knee-jerk reflex

The knee-jerk reflex is an automatic response that happens when the area just below your kneecap is tapped. This stimulates sensory nerves in the muscle, which send a quick signal to the spinal cord. The spinal cord then sends a rapid response back through motor nerves, causing the muscle to contract instantly. This reflex helps maintain balance and posture by ensuring your leg moves appropriately in response to sudden changes, without needing your brain to think about it. It’s a simple, protective mechanism that keeps your body responsive and stable.