Designed for use in alert (GCS 15), haemodynamically stable adults (≥16 years) with acute blunt head or neck trauma where cervical spine injury is a concern and history and examination are reliable.

Evidence summary

Study	Population	Key findings
Derivation study (Stiell 2001)	8924 alert, stable adults with potential cervical spine injury in Canadian emergency departments. mean age about 37 years. Clinically important injury in 1.7%.	The Canadian C-Spine Rule showed 100% sensitivity for clinically important injury with specificity around 43%, and could have reduced cervical spine radiography use from about 69% to 58%.
Prospective validation vs NEXUS (Stiell 2003)	7438 similar adults with blunt head or neck trauma, GCS 15 and normal vital signs.	Clinically important injury in about 2%. the rule maintained sensitivity around 99–100% with specificity about 40–45%, while the NEXUS criteria had lower sensitivity (around 91%) and lower specificity.

Clinically important cervical spine injury was defined as fracture, dislocation or ligamentous instability requiring active management. minor avulsion and small compression fractures were classified as clinically unimportant.
Derivation and validation studies excluded patients under 16 years, those with penetrating neck trauma, acute paralysis, known vertebral disease, previous cervical spine surgery or pregnancy.
NICE spinal injury guidance recommends CT of the cervical spine in adults when imaging is indicated by the Canadian C-Spine Rule, and supports avoiding imaging when low-risk factors are present and the patient can actively rotate the neck 45 degrees left and right without other red flags.

Canadian C-Spine Rule