Traumatic anterior atlanto-occipital dislocation.

The five cases of atlanto-occipital dislocation reported in the world literature are reviewed, and four additional cases are presented, including two survivors. The pathological anatomy of this potentially catastrophic injury and its management are briefly discussed. Because immediate recognition of the atlanto-occipital dislocation is critical to proper treatment and because the neurological findings are extremely varied, a new radiographic criterion for its identification has been developed.