Sciatica or something else? How physios tell the difference
Sciatica might be the most borrowed word in musculoskeletal health: almost any pain that travels down a leg picks up the label eventually. Yet a good share of the leg pain we assess at PACT is not sciatica at all, and the difference is not academic, because the imposters need different treatment. Here is how physiotherapists actually tell true nerve pain from the rest, and why getting the label right early matters.
By Andrew Ellis, AHPRA registered physiotherapist · September 2026
The short version
- Sciatica is a description, not a diagnosis: irritation of the sciatic nerve or its roots.
- True nerve pain traces a line down the leg, usually past the knee.
- Duller pain that stops above the knee is more often referred from the back or hip.
- A physical assessment usually separates the two without a scan.
The short answer
Sciatica is not a diagnosis, it is a description: pain caused by irritation of the sciatic nerve or the nerve roots that form it. True sciatica tends to be sharp, burning or electric, travels down the leg in a fairly consistent line, usually past the knee, and often brings pins and needles, numbness or weakness with it. Coughing, sneezing and long periods of sitting commonly stir it up.
Plenty of leg pain does not fit that picture. Referred pain from the joints, discs and muscles of the back and hip is more common than true nerve pain, and it behaves differently: duller, patchier, harder to pin to a line, and it rarely travels below the knee. The distinction matters because the imposters need different treatment, and getting the label right early saves weeks of treating the wrong thing.
Two very different pictures
True nerve pain
Sharp, burning or electric. Follows a line past the knee, often with pins and needles or numbness.
Referred pain
Duller and patchier. Rarely passes the knee, no pins and needles.
What true sciatica looks like
The sciatic nerve is the largest nerve in the body, formed from nerve roots in the lower back and running deep through the buttock and down the back of the leg. When one of those roots is irritated, most commonly by a disc bulge pressing on it or inflaming it, the pain is felt along the nerve's territory rather than at the spine itself. That is why some people with significant nerve root irritation have marked leg pain but surprisingly little back pain.
The pattern is the giveaway. Nerve pain follows a line you can trace: buttock to the back of the thigh, into the calf, sometimes the foot. It has an electric, burning or shooting quality that people describe with real precision. And it often travels with other nerve signs: pins and needles, patches of numbness, or a leg that feels weaker on stairs. When someone points instead to a vague ache across the whole thigh that stops at the knee, we start thinking about the imposters.
The imposters: leg pain that is not sciatica
Imposters we work through
| What we assess for | How it tends to behave |
|---|---|
| Back joints, discs or muscles | Deep, dull ache in the buttock or thigh, rarely past the knee |
| Gluteal tendinopathy or hip bursitis | Outside of the hip, worse lying on that side at night |
| Piriformis and neighbouring muscles | Deep buttock pain that flares with sitting |
| High hamstring problems | Felt right on the sitting bone |
| Spinal stenosis, in older adults | Heavy, tired or tingling legs after walking, eased by sitting down |
Referred pain is the most common one. Joints, discs and muscles in the lower back can all send a deep, dull ache into the buttock and thigh without any nerve being caught. It does not follow a neat line, rarely passes the knee, and does not bring pins and needles. Sacroiliac joint problems sit in this camp too, usually felt low and to one side of the back.
The great hip mimic
The hip is the next great mimic. Gluteal tendinopathy and hip bursitis cause pain over the outside of the hip that can spill down the outer thigh, classically worse lying on that side at night, on stairs and on longer walks. Deep buttock pain that flares with sitting can come from the piriformis and its neighbouring muscles, which sit directly over the sciatic nerve and can produce genuinely nerve like symptoms. High hamstring problems announce themselves right on the sitting bone.
In older adults, spinal stenosis deserves its own mention: narrowing around the nerves that typically causes heavy, tired or tingling legs after walking a distance, eased quickly by sitting down or leaning forward on a shopping trolley. And occasionally leg symptoms come from circulation rather than nerves or joints at all, which is one of the reasons a proper assessment screens more than just the spine.
How we tell the difference in the clinic
How the assessment narrows it down
- The historyWhere the pain is, whether it passes the knee, and what sets it off.
- Physical testingStraight leg raise puts gentle tension on the nerve, plus reflex, strength and sensation checks.
- Working through the impostersSpine, hip and sacroiliac testing, loading each structure in turn.
- Imaging, only if neededReserved for progressive weakness, warning signs, or a problem not tracking as predicted.
The history does most of the work. Where exactly is the pain, and can you trace it with one finger or only wave at a region? Does it pass the knee? What sets it off: sitting, standing, walking, coughing? How does it behave overnight and first thing in the morning? Are there pins and needles or numb patches, and precisely where? Each answer narrows the picture before any physical testing begins.
Then we test it. Neural tests such as the straight leg raise put gentle tension on the nerve to see whether that reproduces your symptoms. Reflex, strength and sensation checks tell us whether a nerve root is genuinely affected and which one. Spine, hip and sacroiliac testing then works through the imposters one by one, loading each structure to see which reproduces your pain. By the end of a thorough first assessment the pattern is usually clear.
Usually no scan needed
Most people do not need a scan for any of this. The assessment reaches a working diagnosis, treatment starts, and imaging is reserved for the situations where it would change the plan: progressive weakness, warning signs in the history, or a problem that is not tracking the way the diagnosis predicts. Our guide on scans before physio, linked below, covers that decision in detail.
What helps, and when to move fast
These should not wait
New bladder or bowel difficulty, numbness around the saddle area, or worsening weakness in both legs needs emergency care the same day. Progressing weakness in one leg, night pain that never eases, or unexplained weight loss deserves a prompt GP review.
For most true sciatica the evidence is reassuring: the majority of episodes improve substantially over weeks to a few months, and staying active beats prolonged bed rest. Treatment is built around exactly that: keeping you moving with a graded plan, settling pain enough to make movement possible, and rebuilding the strength and tolerance of the back, hip and leg. The imposters each get their own plan, which is precisely why the label matters.
At PACT that starts with an unhurried assessment at our Miranda clinic or by telehealth, a plain English explanation of what is and is not driving your leg pain, and a plan you can actually follow. Hands on treatment and trigger point dry needling are used where the assessment shows guarded, restricted muscle is part of the picture, alongside the exercise work that does the long term heavy lifting.
A small number of situations should not wait for a routine appointment. New difficulty controlling your bladder or bowel, numbness around the saddle area, or worsening weakness in both legs needs emergency care the same day. Steadily progressing weakness in one leg, night pain that does not ease in any position, or unexplained weight loss deserves a prompt GP review. These situations are rare, and screening for them is built into every first assessment.
Related pages
Good to know before you book
How can I tell if my leg pain is sciatica?
Does sciatica mean I have a disc bulge?
Will sciatica go away on its own?
Do I need a scan before starting treatment?
When is leg pain an emergency?
This guide is general information, not a diagnosis or a substitute for an assessment. If you are concerned about your symptoms, book an appointment or see your GP.
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