Anatomical Variations in the Division and Innervation of the Sciatic Nerve with its Clinical Consequences

Abstract

Introduction: Commonly encountered peripheral nerve in emergency, trauma, routine surgical medical practice and neurology is Sciatic Nerve (SN). Its vulnerability to injury is because of its thickness and long course. Its vast clinical involvement warrants a more definitive study. So the study was planned with the following aims and objectives. Aim: To study the anatomical variations in the division and innervation of the sciatic nerve and to correlate these variations with the clinical consequences of the nerve. Materials and Methods: This study was carried out on 30 lower limbs of human cadavers of Indian origin. The sciatic nerves of these cadavers were dissected, photographed, observed, analysed and interpreted in the Department of Anatomy. Results: It was found that in 43% of cases division of sciatic nerve was just below the lower border of piriformis, in 36%, between the piriformis and the mid of the thigh, in 14% near the mid of the thigh, in 7%, between midway of thigh and joint line of the knee and not even in a single case, the division was found to be, in the pelvis and below the knee joint line. Conclusion: Most common site of exit and bifurcation of SN were found to be just below the piriformis which is in contradiction to the earlier reports which state apex of the popliteal fossa to be the most common site of SN bifurcation. So we emphasize that this fact should also be there in the mind of concerned surgeons, orthopedicians, anaesthesiologists and neurophysicians while dealing with and planning for the pathologies involving SN, not only for better diagnosis and treatment but also for avoidance of iatrogenic complications.

Keywords

• injury
• neuropathy
• peripheral nerve
• piriformis
• sciatica
• surgery