Figuring out what’s behind your back pain isn’t always easy. For one thing, there are a lot of confusing back-pain terms (is a “bulging” disc the same as a “slipped” disc?), so it helps to understand a bit more about your anatomy. An adult’s spine consists of a stack of 24 bones called vertebrae plus the bones of the sacrum and coccyx. These bones support the body and protect the spinal cord—a major column of nerve fibers connected to the brain that runs through the vertebrae via the spinal canal. A disc, made of cartilage and filled with a gel-like material that acts like a shock absorber, is found between each vertebra. Ligaments, muscles, tendons and small joints called facets hold the vertebrae together.
With that information in mind, we’ve broken down eight possible sources of your back pain into two groups:
Mechanical Sources of Pain
1. Disc pain. If one of the discs in your spinal cord is pushed a bit out of place, often as a normal part of aging, it’s called a “bulging” disc. If this disc has some cracked cartilage—due to an inherited trait, wear-and-tear, or sudden trauma—and some of the shock absorbing gel inside the cartilage protrudes out, it’s called a “herniated” (or “ruptured” or “slipped”) disc. Bulging and herniated discs may or may not cause pain.
You may also have heard the term “degenerative disc disease.” It’s not actually a disease, but rather a catch-all term that refers to the condition of the discs, which lose their water content and sponginess with age. This can lead to osteoarthritis, herniated discs, or bulging discs.
2. Facet joint pain. Facet joints are supplied by two nerves, and if either becomes inflamed or pinched, it can be painful.
3. Pinched nerve. Discs pushed out of place may compress a nerve. Often it’s the sciatic nerve (which runs out of the lower spine and into the leg) that is compressed or inflamed. This causes shooting pain called sciatica in the lower back, leg, and buttock.
4. Spinal stenosis. This occurs when the spinal canal becomes narrowed (most often due to arthritis) and impinges on nerves, causing pain.
Other Sources of Pain
5. Muscle or ligament strain. An intense workout or lifting something heavy is also a frequent source of pain, especially in the lower back. Low-back pain is the most common form of back pain because those muscles, ligaments, and discs are under the most pressure when you’re sitting or lifting.
6. Osteoarthritis. “As we age, our nice spongy cartilage becomes thinner and is not as compressible,” explains Mary-Ann Fitzcharles, MD, a Montreal rheumatologist and associate professor of medicine at McGill University. “The underlying bone senses this and then it responds by generating little extra ridges of bone called osteophytes or bone spurs. These little ridges rub against each other, and this mechanical irritation can cause pain.”
7. Fibromyalgia, which for the most part affects women, is recognized as a disturbance of the natural way the body deals with pain. “For many patients who experience back pain, it’s not because of a structural abnormality,” says Dr. Fitzcharles. “Rather, the impairment of pain-processing mechanisms means the brain is hypersensitive to incoming sensory input, or there is a lack of natural mechanisms to inhibit pain.”
8. Other health issues. Back pain is occasionally a symptom of a serious condition. If you have a history of cancer, or if your back pain is associated with fever, unexplained weight loss, or loss of bowel or bladder control, or gets severely worse when you’re lying down or at night, see a doctor immediately.
While the source of your pain could be found in any of these common issues, it’s possible, even likely, that you may never know the exact cause. “In about 85 percent of back pain, we don’t have a specific underlying pathology that can be identified as the cause,” notes Michele Crites Battié, a professor of physical therapy at the University of Alberta.
October 2010 issue of Best Health magazine