Study of Variations in the Divisions, Course and Termination of the Sciatic Nerve

Background: The sciatic nerve is the large stand thickest branch of lumbosacral plexus. It has a long course in the pelvic cavity and in the lower extremity. It separates into its two branches, the tibial and common peroneal nerves outside the pelvis. But the division can occur at any level from the sacral plexus to the inferior part of the popliteal fossa. These anatomical variations in division may cause nerve compression resulting in sciatica, piriformis syndrome, and coccygodynia. Aim: The aim of this study is to observe the variations in division of sciatic nerve as compared to known facts. Methods: The study was performed on cadavers. The inferior extremities of 45 cadavers were examined and variations of division of sciatic nerve were noted and classified. Results: The highest incidence of sciatic nerve variation was observed in its termination. In 11.11% of cases the sciatic nerve was found to be divided in the gluteal region. In 11.11%specimens, the common peroneal nerve pierced the piriformis muscle. Conclusion: The higher division of sciatic nerve can result in the involvement of only one out of the two divisions for the sciatic neuropathy. It is important to consider the higher divisions while performing opliteal block anaesthesia.