FIGURE 112.33 Rotary subluxation of C1 and C2 A: Grossly normal lateral neck radiograph in an 8-year-old child with rotary subluxation B: Grossly normal open-mouth (odontoid) radiograph in an 8-year-old child with rotary subluxation C: Computed tomographic (CT) scan demonstrating marked rotary subluxation of C1 clockwise around dens Actual measurement was 22 degrees of rotation D–G: CT evidence of fixed rotary subluxation in a 6-year-old child D: Lateral radiograph demonstrating mild increased distance of predental space E: Axial CT scan demonstrating asymmetry between right and left sides and increased distance between dens and patient’s left side of C1 (star noted on E–G ) (asymmetry between right and left sides) F: Axial CT scan with patient’s head turned to the right, demonstrating asymmetry between the dens and ring of C1 G: Axial CT scan with patient’s head turned to the left, demonstrating fixed asymmetry between the dens and the ring of C1 Spinal Cord Syndromes Several specific spinal cord syndromes may be encountered in the ED ( Fig 112.34 ) A spinal cord concussion (transient traumatic paresis or paralysis) involves neurologic symptoms that completely resolve over a short period This condition can occur with or without associated fracture or dislocation A complete cord transection (either mechanical or physiologic) results in immediate and permanent loss of all neurologic functions distal to that level ( Fig 112.34 ) The