Anatomy of sciatic nerve bifurcation in popliteal fossa: a fetal study

Abstract

Background: We studied the bifurcation of sciatic nerve into two components which change their position throughout the early period of life. We proposed dimensions that would help reducing failure rates of anesthesia in popliteal fossa region and screening of malignancy related to sciatic nerve. Methods: The back of thigh and popliteal fossa of both sides of 50 fetuses (24 male and 26 female) were dissected. Skin over the gluteal region was dissected upto back of the knee. Sciatic nerve was traced from gluteal region to back of the thigh. The level where common fibular nerve and tibial nerve diverge from sciatic nerve and the diameter of sciatic nerve at various levels were evaluated. Results: In 97.7% (41/42) specimens,the bifurcation was above (5.1-20.86 mm) and in 2.3% (1/42) specimens, it was below (2.37 mm) the lateral condyle of femur. In 66% cases, sciatic nerve splits into two at or within 11 mm proximal to lateral condyle, while in 75% cases within 13mm, and in 100% cases within 21mm proximal to lateral condyle. Conclusion: This study provides quantitative data about the sciatic nerve in the gluteal region and back of the thigh. This data has a significant implication in diagnostic and anesthetic practice.

Keywords

sciatic nerve - bifurcation - diameter - fetus - popliteal fossa