NCJ Number
136024
Journal
Journal of Forensic Sciences Volume: 37 Issue: 2 Dated: (March 1992) Pages: 556-564
Date Published
1992
Length
9 pages
Annotation
This study is part of a review of fatal traffic crashes investigated by the Office of the Chief Medical Examiner in Central Massachusetts during the period July 1985 through July 1987.
Abstract
The study was limited to 155 traffic deaths in which the autopsy was performed by the author. Twelve of the 155 persons had occipitoatlantal dislocations. Nine were vehicular occupants, 2 were cyclists, and 1 was a pedestrian. The dislocations involved various combinations of lacerations of the alar ligaments, the occipitoatlantal joint capsules, the dura mater, the tectorial membrane, the rectus capitis muscles, and the suboccipital muscles. In two instances an occipital condyle failed instead of the corresponding alar ligament, producing condyle fractures. Atlas ring fractures occurred in three instances. Axial and subaxial cervical trauma were uncommon. Facial or mandibular fractures occurred in a majority of cases; vault skull fractures were uncommon; and basilar fractures were absent. Pontomedullary brainstem lacerations occurred in 9 of the 12, and 4 had midbrain lacerations. The majority of the victims experienced neurogenic shock as the sole or the major mechanism of death. This article discusses the biomechanical basis for occipitoatlantal dislocation. The article indicates that distraction -- in concert with variable combinations of extension, rotation, and posterior translation -- is responsible for occipitoatlantal dislocations. 2 figures, 1 table, and 24 references (Author abstract modified)