Stage 1 :Patient unaware of neural deficit, physician detects plantar extensor and/or ankle clonus. Stage II : Patient aware of deficit but manages to walk with support, clumsiness of gait. Stage III : Paralysis in extension, sensory deficit less than 50% Stage IV : III + flexor spasm/ paralysis in flexion/ flaccid/ sensory deficit more than 50%/ sphincters involved.