Double gluteus maximus muscle with associated variations in the gluteal region.

We report bilateral muscular and neurovascular anomalies of the gluteal region in a cadaver. On the right side, the gluteus maximus muscle had two parts, one of which was fibrous and the other muscular. In addition, there were duplicated piriformis muscles and high division of the sciatic nerve. The common peroneal nerve passed between the two parts of the piriformis muscle, and the tibial nerve emerged from under the lower piriformis muscle (infrapiriform foramen). At the same time the internal pudendal vessels and pudendal nerve passed over the sacrotuberous ligament on the left side. The double piriformis muscles and high division of the nerve are known as an anomaly which is believed to cause a nerve compression syndrome called the syndrome of the piriformis muscle. To the best of our knowledge anomalies of the gluteus maximus muscle and pudendal structures have not yet been reported. This complex anomaly should be kept in mind in connection with intramuscular injections of the gluteal region, the piriformis syndrome, and the surgery of this region.