What is a disc herniation?
You may have heard someone describe it as a “slipped disc,” but that term is not quite accurate. The disc does not slip out of place—it bulges. Herniation happens when the disc between vertebral bones of the spine is weakened and bulges out, causing pain and other problems.
The structure of the spine
The spine is the large set of bones along the neck and back that provides support of weight, allows dynamic torso movement, and protects the spinal cord. The spine is a column of bones called vertebrae that sit one on top of another. The vertebrae of the neck are called the cervical vertebrae, the upper back are thoracic vertebrae, and the lower back consists of the lumbar vertebrae.
These vertebrae have two main parts: the body, which is round and stable and carries most of the body's weight; and the vertebral arch, which is made up of many prongs and plates that interlock and create gaps that allow the nerves that tocome from the spinal cord to exit the spine and to supply the motor (movement) and sensory function to the limbs and torso. The spinal cord is a large bundle of nerve cells that runs from the brain down through the middle of the vertebral or spinal columne and carries major nerve functions throughout the body.
The importance of a properly working vertebral disc
In between each vertebra is an intervertebral disc that cushions the vertebrae and keeps them from sliding directly against one another. They are the shock absorbers of the spine, but they also allow broad, stable range of motion such as twisting, bending, and stretching.
The outer shell called the annulus fibrosus is made of a firm fibrocartilaginous substance that protects the inner gelatinous (nucleus) portion. Sometimes, the firmer, outer part of the disc is weakened or is damaged by the movement of the bones in the spine. In these cases, the softer, interior portion expands out (herniates) and can compress a spinal nerve.
Symptoms of a herniated disc
Herniated disc material—the softer inner part that extends beyond the outer, firmer part—may compress nerves, causing pain, weakness, or problems with sensation. The symptoms correspond to the place, or level, of the spine where the disc is herniated. A cervical herniated disc will cause neck pain and usually symptoms in the arms. LumbaLumbaer disc herniation causes low back pain and symptoms in the legs. Sciatica is caused by a lumbar disc herniation. Sciatica is associated with shooting pain down the leg and/or foot, numbness, and/or leg tingling.
It is also possible to have a herniated disc with no symptoms if the hernia does not protrude into a nerve. More likely, the herniated disc will cause pain but no neurological symptoms such as weakness.
Causes of disc herniation
Disc herniation can be a result of age, degeneration or wear and tear, or trauma. Age tends to stiffen the gelatinous inner part of the disc, weakening its ability to hold and cushion weight. The outer portion of the disc (annulus) develops fissures or tears that weakens the disc and allows the nucleus to extrude or herniate.
The most common cause of herniation is from lifting heavy loads while the spine is curved. While the back is straight, the intervertebral discs carry weight evenly, but a curved spine puts disproportionate pressure on one part of the disc, potentially causing a bulge or herniation.
Prevention and lifestyle
Maintaining a healthy weight and exercising regularly can help prevent symptoms from disc herniation by strengthening the muscle around the spine. Likewise, strengthening the core muscles can lower the risk of injury to the spine. These conditioning exercises stabilize the spine, help support and distribute body weight, and reduce the amount of weight the discs must cushion. Smokers are more prone to disc problems so this habit should be avoided.
Treatment for lumbar and cervical disc herniation
Treatment for a herniated disc typically involves temporary rest and anti-inflammatory pain medications. A corticosteroid injection may help relieve pain. Severe disc herniation, such as those causing neurological symptoms (weakness, tingling, numbess), may require surgical treatment by a spine surgeon.