"Sciatica" gets used for almost any leg pain, which is part of why it causes so much confusion. Strictly, it describes irritation or compression of the sciatic nerve, the thick nerve formed from roots in the lower spine that runs through the buttock and down the back of the leg.
The distinction matters because sciatica is a symptom, not a diagnosis. The useful question is never "do I have sciatica?" but "what is irritating the nerve, and where?"
What real sciatica feels like
Genuine nerve involvement has a recognisable character:
- Pain that travels in a line down the leg, often past the knee
- A sharp, electric or burning quality rather than a dull ache
- Pins and needles or numbness in a defined patch of skin
- Symptoms provoked by coughing, sneezing or straining
- Often worse with sitting, better with walking or standing
If your pain stops at the buttock and feels deep and achy, it is more likely referred pain from a joint or muscle. That is good news, it usually settles faster.
The common causes
| Cause | Typical picture |
|---|---|
| Disc bulge or herniation | Most common under 50. Worse with sitting and bending forward |
| Spinal stenosis | More common over 60. Worse with walking, eased by sitting or leaning forward |
| Piriformis / deep gluteal irritation | Buttock-dominant, worse with prolonged sitting on hard surfaces |
| Sacroiliac joint | Pain around the dimple of the back, rarely below the knee |
A skilled assessment can usually distinguish these from history and a handful of movement tests, which is why scans are rarely the first step.
Do you need an MRI?
Usually not, and this surprises people. Disc bulges are extremely common in people with no pain at all; by their 40s, a large proportion of entirely symptom-free adults have them on imaging. So a scan showing a bulge does not prove the bulge is causing your pain.
Imaging becomes genuinely useful when symptoms are severe, progressive, not responding to treatment, or when surgery is being considered.
What actually helps
Keep moving. The strongest evidence in acute sciatica supports staying as active as symptoms allow. Bed rest beyond a day or two makes outcomes worse.
Find your directional preference. Many disc-related cases ease markedly with gentle repeated extension (lying on your front, propping onto the elbows). Others prefer flexion. An assessment identifies which direction decreases the leg symptoms, this is one of the most useful things you can learn about your own back.
Watch the leg, not the back. A treatment that reduces leg pain while slightly increasing back pain is usually moving in the right direction. This is called centralisation.
Nerve glides. Once the acute irritability settles, gentle mobility work helps restore the nerve's ability to slide through surrounding tissue. These should feel like a mild stretch, never sharp or lingering.
Progressive loading. The long-term answer for most people is a stronger, better conditioned trunk and hips. This is the part that prevents recurrence, and it is the part most commonly skipped once the pain eases.
How long does it take?
Most acute sciatica improves substantially within six to twelve weeks. Nerve tissue recovers more slowly than muscle, so lingering pins and needles can persist after pain has gone, usually a sign of a healing nerve rather than ongoing damage.
Seek help urgently if
Some symptoms need same-day medical assessment rather than physiotherapy:
- Numbness in the saddle region, inner thighs, groin, buttocks
- Any loss of bladder or bowel control
- Progressive weakness in the leg or a foot that drops when walking
- Symptoms in both legs at once
These are uncommon, but they need ruling out immediately.