Variations in Course and Branching of Sciatic Nerve and it’s Relation to Pyriformis Syndrome

Abstract

Background: Sciatic nerve is a branch of sacral plexus. It passes below the pyriformis and divides in the popliteal fossa. Higher division and relation of sciatic nerve to pyriformis have been documented. Beaton and Anson have classified relation of sciatic nerve to pyriformis. The aim of this study is to find incidence of variant anatomy of sciatic nerve as per Beaton and Anson classification. Materials and methods: 48 formalin embalmed lower limbs used for regular anatomy teaching were used. Branching and course of sciatic nerve was observed in gluteal region,thigh and popliteal fossa. Observations: As per Beaton and Anson classification, we found 81.2% showed type A or normal arrangement. Type B variation was seen in 14.6% while 4.2% showed type D variation. Conclusion: Variations in branching of sciatic nerve and it’s relation to pyriformis muscle are important from point of view of Surgeons and Anaesthetists. Knowledge of these variations will help reducing block failures in cases of sciatica, pyriformis syndrome and hip replacement surgeries. KEY WORDS: Sciatic nerve, Sacral plexus, Pyriformis Syndrome, Hip replacement.