[Ring fractures of the base of the skull]

Besides complete ring fracture, also incomplete fractures open to the front, back, or side(s) are discussed on the basis of 61 ring fractures of the base of the skull. The fractures were found in casualties from traffic accidents (car passengers, cyclists and motorcyclists, pedestrians), after falls and other accidents. In traffic accidents, compression, traction, hyperextension, extreme lateral movements, and torsional forces can lead to ring fractures. In falls, compression and traction are the main forces. A fall in one plane is also capable of producing an incomplete ring fracture. Incomplete ring fractures may show lateral emphasis. The greater fracture length is found on the impact side (e.g., in falls). In contrast to complete ring fractures, incomplete ring fractures are compatible with longer survival times. Ring fractures are to be classified under direct fractures. This does not exclude the possibility that overall deformations of the skull with bursts can partly determine the course of the fracture.