The knee reflex is one of the deep reflexes of the body, and there are two main methods of examination.1. Sitting method, the patient takes a sitting position with the knee flexed to 90 degrees and the lower leg naturally sagging at a right angle to the thigh. The patient must be instructed to relax and not to have muscle tension, otherwise the effect of the examination will be affected. Then the examiner uses a percussion hammer to tap the tendon of the quadriceps under the patella, the reflex effect is calf extension. 2, take the supine position for examination, the patient is in the supine position, the examiner uses the left hand to hold the joint from behind both knees at 120 degrees of flexion, also ask the patient’s muscles to relax, and then tap the tendon of the quadriceps.