Fractures of the atlas vertebra. The two-part burst fracture of Jefferson.

Burst fractures of the atlas are usually diagnosed and treated as four-part fractures as described by Jefferson in 1920. Review of the literature, roentgenogram, computed axial tomography (CAT) scans, and laboratory studies, indicates that the burst fracture is usually, if not always, a two-part fracture. These findings are contrary to the accepted concept of burst fractures, and indicate that routine roentgenograms are not adequate for proper diagnosis. Also, with disclosure of the true nature of these injuries, there is indication for further consideration and study relating to treatment of these injuries.