Key takeaways
- Leg pain that's worse when sitting often points to a disc; worse when standing and walking often points to stenosis.
- Tight buttock muscles, such as the piriformis, can squeeze the sciatic nerve and are often overlooked.
- Sometimes the nerve is irritated in two places at once (a "double crush"), so treating one spot only partly helps.
- See a specialist if sciatica lasts more than about two months, is severe, or comes with numbness or weakness.
The sciatic nerve is the largest nerve in your body, as you can probably tell if you're feeling it right now. It's formed by nerves leaving the lower back, travels through the muscles of the buttock, and runs down the back of the thigh toward the foot. When it's irritated, we call it sciatica.
Most cases get better within a few weeks with rest and routine care. If yours hasn't, the answer is usually to look harder for what is causing it, because there is often more than one cause.
Clues from your symptoms
- Worse with sitting - often a herniated, bulging or damaged disc
- Worse with standing and walking, better when you bend forward or pull your knees to your chest - often spinal stenosis
- Deep buttock pain, worse with sitting on hard surfaces or crossing your legs - possibly piriformis syndrome
Piriformis syndrome: the often-missed cause
The sciatic nerve runs beneath the piriformis muscle deep in the buttock, with the gluteal muscles on top. When these muscles are tight or in spasm, they can squeeze the nerve. This is called piriformis syndrome. When properly diagnosed, it often responds well and fairly quickly to treatment that lengthens and releases the muscle.
Alignment and structural causes
Sciatica can start when lower-back vertebrae shift slightly out of alignment after a fall, from lopsided postures, or because of a small structural difference present from birth, such as a leg-length difference. These can narrow the opening where the nerve exits, or stress the nearby disc until it bulges into the nerve.
The "double crush"
Sometimes the nerve is irritated in two places, for example at a disc in the lower back and at the piriformis. Treating only one site gives partial relief at best. These cases need a careful exam to find every point of compression.
Discs, degeneration and synovial cysts
Discs are the fibrous shock absorbers between the vertebrae. If a disc weakens from injury or uneven loading, it can tear or bulge into the nearby nerve. Between L4 and S1, that usually sends pain or numbness down the back of the thigh, below the knee and sometimes into the foot, and can cause leg weakness. Synovial cysts from the small facet joints can press on the nerve in a similar way.
How difficult cases should be treated
Minor sciatica often responds to gentle stretching and routine chiropractic or physical therapy. Stubborn cases need more precision: adjustments that are more specific, exercises matched to your particular asymmetry, non-surgical decompression when a disc is involved, and sometimes a heel lift to correct a structural imbalance. Surgery should generally be a last resort, though when it's the right choice, we work with excellent surgeons.
When to see a specialist
Come see us if your sciatica has lasted more than about two months, is especially severe, comes with numbness, tingling or weakness, or if surgery has been recommended and you'd like another opinion first.
Seek emergency care right away for loss of bladder or bowel control, numbness in the groin area, or rapidly worsening leg weakness.