Which muscle originates from the outer surface of the ilium and inserts into the iliotibial band and posterior femur?

• A. Gluteus Medius
• B. Gluteus Minimus
• C. Gluteus Maximus
• D. Tensor Fasciae Latae

Answer: (C)

The muscle described is the gluteus maximus. It originates from the outer surface of the ilium (the posterior part of the pelvic bone) and also from the sacrum and coccyx, and it inserts into the iliotibial band (tract) as well as the gluteal tuberosity on the posterior surface of the femur. This combination—origin on the ilium and insertion into both the iliotibial band and the posterior femur—is unique to gluteus maximus.

Functionally, this muscle is a powerful hip extensor and external rotator, and it helps stabilize the pelvis during activities like standing up, climbing, and walking. The involvement with the iliotibial band also helps transmit force down the leg for knee stabilization.

In contrast, the other muscles originate from the outer ilium but insert primarily on the greater trochanter (and not into the posterior femur). Tensor fasciae latae inserts into the iliotibial band as well but doesn’t attach to the posterior femur. So the only muscle that fits both parts of the description is the gluteus maximus.