Piriformis syndrome


  • "Sciatica" entrapment not originating from nerve root compression.
  • Probable compression of sciatic nerve, by piriformis muscle.
  • Piriformis normally helps ext rotate hip.
  • Inactive gluteals vs tight hip flexors (so piriformis strains at hip extension & rotation → compressing the sciatic N.).


  • Clinical diagnosis.
  • Unilateral (rarely bilat.) buttock pain radiating to hamstrings or below.
  • F:M = 3:1.
  • 30 - 40 yo.
  • Exacerbated by sitting or prolonged "flexion" exercise (e.g. cycling).
  • Associated pudendal nerve compression may result in transient saddle paraesthesia or sphincter symptoms.
  • Symptoms relieved by hip extension or ext. rotation (patients walk "toe out").
  • No red flags.
  • No convincing root irritation (e.g. valsalva) symptoms.
  • Nil constitutional.
  • SLR near normal.
  • No motor, sphincter or perianal pinprick sensation abnormalities.
  • Trigger point at sciatic notch (½ way between ischium & Gr. trochanter).
  • FAIR (hip flexion/adduction/int. rotation) manoeuvre triggers symptoms.

Differential Dx


  • EMG studies in difficult cases (GP to arrange).


  • Muscle stretching & gluteal strengthening exercises and education (physio referral).
  • NSAIDs.
  • Ice.

Content By Dr √ćomhar O' Sullivan 25/02/2009. Last review Dr ÍOS, Dr C Luke 16/12/19.