0

No increase in muscle tone

1

Slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end of the range of motion when the affected part(s) is(are) moved in flexion or extension

1a

Slight increase in muscle tone, manifested by a catch followed by minimal resistance through the remainder of the range of motion but the affected part(s) is(are) easily moved

2

More marked increase in muscle tone through most of the range of movement, but the affected part(s) is (are) easily moved

3

Considerable increases in muscle tone, passive movement difficult

4

Affected part(s) is (are) rigid in flexion or extension