The common peroneal nerve passing between two bellies of the piriformis: a case report and short review of the piriformis syndrome

ÜZEL M., TANYELİ M. E., AKKIN S. M., SOYLUOĞLU A. İ., KAHRAMAN YILDIRIM F. G.

Joint Meeting of Anatomical Societies, Bursa, Turkey, 19 - 22 May 2011, pp.164

  • Publication Type: Conference Paper / Full Text
  • City: Bursa
  • Country: Turkey
  • Page Numbers: pp.164
  • Istanbul University Affiliated: Yes

Abstract

The ischiadic nerve -or its components- passing between the bellies of the piriformis muscle can cause piriformis syndrome. There are many etiologies of the piriformis syndrome. It can be a result of trauma to the pelvis and buttock, leg length discrepancies, piriformis hypertrophy or myositis. The pain can be felt on the buttock region, and can radiate to the back of the thigh or lower back regions. The syndrome can be mistaken for a herniated disc, spinal stenosis, and trochanteric bursitis. There may be history of trauma, palpable mass in the gluteal region, gluteal atrophy, and pain. Although the diagnosis is mainly based on clinical findings, CT, electromyography, and MRI have been reported to have diagnostic value. Management of the syndrome includes physical therapy, ultrasound therapy, local injection therapy, and surgery.
In this paper we present case of a common peroneal nerve passing through the two bellies of a double piriformis muscle on the right side of a 67-year-old male cadaver during our routine dissections. The piriformis muscle had two distinct bellies which did not unite each other any point. The common peroneal nerve passed between those two bellies and did not unite to the tibial nerve to form the ischiadic nerve. The tibial nerve passed through the infrapiriform foramen as usual. Our case corresponds to Beaton and Anson type B variation of ischiadic nerve and piriformis muscle which can cause the piriformis syndrome.