Whiplash is a common type of injury, affecting as many as three million people per year in the United States. Unfortunately, about one in ten people who experience a whiplash injury will go on to experience chronic neck pain as a result of that injury. To understand why whiplash injuries occur, as well as why some of these injuries can lead to chronic pain, it’s first necessary to understand exactly what constitutes a whiplash injury.
The term whiplash refers to an injury resulting from a whip-like movement of the head and neck.
The head’s support system is a complex series of supports. The seven spinal bones, called vertebrae, just below the skull are called the cervical spine. There are several types of joints associated with each vertebra, including facet and zygapophysial joints. Between the vertebrae are intervertebral discs, which act as cushions and shock-absorbers for the vertebrae. The vertebrae are connected to each other by ligaments. Tendons connect the vertebrae to the surrounding muscles. Nerves also run out from the cervical spine to the body.
All of these parts work together seamlessly most of the time, but injuries to the neck – like whiplash – can cause some serious problems. Whiplash occurs when an impact of some sort forces the head in one direction very quickly and then in the opposite direction very quickly. This motion causes the structures of the neck to be stretched too far.
The specific injuries that can occur with whiplash include:
- Stretching or tearing of the ligaments
- Straining or spraining of the muscles and tendons
- Pinching, straining, or inflammation of the nerves
- Damage to the capsule surrounding the joints
- Fracturing of the vertebrae
A whiplash injury most commonly results in sprains or strains of the various structures of the neck. More extreme whiplash injuries, like vertebral fractures, typically only occur in extreme conditions or in people with osteoporosis.
Whiplash can sometimes lead to chronic pain and discomfort.
Until relatively recently, it was unclear why whiplash injuries – which are sometimes so subtle that they’re undetectable on imaging studies – can lead to pain that lasts for weeks, months, or even years. However, researchers have been studying chronic pain from whiplash and have come to a few conclusions.
First, it’s become clear that a large number of people who suffer from chronic neck pain have also suffered from acute whiplash injuries in the past. This suggests that many people’s chronic neck pain may originate from a past whiplash injury.
As far as why pain persists after a whiplash injury, there are a few possibilities. One of these possibilities is damage to some of the joints in the neck. While severe damage to the joint structures in the neck is visible in traditional imaging studies (such as X-rays), it’s possible that some people experience difficult-to-detect damage to the bones, tendons, cartilage, or other structures.
“The cervical zygapophysial joints are particularly relevant. Clinical and experimental studies of whiplash injuries in humans and animals have revealed tears of the joint capsules, hemarthroses, and fractures of the articular cartilage and subchondral bone[of these joints]. Detecting these injuries in vivo is difficult. It has been clearly demonstrated that injuries to the cervical zygapophysial joints frequently are undetectable on conventional x-ray examinations, and there are no known clinical features that permit their identification.”
Another possibility is nerve-related. It is, of course, possible that structural damage to the neck can result in a nerve becoming irritated or pinched, but there may be a deeper connection between whiplash and nerve-related pain. Researchers considered people with chronic neck pain or headaches from a past whiplash injury, and they found that these people had significantly lower pain thresholds as compared to people without whiplash-related chronic pain.
Additionally, this lower pain threshold was observed both in the neck and in the (uninjured) lower limbs. Because the lower pain threshold also extended to body parts that were uninjured by whiplash, it suggests that a whiplash injury can affect the way the central nervous system (which runs throughout the entire body) interprets stimuli. In other words, if a whiplash injury (or other type of trauma) causes the central nervous system to become hypersensitive, it can lead to more pain even in uninjured areas of the body. When this happens, it’s referred to as generalized central hypersensitivity.
Perhaps because of the different types of damage that can occur with whiplash, there is a large variety of potential symptoms.
Some of the potential symptoms of whiplash include:
- Pain or sensitivity in the neck
- Decreased range of motion in the neck
- Muscle tightness or spasms in the neck
- Stiffness or pain in the shoulders
- Pain or weakness in the arms
- Ringing in the ears
- Difficulty concentrating
It’s also worth noting that the symptoms of whiplash often take 24-48 hours to appear. Because of this, whiplash injuries sometimes go unreported or untreated. If you ever experience an accident or incident that causes a whip-like movement of your head, stay alert for symptoms a day or two after the incident and see a physician as soon as possible if you begin to experience discomfort.
Although typically associated with car accidents, whiplash can occur during any activity that causes the quick back-and-forth whip-like movement of the head.
Car accidents are certainly the most common cause of whiplash injuries, but sports, especially contact sports, can also cause problems. For instance, injuries of all sorts, including whiplash, are highly possible during sports like football, hockey, or boxing. Other potential causes of whiplash include falling down, riding rollercoasters with high-speed twists and turns, and even intense head-banging at a rock concert.
The best way to prevent whiplash injuries is to utilize safety equipment properly. Make the proper adjustments in vehicles, and wear protective gear during sports. It’s also a good idea to avoid unnecessary activities that may lead to whiplash.
Have you ever experienced whiplash? What were you doing when your whiplash injury occurred?
Image by Aidan Jones via Flickr