Whiplash is a common neck injury that often occurs during rear-end automobile collisions, when your head suddenly moves backward and then forward — similar to the motion of someone cracking a whip. These extreme motions push your neck muscles and ligaments beyond their normal range of motion.

Whiplash injuries can be mild or severe. Treatment typically begins with over-the-counter pain relievers and ice applied to the painful neck muscles. If pain persists, prescription medications and physical therapy may be helpful.

Most people recover quickly from whiplash — usually within four to six weeks — but some people with whiplash injuries develop chronic symptoms that can be extremely painful and disabling.

Whiplash symptoms can occur immediately after the injury, or may develop only after a few days following the injury. Signs and symptoms may include:

• Neck pain and stiffness
• Headaches
• Pain in the shoulder or between the shoulder blades
• Dizziness
• Ringing in the ears
• Blurred vision
• Difficulty concentrating
• Memory problems
• Irritability
• Sleep disturbances
• Fatigue

Whiplash typically occurs when sudden force throws your head backward and then forward, straining the neck's muscles and ligaments. This type of injury may result from:

• Auto accidents, particularly for people whose vehicle has been rear-ended
• Amusement park rides, such as roller coasters
• Collisions while playing contact sports
• Incidents of being punched or shaken

Risk factors for whiplash include:

• Being female
• Younger age
• Prior history of neck pain
• Rear-end collision

Contact your doctor promptly if:

• The pain spreads to your shoulders or arms
• It becomes painful to move your head
• You experience numbness, tingling or weakness in your arms

Your doctor will ask how the injury occurred and will measure how far your neck can move in different directions. He or she will also check to see if any parts of your neck are especially tender to pressure. X-rays may help to rule out other causes of neck pain such as vertebral fractures, dislocations or arthritis. CT or MRI scans might be requested to check for soft-tissue damage or pressure on nerves.

Between 15 percent and 40 percent of people who experience whiplash will continue to have pain months after the injury occurred. In some people, this chronic pain can be traced to damage in the joints, disks and ligaments of the neck. But in many cases, no abnormality can be found to explain this persistent neck pain.

Medications
Over-the-counter pain relievers, such as acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin, others), often can control mild to moderate whiplash pain. People with more severe pain may benefit from short-term treatment with prescription pain relievers containing codeine. Muscle relaxants also may be prescribed, but these drugs often cause drowsiness so your doctor may want you to take them only at bedtime.

Ice, heat and exercise
Many people with whiplash pain find it helpful to use ice or heat on their necks and upper backs. In general, ice should be used early in the recovery period, to reduce inflammation, while heat is especially helpful to relax muscles before range-of-motion exercises.

Once your pain is under control, your doctor will likely want you to regularly perform gentle stretching exercises to help restore your neck's range of motion. These usually involve rotating your head from side to side, and bending your neck forward, backward and to the sides.

If pain persists for several months, your doctor may recommend physical therapy to help strengthen the muscles supporting your head.

Injections
An injection of corticosteroid medicine or lidocaine (a numbing medicine) into painful muscle areas may relieve the muscle spasms that can be associated with whiplash injuries. This will make it easier for you to perform the stretching exercises that are crucial to recovery.

Cervical collars
Although soft foam cervical collars were once commonly used for whiplash injuries, they no longer are recommended routinely. Immobilizing the neck for long periods of time can lead to decreased muscle bulk and strength and impair recovery.

During the day, cervical collars should be worn for no longer than three hours at a time and for only the first few weeks after the injury. If you're continually being awakened at night by whiplash pain, wearing a cervical collar may help you sleep.

Many nontraditional therapies have been employed to treat whiplash pain, including:

• Acupuncture. By inserting ultrafine needles through specific locations on your skin, acupuncturists can relieve many different types of pain. But research studies have been split pretty evenly as to whether acupuncture can help relieve persistent neck pain caused by strains.
• Chiropractic care. Many people seek chiropractic care for neck pain, and it has been shown to work just as well as, but no better than, physical therapy. Pairing spinal manipulation with exercise provides more benefit. However, manipulation of the neck has been associated, in very rare instances, with potentially life-threatening injuries.
• Massage. Kneading the tight muscles in your neck may be helpful if you continue to have muscle spasms for more than a week or two. Relax the muscles in your neck first by taking a hot shower or bath, or by using a moist towel warmed in the microwave.
• Transcutaneous electrical nerve stimulation (TENS). TENS is a device that applies a mild electric current to the skin, which decreases some types of pain by interfering with the transmission of pain signals. TENS can help relieve chronic neck pain, but only when combined with exercise.