A sciatic nerve with three roots and its perforation by the enlarged ischiadic artery

Abstract

Knowledge about the variations of the sciatic nerve (SN) is important for many medical science disciplines. Its compression, entrapment or injury of any kind can result in loss of sensation, pain or motor disabilities in the lower limbs. We observed concurrent neurovascular variations in the gluteal region of an adult female cadaver. The SN had three roots as it emerged out of the greater sciatic foramen. The upper root passed above the piriformis; the middle and lower roots passed below the piriformis. The three roots joined to form the SN in the gluteal region. The inferior gluteal artery (IGA) was large, and it passed below the piriformis, between the middle and lower root of the SN. After a tortuous course, this artery continued down as the sciatic/ischiadic artery. The ischiadic artery (IA) was large in size and pierced the SN in the thigh. After piercing the nerve, it terminated by dividing into muscular branches. The inferior gluteal nerve emerged out from the pelvis through the greater sciatic foramen, above the level of the piriformis. The SN in this case was highly predisposed to compression by the piriformis, IGA or IA, which in turn may lead to altered cutaneous sensation or weakness of the muscles.