Bilateral Accessory Piriformis Variant and its Implications – A Case Report

Author(s): Bassam Ballout*, Braden Van Alfen, Yassine Ballout and Armando Rosales

The piriformis muscle is a major muscle of the gluteal region and can be a cause of sciatic pain known as piriformis syndrome. Routine dissection of a cadaver of unknown age presented with bilateral accessory piriformis muscles. The main piriformis muscle was noted bilaterally with a smaller, accessory muscle separate and distinct from the main piriformis muscles. These accessory muscles originated and attached at the same anatomical landmarks as the main piriformis. The tibial nerve exited from below both piriformis muscles and the common fibular nerve exited between the two muscle bellies. This presentation of accessory piriformis is unique and has seldom been presented in the literature. Anatomical accessory muscles such as this one has important clinical considerations including in surgery, radiology, and the diagnosis of sciatic pain caused by piriformis syndrome.

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