Guys I'm having difficulty understanding what that line is. It appears to come from the corner of the iliac crest and goes behind some muscle... what I think is the vastus lateralis?

But I don't see how it's possible because from the corner pulls the rectus femoris but I don't see that... And I don't see how the tensor of the fascia latia, which pulls from the same corner and goes over the vastus lateralis, fits in either.

And how do all the gluteus muscles work when the leg is bent? In female models I see a huge pulling from that area round to through the side and to the back of the rib-cage but I can't place it on any anatomical fact other than the external oblique... but it can't be because it pulls from lower... as if it were pulling from deep inside the femur.