What causes sciatica, and do I have it?

This episode is entitled, ‘what is sciatica, and do I have it?’. You will learn why sciatica isn’t what you think it is, exactly which parts of your sciatica can affect you, how to differentiate the two main types of sciatica, what symptoms can be part of sciatica and how to improve it as a label.

Why sciatica isn’t what you think it is

Often people think of sciatica as a diagnosis. However, it is not, it’s simply a label. Comparatively, it’s like going to a doctor and saying I have a sore head, it hurts me here. Then they diagnose you with a headache. You’d probably think that’s not a lot of use. That is the same with sciatica. As sciatica simply means pain and/or pins and needles in the distribution of your sciatic nerve. That’s it. So the term is not terribly valuable as a diagnosis because it isn’t one, that’s just a label. It tells you where the problem is, but not why you have it.

Exactly which parts of you sciatica can affect

To understand which parts sciatica affect we will need to examine what the distribution of the sciatic nerve is. So your sciatic nerve is a whopping big nerve. It has tributaries. Imagine your sciatic nerve is like the Amazon river. It’s very big and long and in your case ends up at your toes, but it originates deep in your pelvis and it has tributaries.

Those tributaries are called spinal nerve roots. They originate from the spine. They are small nerves that exit between the vertebrae in your lower back. We have lumber four (L4), L5, S1 and S2. These branches join together and form your sciatic nerve deep in the pelvis. The sciatic nerve then comes out through what’s called a sciatic notch, a sort of groove in your pelvis and then travels through the buttock down the back of your thigh, all through its root, giving off branches of its own. Through the back of your thigh and then down round the side of your knee and down into the lower leg and foot. The distribution the sciatic nerve supplies are part of the buttock, the back and outside of your thigh and pretty much everything below the knee.

So if you have pain in the front or inside of your thigh, that is not sciatica. But pain and/or pins and needles in buttock, back or outside of thigh and pretty much everything below the knee could be described as sciatica. If it’s originating from irritation to your sciatic nerve or structures related to your sciatic nerve.

What causes sciatica?

How to differentiate the two main types of sciatica

So this brings me onto how to differentiate the two main types of sciatica. So the two main types of sciatica are ‘nerve compression sciatica’ and ‘non nerve compression sciatica’. We differentiate into two types of sciatica as each needs a different management approach.

Nerve compression sciatica

Nerve compression sciatica is the more serious of the two. If your sciatic nerve or one of its tributaries is compressed, that’s nerve compression sciatica. Now you may think of this using terms like a ‘pinched nerve’, ‘trapped nerve’ and so on.

Non nerve compression sciatica

Non nerve compression sciatica means that you have symptoms in the distribution of your sciatic nerve, but it is not due to compression of a nerve. The pain, or the mechanism here, is usually what we call referred pain. So let’s imagine you have strained a muscle in your buttock. If that buttock muscle has a nerve supply, either from the sciatic nerve directly or one of the tributaries to that sciatic nerve, for example your L4 nerve root. You could feel the pain directly in the buttock, but you could also feel it elsewhere along the distribution of the sciatic nerve. And this is through the mechanism of referred pain. So you might feel a strained buttock with pain in your calf, but the pain is actually coming from the strained buttock. That’s just one example.

Do I have sciatica?

Symptoms of sciatica

The area sciatica affects would be around buttock, back of outside of thigh, pretty much everywhere below the knee. Symptoms include pain, pins and needles, which is sometimes accompanied by numbness. By that I mean if you touch the skin, it doesn’t feel right. As well as feelings of running water, hot and cold sensations, sweatiness/clamminess in the foot, particularly in severe cases of nerve compression sciatica.

How do you differentiate between the two types?

In clinical practice we have a number of tests that we would employ to differentiate between them. But I’m going to give you a couple of home tests that you can try.

Differentiating symptoms

If you have nerve compression sciatica, it is typically worse below the knee than it is above the knee. Not always. And often includes pins and needles, usually in the foot, but could be anywhere in the leg. Whereas usually, non nerve compression sciatica is normally worse above the knee and doesn’t usually involve pins and needles. This, however, is a rough guide.

