Anatomical structure and topographic anatomy of sciatic nerve in human fetuses

Abstract

IntroductionSciatic nerve is the longest and thickest nerve of the human body which divides into two branches in popliteal fossa. Variations of sciatic nerve can be observed during the course of the nerve. These anatomical variations contribute to some clinical manifestations such as piriformis syndrome, sciatalgia. MethodsThis study was conducted on 60 aborted fetuses aged between 9 and 40 gestational weeks and with no gross anomalies. Morphometrical measurements related to the nerve and the neighboring structures were performed and also incidence of anatomical variations was determined. ResultsAll parametric data were seen increased with gestational age (p<0.05). Also, no statistical differences between the parameters from right and left were found (p>0.05). The sciatic nerve division was observed in 99 (82.5%) lower extremities in the popliteal fossa, 19 (15.83%) at a level above the popliteal fossa, and in 2 lower extremities (1.67%), high division was observed. Also, the status of sciatic nerve was assessed in regard to piriformis muscle. In 118 of the lower extremities (98.3%), sciatic nerve was observed leaving from underneath the piriformis muscle as one piece and the remaining 2 (1.67%) were observed as giving division at higher levels. In one of these lower extremities of the right side, tibial nerve branch was observed following a path under piriformis muscle and common peroneal nerve was observed passing through the piriformis nerve. DiscussionWe believe that our study will provide data regarding the development of sciatic nerve in fetal period and that data will contribute to related clinical studies and applications.