There are 6 levels of muscle strength in the limbs, from 0 to V. Level 0 means that the muscles are completely immobile, even without contraction of muscle fibers. Grade I means that the muscle fibers can contract and move, but cannot drive the joint movement. Grade II means that the patient’s joints can move, but cannot resist gravity, and cannot lift the limb off the bed if the patient is in a flat position. Grade III patients have muscle strength that can resist gravity and can lift all limbs, but cannot resist external resistance and will fall at any time with slight downward pressure. Grade IV, the patient can resist gravity while lifting and resisting external resistance, but not up to the normal range, in this case the patient can stand and walk on his own. Grade V, the patient moves freely and is in a completely normal state.