A rare case of bilateral supra‐piriformis pelvic exit of the common fibular nerve and its clinical relevance

Abstract

Bilateral supra‐piriformis pelvic exit of the common fibular nerve (CFN) was observed during dissection of the pelvis and gluteal region. The donor was a 70‐year old Caucasian female who died of coronary vascular disease. The sciatic nerve (SN) is an integrated lumbosacral plexus of nerves that exits the pelvis through the greater sciatic foramen inferior to the piriformis muscle and later divides into the tibial nerve (TN) and CFN. In the present case, the right and left CPN exited the pelvis superior to the piriformis muscle while the TN exited inferior to the muscle. Further pelvic dissection showed that TN and CFN followed an independent course and did not unite to form the SN prior to pelvic exit. The TN exited inferior to piriformis and descended in the middle of the thigh whereas the CFN pursued a lateral course through the gluteal region, posterior thigh and popliteal fossa. Variations in the pelvic exit of the TN, CFN and the SN have been observed and classified. Knowledge of the potential alterations in the course of the sciatic, TN and/or the CFN are of clinical importance when performing such procedures as hip arthroplasty, piriformis tendon release for treatment of piriformis syndrome or, sciatic anesthesia in the popliteal fossa for foot and ankle surgery. This poster will depict a number of actual images of the variation and its’ classification based on previously established classification systems.Support or Funding InformationThis study was supported by the Department of Biomedical Sciences.