Crepitation

Crepitation, also known as crepitus, refers to a crackling, grating, or popping sensation or sound produced by movement of tissues, joints, or air within soft tissues. The term is used in several medical contexts to describe qualitatively similar phenomena arising from different underlying causes. Etymologically, it derives from Latin crepitus, meaning a crackling noise.

Subcutaneous crepitus occurs when air enters the subcutaneous tissues, a condition known as subcutaneous emphysema. This can follow chest or neck trauma, surgical procedures, or certain infections and gas-forming organisms. Palpation or gentle pressing of the affected area yields a noticeable crackling sensation as air bubbles under the skin move.

In the respiratory system, “crepitations” or crackles are sounds heard with auscultation of the lungs. These lung crepitations are typically described as fine or coarse and can indicate fluid in the airways or interstitial/alveolar involvement, such as pneumonia, pulmonary edema, fibrosis, or atelectasis. They differ from wheezes and rhonchi in quality and clinical implications.

Joint and tissue crepitus refers to a crackling sensation or grinding upon movement of a joint, often resulting from roughened articular surfaces, cartilage wear, or the presence of loose bodies. It may accompany osteoarthritis, meniscal injury, or after joint injury. In some gas-producing infections, a crepitant feel can occur in soft tissues due to rapid gas production.

Overall, crepitation describes a physical sign that can arise from several distinct pathophysiologies, and its interpretation depends on the clinical context and associated findings.