As well as a sensory element, the sciatic nerve also controls muscles in your leg. So you can look for other signs such as: you may find that you are dragging your foot or catching your toe on the curb of the pavement. That would suggest that have an L5 problem. As above, the nerve roots of L4, L5, S1 and S2 supply the sciatic nerve. L5 is directly related to the ability to lift your big toe up. So if you find you’re catching your toe on things that may be that you have an L5 nerve root problem, which is nerve compression sciatica. Equally, if you find that you’re struggling to push off with your big toe of that foot, then it may be due to compression of the S1 nerve root. Also one of the tributaries of your sciatic nerve.

How to test compression of nerve roots


If you try walking on your heels or even just walking on the spot on your heels with your big toes lifted up off the ground. If you struggle to do that on one foot, you may very well have an L5 nerve root problem.


If you go up onto the toes onto the balls of your feet. If you struggle to do that on one foot, then you may well have an S1 nerve root problem. The way to test that further is go up and down on one foot, but grab a hold of something so you don’t fall over. Go up and down on the toes of one foot. And if that’s easy, then try your as it were ‘bad leg’ up and down on those toes. If you find you’re struggling with that, you may very well have an S1 nerve root problem as well.

These simple tests can help you determine whether you have sciatica, differentiate between which type you have and ultimately what may be causing your symptoms.

How to improve sciatica as a label

That label of “sciatica” is not terribly helpful and we always strive to improve things. So at ActiveX backs, we use a system of labeling sciatica (we use it for lower back pain as well). The purpose of labeling it more fully is to inform you how to manage it. And certainly to inform us as clinicians how to manage your sciatica.


What we’re most interested in is duration. How long have you had it? And for that we use the terms acute, subacute, and chronic. You might think those referred to severity, but in clinical terms they don’t. They refer to duration. So acute means you’ve had it for less than six weeks. Subacute means you’ve had it for between six and 12 weeks. And chronic means you’ve had it for more than 12 weeks.

Previous episodes

Then we’re interested in, have you had bouts of this before in the last 12 months? If you have had more than this one episode in the last 12 months, we would add the word recurrent.

Aggravating factors

Then we have what makes it worse. This is really important because it informs you as to what you should and shouldn’t do with your sciatica. So if the pain in your leg or buttock increases when you bend forward we call that ‘flexion intolerant’. If it’s worse when you arch backwards, we call it ‘extension intolerant’.

A functional label example

Acute, recurrent, flexion intolerant nerve compression sciatica.

We love our labels here, but the importance of this is that it helps us to decide how to manage your sciatica, how to advise you what you should and should not do.

Acute- less than six weeks

Recurrent- you’ve had it before in the last year

Flexion intolerant- it’s worse for bending forwards and sitting. When sitting, typically, most people bend forwards.

Nerve compression sciatica- so we believe that you have some irritation directly to the sciatic nerve or one of its tributaries.

I hope in this episode you’ve learned why sciatica isn’t what you think it is and exactly what it is- a label. Which parts of you sciatica can affect, how to differentiate between the two main types of sciatica. Some tests that you can do at home, what symptoms are part of sciatica and how we improve sciatica as a label.

Now very importantly and related to this, there are some safety issues around sciatica. And if you go to our website you’ll come across a blog post where there are a eight or nine questions that will help to differentiate whether this is something serious and whether you ought to be going to see a medical or health professional, like us, about it. And if you answer no to all of those questions, then you’re probably safe to manage yourself. 

Okay, so there we have it. What is sciatica and do I have it? Thanks for listening. And if you have not already listened to the first six episodes of the podcast, or even the first one, please go back and start at the beginning. There’s a huge amount of value, the foundations for how we can help you to manage your lower back pain and/or sciatica are in those first six episodes. Start at number one. And in the meantime, thanks for listening. Please give us a review on iTunes, Spotify, Google, wherever you’re listening to this, and I look forward to our next episode.

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