ISNCSCI Level
Neurological Level of Injury (NLI)
Guidelines & Evidence
Verified
Last Review: 2026
Last Comprehensive Review: 2026
Key Motor Dermamyotomes
C5
Elbow FlexorsBiceps
C6
Wrist ExtensorsExtensor Carpi Radialis
C7
Elbow ExtensorsTriceps
C8
Finger FlexorsFlexor Digitorum Profundus
T1
Finger AbductorsAbductor Digiti Minimi
L2
Hip FlexorsIliopsoas
L3
Knee ExtensorsQuadriceps
L4
Ankle DorsiflexorsTibialis Anterior
L5
Long Toe ExtensorExtensor Hallucis Longus
S1
Ankle Plantar FlexorsGastrocnemius
NLI = Most caudal segment with grade 3+ motor and normal sensory function.
The Motor Rule
Determining the Motor Level
The motor level is the lowest muscle grade ≥ 3, provided all segments above are grade 5.
Clinical Tip
For segments without a key muscle (like T2-L1), the motor level is assumed to be the same as the sensory level.
Sensory Integrity
The sensory level is the most caudal segment where both Light Touch and Pin Prick are graded as 2 (Normal).
2 = Normal1 = Impaired0 = Absent
