The disc is made up of connective
tissue, which wears normally as we
age. However, many of the problems
that cause neck pain are from abnormal
wear and tear. This process is called
degeneration of the
intervertebral disc. Degeneration
often results from small injuries
that may not cause pain at the time
the injuries actually occur.
Over time, these injuries add up and
the abnormal wear and tear can weaken
the connective tissue that makes up
the disc. Once the connective tissue
is weak, sudden stress, such as a
whiplash type movement, may injure
the disc more easily. The entire process
of disc degeneration is sometimes
referred to as spondylolysis. You
may hear your doctor refer to your
neck problem as spondylolysis of the
cervical spine.
To really understand neck pain, you
need an understanding of the wear
and tear process, called disc degeneration.
This will also help you later understand
what can happen to the neck when a
sudden injury can cause immediate
pain and dysfunction. The next section
will explain both the process of degeneration
and the most common causes of pain
in the neck.
Degenerative
Disc Disease
To
help you understand disc degeneration,
compare a spinal segment to two
vanilla wafers (the "vertebrae")
and a marshmallow (the "disc").
Imagine a fresh marshmallow between
the two wafers. When you press
the wafers close together, the
marshmallow gives or "squishes
out". Suppose you leave the
marshmallow out for a week and
it starts to dry out. When you
press it between the wafers, it
is not quite as spongy. If you
press hard enough, the outside
of the marshmallow may even tear
or split. Suppose you left the
marshmallow out for a month. It
would probably be so dried out
it would be hard and very thin
and would not have any "shock
absorbing" ability.
As
we age, the disc loses some of
its water content and, as a result,
some of its shock absorbing ability.
Like the marshmallow, the first
changes that occur in the disc
are tears in the outer ring of
the disc, called the annulus.
Tears in the annulus may occur
without symptoms. Therefore, you
may not notice when they occur
or what caused them. These tears
heal by forming scar tissue. Scar
tissue is weaker than normal tissue.
Repeated injuries and tears cause
more wear and tear to the disc.
As the disc wears, it loses more
of its water content. It becomes
less and less "spongy",
eventually no longer able to act
as a shock absorber.
As
the disc continues to wear, it
begins to collapse. The space
between each vertebra becomes
smaller. The collapse also affects
the way that the facet joints
in the back of the spine "line
up". Like any other joint
in the body, the change in the
way the bones fit together causes
abnormal pressure on the articular
cartilage. Articular cartilage
is the smooth shiny material that
covers the end of the bones in
any joint. Over time, this abnormal
pressure causes wear and tear
arthritis (osteoarthritis) of
the facet joints.
Bone
spurs may form around the disc
and facet joints. It is thought
that too much motion in a spinal
segment causes the bone spurs
to form. Eventually, bone spurs
can form around the nerves of
the spine, causing a condition
called spinal stenosis.
Spinal
Conditions
Degeneration
of the disc and spinal segment
can result in several different
spinal conditions that cause problems.
These include: mechanical neck
pain, cervical radiculopathy,
and spinal stenosis. Sometimes
we may injure our neck with a
relatively minor injury. These
minor injuries may cause neck
pain for a few days and then go
away. This is commonly referred
to as a neck, or muscle strain.
Actually, we may never fully understand
what has been injured in one of
these episodes.
Muscle
Strain Of Neck
A
"muscle strain" of the
neck is a common diagnosis given
when a patient presents a stiff
neck. In some cases, this may
represent a true "muscle
strain", or "pulled
muscle" involving the muscles
around the spine of the neck.
However, muscle spasm is a common
symptom that can result when other
areas of the neck are injured.
Problems that are commonly referred
to as a muscle strain may also
involve injury of other soft tissues
of the neck including: the disc,
the ligaments around the spinal
segment, and the muscles. Injury
to any, or all, of these structures
may cause similar symptoms.
Mechanical
Neck Pain |
