Report of a Novel Bilateral Variation of Sciatic and Inferior Gluteal Nerve

Sciatic nerve is the thickest nerve of the sacral plexus, which innervates many muscles and vast areas of the skin of the lower limb. It leaves the pelvis via the greater sciatic foramen, emerges into the gluteal region by passing under the piriformis muscle, and descends beneath the gluteus maximus to divide into its terminal branches: tibial and common peroneal nerve at the superior angle of the popliteal fossa. In some cases, the sciatic nerve divides into the tibial and common peroneal nerve at a higher level, and one of them or both passes through or over the piriformis muscle. In conditions such as intramuscular injection, gluteal surgery, and piriformis syndrome, such variations may increase the risk of injury, and the medical team should be aware of them. In this paper, by reporting many variations in a cadaver, we emphasize the importance of anatomical variations, especially for surgeons and nurses.