For the examination of knee tendon reflexes, if the patient is in the sitting position, it is recommended that the patient’s knee joints be flexed at about 90 degrees, with the lower legs naturally relaxing and drooping at right angles to the thighs. If the patient is in supine position, let the examiner use his left hand to lift the joints from behind the knees and flex them at about 120 degrees, and the examiner’s right hand will use a percussion hammer to strike the quadriceps tendon under the patient’s patella, and the reflex will manifest as a natural extension of the calf. The knee reflex is innervated by L2-L4 and is transmitted via the femoral nerve. If the knee tendon reflex is diminished or absent, it represents an important sign of lower motor neuron paralysis, such as the more common clinical disorders such as myasthenia gravis or periodic paralysis. If the knee tendon reflex is increased, this represents damage to the upper motor neurons, most commonly cone-bundle injuries.