Consideration should be given to avoid unnecessary radiation exposure when appropriate. For instance, clinical decision-making tools incorporate three or more variables from history, physical examination, or simple clinical tests to guide patient management. Results from the National Emergency X-Radiography Utilization Study (NEXUS) and the Pediatric Emergency Care Applied Research Network (PECARN) provide a high negative predictive value for significant cervical spine injuries in pediatric patients. Low-risk criteria from NEXUS include: no posterior midline cervical spine tenderness, no evidence of intoxication, normal level of consciousness, no focal neurological deficit, and no painful distracting injuries. PECARN developed a model that was highly sensitive for a normal cervical spine in the absence of: altered mental status, focal neurologic findings, neck pain, torticollis, substantial torso injury, conditions predisposing to cervical spine injury, high-risk motor vehicle crash, and diving. In comparison to NEXUS, the PECARN model takes into account mechanism of injury and specific extent and location of other associated injuries.