How can sudden deceleration in vehicle accidents cause whiplash?

Sudden deceleration during a vehicle accident causes whiplash by subjecting the neck to forceful, rapid movement. When a vehicle stops abruptly, the body is restrained, but the head continues to move forward or backward due to inertia. This creates a violent oscillation—a rapid back-and-forth or forward-and-backward motion—that forces the cervical spine into extreme flexion or extension.12

This intense, sudden movement can result in damage to the soft tissues of the neck, including sprains, or in more severe cases, fractures or dislocations. The injury is often accompanied by symptoms such as pain, muscle spasms, and a restricted range of motion, and it may sometimes involve a concussion.12