A bulging disc is a problem with one of the shock-absorbing spinal discs that lies between each vertebra—the bones that make up the spine. Each disc is like a jelly-filled donut, with a gelatinous inner layer and firm outer layer. Typically, pressure created by everyday activities like walking, bending, sitting, and lifting is distributed evenly across discs. But bad posture, repetitive movements, and a lack of strength in the muscles that support the spine can cause unhealthy pressure to build in these discs. When the pressure gets too great in one part of the disc, the inner liquid can push into the outer layer causing a “bulge” to form—this is referred to as a bulging disc. When pressure and the bulge become extreme, the outer layer tears and the inner liquid spills out, resulting in a disc herniation —a herniated disc is a potentially much more serious issue.
The spine is made up of a group of bones called vertebrae that are stacked on top of each other with shock-absorbing discs between each bone. The jelly-like inner layer of the disc, called the nucleus pulposus, has no direct blood supply and needs alternating compressing (think: sitting) and decompressing forces (think: physical activity such as walking) to receive nutrients from the body and stay healthy. One purpose of the discs is to distribute pressures evenly as we go through activities of daily living so that the surrounding joints and other structures are not damaged. When this process malfunctions, problems and pain can occur.
What Causes Pain From a Bulging Disc?
A bulging disc can be diagnosed by a thorough evaluation by a health care professional and also by imaging such as an MRI. Symptom patterns common to bulging discs include pain with forward bending, pain with coughing, sneezing or bowel movements, and pain with prolonged sitting. The pain can occur in the back, buttocks or even down the leg or into the foot if a nerve is irritated by the bulge. Contrary to common perceptions, many people that have findings of bulging discs on an MRI experience no pain. When bulging discs do cause pain, it is because of the following scenario: a spinal disc bulges causing the shock-absorbing function of the disc to be disrupted. The weight that is usually distributed evenly through the disc by daily activities (walking, sitting, and bending over) is now distributed in an uneven pattern, putting unhealthy pressure on the affected disc and the surrounding discs, joints, and ligaments. Eventually this pressure causes problems which can result in pain. Pain and/or dysfunction can be caused in four general ways:
- If the other structures around the disc become overloaded because the damaged disc in unable to absorb shocks, they wear down and become inflamed, resulting in arthritis.
- If the muscles around the spine become stressed due to the overload from the bulge, they become tight and painful.
- If the bulge is big enough to hit a nerve, pain can be felt along the path of the nerve. When the affected nerve is the sciatic nerve, this is referred to as sciatica. To learn more about pinched nerves, click here.
- If the nerves from the surrounding tissues grow into the disc, they can transmit pain signals. (Normal discs do not have a direct nerve supply.)
Treatment for a Bulging Disc
With proper exercise and healthy spine habits, a bulging disc rarely requires surgery. In fact, it can typically be treated at home and can usually heal on its own within 6 to 12 months. The most important thing is to give the bulging disc the opportunity to heal by:
- Changing the movements and habits that put unhealthy loads through the disc.
- Building strength in the appropriate muscles to give the disc the support it needs.
Written by Dr. Jeremy James. Dr. James founded and was director of the Aspen Club Back Institute in Aspen, Colorado, is the coauthor of the bestselling The Younger Next Year Back Book and earned his Doctor of Chiropractic from the University of Western States. Learn more about Dr. James here.