VARIATIONS OF SCIATIC NERVE BIFURCATION: A CADAVERIC STUDY

Background: The sciatic nerve is formed in the pelvic cavity and leaves the cavity through the greater sciatic foramen below the piriformis muscle. It terminates by giving tibial and common peroneal (fibular) nerve near the superior angle of the popliteal fossa. Awareness of variations in bifurcation of sciatic nerve is significant during deep intramuscular gluteal injections, clinical conditions such as piriformis syndrome, sciatica, coccygodynia and muscle atrophy. The main objective of this study was to highlight the site of bifurcation of sciatic nerve. Methods: An observational cross–sectional study was performed in the Department of Anatomy of KIST medical college & Teaching Hospital, Lalitpur, Nepal. The data was collected after ethical approval from Institutional Review Committee. 50 specimens were taken in the study by convenient sampling method. Sciatic nerve was observed in respect to its site of bifurcation. Results: Out of 50 lower limbs, in 30 specimens (60%) the sciatic nerve showed bifurcation near the superior angle of popliteal fossa. 20 lower limbs (40%) showed variations,of which eight limbs (16%) showed division of nerve prior to its exit in the gluteal region, eight limb (16%) showed division in upper 2/3rd of back of thigh and four limbs (8%) showed division of the nerve in the popliteal fossa. Conclusions: This study concludes that the majority of sciatic nerve divides at the superior angle of the popliteal fossa while some divided into other regions such as pelvis, thigh & popliteal fossa.