whiplash, injury to the cervical spine and its soft tissues caused by forceful flexion or extension of the neck, especially that occurring during an automobile accident. It may involve sprain, fracture, or dislocation and may vary greatly in location, extent, and degree. Sometimes it is accompanied by concussion. Whiplash is characterized by pain, muscle spasm, and limited motion. Treatment includes protective support for the neck and back and sometimes the attachment of weights to the head or legs to stretch the injured muscles and relieve pressure on nerves.