Like a lot of issues in health care, whiplash is not as simple as it seems.

Researchers have done a number of human volunteer crash studies (at relatively low speeds, for obvious reasons) that have exposed some of the forces involved in these accidents. One of the first findings is that there truly can be a “whip” to the neck, especially in rear-end crashes. Headrests are somewhat helpful in preventing this, as they limit backward motion of the head, but they cannot completely protect the neck.

One researcher, Dr. Arthur Croft, a chiropractic orthopedist, found that there tend to be stronger “whiplash” forces at the neck in a 10 mph crash than in an 18 mph crash. This is the opposite of what you would expect, but the reason is simple: Once the bumper begins to crumple, typically at about 12 mph, it absorbs some of the impact, reducing the forces to the neck of the occupant. This explains why the neck can be injured in a low-speed impact, without any damage to the car.

A commonly asked question is at what speed do we start to see injury to the tissues of the neck? In one study, volunteers were used to study the effects of a low-speed, rear-impact crash. Their necks were monitored by both regular video as well as a high-speed motion X-ray. Early in the crash, the motion X-ray showed excessive and abnormal motion in the joints of the neck. This was seen despite the fact that the video did not show that much overall motion of the neck, certainly not beyond a normal range. It is unlikely that a headrest would protect against this part of the impact. And the real kicker? These studies were done at speeds of just 2.5 mph.

But just because someone has been in a crash does not guarantee an injury. Dr. Croft found large variations in the forces transmitted to the neck, even when two people are seated side by side in the same car, or when the same two cars are crashed at the same speed several times in a row.

It is usually assumed that the pain of whiplash comes from the muscles, and in more severe cases, from the discs or a “pinched nerve.” But an interesting study has debunked that idea. The researchers used Novocain-type painkillers, injected directly into the joints of the neck of 68 patients with chronic neck pain from whiplash. In 60 percent of the patients tested, the pain came from the joints of the neck, not the muscles, discs or nerves.

The results of that study naturally lead to this next one, and together they provide some hope for chronic whiplash sufferers. Researchers took 28 patients with chronic whiplash pain and had them go through a course of chiropractic care, which focuses on treating joint injury. The results were very positive, with 93 percent of the subjects getting at least some relief. The authors concluded, “Whiplash injuries are common. Chiropractic is the only proven effective treatment in chronic cases.”

That certainly isn’t to say that other treatments aren’t helpful, but treating the injured joints was the key.

Dr. Michael Noonan practices chiropractic, acupuncture and other wellness therapies in Old Town. He can be reached at