Sciatica Explained: Why Your Leg Pain Starts in Your Back

Every week someone tells me some version of the same story: a deep ache or electric pain running down the back of one leg, sometimes into the calf or foot, that no amount of rubbing the leg seems to touch. That is usually because the problem is not in the leg at all. Sciatica is leg pain with its roots in the lower back, and understanding that single fact changes how you treat it. Having provided sciatica treatment across Liverpool and Merseyside for over ten years, I want to walk you through what is actually going on and what genuinely helps.

What sciatica actually is

Sciatica is not a diagnosis in itself; it is a description of symptoms. The sciatic nerve is the largest nerve in your body, formed from nerve roots that exit the lower spine, merging and travelling through the buttock and down the back of each leg. When one of those nerve roots is irritated or compressed, you feel pain along the nerve's territory, which is why a problem at spine level is experienced in the thigh, calf or foot.

The most common culprit is a disc bulge or herniation pressing on or chemically irritating a nerve root. Less often, it is narrowing of the spaces the nerves pass through, which we call stenosis and see more in people over 60.

Common symptoms

• Pain radiating from the lower back or buttock down one leg, often below the knee
• Burning, electric-shock or shooting qualities rather than a dull ache
• Pins and needles or numbness in parts of the leg or foot
• Symptoms aggravated by sitting, coughing, sneezing or bending
• Occasionally, weakness such as a foot that slaps or drags

True sciatica usually affects one leg. Pain across both legs, or back pain alone without leg symptoms, generally points to something different, which is one reason assessment matters.

Why it happens

Discs are living tissue, and like tendons or muscle they can be sensitised or injured when load outpaces their capacity: a heavy garden weekend after a sedentary winter, a sudden lifting job at work, or simply the wear that comes with normal life. Genetics, smoking, low activity levels, prolonged sitting and heavy manual work all nudge the risk upwards. What I want you to hear clearly is that a disc problem is not a life sentence. Discs have a blood supply at their margins, they heal, and research consistently shows that most disc herniations shrink over time without surgery.

What an assessment involves

When I assess sciatica, whether in a Liverpool living room or over a video call, I am doing three things. First, ruling out the rare but serious causes, through careful questioning about bladder, bowel and saddle sensation, and checking strength and reflexes. Second, working out which nerve root is involved and how irritable it is, using movement tests and simple neurological screening. Third, and most usefully, identifying what currently aggravates and eases your symptoms, because that tells us exactly where treatment should start. You can read more about my approach on my sciatica treatment page.

Evidence-based treatment

The honest headline: most sciatica improves substantially within six to twelve weeks, and good treatment speeds and smooths that journey rather than performing miracles. What the evidence supports:

• Staying active within tolerance. Complete rest slows recovery. We find your baseline, then build.
• Specific graded exercise. Depending on your presentation this might be direction-specific movements, nerve mobility work, and progressive strengthening for the hips and trunk.
• Education and pacing. Understanding why sitting stirs it up, how to modify your day and what recovery normally looks like reduces both pain and worry.
• Short-term pain relief strategies, including positions of ease and appropriate medication discussed with your GP or pharmacist, to keep you moving while nature does its work.

Injections and surgery have a place for a small minority with severe, persistent symptoms or progressive weakness, but NICE guidance is clear that conservative care comes first for most people. This is the core of the musculoskeletal physiotherapy I provide.

What you can do yourself this week

Keep gently mobile: short, frequent walks beat long sits. Change position every 30 minutes. Experiment with positions of ease, such as lying on your back with calves resting on a chair. Sleep with a pillow between your knees if you are a side sleeper. And resist the urge to stretch aggressively into the pain; irritated nerves prefer gentle, repeated movement over brute force.

When to seek help urgently

See a doctor the same day, or attend A&E, if you develop numbness around your genitals or back passage, new difficulty passing or controlling urine, loss of bowel control, or rapidly worsening weakness in the leg. These can signal cauda equina syndrome, which is rare but a genuine emergency. Separately, book a routine review if your symptoms are not trending better by six weeks, because earlier structured rehab means an easier road back.

Sciatica is miserable, but it is very treatable, and you do not need to wait it out alone. I offer home visit physiotherapy across Liverpool and Merseyside, and online consultations wherever you are in the UK. Book at /portal/book or call +44 7443 357020, evenings Monday to Friday, plus Saturday and Sunday daytimes; no GP referral needed.