Medscape is available in 5 Language Editions – Choose your Edition here.


Physical Medicine and Rehabilitation for Piriformis Syndrome

  • Author: Milton J Klein, DO, MBA; Chief Editor: Consuelo T Lorenzo, MD  more...
Updated: May 16, 2016


Piriformis syndrome has been a controversial diagnosis since its initial description in 1928.[1] The condition, which can mimic a diskogenic sciatica, usually is caused by a neuritis of the proximal sciatic nerve. The piriformis muscle can either irritate or compress the proximal sciatic nerve due to spasm and/or contracture. Piriformis syndrome is also referred to as pseudosciatica, wallet sciatica, and hip socket neuropathy.



The piriformis muscle is flat, pyramid-shaped, and oblique. This muscle originates to the anterior of the S2-S4 vertebrae, the sacrotuberous ligament, and the upper margin of the greater sciatic foramen. Passing through the greater sciatic notch, the muscle inserts on the superior surface of the greater trochanter of the femur. With the hip extended, the piriformis muscle is the primary external rotator; however, with the hip flexed, the muscle becomes a hip abductor. The piriformis muscle is innervated by branches from L5, S1, and S2, as demonstrated in the image below.

Nerve irritation in the herniated disk occurs at t Nerve irritation in the herniated disk occurs at the root (sciatic radiculitis). In piriformis syndrome, the irritation extends to the full thickness of the nerve (sciatic neuritis).

A lower lumbar radiculopathy may cause secondary irritation of the piriformis muscle, which may complicate diagnosis and hinder patient progress.

Many developmental variations of the relationship between the sciatic nerve in the pelvis and piriformis muscle have been observed.[2, 3, 4] In approximately 20% of the population, the muscle belly is split, with 1 or more parts of the sciatic nerve dividing the muscle belly itself. In 10% of the population, the tibial/peroneal divisions are not enclosed in a common sheath. Usually, the peroneal portion splits the piriformis muscle belly, although in rare cases, the tibial division does so.

In a study of 200 pairs of sacral roots (100 patients, none of whom had piriformis syndrome) by Russell et al, T1-weighted magnetic resonance imaging (MRI) scans revealed that 199 of the S1 nerve roots (99.5%) were positioned above the piriformis muscle, while 150 of the S2 nerve roots (75%) traversed the muscle and 50 of them (25%) were located above it. The images also showed that 194 S3 nerve roots (97%) traversed the muscle and that 190 S4 nerve roots (95%) were below it. The piriformis muscles had an average size of 1.9 cm; in 19% of the study's patients, the muscle was asymmetrical by more than 3 mm.[5]

Involvement of the superior gluteal nerve usually is not seen in cases of piriformis syndrome. This nerve leaves the sciatic nerve trunk and passes through the canal above the piriformis muscle.

Blunt injury may cause hematoma formation and subsequent scarring between the sciatic nerve and short external rotators. Nerve injury can occur with prolonged pressure on the nerve or vasa nervorum.

The etiology of piriformis syndrome can be divided into the following categories:

  • Hyperlordosis
  • Muscle anomalies with hypertrophy
  • Fibrosis (due to trauma)
  • Partial or total nerve anatomical abnormalities

Other causes can include the following:

Piriformis syndrome remains controversial because, in most cases, the diagnosis is clinical, and no confirmatory tests exist to support the clinical findings.

Papadopoulos and colleagues proposed the following classifications for piriformis syndrome[7] :

  • Primary piriformis syndrome - This designation would apply to piriformis syndrome resulting from intrinsic pathology of the piriformis muscle itself, such as myofascial pain, anatomic variations, and myositis ossificans.
  • Secondary piriformis syndrome (pelvic outlet syndrome) - This classification would encompass all other etiologies of piriformis syndrome, with the exclusion of lumbar spinal pathology.



United States

Given the lack of agreement on exactly how to diagnose piriformis syndrome, estimates of the frequency of sciatica caused by piriformis syndrome vary from rare to approximately 6% of sciatica cases seen in a general family practice.[8] Approximately 90% of adults have had at least 1 episode of disabling low back pain (LBP) in their lifetime.


Piriformis syndrome is not life-threatening, but it can have significant associated morbidity. The total cost of low back pain and sciatica is significant, exceeding $16 billion in direct and indirect costs.


Some reports suggest a 6:1 female-to-male ratio for piriformis syndrome.

