Sciatic Nerve: The Most Important Nerve in the Leg

Pain in the Sciatic Nerve
Sciatic Nerve in the Leg

Have you been told you have sciatic nerve pain running down the back of your thigh all the way into your calf muscle causing a sciatica. This is also known as a trapped nerve pain in your leg. There can be a continuous ache or pain in the sciatic nerve that starts from the time you wake up in the morning till the time you eventually fall asleep.

Today I want to delve a little into the world of the anatomy of the sciatic nerve. Do you need to know how the sciatic nerve can cause buttock pain and why this can eventually send sciatica nerve pain down the leg? I will tell you where along its path it can become trapped.

The Sciatic Nerve

If you spelt sciatic right in your Google search, well done. Just for fun here are some common misspellings of the word sciatic – syatic, siatic, cyatic & scatia.

The reason I have written this article is that before you start looking into different sciatic nerve pain relief treatment options I think you need to understand the sciatic nerve anatomy a bit better.

I found this video of a cadaver dissection showing the sciatic nerve exiting all the buttock muscles.

Did you know that the sciatic nerve is one of the major nerve’s in the leg (lower limbs) of our bodies.

Follow me as I show you how the sciatic nerve travels its way through our bodies all the way down to our big toe.

Sciatic Nerve Anatomy
Lumbo-Sacral Plexus: Where the Sciatic Starts

This nerve is actually made up of 5 nerve roots exiting our spines. These nerve roots are from the L4-5-S1-2-3 nerves. This is the first place it can become trapped from a disc herniation.

Together these nerves join into a rope like structure starting inside your pelvis. This nerve rope then leaves the pelvis by exiting through an anatomical landmark called the greater sciatic foramen.

It is at this point in its travels that you can get a common cause of sciatic nerve pain called piriformis syndrome.

This is because the piriformis muscle in the buttocks can compress the nerve. Our sciatic nerve can either pass over, under or directly through the middle of the piriformis muscle. It is different in different people and is how you were born.

This is also near the point where you might have a Vitamin B injection gone wrong.

Ok getting back to the traveling nerve of the leg.

Once the sciatic nerve leaves the buttock region it then runs proceeds to run down the back of the thigh (hamstring muscle). It is at this point where the sciatic nerve then takes a major split to become the two other major nerves of the leg.

It splits to now be called the, common peroneal nerve and tibial nerve.

These are branches of the sciatic nerve.

The common peroneal nerve and the tibial nerve then go to supply different parts of the front and side of the shin, calf muscles, ankle and finally the foot and its toes.

Just another interesting fact for you is that when there is sciatic nerve injury it is 6 times more likely to be the common peroneal side that is damaged. Think of a car accident where the knee slams into the dash.

So What Does it Do?

We get all our skin sensation, motor muscle control and reflexes in the legs from this major nerve. It tells you if your foot is hot or cold.

Maybe while you were waiting in the doctors rooms you were looking at the posters hanging on the wall like the one fo the cutaneous dermatome and myotome nervous system charts below.

Your sciatic nerve can be tested with deep tendon reflexes.

You can see how the patella reflex or knee-jerk reflex is controlled by the L2-3-4 nerve roots. The Achilles reflex or ankle-jerk reflex is controlled by the S1-2 nerve roots. You may have had the Babinski reflex test.This is why your doctor needs to test your reflexes with his reflex hammer, which people either love or hate the feeling.

The chiropractor might then use light touch or hard touch on different areas of your leg skin to see which nerve of the sciatic is being affected. You might find the sensation on the outside of your calf is numb or you can’t feel your big toe properly. This could be signs of a pressure on the sciatic nerve and is testing your dermatomes.

They probably also made you walk on your heels and toes. Maybe made you tense your toe backwards whilst they tried to push it down. These are neurological muscle tests of the nerve looking for lack of signal to the muscle.

Nerves are the way our brain can communicate, listen to and control what is happening to the body. You don’t want a pinched nerve anywhere in your body.

Your healthcare practitioner will need to know which level of the sciatic nerve is being irritated. This is in order to help diagnose and give treatment options for your possible pain and other symptoms.

They may have had to refer you for more advanced nerve tests like a nerve conduction study or MRI scan.

Have you had chronic pain from sciatica? This could help explain why. Don’t worry people can recover like Anthony Field has.

The Bottom Line

The are various places the nerve can be hurt. It is mainly at the lumbar disc, spinal joints, piriformis muscle, and behind the knee. Now that you know the sciatic nerve anatomy and the course it takes from your lower back to the foot you can understand what can cause sciatica pain and now read how to treat sciatic nerve pain.