Canadian C-Spine Rule Calculator

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Step 1 — High risk: Age ≥65 years

Step 1 — High risk: Dangerous mechanism (fall ≥1m/5 stairs, axial load, high-speed MVC/rollover/ejection, bicycle collision, motorised recreational vehicle)

Step 1 — High risk: Paraesthesias in extremities

Step 2 — Low risk: Simple rear-end MVC (excludes pushed into oncoming traffic, hit by high-speed vehicle, rollover, hit by large vehicle)

Step 2 — Low risk: Sitting position in ED

Step 2 — Low risk: Ambulatory at any time since injury

Step 2 — Low risk: Delayed onset of neck pain (not immediate)

Step 2 — Low risk: No midline cervical spine tenderness

Step 3 — Can actively rotate neck 45° left AND right

✓ when to use

Apply to alert (GCS 15), stable adult trauma patients being assessed for cervical spine injury. The patient must be ≥16 years old. The branching algorithm proceeds sequentially: any high-risk factor → imaging; if no high-risk but ≥1 low-risk factor → assess range of motion; if can rotate 45° → clear. More sensitive and specific than NEXUS in head-to-head comparison.

✗ when not to use

Not applicable if: GCS <15, age <16, non-trauma neck pain, penetrating injury, known vertebral disease, previous c-spine surgery, or returning for reassessment after initial injury. The rule requires the patient to be fully alert and cooperative for the range-of-motion assessment.

clinical pearls

The three-step branching structure is critical: you must proceed sequentially. If ANY high-risk factor is present (Step 1), stop and image. Only proceed to Step 2 if no high-risk factors exist. Only proceed to Step 3 if at least one low-risk factor permits safe assessment.
The Canadian C-Spine Rule outperformed NEXUS in direct comparison — higher sensitivity AND specificity. It is the preferred rule when both are applicable, despite being more complex.
'Dangerous mechanism' is clearly defined: fall from ≥1m or 5 stairs, axial load to head (e.g., diving), high-speed MVC (>100 km/h) or rollover or ejection, motorised recreational vehicle, or bicycle collision.
Step 3 (active rotation) requires the PATIENT to actively rotate their own neck. The clinician should NOT passively rotate the neck. If the patient cannot or will not attempt rotation, imaging is required.
The rule was validated in stable, alert patients. Any neurological deficit, intoxication, or distracting injury that prevents reliable assessment means the rule cannot be applied — maintain immobilisation and image.

✓ when to use

✗ when not to use

clinical pearls

The three-step branching structure is critical: you must proceed sequentially. If ANY high-risk factor is present (Step 1), stop and image. Only proceed to Step 2 if no high-risk factors exist. Only proceed to Step 3 if at least one low-risk factor permits safe assessment.
The Canadian C-Spine Rule outperformed NEXUS in direct comparison — higher sensitivity AND specificity. It is the preferred rule when both are applicable, despite being more complex.
'Dangerous mechanism' is clearly defined: fall from ≥1m or 5 stairs, axial load to head (e.g., diving), high-speed MVC (>100 km/h) or rollover or ejection, motorised recreational vehicle, or bicycle collision.
Step 3 (active rotation) requires the PATIENT to actively rotate their own neck. The clinician should NOT passively rotate the neck. If the patient cannot or will not attempt rotation, imaging is required.
The rule was validated in stable, alert patients. Any neurological deficit, intoxication, or distracting injury that prevents reliable assessment means the rule cannot be applied — maintain immobilisation and image.

Canadian C-Spine Rule

inputs

✓ when to use

✗ when not to use

clinical pearls

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