An Introduction to Lower Back Pain
If you have lower
back pain, you are not alone. Nearly everyone at some point will have lower back pain that interferes with work, routine daily activities, or recreation. Americans spend at least 50 billion dollars each year on
lower back pain relief.
Lower back pain is the most common cause of job-related disability and a leading contributor to missed work. Back pain is the second most common neurological ailment (after
headaches) in the United States. Fortunately, most occurrences of lower back pain will go away within a few days.
Acute, or short-term, low back pain generally lasts from a few days to a few weeks. Most acute back pain is mechanical in nature, which means that it is the result of trauma to the lower back or a disorder such as
arthritis. Pain from trauma may be caused by:
- A sports injury
- Work around the house or in the garden
- A sudden jolt, such as a car accident or other stress on spinal bones and tissues.
Symptoms of lower back pain can range from:
- Muscle ache to shooting or stabbing pain
- Limited flexibility and/or range of motion
- An inability to stand up straight.
Occasionally, pain felt in one part of the body may "radiate" from a disorder or injury elsewhere in the body. Some acute pain syndromes can become more serious if left untreated.
Chronic back pain is measured by duration. Pain that persists for more than three months is considered chronic. Chronic lower back pain is often progressive, and the cause can be difficult to determine.
The back is an intricate structure of bones, muscles, and other tissues that form the posterior part of the body's trunk from the neck to the pelvis. The centerpiece is the spinal column, which not only supports the upper body's weight, but also houses and protects the spinal cord -- the delicate nervous system structure that carries signals that control the body's movements and convey its sensations. Stacked on top of one another are more than 30 bones -- the vertebrae -- that form the spinal column, also known as the spine. Each of these bones contains a round hole that, when stacked in register with all the others, creates a channel that surrounds the spinal cord.
The spinal cord descends from the base of the brain and extends in the adult to just below the rib cage. Small nerves ("roots") enter and emerge from the spinal cord through spaces between the vertebrae. Because the bones of the spinal column continue growing long after the spinal cord reaches its full length in early childhood, the nerve roots to the lower back and legs extend many inches down the spinal column before exiting. This large bundle of nerve roots was dubbed by early anatomists as the cauda equina, or horse's tail.
The spaces between the vertebrae are maintained by round, spongy pads of cartilage called intervertebral discs that allow for flexibility in the lower back and act much like shock absorbers throughout the spinal column to cushion the bones as the body moves. Bands of tissue known as ligaments and tendons hold the vertebrae in place and attach the muscles to the spinal column.
Starting at the top, the spine has four regions, which include:
- The seven cervical or neck vertebrae (labeled C1 through C7)
- The 12 thoracic or upper back vertebrae (labeled T1 through T12)
- The five lumbar vertebrae (labeled L1 through L5), which we know as the lower back
- The sacrum and coccyx, a group of bones fused together at the base of the spine.
The lumbar region of the back, where most
back pain is felt, supports the weight of the upper body.
