This is an imprecise term for injury to the cervical vertebrae and adjacent soft tissues. It is produced by a sudden jerking or relative backward or forward acceleration of the head with respect to the vertebral column. People in a vehicle that is suddenly and forcibly struck from the rear may sustain “whiplash” injuries.

Although some believe that whiplash injuries are routinely exaggerated, researchers say they cause real pain, and sometimes enduring problems, for thousands of people every...