Contributor Information and Disclosures

Milton J Klein, DO, MBA Consulting Physiatrist, Heritage Valley Health System-Sewickley Hospital and Ohio Valley General Hospital

Milton J Klein, DO, MBA is a member of the following medical societies: American Academy of Disability Evaluating Physicians, American Academy of Medical Acupuncture, American Academy of Osteopathy, American Academy of Physical Medicine and Rehabilitation, American Medical Association, American Osteopathic Association, American Osteopathic College of Physical Medicine and Rehabilitation, American Pain Society, Pennsylvania Medical Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Michael T Andary, MD, MS Professor, Residency Program Director, Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine

Michael T Andary, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, Association of Academic Physiatrists

Disclosure: Received honoraria from Allergan for speaking and teaching.

Chief Editor

Consuelo T Lorenzo, MD Medical Director, Senior Products, Central North Region, Humana, Inc

Consuelo T Lorenzo, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation

Disclosure: Nothing to disclose.

Additional Contributors

Rajesh R Yadav, MD Associate Professor, Section of Physical Medicine and Rehabilitation, MD Anderson Cancer Center, University of Texas Medical School at Houston

Rajesh R Yadav, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation

Disclosure: Nothing to disclose.

  1. Yeoman W. The relation of arthritis of the sacroiliac joint to sciatica. Lancet. 1928. ii:1119-22.

  2. Windisch G, Braun EM, Anderhuber F. Piriformis muscle: clinical anatomy and consideration of the piriformis syndrome. Surg Radiol Anat. 2007 Feb. 29(1):37-45. [Medline].

  3. Guvencer M, Iyem C, Akyer P, et al. Variations in the high division of the sciatic nerve and relationship between the sciatic nerve and the piriformis. Turk Neurosurg. 2009 Apr. 19(2):139-44. [Medline].

  4. Smoll NR. Variations of the piriformis and sciatic nerve with clinical consequence: a review. Clin Anat. 2010 Jan. 23(1):8-17. [Medline].

  5. Russell JM, Kransdorf MJ, Bancroft LW, et al. Magnetic resonance imaging of the sacral plexus and piriformis muscles. Skeletal Radiol. 2008 Aug. 37(8):709-13. [Medline].

  6. Popovac H, Bojanic I, Smoljanovic T. Leg length discrepancy as a rare cause of a piriformis syndrome. J Back Musculoskelet Rehabil. 2012 Jan 1. 25(4):299-300. [Medline].

  7. Papadopoulos SM, McGillicuddy JE, Albers JW. Unusual cause of 'piriformis muscle syndrome'. Arch Neurol. 1990 Oct. 47(10):1144-6. [Medline].

  8. Yoshimoto M, Kawaguchi S, Takebayashi T, et al. Diagnostic features of sciatica without lumbar nerve root compression. J Spinal Disord Tech. 2009 Jul. 22(5):328-33. [Medline].

  9. Niu CC, Lai PL, Fu TS, et al. Ruling out piriformis syndrome before diagnosing lumbar radiculopathy. Chang Gung Med J. 2009 Mar-Apr. 32(2):182-7. [Medline]. [Full Text].

  10. Beatty RA. The piriformis muscle syndrome: a simple diagnostic maneuver. Neurosurgery. 1994. 34:512-514. [Medline].

  11. Jankiewicz JJ, Hennrikus WL, Houkom JA. The appearance of the piriformis muscle syndrome in computed tomography and magnetic resonance imaging. A case report and review of the literature. Clin Orthop. 1991 Jan. (262):205-9. [Medline].

  12. Lewis AM, Layzer R, Engstrom JW, et al. Magnetic resonance neurography in extraspinal sciatica. Arch Neurol. 2006 Oct. 63(10):1469-72. [Medline]. [Full Text].

  13. Filler AG, Haynes J, Jordan SE, et al. Sciatica of nondisc origin and piriformis syndrome: diagnosis by magnetic resonance neurography and interventional magnetic resonance imaging with outcome study of resulting treatment. J Neurosurg Spine. 2005 Feb. 2(2):99-115. [Medline].

  14. Fishman LM, Zybert PA. Electrophysiologic evidence of piriformis syndrome. Arch Phys Med Rehabil. 1992 Apr. 73(4):359-64. [Medline].

  15. Jawish RM, Assoum HA, Khamis CF. Anatomical, clinical and electrical observations in piriformis syndrome. J Orthop Surg Res. 2010 Jan 21. 5(1):3. [Medline]. [Full Text].

