Piriformis Muscles Syndrome

Topic updated on 12/26/14 2:33pm
  • A condition characterized by sciatic symptoms (leg pain) due to extrapelvic sciatic nerve compression at the hip
    • sometimes called deep gluteal syndrome 
  • Pathophysiology
    • pathoanatomy
      • sciatic nerve entrapment occurs
        • anterior to piriformis muscle or posterior to obturator internus/gemelli complex 
        • at level of ischial tuberosity
      • anatomic anomalies may contribute to compression including
        • bipartite piriformis
        • variations of sciatic nerve path
        • tumors
        • aneurysm of inferior gluteal artery
  • Associated conditions
    • femoroacetabular impingement 
      • decreased internal rotation may contribute to contractures of short external rotators and compression on sciatic nerve
  • Sciatic nerve 
    • exits 
      • inferior to piriformis  
      • superior to gamellus superior
  • Muscles
    • external rotators of the thigh include (superior to inferior)
      • piriformis 
      • gamellus superior 
      • obturator internus 
      • gamellus inferior  
      • obturator externus 
      • quadratus femoris 
  • Symptoms
    • pain in the posterior gluteal region and migrating down the back of the leg
    • pain may be burning or aching in nature similar to sciatica symptoms
  • Physical exam 
    • FAIR test
      • Flexion, Adduction, and Internal Rotation of hip can reproduce symptoms 
      • maneuver places piriformis muscle on tension
  • Radiographs
    • unremarkable
  • MRI
    • usually unremarkable
    • lumbar MRI helpful to rule out spine as cause of compression of sciatic nerve
  • Electrodiagnostic studies
    • can document functional impairment of sciatic nerve
  • Nonoperative
    • rest, NSAIDS, muscle relaxants, PT, steroid injections
      • indications
        • first line of treatment
      • technique
        • focused on stretching the piriformis muscle and short external rotators
        • corticosteroid injection directed near the piriformis muscles
  • Operative
    • piriformis muscle release and external sciatic neurolysis
      • indications
        • only indicated in refractory cases after failed conservative measures


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Qbank (1 Questions)

(OBQ09.37) Which of the following is the most common anatomical pattern of the sciatic nerve as it exits the pelvis? Topic Review Topic

1. As a single nerve, anterior to the piriformis muscle
2. As a single nerve, posterior to the piriformis muscle
3. As two branches, both anterior to piriformis muscle
4. As two branches, one anterior to piriformis and one through the piriformis muscle
5. As two branches, both posterior to the piriformis muscle



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