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
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Defining the Neurological Level of Injury (NLI) in acute spinal trauma.
Standardizing operative reports and clinical handovers.
Differentiating between bony, radiographic, and clinical injury levels.
Assessing progression or recovery during longitudinal follow-up.
Section 2
Formula & Logic
Defining the Level
The NLI is the most caudal (lowest) segment of the spinal cord with normal sensory and antigravity motor function on both sides of the body.
The 3/5 Rule
A segment is considered the Motor Level if the key muscle for that segment is at least Grade 3 (antigravity), provided that the segments strictly above it are Grade 5 (normal).
Section 3
Pearls/Pitfalls
Bony vs. Clinical Level
The clinical NLI often differs from the bony fracture level (e.g., a C5/6 fracture dislocation may result in a C8 neurological level). For neurosurgeons, the clinical NLI is the source of truth for functional prognosis and respiratory drive risks.
Section 4
Evidence Appraisal
Primary Reference
Updates for the International Standards for Neurological Classification of Spinal Cord Injury
Kirshblum SC et al. • Phys Med Rehabil Clin N Am. 2014;25(3):505-517