  16. Gonzalez P, Pepper M, Sullivan W, et al. Confirmation of needle placement within the piriformis muscle of a cadaveric specimen using anatomic landmarks and fluoroscopic guidance. Pain Physician. 2008 May-Jun. 11(3):327-31. [Medline]. [Full Text].

  17. Reus M, de Dios Berna J, Vazquez V, et al. Piriformis syndrome: a simple technique for US-guided infiltration of the perisciatic nerve. Preliminary results. Eur Radiol. 2008 Mar. 18(3):616-20. [Medline].

  18. Al-Al-Shaikh M, Michel F, Parratte B, et al. An MRI evaluation of changes in piriformis muscle morphology induced by botulinum toxin injections in the treatment of piriformis syndrome. Diagn Interv Imaging. 2015 Jan. 96(1):37-43. [Medline].

  19. Mizuguchi T. Division of the pyriformis muscle for the treatment of sciatica. Postlaminectomy syndrome and osteoarthritis of the spine. Arch Surg. 1976 Jun. 111(6):719-22. [Medline].

  20. Fishman LM, Konnoth C, Rozner B. Botulinum neurotoxin type B and physical therapy in the treatment of piriformis syndrome: a dose-finding study. Am J Phys Med Rehabil. 2004 Jan. 83(1):42-50; quiz 51-3. [Medline].

  21. Lang AM. Botulinum toxin type B in piriformis syndrome. Am J Phys Med Rehabil. 2004 Mar. 83(3):198-202. [Medline].

  22. Yoon SJ, Ho J, Kang HY, et al. Low-dose botulinum toxin type A for the treatment of refractory piriformis syndrome. Pharmacotherapy. 2007 May. 27(5):657-65. [Medline].

  23. Jeynes LC, Gauci CA. Evidence for the use of botulinum toxin in the chronic pain setting--a review of the literature. Pain Pract. 2008 Jul-Aug. 8(4):269-76. [Medline].

  24. Kirschner JS, Foye PM, Cole JL. Piriformis syndrome, diagnosis and treatment. Muscle Nerve. 2009 Jul. 40(1):10-8. [Medline].

  25. Fowler IM, Tucker AA, Weimerskirch BP, Moran TJ, Mendez RJ. A randomized comparison of the efficacy of 2 techniques for piriformis muscle injection: ultrasound-guided versus nerve stimulator with fluoroscopic guidance. Reg Anesth Pain Med. 2014 Mar-Apr. 39(2):126-32. [Medline].

  26. Misirlioglu TO, Akgun K, Palamar D, Erden MG, Erbilir T. Piriformis syndrome: comparison of the effectiveness of local anesthetic and corticosteroid injections: a double-blinded, randomized controlled study. Pain Physician. 2015 Mar-Apr. 18 (2):163-71. [Medline].

  27. Jeong HS, Lee GY, Lee EG, Joe EG, Lee JW, Kang HS. Long-term assessment of clinical outcomes of ultrasound-guided steroid injections in patients with piriformis syndrome. Ultrasonography. 2015 Jul. 34 (3):206-10. [Medline]. [Full Text].

  28. Wu O. Piriformis syndrome treated by triple acupuncture with the bai hu yao maneuver. J Tradit Chin Med. Sep 2003. 23(3):197-8.

  29. Barton PM. Piriformis syndrome: a rational approach to management. Pain. 1991 Dec. 47(3):345-52. [Medline].

  30. Beauchesne RP, Schutzer SF. Myositis ossificans of the piriformis muscle: an unusual cause of piriformis syndrome. A case report. J Bone Joint Surg Am. 1997 Jun. 79(6):906-10. [Medline].

  31. Broadhurst NA, Simmons DN, Bond MJ. Piriformis syndrome: correlation of muscle morphology with symptoms and signs. Arch Phys Med Rehabil. 2004 Dec. 85(12):2036-9. [Medline].

  32. Brown JA, Braun MA, Namey TC. Pyriformis syndrome in a 10-year-old boy as a complication of operation with the patient in the sitting position. Neurosurgery. 1988 Jul. 23(1):117-9. [Medline].

  33. Dalmau-Carolà J. Myofascial pain syndrome affecting the piriformis and the obturator internus muscle. Pain Pract. 2005 Dec. 5(4):361-3. [Medline].

  34. Durrani Z, Winnie AP. Piriformis muscle syndrome: an underdiagnosed cause of sciatica. J Pain Symptom Manage. 1991 Aug. 6(6):374-9. [Medline].

