Sciatica: what it actually is, and what helps

“Sciatica” describes pain that travels down the leg along the path of the sciatic nerve. It is a symptom, not a diagnosis — which matters more than it sounds, because two people with identical-sounding sciatica can have entirely different problems needing entirely different treatment.

Getting the cause right is most of the work. The rest is usually more straightforward than people expect.

What the sciatic nerve is, and why it hurts

The sciatic nerve is the largest nerve in the body. It forms from nerve roots leaving the spine in the lower back and pelvis, runs through the buttock, down the back of the thigh, and divides behind the knee to supply the lower leg and foot.

Anything that irritates or compresses it anywhere along that path can produce symptoms further down. That is why sciatica is felt in the leg when the problem is almost always in the back or the buttock — the nerve reports pain from where it ends, not from where it is being squeezed.

The three common causes

A disc pressing on a nerve root. The most common cause under about 50. The outer wall of a lumbar disc bulges or tears and its inner material presses on, and chemically irritates, the nerve root beside it. Typically one leg, often worse with sitting, bending or coughing.

Narrowing where the nerve exits the spine. More common over 60. Age-related changes reduce the space the nerve travels through. The signature pattern is leg pain and heaviness that comes on with walking and eases when you sit down or lean forward over a trolley.

Irritation further along the nerve. Sometimes the nerve is irritated in the buttock rather than at the spine. Deep buttock pain, worse with prolonged sitting, is the usual presentation.

There is a fourth thing worth naming, because a lot of “sciatica” is not sciatica at all: referred pain from the lower back joints or the sacroiliac joint can produce buttock and thigh pain that stops above the knee. It feels similar and behaves differently, and it responds to different treatment.

How it is assessed

An assessment is looking for two things: whether the nerve is genuinely involved, and how much.

That means testing reflexes, sensation and muscle strength in the leg, plus movement testing to establish what provokes and what eases it. Where the pain stops is informative — pain travelling past the knee into the calf or foot points at genuine nerve involvement far more strongly than pain that stops at the thigh.

Scans are not routinely useful. Disc bulges are extremely common in people with no symptoms whatsoever, so an MRI often finds something that is not the cause of the problem. Imaging is worth doing when the result would change what happens next: suspected serious pathology, symptoms not following the expected course, or a surgical opinion being considered.

When to stop reading and get seen today

Most sciatica is not an emergency. These are:

• Numbness around the genitals, inner thighs or buttocks — the “saddle” area
• Difficulty starting or stopping urination, or loss of bladder or bowel control
• Weakness in both legs, or weakness that is getting worse rather than better
• Sciatica after a significant fall or accident
• Fever, unexplained weight loss, or a history of cancer alongside new back pain

The first two together suggest cauda equina syndrome, which is a surgical emergency measured in hours. Go to an emergency department, not to a clinic.

What treatment involves

For the great majority, conservative treatment and time. What that looks like in practice:

Staying as active as you reasonably can. This is one of the better-evidenced things for back and leg pain, and it is the opposite of the instinct. Bed rest beyond a day or two makes outcomes worse, not better.

Hands-on treatment. Manual therapy to the lower back, pelvis and the muscles that have tightened protectively around it. This addresses the mechanical contribution and usually the pain, though it does not un-bulge a disc — nothing does that on the timescale people hope for.

Specific movement. Which movements to do and which to avoid depends on what provoked yours. Directional preference is real: for some people repeated extension eases the leg pain, for others it worsens it. That is worked out by testing, not by a generic exercise sheet.

Load and habit changes. Sitting position, how long you sit before standing, how you lift. Small and boring, and among the things most likely to stop it recurring.

How long it takes

Most acute disc-related sciatica improves substantially over six to twelve weeks. That is longer than people want to hear, and it is genuinely the usual course — the nerve root irritation settles gradually as the inflammatory response resolves.

Improvement is usually not linear. Good days and bad days inside a generally improving trend is normal. What is worth acting on is the leg pain retreating up the leg towards the back over time — that direction of travel is a good sign, and pain spreading further down is not.

If yours is not following that pattern after several weeks of appropriate treatment, that is information rather than a reason to push on unchanged.

Chiropractic, physiotherapy, or both

Both professions manage sciatica and the emphasis differs. Chiropractic tends to lead with hands-on joint and soft tissue work; physiotherapy tends to lead with loading and rehabilitation. In practice most sciatica benefits from some of each, and the right starting point depends on your presentation rather than on the sign on the door.

At Brunswick Health both work in the same building, so if the assessment points from one to the other it is a conversation rather than a new referral and a new waiting list.