What typically causes a bilateral facet lock injury?

A bilateral facet lock injury is typically caused by a specific mechanism involving rotation combined with severe distraction. This type of injury occurs in the facet joints, which are located between the vertebrae in the spine. When the spine undergoes a significant rotational force in conjunction with distraction (or pulling apart), it can lead to the locking of the facet joints on both sides of the vertebrae. This results in a condition where the vertebrae cannot move freely, leading to intense pain and limited range of motion.

The other mechanisms, such as flexion without rotation, extension with bending, or vertical compression, do not typically lead to a bilateral facet lock because they involve different movements that either isolate one side of the spine or do not create the necessary forces to lock both facets simultaneously. Each of these injuries has its own characteristic presentations and mechanisms, but the combination of rotation and severe distraction is what is specifically noted for causing bilateral facet lock injuries.