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Anatomy of Back Pain
Introduction |
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In this section we discuss the anatomy of the human
spine and what happens at a basic, structural, level when we experience back pain.
There are many things that can go wrong with the spine, but, in essence, up to 98% of all
back pain is either caused by, or directly linked to, compression – the term used to
describe the spine when it becomes squashed, or shortened from its natural length.
However, the spine isn’t a completely solid structure – if it were, it would be
very difficult to compress. Instead, it's made up of individual vertebrae, or units of
bone, that are stacked on top of each other – joined, or linked, by facet joints.
Ultimately, it's the facet joints that become compressed and, as a result, the
spine becomes squashed. |
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When this happens, we become stiff (a
common symptom of back pain) because the joints aren’t able to move freely.
In addition to this, the compression reduces the space between the vertebrae, which, in
turn, leads to compression of the intervertebral discs – if the pressure becomes too
great, the disc ruptures, a condition commonly referred to as a herniated, or slipped disc (shown opposite).
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Compression also causes the joints to rub together and,
over time, they may become arthritic and painful (just like any other joint). Finally, due
to the way in which the spinal cord exits the vertebral column (a structure also known as
the spinal column), compression can lead to nerve-root entrapment, a condition which is
extremely painful.
Like any other form of pain, though, back pain is ultimately caused by damage to the human
nervous system – the nerves simply produce pain in response to a harmful event
(thereby alerting the brain to the problem). But, because the nervous system is
responsible for many other activities, the effects of facet joint compression are wide
ranging – it can also lead to referred pain (e.g. sciatica), organ dysfunction and various other effects (e.g. pins and needles), as well as aggravating
a whole host of bone conditions.
This section is designed to start at the beginning. We first examine the basic structure
of the human spine, and then take a more detailed look at the individual vertebrae –
what they look like and how they come together to form the spinal column. Next we look at
the facet joints and explain how they lock the vertebrae together; we also examine what
happens to the spine when they become compressed.
Finally – and we admit that things get slightly more complex at this point – we
look at the human nervous system. We examine the nerves that exit the spinal column (and
the brain), and divide the peripheral nervous system (PNS) into its various subcomponents.
Next we discuss the function of the individual sub-systems, in terms of both sensory and
motor components, and examine the symptoms of nerve-root compression.
Next >>> The Spinal Column
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