Give the origin and insertion of gluteus medius and its main actions.

• A. Origin: external surface of the ilium (between lines). Insertion: greater trochanter of the femur. Action: abducts the thigh and medially rotates; prevents pelvic drop during gait.
• B. Origin: anterior iliac crest. Insertion: IT band. Action: flexes hip.
• C. Origin: posterior ilium. Insertion: gluteal tuberosity. Action: extends thigh.
• D. Origin: inferior pubic ramus. Insertion: greater trochanter. Action: adducts thigh.

Answer: (A)

Understanding where gluteus medius attaches helps explain what it does at the hip. It originates on the outer (lateral) surface of the ilium between the anterior and posterior gluteal lines and inserts on the lateral aspect of the greater trochanter of the femur. From this position, it abducts the thigh at the hip; the anterior fibers contribute to medial rotation, the posterior fibers to lateral rotation, and, importantly, it stabilizes the pelvis during walking by preventing pelvic drop.

The description you have matches this pattern. Other options describe different muscles: one corresponds to the tensor fasciae latae, which originates on the anterior iliac crest and inserts into the IT band and mainly flexes the hip; another describes the gluteus maximus, which originates on the posterior ilium and inserts on the gluteal tuberosity and extends the thigh; another refers to an adductor muscle originating from the inferior pubic ramus and inserting near the greater trochanter to adduct the thigh.