Abstract

ackground and Aims: The Sciatic nerve is the largest nerve in the body. It originates from    the Sacral plexus. The nerve exits the pelvis by passing through the greater sciatic foramen,  usually below the piriformis muscle. Its terminal division into Common Peroneal nerve and  Tibial nerve may however occur at different levels. The purpose of this study is to identify variation of bifurcation of Sciatic nerve and its relation to piriformis muscle which may lead to various clinical manifestations.Material and Methods: Ten formalin fixed cadavers, comprising of twenty lower lim bs and ten specimens of lower limbs with intact gluteal and thigh regions were used for this study.  Gluteal region and posterior compartment of the thigh were dissected. The sciatic nerve was exposed and bifurcation level of sciatic nerve and its relations were noted and photographed. Results: In 53.33% cases sciatic nerve divided near upper angle of popliteal fossa. 26.66%  showed sciatic nerve division in middle of posterior thigh, while division of the sciatic nerve  at upper one third of posterior thigh was seen in 13.33%. Only in 6.66% the common peronealnerve passed through piriformis muscle and the tibial nerve passed below the piriformis muscle. Conclusion: The anatomical variations of sciatic nerve can lead to piriformissyndrome, coccydynia, sciatica and muscle atrophy. A good knowledge about these variations are  necessary for surgeons and clinicians to avoid surgical complications, prevent failure of sciatic block and prevent sciatic nerve injury during deep intramuscular injections.

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