Variations of the sciatic nerve and its relation with the piriformis muscle in South Indian population

Objective: The sciatic nerve, a largest branch of the sacral plexus is prone to variations in its formation, course and branching pattern which may lead to multiple clinical complaints. The aim of the present study was to analyze the incidence of its variations in South Indian population. Methods: 60 gluteal regions were examined in 30 formalin fixed adult cadavers for the variations in the formation, termination of the sciatic nerve and its relationship with the piriformis muscle. Results: The sciatic nerve showed variations in its formation and as well as termination. High division of the sciatic nerve was the most commonly encountered variation (45%). The relationship of the sciatic nerve and its branches with the piriformis muscle was also variable. In majority of the cases (56.67%), the sciatic nerve and its branches were passing inferior to piriformis. Conclusion: Although the variations of the sciatic nerve are common and are already reported, the present study indicates some additional findings not reported previously and further stresses on its applied significance. These variations are important for surgeons, as this is an area of frequent surgical manipulation, nerve injury during deep intramuscular injections, sciatic nerve block etc. They may lead to in-advertent injury during operations, piriformis syndrome, non-discogenic sciatica, muscle atrophy, failure of sciatic nerve block and many other complications.