Trauma and the improbable anterior displacement.

There is little doubt that an individual involved in a motor vehicle accident has received some shock, whether blunt trauma or a cervical spinal whiplash has occurred. However, the severity of the trauma and the individual response is unique. Anterior disk displacement is easy to explain to third parties, since the lay concept is a cap (disk) on the condyle that is waiting to be dislodged. It is, therefore, the most frequently diagnosed injury and generally accepted without question. The possibility that this is a pre-existing derangement is discussed, and the requirements for displacement are described.