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A 20-year-old man was returning from a “night on the
town” when he drove his car into a garbage truck.
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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.
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His lateral cervical spine radiograph is shown in Figure 1.
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- Are there any abnormalities?
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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.
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The patient was maintained in spinal immobilization and the lateral
view was repeated with greater traction on the patient’s
arms (Figure 2).
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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.
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The second lateral radiograph more clearly reveals the patient’s
injury, although the injury was, in fact, visible on the first lateral
view.
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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).
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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.
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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.
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