Before we discuss the causes of back pain, it will help you to understand
the bones, nerves, and muscles in and around your spine. An abnormal function
of the vertebrae, disks, ligaments, muscles, and nerves coming out of the spine
may cause pain.
The spine is a column of small bones, called vertebrae, that run along the
center of your back. The vertebrae support your trunk and upper body and protect
the nerves that connect the brain to the rest of your body. This. bundle of
nerves is called the spinal cord. The spinal column is grouped into different
- Cervical spine: these 7 vertebrae support the neck.
- Thoracic spine: these 12 vertebrae are attached to the ribs in the
- Lumbar spine: these 5 vertebrae are the lowest and largest bones
of the spinal column.
- The sacrum, a shield-shaped bone, connects your back to your pelvis.
- The coccyx (tailbone) is at the end. It consists of tiny vertebrae
The lumbar vertebrae bear more of your body's weight and stress than any other
part of your back. Therefore, this region (the lower back) is the most likely
to get injured.
Each vertebra is referred to by a particular letter and number. The letter
is the region (C=cervical, T=thoracic, and L=lumbar), and the number is the
spot within that region. For example, C4 is the fourth bone down in the cervical
region, and T8 is the eighth thoracic vertebra.
If you reach around and feel along your spine, you would be touching bony
projections along the back of the vertebrae. These are called spinal processes.
Your doctor counts these (C1-C7, T1-T12, and L1-L5) to tell from where your
pain and injury may be coming. Imaging tests, like an MRI, may be used to pinpoint
the location and cause with more certainty.
For example, you may hear your doctor say after the exam that "your pain is
between L3 and L5." After an MRI, the doctor may indicate the precise location
and nature of the problem. For example, "you have a herniated disk between
L4 and L5."
Between each vertebra is a disk that cushions and protects it. The outside
of the disk, called the annulus fibrosus, is largely made of cartilage. The
inside of the disk, called the nucleus pulposus, is a jelly-like substance
that contains a lot of water.
The vertebrae and disks of the back are surrounded by numerous muscles (called
paraspinous muscles) and ligaments. These provide strength and support for
movement, including lifting and bending. They are often referred to as soft-tissues
because they are not hard, like bone.
Stomach and chest muscles also support your back. When these muscles are strong
and well-conditioned, they help reduce the stress on your lower back by redistributing
Most people fear that they have hurt their spine or disk when they experience
back pain. That is much less common, however, than straining your paraspinous
muscles or other surrounding soft-tissue.
|The spine is surrounded by a surprising number of
muscles and ligaments at different levels. These give the spine great strength.
Click each button above to see different layers of muscles, tendons, ligaments,
and bones of the back.
Review Date: 4/6/2007
Reviewed By: 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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