What are 'retractions' in a clinical setting?

Retractions refer to the visible inward movement of the skin around the ribs during inspiration, indicating that a patient may be experiencing respiratory distress. This phenomenon occurs when the muscles used for breathing, such as the intercostal muscles and diaphragm, must work harder to draw air into the lungs. In cases where the airway is obstructed or there is a decrease in lung compliance, the negative pressure created during inhalation causes the soft tissues in the chest wall to be pulled inward. This can be a critical sign of respiratory distress, especially in pediatric patients.

The other options describe different medical conditions but do not relate to the specific clinical definition of retractions. Swollen lymph nodes indicate an immune response or infection, fluid accumulation in the lungs refers to pulmonary edema, and vocal cord swelling pertains to issues with the airway and voice production. Each of these conditions has its distinct presentation and implications in a clinical context.