ASIA impairment scale

Impairment in spinal cord injury

Grade A

Complete: no motor or sensory function preserved

Grade B

Incomplete: sensory but no motor function preserved below the neurologic level (includes sacral segments S4-5)

Grade C

Incomplete motor: >50% of key muscles below the neurologic level have a muscle strength grade <3

Grade D

Incomplete motor: >50% of key muscles below the neurologic level have a muscle strength grade >=3

Grade E

Normal: sensory & motor function normal.

Reference

Greenberg's Handbook of Neurosurgery, 7th edition