Anatomical variation in bifurcation and trifurcations of sciatic nerve and its clinical implications: in selected university in Ethiopia
The sciatic nerve is the thickest nerve in the body. It leaves the pelvis via the greater sciatic foramen below piriformis and descends between the greater trochanter and ischial tuberosity, along the back of the thigh, dividing into the tibial and common peroneal (fibular) nerves at a varying level proximal to the knee. The common peroneal (fibular) nerve divides at the level of the neck of the fibula in to superficial and deep peroneal nerves. During routine dissection for the first MBBS students, we observed an unusual trifurcation of the sciatic nerve on the back of both the thighs in the middle of the popliteal fossa of a 70 years old, donated embalmed male cadaver in the Department of Anatomy, K.J.Somaiya Medical college, Sion, Mumbai, India. The sciatic nerve terminates in the middle of the popliteal fossa in to the tibial, the superficial and the deep peroneal (fibular) nerves. The sural nerve was formed by the peroneal communicating branch of the deep peroneal nerve in the popliteal fossa, and descends on the posterior surface of the gastrocnemius to enter the superficial fascia about the middle of the back of the leg. It is then joined by the tibial communicating branch from the tibial nerve. The photographs of the trifurcation of the sciatic nerve were taken for proper documentation and for ready reference. The variation was bilateral. There were no associated arterial and muscular variations found in the same cadaver. Conclusion: The trifurcation of the sciatic nerve is very rare. The knowledge of trifurcation of sciatic nerve is important for clinicians and surgeons. Clinically, the sural nerve is widely used for both diagnostic (biopsy and nerve conduction velocity studies) and therapeutic purposes (nerve grafting). Thus, a detailed knowledge of the anatomy of the sural nerve and its contributing nerves are important in carrying out these and other procedures.