[An autopsy case of a bicycle accident with ring fracture at the base of the skull].

We report the autopsy case of a 41-year old passenger who suffered a significant head injury with a typical ring fracture at the base of the skull as a result of a violent fall from a bicycle. Several reports about ring fractures of the base of the skull revealed that they were due to crashing a car at high speed, a collision and/or a fall while riding a motorcycle and a fall in piloting a gyrocopter and so on resulting in severe injury to another part of the body. In this case, the ring fracture occurred when his spine was pushed up by high impact of the parieto-occipital region against the ground.