Fig. 1

In situ observations of the GM. Photographs of a representative in situ specimen (right posterior pelvic and thigh regions) are shown. (a) The superficial surface of the gluteus maximus (GM) and surrounding structures are visible. (b) The proximal origin of the GM was detached and laterally reversed, enabling us to confirm deep surface of the GM. Additionally, an in situ specimen in which all the muscles are located in the gluteal, posterior, and medial thigh regions were removed, except for the GM and part of the quadriceps femoris, is shown. (c) The deep surface of the GM is visible. (d) The medial aspect of the inferior portion of the GM (GM-I) and the lateral intermuscular septum (LFIS) can be observed. The red asterisk marks the distal tendon of the superior portion of the GM (GM-S). The yellow dotted lines (areas) in the posterior pelvic region and deep surface of the proximal end of the GM indicate the proximal attachment site of the GM-S, and both correspond to each other. The light-green dotted lines (areas) indicate the proximal attachment site of the GM-I. Black asterisk marks the proximal tendon located in the uppermost part of the deep surface of the GM. Black arrowheads indicate the attachment site of the GM-I to the LFIS. The magenta dotted lines trace the gluteal tuberosity and the lateral lip of the linea aspera, which are continuous. AM, adductor magnus; BFL, long head of the biceps femoris; BFS, short head of the biceps femoris; GA, gluteal aponeurosis; GM, gluteus maximus; GM-I, inferior portion of the GM; GME, gluteus medius; GM-S, superior portion of the GM; GRT, greater trochanter; IT, ischial tuberosity; ITT, iliotibial tract; LFIS, lateral femoral intermuscular septum; OI, obturator internus; P, piriformis; SM, semimembranosus; SN, sciatic nerve; ST, semitendinosus; STL, sacrotuberous ligament; VI, vastus intermedius.