What is Your Sciatic Nerve
and What Does It Do For You ?
I wouldn't dream of baffling everyone with all the Latin names for all
the parts of your body and the leg nerves that are involved in (or may be involved in) sciatica — I am just as baffled myself! Instead I
will just skim over some of the more technical parts, just enough so that you will understand a little more of what your physician
is talking about when you go for a diagnosis.
If you really want to know more, then there are plenty of good books available.
So! Let's look at the simple side of Sciatica Biology, and try to answer the question: What is your sciatic nerve and what does it do for you
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Leg Nerve Formation
The Sciatic Nerve (also sometimes called the ischiatic nerve) is the longest nerve in your body. There are two of them, starting in your lower
back, then each one runs through one of your buttocks and down into your thigh and then down the remainder of each leg.
The sciatic nerve is actually a bundle of nerves that emerge from various places in your spine:
The part of your sciatic nerve that emerges from between your lumbar segments L4 and L5 is called the
L4 nerve root. The part that emerges from between your lumbar L5 and sacral S1 is called the L5 nerve root. The parts of your sciatic nerve that emerge from various places in your sacrum are called the S1, S2, and S3
nerves.
"Lumbar" refers to your lower back -- where it normally curves inwards. The "Sacrum" is the
large fused bone just below that, at the top of the cleft between your buttocks.
Biology of Sciatica
The precise nature of your sciatica pain and its condition depends on the precise nature of the irritation of your sciatic nerve,
and its precise location. Some of the different ways that sciatica can present itself are: 
- L4 Sciatica: you may have pain or numbness in your leg below
the knee and foot; you may have trouble walking on your heels; your knee-jerk reflex may not work
properly.
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- L5 Sciatica: you may have pain or numbness on the top of your foot, especially between your big toe
and the next one; you may experience weakness in your big toe and ankle.
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- S1 Sciatica: you may have pain or numbness on the left or right side of your foot; you may have
trouble walking on your toes; your ankle-jerk reflex may not work properly.
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- Sacroiliac Joint Dysfunction: problems in this area can put
pressure on your sciatic nerve, and cause a deep ache that feels in some ways like sciatica.
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- Piriformis Syndrome: this causes pressure on your sciatic
nerve and cause sciatica-like symptoms.
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Sciatica Radiculopathy
But what causes the problems for L4, L5, and S1? Have a look at
a more detailed description of the causes of sciatica, but note for now that it can be problems with
one of your discs (or possibly a tumour). The discs in your spine are like shock absorbers that also allow your back to bend and
swivel.
As you grow older, the discs can become weak or damaged, and a disc can bulge out or even split, and put pressure on your sciatic nerve.
The clinical diagnosis of sciatica may be referred to by your doctor as a
radiculopathy; that simply means that a protrusion from one of the discs in your spine is putting pressure on the nerve root
(properly called the radicular nerve) – the start of your sciatic nerve – in the lower part of your back.
The information on this page could be useful if you talk to a healthcare professional during a diagnosis session.
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