All of the following statements are true of Jefferson's fracture of the atlas except:

B. The fracture fragments characteristically displace into the spinal canal.

DISCUSSION: Fracture of the atlas (Jefferson's fracture) occurs from an axial load, usually to the top of the head. The resulting forces fracture the ring of C1 and displace the fragments outward. This results in an increase in the cross-sectional area of the spinal canal at the level of injury. Neurologic injury is, therefore, unusual in this fracture. CT is the best roentgenographic study available to evaluate fractures of the atlas.