Abstract
Introduction: Sciatic nerve arises from lumbosacral plexus. It divides into tibial and common peroneal nerves from pelvis to popliteal region. The sciatic nerve usually exits from gluteal region below the piriformis muscle. Variations in course and level of division of sciatic nerve are well documented in the literature.
Aim: The aim of the study is to evaluate for variations in relationship between the piriformis muscle and sciatic nerve and also the variations in the level of division of sciatic nerve.
Materials and Methods: This study was done on 80 lower limbs of the 40 embalmed cadavers during routine anatomical dissections in the Department of Anatomy, Siddhartha Medical College, Vijayawada. Regions were dissected according to the guidelines and variations in sciatic nerve course and level of division were noted.
Results: In this study we noted that relationships between sciatic nerve and piriformis muscle are of type A in 82.50%, type B in 8.75%, type C in 5.0%, type D in 2.5% and rare type G in 1.25%. With regard to the level of the division of sciatic nerve these are of type I in 28.75%, type II in 8.75%, type III in 6.25%, type IV in 3.75% and type V in 52.5%.
Conclusion: The study establishes the variations in sciatic nerve relationship with piriformis muscle and its level of division in south Indian population. These are important to understand the variable symptoms in cases of sciatic nerve injury or compressions, complications during surgeries on gluteal region and also sciatic nerve block anesthesia.

Key words: Sciatic nerve, Tibial nerve, Common peroneal nerve, Piriformis muscle