Abstract: An apparatus for preventing whiplash related injuries has a support member adjustably supported within the seat of a vehicle, and adapted to be moved upwardly or downwardly relative to a passenger in the seat. A frame is supported on the support member and located behind the cranium and cervical spine of the passenger. A layer of resilient material is supported on the frame, and defines a supporting surface. The supporting surface defines a contour that corresponds to the posterior contour of the passenger's cranium and cervical spine. The supporting surface is therefore adapted to simultaneously decelerate the cranium and cervical spine during a vehicle collision and, thus, prevent whiplash related injuries to the passenger.