When you hear the word whiplash, you almost immediately get a visual of a motor vehicle accident with a passenger flying forward then being slammed back into the seat. While we’ve heard this term and can picture the cause of injury in our mind, most don’t understand what whiplash really is and the other disorders that can stem from it. To get technical, “Whiplash is an acceleration-deceleration mechanism of energy transfer to the neck. It may result from rear-end or side-impact motor vehicle collisions but can also occur during diving or other mishaps. The impact may result in bony or soft-tissue injuries (whiplash injury), which in turn may lead to a variety of clinical manifestations (whiplash-associated disorders—WAD).”
Approximately four per 1,000 persons have experienced whiplash. Biomechanics studies have determined that after rear impact a vertebra in your neck (C6 to be specific) is rotated back into extension before movement of the upper cervical vertebrae. Thus, the lower cervical vertebrae were in extension while the upper vertebrae were in a position of relative flexion, producing an S shape in the cervical spine. More recent studies report rest and restriction of motion to be detrimental and can slow the healing process, which is why physical therapy could be beneficial. Three components of WAD (whiplash-associated-disorders) that can be treated by physical therapy are joint dysfunction, muscle dysfunction, and faulty movement patterns.
These are the clinical classifications of WAD.

Type 0: No complaints about neck, no physical sign(s)

Type I: Neck complaints of pain, stiffness, or tenderness only, no physical sign(s).

Type II: Neck complaints and musculoskeletal signs, including decreased range of motion and point tenderness.

Type III: Neck complaints, and musculoskeletal signs (above) and neurological sign(s) (reflex, sensory, and motor deficits).

Type IV: Neck complaints and fracture of dislocation.

Whiplash and Joint Dysfunction

Joint dysfunction from whiplash occurs when one of the joints in the spine or limbs loses its normal joint play (resiliency and shock absorption). When a joint develops dysfunction, its normal range of movement may be affected, and it can become painful, leading to muscle imbalance and the following cycle:

Abnormal signals to the nervous system because of nerve receptors in the joint
The muscles related to that joint can become tense or underactive
The resulting muscle imbalance can place increased stress on the joint

Whiplash and Muscle Dysfunction

Some muscles become tense/overactive, some muscles become inhibited/underactive, and both cause trigger points. “Trigger points are areas of congestion within the muscle where toxins accumulate. These toxins can irritate the nerve endings within the muscle and produce pain.”
Muscle can also affect the nervous system with altered neurological signals to properly regulate muscles throughout the body, contributing to faulty movement patterns. Altered movement patterns increase force and strain through the muscles and joints creating neck/back pain or even instability.
Sometimes, disc herniation or disc derangement may occur. If so, you may experience sharp, shooting pain down the arm and possibly neurological symptoms such as numbness, tingling and muscle weakness.

Prognosis for Whiplash

Whiplash can last a few days following a mild car collision and pain in the neck and upper back may be combined with headaches. After a more serious accident there can be severe pain and difficulty moving the neck and head and full symptoms may only present themselves a day or two after the impact with initial indications of an injury being felt 12 hours after that accident.
Serious whiplash injuries can last for months and in rare occasions the symptoms may never fully disappear. The pain and stiffness in the neck can be accompanied with upper or lower back pain, severe headaches, sleepless nights and affected vision among other symptoms.
If whiplash lasts longer than six months, then it’s usually referred to as chronic whiplash and treated with prescribed painkillers and physical therapy. It is advisable to try and keep the head and neck mobile rather than put in a brace as this can aid the healing process.

How We Can Help

Allowing the body to function in proper alignment decreases responses from the nervous system that increase muscle tightness and pain. Physical Therapy can assist with the healing process of whiplash by releasing trigger points with soft tissue work, restoring proper joint alignment to allow for normal range of motion, and decrease pain responses throughout the affected area.

Sources
http://www.spine-health.com/treatment/chiropractic/sources-whiplash-pain
http://www.bcmj.org/article/incidence-whiplash-associated-disorder
http://www.ncbi.nlm.nih.gov/pubmed/11382374
http://www.bottonline.co.uk/guides/how-long-does-whiplash-last

Whiplash Associated Disorders