Which muscle is NOT attached to the greater trochanter?

The correct answer highlights that the rectus femoris muscle is not attached to the greater trochanter. The rectus femoris is part of the quadriceps muscle group and originates from the anterior inferior iliac spine and the acetabular rim of the pelvis. It primarily acts to extend the knee and flex the hip. Its origin is located in the front of the pelvis, well above the site of the greater trochanter of the femur.

In contrast, the piriformis, obturator internus, and obturator externus are all muscles that have their origins or insertions at or near the greater trochanter. The piriformis, for instance, originates from the anterior surface of the sacrum and inserts onto the greater trochanter, playing a vital role in lateral rotation and abduction of the hip. Similarly, both obturator internus and obturator externus are involved in the lateral rotation of the hip and also attach to the greater trochanter.

This differentiation in attachment points is crucial for understanding the functional anatomy of the hip and the muscular interactions that support movement.