Deep buttock pain that radiates down your leg — but your MRI is normal?
Piriformis Syndrome — a small deep muscle in your buttock is compressing the sciatic nerve.
A hard chair makes one buttock ache deep inside, and the entire leg goes numb. The discomfort is not in the back but deep within the buttock, and pressing on the right spot produces sharp, intense pain. The symptoms mimic a herniated disc, but the cause is different.
Quick Answer: The piriformis is a deep pelvic muscle connecting the sacrum to the femur. When it becomes tight or overactive, it compresses the sciatic nerve running nearby — or directly through it in some people — triggering sciatica-like symptoms originating in the buttock muscle rather than the spine. Unlike disc herniation or stenosis, the problem here is a muscle, not a spinal structure.
Seek immediate medical attention if you have:
- Bladder or bowel dysfunction (incontinence or inability to urinate)
- Simultaneous severe pain and numbness in both buttocks and legs
- Sudden severe buttock/leg pain after a fall or direct impact
3 Key Points on This Page
- What the piriformis is and why it compresses the sciatic nerve
- How to tell piriformis syndrome apart from lumbar disc herniation
- Releasing piriformis tightness and preventing recurrence through Circulation Therapy
Signs that suggest piriformis syndrome
- Deep ache in one buttock when sitting — Hard surfaces make it noticeably worse; the buttock feels blocked or seized up deep inside.
- Numbness and tingling radiating down the leg — The thigh, calf, and sometimes the foot feel numb or pulled.
- Worsens with prolonged sitting — Sitting stretches the piriformis, tightening its grip on the sciatic nerve over time.
- Extreme tenderness when pressed — Direct pressure on the piriformis location produces sharp, intense pain.
- Forward bending sometimes brings relief — Positions that reduce piriformis tension ease the symptoms.
What causes piriformis syndrome?
The piriformis externally rotates the hip joint. When specific movements or postures are repeated excessively, the muscle over-contracts and its fascia becomes knotted, squeezing the sciatic nerve beneath it.
- Prolonged sitting — Common in desk workers. The piriformis is kept in a lengthened, blood-flow-restricted position for hours, making it chronically tight.
- Running and cycling — Repetitive hip external rotation movements overwork the piriformis.
- Pelvic asymmetry — Misaligned pelvis creates abnormal tension on the piriformis, leading to chronic tightness.
Piriformis Syndrome vs. Disc Herniation
- Piriformis syndrome — Pain deep in buttock, tender to palpation. Lumbar tests negative. Worse when sitting. Back bending has little effect on leg symptoms.
- Disc herniation — Back pain accompanies leg symptoms. Lumbar tests positive. Coughing worsens it. Forward bending increases leg pain.
Both conditions frequently coexist, making thorough assessment essential.
Our Approach at Yonsei SM Pain Clinic
Piriformis syndrome requires releasing the fascial tightness of the piriformis and correcting the underlying pelvic imbalance.
- Phase 1: Calm Down (Circulation HD)
Release fascial knotting in the piriformis. Hydrodissection breaks up adhesions between the piriformis and the sciatic nerve, restoring local blood flow. Calming nervous system sensitization settles the hypersensitive state caused by prolonged nerve compression. - Phase 2: Wake Up (Circulation PT)
Strengthen the hip external rotators and gluteus medius so the piriformis no longer has to work alone. Movement correction reduces the repetitive stress loaded onto the piriformis. Activating surrounding muscles distributes load more evenly. - Phase 3: Connect
Correct sitting posture and walking patterns. Gait analysis reveals movement habits that overload the piriformis, then guides you to apply the optimal pattern in daily life.
Frequently Asked Questions
Can I stretch the piriformis on my own?
Piriformis stretching is helpful in principle, but if the muscle is already over-lengthened, stretching can make things worse. The first step is to release the fascial tightness (Calm Down), then strengthen surrounding muscles (Wake Up) — not stretch more of an already overstretched muscle.
I’ve had steroid injections but they didn’t help much.
Steroid injections reduce inflammation but do not resolve fascial adhesions or muscle imbalances. Hydrodissection addresses the fascial knots, and subsequent muscle strengthening with pattern correction is needed to prevent recurrence.
I sit for work all day. How do I manage this?
Standing and moving every 30 minutes is the single most important habit change. Chair height and angle should be adjusted so the piriformis isn’t under sustained pressure. Post-treatment movement correction refines your sitting posture systematically.
Can I keep running?
During acute flare-ups, reduce or pause running. Gait analysis checks your running mechanics to identify patterns that overload the piriformis, and you can return to running gradually after pattern correction.
How long does treatment take?
Treatment duration depends on the degree of fascial tightness and pelvic imbalance. Circulation HD releases piriformis tension, and concurrent muscle strengthening leads to stepwise recovery. Treatment Duration Q&A →
References
- Boyajian-O’Neill LA, et al. Diagnosis and management of piriformis syndrome: an osteopathic approach. J Am Osteopath Assoc. 2008;108(11):657–664.
- Hopayian K, et al. The clinical features of the piriformis syndrome: a systematic review. Eur Spine J. 2010;19(12):2095–2109. PMID 20596735
- Tonley JC, et al. Treatment of an individual with piriformis syndrome focusing on hip muscle strengthening and movement reeducation. Phys Ther. 2010;90(8):1240–1252.
- Cassidy L, et al. Piriformis syndrome: implications of anatomical variations, diagnostic techniques, and treatment options. Surg Radiol Anat. 2012;34(6):479–492.
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