Three questions split most cases. Where did it start? Radicular pain almost always involves the low back; piriformis pain starts in the buttock and stays there. What makes it worse? Coughing or sneezing reliably points back to the spine; pain after a long drive or from crossing your legs points at the piriformis. Any real numbness or weakness? A clean numb patch on the calf or foot, or a foot that slaps when you walk, is a nerve-root sign and pushes hard toward the disc side 1.
The piriformis is only one of several muscles in that deep buttock space that can squeeze the nerve, so specialists increasingly call the whole thing deep gluteal syndrome 1. Its diagnosis is one of exclusion: four features together (buttock pain, pain much worse after sitting, tenderness near the notch where the nerve leaves the pelvis, and pain on stretching the muscle) are the closest thing to a clinical verdict 2.
Read your own case before anyone reaches for a scan.
The usual arc. Most people recover with movement and time; surgery is the exception.
- Weeks one to four: the sharp pain softens, sitting through a meal gets easier, the limp eases out of your walk.
- Weeks six to twelve: numbness fades and the leg feels like yours again. Between 60 and 90% of disc-related sciatica is largely resolved by twelve weeks 4; piriformis pain runs a similar course with steady stretching 5.
- Months six to twelve: long drives and flights come back. Surgery gets people there faster early on, but by a year the operated and conservative groups land in roughly the same place 4.
The fine print β when to skip it, and what people get wrong
Saddle numbness, sudden bladder or bowel trouble, both legs affected, or a rapidly weakening foot means A&E now, even if the pain has eased. That is cauda equina syndrome, and decompression is measured in hours 3.
A normal MRI doesn't confirm piriformis; hip, sacroiliac and hamstring problems mimic it 1. And a disc on the scan can be innocent: about a third of pain-free twenty-somethings have one 6, 7.
The core failure is treating the wrong target: an innocent disc bulge gets blamed and injected while the buttock muscle goes untreated 6. The dangerous one is stretching through worsening weakness: pain easing while strength fades means the nerve is failing, and a growing foot drop needs same-week review.
- 1Martin HD, Reddy M, GΓ³mez-Hoyos J (2015). Deep gluteal syndrome. Journal of Hip Preservation Surgery. link
- 2Hopayian K, Danielyan A (2018). Four symptoms define the piriformis syndrome: an updated systematic review of its clinical features. European Journal of Orthopaedic Surgery & Traumatology. link
- 3NICE (2020). Low back pain and sciatica in over 16s: assessment and management (NG59). link
- 4Jacobs WC, van Tulder M, Arts M et al. (2011). Surgery versus conservative management of sciatica due to a lumbar herniated disc: a systematic review. European Spine Journal. link
- 5Fishman LM, Dombi GW, Michaelsen C et al. (2002). Piriformis syndrome: diagnosis, treatment, and outcome β a 10-year study. Archives of Physical Medicine and Rehabilitation. link
- 6Brinjikji W, Luetmer PH, Comstock B et al. (2015). Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. American Journal of Neuroradiology. link
- 7Jensen MC, Brant-Zawadzki MN, Obuchowski N et al. (1994). Magnetic resonance imaging of the lumbar spine in people without back pain. New England Journal of Medicine. link
Related in the handbook (3)
- β A disc bulge on MRI is often blamed for sciatica it didn't cause β match the symptoms before trusting the scan.
- β Buttock and hip pain from the gluteal tendons or joint can masquerade as sciatica β worth telling them apart.
- β When low back trouble shoots pain down the leg, the question becomes whether it's a pinched root or the piriformis muscle.