest wall, and sometimes extending to the face and upper extremities, accompanied by a characteristic crackling sensation upon palpation known as crepitus. The pathophysiology of subcutaneous emphysema involves air leakage from the respiratory tract or other air-containing structures into the soft tissues, commonly occurring following trauma, medical procedures, or spontaneous rupture of alveoli. Pneumomediastinum, where air accumulates in the mediastinal space, frequently accompanies subcutaneous emphysema as air tracks along fascial planes from the mediastinum to the subcutaneous tissues. Common causes include barotrauma from mechanical ventilation, esophageal rupture, tracheobronchial injury, and complications from medical procedures such as central line placement or bronchoscopy. While subcutaneous emphysema itself is typically not life-threatening, it often indicates underlying serious pathology that requires immediate evaluation and management. The visual changes can be dramatic, with patients developing a characteristic "Michelin man" appearance in severe cases, where extensive air accumulation creates significant soft tissue distension. Healthcare providers must recognize subcutaneous emphysema as a potential sign of serious underlying injury or disease, warranting comprehensive evaluation including chest imaging and assessment for associated complications such as pneumothorax or pneumomediastinum.