Sciatica is one of the most common and recognisable types of pain we see at Zest Chiropractic. This guide covers the five main causes, how to tell sciatica from other types of back and leg pain, and what to do about it. For the full clinical picture, see our back pain diagnosis and causes guide.
Key takeaways
- Sciatica is a symptom — pain along the sciatic nerve path — not a diagnosis in itself.
- The sciatic nerve is the longest nerve in the body, running from the lower back through the buttock and down the leg.
- A disc herniation pressing on a nerve root is the most common cause of sciatica.
- Other causes include spinal stenosis, piriformis syndrome, facet joint irritation and spondylolisthesis.
- Identifying the specific cause matters — because the most effective treatment is different for each one.
What is sciatica?
Sciatica is pain that travels along the path of the sciatic nerve — from the lower back through the buttock, down the back or side of the thigh, and often into the calf or foot. It’s caused by compression or irritation of one or more of the nerve roots (usually L4, L5, or S1) that form the sciatic nerve. It is always caused by something. If you’re experiencing this kind of pain, our sciatica treatment page covers how we approach it in practice.
The 5 main causes of sciatica
1. Disc herniation
A herniated disc is the most common cause of sciatica. (You may also have heard of this being called a slipped disc, or a disc bulge.) When the inner material of a disc pushes outward (herniates), it can press directly against a nerve root as it exits the spine. The pain is typically sharp, burning, or electric in character and follows a specific path depending on which nerve root is affected. L4 involvement commonly causes pain in the thigh. L5 involvement usually produces pain into the outer calf and top of the foot. S1 involvement tends to run down the back of the calf into the heel. Pins and needles or numbness may also follow the path of the pain and in some cases you may notice muscle weakness.
2. Spinal stenosis
Spinal stenosis is a narrowing of the spinal canal, usually due to age-related changes — disc degeneration, facet joint enlargement and thickening of the spinal ligaments. As the canal narrows, the nerve roots passing through it come under pressure. Stenosis-related sciatica tends to come on gradually, is often bilateral (affecting both legs) and is characteristically worse with walking and better with sitting, or bending forward slightly.
3. Piriformis syndrome
The piriformis is a muscle deep in the buttock and the sciatic nerve runs directly beneath it (and in some people, directly through it). When the piriformis becomes tight or inflamed — often from sedentary habits, prolonged sitting, or hip movement problems — it can compress the nerve and produce sciatic-type symptoms. Unlike disc-related sciatica, the pain with piriformis syndrome typically starts in the buttock rather than the lower back.
4. Facet joint irritation
Inflamed or degenerated facet joints can irritate the nearby nerve roots through a combination of direct pressure and inflammatory chemicals. This type of sciatica is often associated with facet joint pain in the lower back as well and tends to be worse with extension and rotation rather than with prolonged sitting.
5. Spondylolisthesis
Spondylolisthesis is where one vertebra slips forward on the one below it. This can narrow the space through which the nerve root exits the spine, causing ongoing sciatic symptoms. It’s more common in adults over 50 with degenerative changes and also in younger athletes in sports involving repetitive lumbar extension – like gymnastics, tennis and cricket.
If you’re experiencing leg pain that could be sciatica, we’d encourage you to get it properly assessed rather than guessing. You can book a consultation — getting the cause right is the difference between targeted treatment and months of managing symptoms that don’t fully resolve. If you’re unsure whether to book, you’re welcome to call, we’re always happy to help give advice to help you come to a decision that’s right for you.
How do I know if it’s sciatica?
Sciatica typically produces pain, tingling, numbness, or weakness that travels from the lower back or buttock into the leg — often past the knee and into the calf or foot. The character is usually quite distinct from muscular pain: burning, electric, or shooting rather than a dull ache. It typically affects one side only. If your leg symptoms are accompanied by lower back pain and are worse with sitting or bending forward, disc-related sciatica is a likely cause.
Sciatica causes compared
| Cause | Where pain starts | Key feature | Age group |
| Disc herniation | Lower back | Worse sitting, better walking | 30s-50s most common |
| Spinal stenosis | Buttocks/legs | Worse walking, better sitting | 50s onwards |
| Piriformis syndrome | Deep buttock | No lower back pain | Any age |
| Facet joint | Lower back, buttock | Worse extension/rotation | 40s onwards |
| Spondylolisthesis | Lower back, leg | Ache with activity | 50s+, or young athletes |
Frequently asked questions
What does sciatica feel like?
Sciatica typically feels like a burning, shooting, or electric pain that travels from the lower back or buttock down into the leg, often past the knee. Many people also describe tingling or numbness in the leg or foot alongside the pain. Unlike a muscular ache, it follows a specific path determined by which nerve root is affected.
Can sciatica go away on its own?
Sciatica caused by a disc herniation often does improve over weeks to months as the disc reabsorbs and pressure on the nerve reduces. However, this process is faster and more complete with appropriate treatment. Without addressing the underlying cause, sciatica has a tendency to recur. See our page on sciatica treatment in Birmingham for more on what recovery looks like.
How long does sciatica last?
Acute sciatica from a disc herniation often improves significantly within six to twelve weeks with appropriate care. Sciatica from spinal stenosis or spondylolisthesis tends to be more chronic and requires ongoing management. The sooner the underlying cause is identified and treated, the shorter and less severe the episode tends to be.
Is sciatica caused by sitting too much?
Prolonged sitting is a significant contributing factor to disc-related sciatica because it increases intradiscal pressure and can accelerate disc degeneration over time. It also tightens the piriformis and hip flexors, which can compress the sciatic nerve in the buttock. Sciatica from sitting is one of the most common presentations we see in people who work at desks.
What should I do if I think I have sciatica?
Get it assessed. Sciatica has several distinct causes and effective treatment depends on which one it is. You’re welcome to call us for advice, or book a consultation and we can establish the cause and put a plan in place.