Table 1.

ASIA Impairment Scale¹

AIS
A = Complete	No sensory or motor function is preserved in the sacral segments S4–S5.
B = Sensory incomplete	Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4–S5.
C = Motor incomplete	Motor function is preserved at the most caudal sacral segments on voluntary anal contraction (VAC) OR the patient meets the criteria for sensory incomplete status (sensory function preserved at the most caudal sacral segments [S4–S5] by LT, PP, or DAP), and has some sparing of motor function more than three levels below the ipsilateral motor level on either side of the body. More than half of the key muscles below the neurological level have a muscle grade less than 3.
D = Motor incomplete	Motor function is preserved below the neurological level, and at least half of the key muscles below the neurological level have a muscle grade of 3 or more.
E = Normal	Complete return of all motor and sensory function, but one may still have abnormal reflexes.

AIS American Spinal Injury Association Impairment Scale; LT, light touch; PP, pinprick; DAP, deep anal pressure.

¹American Spinal Injury Association (2019). International Standards for Neurological Classification of Spinal Cord Injury. ASIA: Richmond. (Used by permission.)