Grade 0: complete muscle paralysis, no muscle contractility at palpation. Clinical manifestations are complete paralysis, unable to do any free exercise.

1 grade: Muscle has active contraction force, but it can't drive joint activity. The clinical manifestation is slight muscle contraction, but it can't produce movement. ?

Level 2: It can drive the joint to move horizontally, but it can't defying gravity. The clinical manifestation is that the limbs can move in parallel on the bed, but they cannot be lifted.

Level 3: Can do active joint activities against gravity, but can't resist resistance. The clinical manifestation is that the limbs can be lifted off the bed surface, but they cannot resist the resistance.

Level 4: can resist greater resistance, but weaker than normal people. The clinical manifestation is that the limbs can resist the movement of external resistance, but it is worse than normal.

Grade 5 normal muscle strength. The clinical manifestations are normal muscle strength and free movement.