"Normal" Cervical Spine Radiographs and Computed Tomography Scans in the Emergency Department: Beware of Posttraumatic Instability of the Mobile Segment of the Lower Cervical Spine.

The NEXUS criteria have been introduced in the 1990s to assist emergency department physicians to decide whether to perform radiographic work-up following cervical whiplash injury. Four criteria have been described on these profile radiographs of the cervical spine including angulation between cervical endplates, 3-mm listhesis, posterior facet joints overlap, and widened interspinous space. Although these criteria could help to detect patients suffering from unstable trauma of the mobile segment if the lower cervical spine, the radiographic signs may be so subtle that even specifically trained physicians like spine surgeons and neuroradiologists may miss them, especially during after-hour shifts. Hence, we present the striking case of a young female patient whose radiographs displayed slight but abnormal signs of lower cervical spine instability, but was nonetheless discharged home with dynamic X-rays of the cervical spine to be performed in a delayed setting. We hope that these striking features will help us remind the importance of radiologic semiology of posttraumatic unstable cervical spine.