Parts of the Spine
Your spine is divided into regions: there's your
neck (cervical spine), mid-back (thoracic spine), and low back
(lumbar spine). At the bottom of your spine, you also have the
sacrum and the coccyx, which is commonly called your tailbone.
The vertebrae in your neck are labeled C1-C7,
meaning that you have seven vertebrae in that region. Most
adults have 12 vertebrae in the thoracic spine (T1-T12), which
goes from your shoulders to your waist. Then there are five
vertebrae in your low back (L1-L5), and below that, your sacrum
is made up of five vertebrae between the hipbones. By the time
you're an adult, these five bones have fused into one bone. The
coccyx is small fused bones at the very tail of your spine
(hence the tailbone).
Your spine also has facet joints, which are on
the posterior side (back) of your vertebrae. These joints (like
all joints in your body) help facilitate movement and are very
important to your flexibility.
Another vertebral bone structure is the pedicle.
These are on either side of your vertebrae, and they are part of
the "walls" for your spinal canal. In between your vertebrae,
you have intervertebral discs. These act like pads or shock
absorbers for your spine as it moves. Each disc is made up of a
tire-like outer band called the annulus fibrosus and a gel-like
inner substance called the nucleus pulposus.
Together, the vertebrae and the discs provide a
protective tunnel (the spinal canal) to house the spinal cord
and spinal nerves. These nerves run down the center of the
vertebrae and exit to various parts of the body, where they help
you feel and move. Your back also has muscles, ligaments,
tendons, and blood vessels. Muscles are strands of tissues that
act as the source of power for movement. Ligaments are the
strong, flexible bands of fibrous tissue that link the bones
together, and tendons connect muscles to bones and discs. Blood
vessels provide nourishment. These parts all work together to
help you move.
Back pain may be a result of injury to any or
all of these body parts. Injury to the muscles, ligaments,
tendons can result in sprains or strains, which are generally
not considered serious. However, injury to bones, nerves, or
blood vessels may be more serious. Also, the outer layers of the
intervertebral discs can get tears or cracks, allowing the
annulus fibrosus or nucleus pulposus to bulge out. Any of these
injuries can cause inflammation and pain.