Among 66 victims with neck injuries, there were 14 with injuries at the level of the atlantoaxial motion segment; victims ranged in age from 8 months to 93 years. Thirteen had sprains or lacerations of the atlantoaxial facet joints, and one had a healed C1 fracture. Six of the 14 had odontoid fractures. None had transverse ligament lacerations. Injuries of the alar ligaments and the tectorial membrane were frequent. Only three victims had subaxial cervical injury. All 14 had evidence of impact to the head or neck. Four had fractures of the mandible or facial bones, and five had skull fractures. Subdural and subarachnoid hemorrhages were found in seven and six victims, respectively. Brainstem lacerations were not uncommon, but only one had a pontomedullary laceration. Spinomedullary cord injuries occurred in five victims. Acute neurogenic shock was the major mechanism of death in 9 of the 14, including 5 with major cardiovascular lacerations. Delayed effects of craniocerebral trauma accounted for the majority of the remaining deaths. The biomechanical mechanisms of the injuries are discussed. 2 figures and 17 references (Author abstract modified)