In children, the occiput is relatively large compared to the rest of the head. This means that when a child lies flat, the cervical spine is not in the neutral position, but partially flexed. This can result in pseudosubluxation and increase in the posterior interspinous distance even when there is no associated ligamentous injury.

Pediatric patients are much more likely to have ligamentous rather than osseous spinal injury and while a limited CT through the craniocervical junction could be performed, an MRI will give more soft tissue information and exclude ligamentous injury.  If there is concern for fracture, a limited CT could be performed subsequently.