Duplication of the gemellus superior and misplacement of gemelli - obturator internus complex

Introduction Normally, the gemelli muscles are distinguished as attaching along the tendon of the obturator internus (OI) and collectively inserting onto the greater trochanter of the femur [1]. The usual origin of the gemellus superior (GS) lies on the external aspect of the ischial spine with the gemellus inferior (GI) originating from the superior surface of the ischial tuberosity [1, 2]. The OI is commonly noted originating from the medial aspect of the obturator membrane and surrounding bone [1, 2]. Lateral rotation of the hip joint and abduction of the femur are the primary actions of the gemelli and OI muscles. The OI also composes the anterolateral wall of the pelvic cavity and lateral wall of the ischio-anal fossa [1]. Prior publications have demonstrated variation of GS and GI muscles by identifying a doubled appearance or absence [2]. Fusion has also been noted between the GS with the piriformis or gluteus minimus and the GI with the quadratus femoris [3]. Minimal variations of the OI have been found, which include complete absence or division into two parts [3]. This paper describes the bilateral presence of the GS doubled with the superior GS in the correct location and the duplicated inferior GS in an improper location. The duplicated GS muscle along with the OI and GI were found lying on the superior surface of the quadratus femoris. This report describes previously unreported variations, which include bilateral improper origins and insertions of the GS, OI, and GI.