Any injury that forcibly causes hyperextension and flexion of the neck can result in whiplash. Common causes include motor vehicle accidents, sports accidents, and falls. For example, in a motor vehicle accident, a rear-end collision propels the patient’s trunk forward on the pelvis, throwing the head into hyperextension and stretching the anterior structure of the neck; a head-on impact initially produces acute flexion and subsequently a reflex hyperextension.

Although rare, nerve damage that results in numbness, tingling, or weakness is a possible complication of acceleration-deceleration injuries.

The patient’s history reveals an acceleration-deceleration injury. He usually reports that symptoms first appeared 12 to 24 hours after the injury. If the injury is mild, symptoms may not appear for an additional 12 to 24 hours.

The patient typically complains of moderate to severe pain in the anterior and posterior neck. Within several days, the anterior pain diminishes but posterior pain persists or even intensifies. (You may not see the patient until he has reached this point, because many patients don’t seek medical attention right away.) He also may report dizziness, headache, and vomiting.

During inspection of the neck, you may note neck muscle asymmetry. Neurologic examination may reveal gait disturbances, rigidity or numbness in the arms, and spatial instability that affects balance. Palpation reveals pain at the exact location of the injury.