An unusual case of trifurcation of the sciatic nerve

The sciatic nerve, as the largest branch of the sacral plexus, leaves the pelvis through the greater sciatic foramen beneath the piriform muscle. Afterwards, it divides into the tibial and the common peroneal nerves, most frequently at the level of the upper angle of the popliteal fossa. Higher level of the sciatic nerve division is a relatively frequent phenomenon. The tibial nerve gives muscular, genicular and sural branches, whereas the common peroneal nerve gives genicular, lateral cutaneous nerve of the calf and peroneal communicating nerve in the region of popliteal fossa. The sural nerve, peroneal communicating nerve and lateral cutaneous nerve of the calf receive sensations from the posterior and lateral aspects of the leg.