The back is the structure that supports your upper trunk,
houses and protects the spinal cord, and helps you move.
A healthy back is strong and pain free. The low back area
bears the most stress of movement and, therefore is usually
the site of most problems. The low back is made up of
four parts:
The discs are the cushiony material
between the vertebrae. The center of the disc is jellylike,
and the outer part is made up of slightly elastic woven
bands. They act as shock absorbers and permit movement
between the vertebrae.
The vertebrae are the bony segments
of the spine. The vertebrae are stacked one upon another,
forming three large curves. The low back area curves
forward or inward. This is called lumbar lordosis. The
purpose of the vertebrae is to house and protect the
spinal cord and its nerve roots and give support to
the body.
The sacrum is the large triangular-shaped
bone at the base of the spine.
The coccyx is the small bone at the
end of the spine. It is also called the tailbone.
Though humans are born with 33 separate vertebrae,
by adulthood most only have 24. Physicians use a code
to identify the vertebrae. The seven in the neck, the
cervical vertebrae that support and provide movement
for the head, are called C1 to C7. The thoracic vertebrae
numbered T1 to T12, join with and are supported by the
ribs, which protect the heart and lungs. Because they
are fairly rigid, thoracic vertebrae don't permit much
movement and consequently, aren't injured as often as
the other vertebrae. The lumbar vertebrae, below the
thoracic vertebrae and above the sacrum, are most frequently
involved in back pain because they carry most of the
body's stress. They are known as L1 to L5.
Sandwiched between each pair of adjacent vertebrae
is a spinal disc, 23 discs in all. Discs are flat, round
structures-about one-quarter of an inch thick-of tough
outer rings of tissue that contain a soft, white jelly
center. Each disc is connected to the vertebrae above
and below it by flat, circular plates of cartilage.
The discs not only keep the vertebrae apart, but act
as shock absorbers. They compress when weight is put
on them, and spring back when the weight is removed.
The spinal cord, an extension of the brain, extends
as far as L1, where it ends in a sheaf of nerves. Throughout
the length of the spine, 31 pairs of nerves branch off
from the spinal cord and serve all parts of the body,
transmitting sensory messages to the brain, and messages
from the brain to the muscles.
The 33 vertebrae, 23 discs, 31 pairs of spinal nerves,
140 muscles that hook on to the vertebrae, plus ligaments,
tendons, cartilage are all very complicated and are
potential sources of back trouble.
Torn Annulus
A sudden movement may cause a tiny tear in the tough
outer ring of your disc. Nearby ligaments may also stretch.
Since the annulus and ligaments contain pain fibers,
a tear may cause pain.
Bulging Disc
Repeated movement may cause a disc to dry out and degenerate
earlier than normal. As the disc wears out, the inner
jelly like center begins to bulge, pressuring the outer
ring causing pain.
Ruptured Disc
As a disc bulges, its center (nucleus) moves closer
to the outer ring (annulus). Sometimes a sudden movement
will cause the annulus to rupture and the nucleus squeezes
out and irritates the nerve, causing pain.
Arthritis
Bone spurs can form at the joint between your vertebrae
as discs wear out over time. Poor posture can contribute
to the degeneration of your discs earlier than usual.
These problems may cause a narrowing of the space where
your nerve runs and cause pain.
Instability
As a disc stretches and flattens, the vertebrae can
slip back and forth, creating an unstable spine which
puts pressure on the annulus causing pain.
Treatments
Every patient is an individual who will be
treated in a variety of ways. In general,
conservative treatments such as medications,
changes in lifestyle, and a physical therapy
regimen will be tried before more invasive
treatments such as injections or surgery would
be considered. |
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