Reflex assessment is a medical evaluation that tests the body's automatic responses to stimuli. It helps healthcare professionals determine the functioning of the nervous system by checking reflexes such as the knee-jerk reaction. This assessment can identify potential issues with the spinal cord, nerves, or muscles. During a reflex assessment, a doctor typically uses a small hammer to tap specific areas, like the patellar tendon below the knee. The resulting movement indicates how well the nervous system is working. Abnormal reflex responses may suggest underlying conditions that require further investigation or treatment.