What Is Sciatica, Really? (And Why It Runs Down Your Leg)

Here’s the first thing you need to understand about sciatica: it’s not actually a diagnosis. It’s a symptom. So many people think they can go and get a scan and someone says, “there it is, you’ve got sciatica.” That’s not how it works, because sciatica isn’t a condition in itself. It’s simply the name we give to pain that travels down the leg from an irritated nerve. It tells you what you’re feeling, but not why. So in this video I just want to explain what sciatica actually is, and why it runs down your leg. (We’ll get into all the different things that can cause it in another video — but first, you need to understand what it really is.) To understand sciatica, you need to picture where the nerve runs. The sciatic nerve is the big one, the largest nerve in your body. It starts at the bottom of your spine, runs straight through your buttock, down the back of your thigh through the hamstring, down through the calf, and all the way into your foot. And that’s the key: because that nerve runs all that way, when it gets irritated or compressed you don’t just feel it in your back, you feel it travelling down the line of the nerve, into the buttock, down the thigh, into the calf, and sometimes all the way to the foot. That’s what sciatica is: irritation of the sciatic nerve, and the pain that travels down its path. So when people say they’ve got sciatica, what they really mean is they’ve got that nerve pain running down the leg. It might be pain, pins and needles, numbness, or a burning feeling, but the common thread is that it follows the nerve, down from the back into the leg. And this is the important bit: sciatica is the symptom, not the cause. Something is irritating that nerve to create it, and that something can be one of several different things, which is exactly what we’ll get into in another video. For now, the thing to walk away with is simple: sciatica isn’t a diagnosis you get off a scan. It’s a symptom, irritation of the sciatic nerve, causing pain that travels down the leg. It starts in the lower back and follows that nerve all the way down. Understand that, and you’re already thinking about it the right way. If this made sciatica a bit clearer, give it a like and subscribe, the whole series is about understanding your back and getting on top of it. In the next video I’ll talk about what sciatica actually feels like, the different sensations people get and what they can tell you. And drop me a comment... where does your pain travel to? Buttock, hamstring, calf, foot? That tells me a lot. -------------------------------------------------------------- Book a Free Discovery Call: https://sharpphysiotherapy.co.uk/free... Find Your Nearest Clinic: Doncaster | Lincoln | Newark Welcome to Sharp Physiotherapy, we specialise in keeping people active, pain-free, and away from medication. This video is for educational purposes only and not a substitute for medical advice. If you're dealing with pain, book a free call with our team to find out what’s going on. Check out our website at...https://www.sharpphysiotherapy.co.uk Follow Our Socials... Instagram:   / sharp_physio   TikTok:   / sharp_physiotherapy   Facebook:   / jsphysio1   © Sharp Physiotherapy {{2025}}. All rights reserved. Chapters 00:00 What Is Sciatica? Introduction 00:48 Where the Sciatic Nerve Runs in Your Body 01:12 Why Sciatica Pain Travels Down Your Leg 01:26 Where You Can Feel Sciatica Pain 01:42 Sciatica Pain Pins and Needles Numbness and Burning 02:06 Sciatica Is a Symptom Not a Cause 02:21 What Causes Sciatica? Coming Next 02:324 Key Takeaway What Sciatica Actually Is 02:45 Like and Subscribe 02:58 What Sciatica Feels Like Next Video