  35. Freidberg AH. Sciatic pain and its relief by operation on muscle and fascia. Arch Surg. 1937. 34:337-49.

  36. Frymoyer JW. Back pain and sciatica. N Engl J Med. 1988 Feb 4. 318(5):291-300. [Medline].

  37. Halpin RJ, Ganju A. Piriformis syndrome: a real pain in the buttock?. Neurosurgery. 2009 Oct. 65(4 Suppl):A197-202. [Medline].

  38. Hopayian K, Song F, Riera R, Sambandan S. The clinical features of the piriformis syndrome: a systematic review. Eur Spine J. 2010 Dec. 19(12):2095-109. [Medline]. [Full Text].

  39. Kanakis DN, Lazaris AC, Papadopoulos EC, Kallitsis EA, Patsouris ES, Paraskevakou HA. Piriformis syndrome--an attempt to understand its pathology. Clin Neuropathol. 2010 Mar-Apr. 29(2):65-70. [Medline].

  40. Karl RD Jr, Yedinak MA, Hartshorne MF, et al. Scintigraphic appearance of the piriformis muscle syndrome. Clin Nucl Med. 1985 May. 10(5):361-3. [Medline].

  41. Kulcu DG, Naderi S. Differential diagnosis of intraspinal and extraspinal non-discogenic sciatica. J Clin Neurosci. 2008 Nov. 15(11):1246-52. [Medline].

  42. Noftal F. The piriformis syndrome. Can J Surg. 1988 Jul. 31(4):210. [Medline].

  43. Pace JB, Nagle D. Piriform syndrome. West J Med. 1976 Jun. 124(6):435-9. [Medline]. [Full Text].

  44. Papadopoulos EC, Khan SN. Piriformis syndrome and low back pain: a new classification and review of the literature. Orthop Clin North Am. 2004 Jan. 35(1):65-71. [Medline].

  45. Parziale JR, Hudgins TH, Fishman LM. The piriformis syndrome. Am J Orthop. 1996 Dec. 25(12):819-23. [Medline].

  46. Parziale JR, Hudgins TH, Fishman LM. The piriformis syndrome. Am J Orthop (Belle Mead NJ). 1996 Dec. 25(12):819-23. [Medline].

  47. Rask MR. Superior gluteal nerve entrapment syndrome. Muscle Nerve. 1980 Jul-Aug. 3(4):304-7. [Medline].

  48. Retzlaff EW, Berry AH, Haight AS, et al. The piriformis muscle syndrome. J Am Osteopath Assoc. 1974 Jun. 73(10):799-807. [Medline].

  49. Robinson D. Piriformis syndrome in relation to sciatic pain. Am J Surg. 1947. 73:355-8.

  50. Schiowitz S. Facilitated positional release. J Am Osteopath Assoc. 1990 Feb. 90(2):145-6, 151-5. [Medline].

  51. Steiner C, Staubs C, Ganon M, et al. Piriformis syndrome: pathogenesis, diagnosis, and treatment. J Am Osteopath Assoc. 1987 Apr. 87(4):318-23. [Medline].

  52. Stewart JD, Foye PM, Cole JL. Piriformis syndrome. Muscle Nerve. 2010 Mar. 41(3):428-9; author reply 429-30. [Medline].

  53. TePoorten BA. The piriformis muscle. J Am Osteopath Assoc. 1969 Oct. 69(2):150-60. [Medline].

  54. Thiele GH. Tonic spasm of the levator ani, coccygeus and piriformis muscles. Trans Am Proct Soc. 1936. 37:145-55.

  55. Tonley JC, Yun SM, Kochevar RJ, Dye JA, Farrokhi S, Powers CM. Treatment of an individual with piriformis syndrome focusing on hip muscle strengthening and movement reeducation: a case report. J Orthop Sports Phys Ther. 2010 Feb. 40(2):103-11. [Medline].

  56. Uchio Y, Nishikawa U, Ochi M, et al. Bilateral piriformis syndrome after total hip arthroplasty. Arch Orthop Trauma Surg. 1998. 117(3):177-9. [Medline].

  57. Yoshimoto M, Kawaguchi S, Takebayashi T, et al. Diagnostic features of sciatica without lumbar nerve root compression. J Spinal Disord Tech. 2009 Jul. 22(5):328-33. [Medline].

Nerve irritation in the herniated disk occurs at the root (sciatic radiculitis). In piriformis syndrome, the irritation extends to the full thickness of the nerve (sciatic neuritis).
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.