A double belly composition of piriformis muscle with superior gluteal nerve entrapment between the two muscle masses was detected. Piriformis muscle and its relation to sciatic nerve has been suggested as a cause of piriformis syndrome. Patients suffering from buttock pain are most often diagnosed as having piriformis syndrome, where anatomical variation of the piriformis is an important contributor. The present variation showed two distinct bellies of piriformis muscle. Interestingly the superior gluteal nerve was interposed between the two bellies. Such incidental findings on cadavers may help the clinicians to establish a rare yet important cause of piriformis syndrome. Furthermore, such observations are also relevant to the radiologists while interpreting MRI scans in cases of undiagnosed chronic gluteal pain.
