The anatomical and functional relation between gluteus maximus and fascia lata

Summary

There is not full agreement regarding the distal insertions of the gluteus maximus muscle (GM), particularly the insertions into the iliotibial band and lateral intermuscular septum. 6 cadavers, 4 males and 2 females, mean age 69 yr, were dissected to evaluate the insertions of the GM into the iliotibial band, fascia lata, lateral intermuscular septum and femur. The iliotibial band is a reinforcement of the fascia lata and cannot be separated from it. Its inner side is in continuity with the lateral intermuscular septum, which divides the quadriceps from the hamstring. In all subjects the gluteus maximus presented a major insertion into the fascia lata, so large that the iliotibial tract could be considered a tendon of insertion of the gluteus maximus. The fascial insertion of the gluteus maximus muscle could explain the transmission of the forces from the thoracolumbar fascia to the knee.

Introduction

In the literature, GM is described as the largest muscle of the human body (Standring, 2008; Encyclopædia Britannica, 2011; Van de graff 2002) having various functions (Eizenberg et al., 2008). Some studies have identified GM as having the largest capacity for external rotation of the hip thanks to its insertion into the linea aspera of the femoral bone (Janecki, 1977; Preece et al., 2008). For Lieberman et al. (2006) fibers from the more cranial sites of origin primarily end in a thick laminar tendon that inserts on the iliotibial tract. The activity of the cranial portion is ‘considerable’ increases during jogging and running (Stern et al., 1980). Other studies have identified a role in hip flexion due to the insertion of the GM in the iliotibial tract (Sahrmann, 2002; Jonkers et al., 2003).

For Benninghoff (1994) the most important insertion of GM is the iliotibial band. Stern found that some fibers from deeper portions of the muscle insert onto the gluteal ridge of the femur, generally on the proximal 25% of the femur (Stern, 1972). If this is confirmed, the real function of GM has to be modified. Indeed the latest studies suggest the iliotibial band is just a reinforcement of the fascia lata (Stecco et al., 2008; Fairclough et al., 2006). Also for Terry et al. (1986) the iliotibial tract has to be considered together with the fascia lata, the lateral femoral intermuscular septum and the crural fascia as creating a combined musculo-ligamentous unit. Gerlach and Lierse (1990) also found that the lateral femoral intermuscular septum collaborates in the muscular force transmission to the bone.

It is evident that GM has various functions according to the fibers involved in the contraction. This previous Author report a complex function of the GM that are not possible to explain through the current anatomical description of its insertions.

The purpose of this study was to analyze the distal insertions of GM in embalmed cadavers to better understand how many fibers insert into the fascia lata, iliotibial tract and lateral intermuscular septum and ultimately understand if GM could be considered also a fascial tensor. This hypothesis is supported by Lieberman et al. (2006) who described that fibers from the more cranial sites of origin primarily end in a thick laminar tendon that inserts on the iliotibial tract.