Sciatica: Understanding the Pain, Causes, and Relief with an Osteopath in Manchester
Most people have either experienced sciatica or know someone who has. It's one of the most recognisable and debilitating presentations in I see in practice — and one of the most misunderstood.
What is Sciatica?
Sciatica is not a diagnosis in itself — it's a symptom. A description of what's happening to the sciatic nerve rather than an explanation of why. Which is why anyone treating sciatica — osteopath, physio or chiropractor — should always be looking for the underlying cause, not just treating the leg pain.
The sciatic nerve is the longest and widest nerve in the body. It originates in the lower back, runs through the buttock and travels down the back of the leg, sometimes as far as the foot. When it's irritated or compressed, it can produce pain, altered sensation — tingling, numbness, pins and needles — and sometimes weakness in the leg or foot.
The pain has a distinctive quality that most people recognise immediately once they've experienced it. Gnawing, burning, sometimes electric. It can be constant or come and go. Certain positions — particularly sitting for prolonged periods — tend to aggravate it, while movement sometimes eases it.
What causes sciatica?
The most common cause by far is a disc herniation — when the inner gel, the nucleus, material escapes through the outer disc wall and contacts the nerve root. What makes this particularly interesting is that it's not just mechanical compression that causes the pain. Research by Olmarker and colleagues in 1993 demonstrated that nucleus pulposus material applied directly to nerve roots — without any compression whatsoever — caused measurable nerve degeneration within days. A fatty tissue control produced no such effect.
This tells us something important: it's the specific inflammatory chemical environment created by disc material that irritates the sciatic nerve. Which is also why piriformis syndrome as an explanation for true sciatica doesn't hold up well clinically. Nerves run through and alongside muscles throughout the entire body. If muscle compression or tightness were capable of causing true nerve irritation and radicular pain, we'd see it everywhere. We don't. The straightforward explanation is that muscles simply don't produce the inflammatory environment that disc material does.
Other causes include spinal stenosis — a narrowing of the spinal canal that can compress nerve roots — spondylolisthesis, where one vertebra slips forward over another, and in rare cases space occupying lesions such as cysts or tumours. Trauma to the lower back can also damage the nerve roots directly. Have a look at my blogs on arthritis of the spine and degenerative disc disease for some causes of spinal stenosis.
Sciatica can also occur in pregnancy, though always as a result of one of the structural causes above rather than pregnancy itself being the cause.
Why does sciatica sometimes take a while to come on?
This is something many patients find confusing — they injure their back and expect immediate leg pain, but the sciatica develops days or even weeks later. This is actually well explained by the research.
Disc herniations don't always happen all at once. Studies have shown that some herniations develop gradually over days or weeks, progressively encroaching on the nerve root. And even when disc material contacts the nerve immediately, the inflammatory and neurological processes that produce radicular pain take time to build — research suggests ectopic firing patterns in the nerve, which produce the characteristic shooting pain, can take days to weeks to develop fully after the initial injury.
So a fortnight between injuring your back and developing leg pain is not unusual — and doesn't mean something new has gone wrong.
Signs and symptoms
Symptoms vary depending on which nerve root is affected and how severely:
Radiating pain from the lower back or buttock into the leg — ranging from a dull ache to sharp and severe.
Altered sensation — tingling, numbness or pins and needles in the leg or foot.
Muscle weakness — difficulty lifting the foot, weakness in the calf, or reduced power in the leg.
Pain worse with sitting — particularly with disc related sciatica, prolonged sitting loads the disc and tends to aggravate symptoms.
Symptoms that change with position — moving around often eases things, which distinguishes sciatica from other causes of leg pain.
If you experience sudden loss of bladder or bowel control alongside numbness in the saddle area — the region you'd sit on a bike — seek urgent medical attention. These can be signs of cauda equina syndrome.
Treatment and recovery
The good news is that most sciatica resolves with conservative management. Surgery is rarely necessary and should always be a last resort.
Hands-on osteopathic treatment focuses on the underlying cause — identifying which structure is irritating the nerve, addressing movement restrictions in the spine, and reducing the compensatory muscle guarding that develops around an acute nerve root injury.
Load management is central to recovery. Understanding which positions and movements aggravate the nerve and modifying them intelligently — rather than avoiding all activity — tends to produce better and faster recovery than rest alone.
As sciatica is often inflammation driven, applying something cold to the lower back — an ice pack or a bag of frozen peas wrapped in a cloth — can help reduce the inflammatory response in the early stages. Apply for 15-20 minutes at a time. It won't resolve the underlying cause but can take the edge off in the early days when symptoms are at their worst.
Graduated exercise and rehabilitation — building the strength and load tolerance of the structures supporting the spine — reduces the risk of recurrence once the acute episode has settled.
Stronger pain relief or epidural steroid injections are sometimes appropriate where pain is severe and persistent. Your GP is the right person to discuss these options with.
Preventing recurrence
Sciatica caused by a disc herniation has a reasonable chance of recurring if the underlying loading patterns that contributed to it aren't addressed. The focus should be on:
Building genuine spinal strength and resilience — not just avoiding aggravating activities but progressively loading the spine so it can tolerate more.
Understanding your own aggravating and relieving factors — most people with disc related sciatica find certain positions or activities consistently worsen symptoms. Knowing these and managing load around them is practical, actionable self management.
Addressing prolonged sitting — if your work involves sitting for long periods, regular movement breaks and attention to how you're loading the spine matter more than any specific exercise.
If you're based in Manchester or Didsbury and would like to discuss your symptoms, I offer initial appointments at Holland Osteopathy — book online below.
The Sciatic Nerve
The sciatic nerve is the longest and widest nerve in the human body, comprising lumbosacral nerve roots (L4–S3) that originate in the lower back. It extends from the lumbar spine through the buttocks and down the back of each leg and into the foot. The sciatic nerve plays a crucial role in transmitting signals from the spinal cord to the lower body, enabling various motor (movement) and sensory functions.
Motor function: The sciatic nerve supplies the hamstring muscle group (biceps femoris, semimembranosus and semitendinosus) and the hamstring portion of the adductor magnus (groin/adductor muscle of the thigh). And then the sciatic nerve branches off as it indirectly supplies all the muscles of the lower leg and foot.
Sensory function: Indirectly supplies (via its terminal branches) the skin of the outside leg, heel, and both the top (dorsal) and bottom (plantar) surfaces of the foot.