Clinical implications and embryological explanation for unilateral variation in formation of sciatic nerve in relation to piriformis muscle – A case report

During routine cadaver demonstration the cadaver has been observed with a variation in the course of the sciatic nerve in relation with the piriformis. It is necessary for the orthopedic surgeon to be aware of the variations of different structures that are located in and around the Hip joint and Sacro Iliac Joints which are treated in most common and frequent surgeries. Anatomical variations in the formation and division of sciatic nerve shows clinical significance in piriformis syndrome, coccygodynia, sciatica. There is close relationship between piriformis and sciatic nerve. The piriformis may compress sciatic nerve and cause piriformis syndrome. Dorsal and ventral divisions of ventral rami of lower lumbar and sacral spinal nerves passed ventral (Tibial component) and dorsal (Common peroneal component) to piriformis muscle and fused below it in gluteal region to form sciatic nerve instead of fusing in pelvic cavity. The lower formation of sciatic nerve and its relations with piriformis muscle has clinical importance. Division of Right Sciatic nerve variation Division of Right Sciatic nerve variation