A CADAVERIC STUDY OF NORMAL AND VARIANT LEVELS OF DIVISION OF SCIATIC NERVE AND COUPLED ANOMALIES WITH CLINICAL APPLICATION IN SURGICAL INTERVENTIONS

Background: Sciatic nerve, the thickest and the largest nerve of the body, is formed in the pelvis. After passing through the greater sciatic foramen, it enters the gluteal region, and subsequently the nerve passes on the back of thigh to reach the superior angle of popliteal fossa where it bifurcates into tibial and common fibular nerves. It usually divides into its terminal branches outside the pelvis; however it may rarely divide within the pelvis. In such cases, the tibial nerve and the common fibular nerve may leave the pelvis through different routes. The knowledge of different routes of exits of the sciatic nerve is of utmost importance for the surgeons and the interventionists dealing with this region as this is the site of innumerable surgical manipulations as well as nerve injuries during deep intramuscular injections in gluteal region, failed sciatic nerve block in anaesthesia and injury during posterior hip surgeries. These variations may result in non-discogenic sciatica because of the nerve compressions under other adjacent anatomic structures. Purpose of the study: This study is an attempt to analyse the course, distribution and levels of the division of sciatic nerve into tibial nerve and common fibular nerve and their clinical implications. Results: Out of the total 120 lower limbs studied, deviation from the usual described pattern was observed in four limbs. One cadaver showed bilateral variation while other two described unilateral disparity from the standard prototype. Conclusion: This knowledge of variant anatomy of division and course of sciatic nerve and its terminal branches will not only assist surgeons to take care during interventions, but also facilitate to plan accordingly during various surgical procedures and management.