Chapter V-3. Hangman’s Fracture of C2—Posterior Cervical Line

A 20-year-old man was returning from a “night on the town” when he drove his car into a garbage truck.

On arrival in the ED, the patient appeared intoxicated. He was hemodynamically stable. He had a forehead contusion. The neurological examination was normal, as was examination of the chest, abdomen and extremities.

His lateral cervical spine radiograph is shown in Figure 1.

• Are there any abnormalities?

The initial lateral view was interpreted as negative for an acute injury. However, the inferior portion of C7 was not seen. In addition, the patient’s positioning was rotated; the left and right lateral masses are widely separated.

The patient was maintained in spinal immobilization and the lateral view was repeated with greater traction on the patient’s arms (Figure 2).

Although this second view did not show C7, the injury is now more easily seen. The injury, however, was visible on the initial lateral view.

See patient outcome.

The second lateral radiograph more clearly reveals the patient’s injury, although the injury was, in fact, visible on the first lateral view.

Although a definite fracture is difficult to detect, there is indirect evidence that a fracture is present, i.e., malalignment of the upper cervical spine. The C2 vertebral body shows slight anterior displacement (anterolisthesis) relative to C3 (asterisk in Figures 3 and 4). This displacement is easier to see in the second radiograph (Figure 3).

Slight anterior displacement of the C2 vertebral body relative to C3 may be normal, especially with supine cross-table lateral radiographs in which the neck is slightly flexed. However, a second radiographic finding indicates that this C2 anterolisthesis is abnormal.

The spinous process of C2 is displaced slightly posteriorly. This is determined by drawing a line through the C1–C3 spinolaminar junctions: the posterior cervical line (PCL) (lines in Figures 3, 4, and 5). Normally, the C1, C2, C3 spinolaminar junctions are within 2 mm of a straight line. In this patient, the C2 spinolaminar junction is displaced 3 mm posterior to the PCL (arrowheads in Figures 3 and 4). Because the anterior part of C2 is displaced anteriorly, and the posterior part of C2 is displaced posteriorly, the neural arch of C2 must be fractured.