A retrospective study of 55 patients with acute cervical spinal cord injury caused by trauma was performed. On radiographic examination of the cervical spine in each of 55 cases showed no fracture or dislocation but developmental stenosis determined on lateral view radiograms. Ninety five point nine percent of this cases had block of the dyeing columns myelographically both in prone and supine positions. Eighty point nine percent of 47 cases demonstrated segmental instability of the cervical spine on full extension and flexion radiograms. Thirty eight cases suffered a minor trauma but resulted in incomplete spinal cord injury with moderate neurologic deficits. Most patients who had been treated conservatively for about 3 years demonstrated the neurologic deficits worsened gradually. In the later 50 cases underwent surgical treatment. A follow-up study showed that Robinson's procedure and laminectomy resulted in unsatisfactory outcome, in contrast to those of open-door technic. It is suggested that developmental stenosis may be a potential factor in the spinal cord injury.