Back (Lumbar)
Piriformis Syndrome / Sciatica
이상근 증후군 / 좌골신경통
Piriformis muscle compressing the sciatic nerve, causing buttock and leg pain
- How common
- Common
- Typical age
- Ages 30–50
What is it?
The piriformis muscle (hip external rotator) becomes hypertonic or enlarged, compressing the sciatic nerve as it passes beneath or through the muscle. True disc herniation is absent.
Commonly affected: Piriformis muscle (often right), sciatic nerve in infrapiriform foramen
How it develops
- Piriformis Hypertrophy/SpasmOveruse, direct trauma, or poor posture causes piriformis spasm/enlargement
- Sciatic Nerve CompressionHypertonic piriformis compresses the sciatic nerve in the infrapiriform foramen
- Neural IrritationNerve compression causes buttock pain radiating down the posterior leg
- Functional ImpairmentPain with sitting, climbing stairs, and hip internal rotation movements
Symptoms
- Worse with SittingMarkedly worse with prolonged sitting, especially with legs crossed
- Deep Buttock PainDeep aching pain in the buttock, tender to deep palpation over piriformis
- Posterior Leg RadiationPain radiates down the posterior thigh and calf (sciatic distribution)
- Pain with Hip Internal RotationHip internal rotation stretches piriformis, reproducing pain
- Minimal/No Back PainAbsence of significant low back pain helps differentiate from disc herniation
How it is examined
- Positive FAIR TestHip Flexion, Adduction, Internal Rotation stretches piriformis — reproduces pain
- Piriformis Point TendernessDeep palpation over piriformis (midway between greater trochanter and sacrum) reproduces pain
- Negative SLRStraight leg raise typically negative — helps rule out disc herniation
Imaging
X-ray is typically normal. Obtained to exclude bony pathology of the pelvis and hip.
- Usually normal
- Excludes hip/pelvic bony pathology
MRI of the pelvis shows piriformis enlargement/signal change and sciatic nerve compression. Also rules out lumbar disc pathology.
- Piriformis hypertrophy or edema
- Perineural signal change around sciatic nerve
- No lumbar disc pathology
Non-surgical care
- Piriformis StretchingFigure-4 stretch: hip flexion + internal rotation to lengthen piriformis
- Posture CorrectionAvoid crossing legs, take frequent standing breaks, ergonomic chair adjustment
- NSAIDs + Muscle RelaxantsNSAIDs for inflammation; muscle relaxants for acute spasm
- Piriformis InjectionUltrasound or fluoroscopy-guided injection (steroid or botulinum toxin) into piriformis
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Surgical release of piriformis muscle (rare) when all conservative measures fail
Procedures that may be discussed
- Piriformis surgical release (rare)
Outlook
Most cases resolve with stretching, posture correction, and injections.