Although the recommendations to evaluate possible cervical spine injuries in patients with isolated head injuries are identical to those with multiple trauma, to date, no such study has confirmed that risk factors are the same for both injuries. We reviewed the charts of 268 pediatric patients with isolated head injuries admitted to the Intensive Care Unit at Children's Hospital Medical Center (1985-1990) to determine which risk factors were present. In this retrospective study, we divided the patients into two groups: low risk and high risk. The low-risk patients (n = 135) were those capable of verbal communication who did not report cervical discomfort. The high-risk patients (n = 133) either were incapable of verbal communication (preverbal or physically unable due to head injury) or reported neck pain. All patients under 2 years of age were considered preverbal and at high risk. The patients in both groups were indistinguishable by age, sex, mechanism of injury, and type of injury sustained. No patient in the low-risk group suffered cervical spine injury. Cervical spine trauma was present in 10 (7.5%) high-risk patients. Using the method of adjusted odds ratio, we found that high-risk patients had 23 times the likelihood of neck injury when compared with low-risk patients (p = 0.003, 95% confidence limit). Our results indicate that cervical spine X-rays (i.e., anteroposterior, odontoid, lateral views) are indicated only in high-risk pediatric patients with head injuries who either complain of neck pain or cannot voice such complaints because of significant head injury or preverbal age.(ABSTRACT TRUNCATED AT 250 WORDS)