This post is all about one nerve. It is the most important nerve in your leg, the sciatic nerve. Have you been told that you might have sciatica pain running down the back of your thigh all the way into your calf muscle or into the ankle and foot? This is the common trapped nerve in the leg pain lots of people suffer.
You could be feeling a continuous ache or pain that starts from the time you wake up in the morning till the time you eventually fall asleep at night.
To understand the cause of sciatic nerve pain in the leg it is useful to visualise the anatomy of the sciatic nerve. Find out how this big important nerve can cause pain anywhere from the buttock (bum, gluts, hip region), the back of the thigh (hamstring region), behind the knee, along the outside of the lower leg (calf muscle region) into the ankle all the way down to your big toe in your foot.
Sciatic Nerve Anatomy
If you spelt sciatic right the first in your Google search, well done. Just for fun here are some common misspellings of the word sciatic:
- syatic, siatic, cyatic & scatia.
Before you start looking into different sciatic nerve pain relief treatment options it is good to see and understand the human anatomy.
Cadaver Dissection Video
I found this video of a cadaver dissection examination that shows you the relationship of sciatic nerve and the gluteal muscles.
Where The Nerve Starts and Ends
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 guide you along its travels through our bodies and where it can get trapped, pinched or damaged.
- 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 depends on what you were born with.
- This is also the site where I have seen getting a Vitamin B injection that has gone wrong.
- 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.
The Function of The Sciatic Nerve
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 of the dermatome anatomical chart and myotome nervous system charts below.
How to Test the Nerve
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.
MRI of the Nerve Roots
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.
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.