Seat belt asphyxia as a lethal mechanism in motor vehicle crashes.

A 28-year-old driver was found dead in his car after impact with a truck. At the scene he was seated in the driver's seat partially hanging out of the vehicle with the sash component of the seatbelt tightly pressed into his neck. At autopsy there was evidence of neck compression with bilateral conjunctival petechial hemorrhages and fracture of the right superior horn of the thyroid cartilage. Limb fractures and internal injuries were not associated with significant hemorrhage. There was no evidence of brain trauma. Death was, therefore due to neck compression from the seatbelt demonstrating an additional rare lethal mechanism that may be encountered in vehicle crashes. External bruises and abrasions may not be present around the neck due to padding from clothing, however conjunctival petechiae and neck injuries are supportive of the diagnosis.