The vertebral column, also called the spine, provides support for the trunk
of the body, protects the spinal cord, and provides attachment points for
the ribs and muscles of the back and trunk.
The spine has 4 natural curves. This "S" shape allows for it to act more
like a spring for the body rather than a straight stiff rod and helps to
provide resilience for bearing the weight and motion of the body.
The vertebral column consists of 5 major divisions:
- 7 cervical vertebrae
- 12 thoracic vertebrae
- 5 lumbar vertebrae
Located between the individual vertebrae are cushions called intervertebral
disks. These disks act like shock absorbers during physical activity such
as walking, jumping, or lifting, and allow the spine to extend and flex.
Each vertebra and disk is named by its division and order. For example,
the first lumbar vertebra is called "L1", the second is called "L2" and the
disk in between is called the "L1 - L2 intervertebral disk." The lumbar portion
of the spine supports most of the body's weight and is the most common area
for back pain.
The vertebrae are designed to help protect the spinal cord and the spinal
nerves that extend from the spinal cord to the various parts of the body.
The protection of the spinal cord and its nerves are important for maintaining
good body function and health. Each intervertebral disk consists of 2 parts.
The center of the disk is called the nucleus pulposus, which acts like a
rubber ball to provide cushioning during compression. The nucleus pulposus
is surrounded by a tough fibrous outer covering called the annulus fibrosus.
The annulus fibrosus protects the nucleus pulposus and keeps its jelly-like
material contained within the disk.
Over time or as a result of injury, the outer covering of the disk may wear
out or become torn. If this happens, the center jelly-like material may bulge
out and put pressure on a nearby spinal nerve. The protrusion or rupturing
of a disk is often called a "slipped disk." This condition may result in
severe pain or even limit motion and your ability to do certain physical
Other common causes of low back pain are:
- Narrowing of the spinal canal, also called spinal stenosis
- Small fractures to the vertebral bodies
- Strains or tears of the muscles, tendons, or ligaments that support the
- Poor alignment of the vertebrae
- Spasms of the muscles in the back
Various treatments are available for low back pain, including medication,
physical therapy, chiropractic treatments, acupuncture, massage therapy,
and surgery. However, the best medicine of all is prevention through proper
exercise, keeping good posture during working and resting times, and maintaining
healthy living habits.
Review Date: 4/6/2007
Benjamin D. Roye, M.D., M.P.H., Orthopaedic Surgery, The Mount Sinai Hospital, New York, NY. Review provided by VeriMed Healthcare Network.
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