Which muscle abducts the hip joint?

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

Answer: (D)

Abduction of the hip means moving the thigh away from the midline in the frontal plane. The gluteus medius sits on the outer surface of the pelvis and attaches to the greater trochanter, so when it contracts it pulls the femur laterally, producing hip abduction. It is the main muscle responsible for this action, with its different fibers also contributing to slight variations in rotation and in flexion/extension depending on the part activated.

The other muscles listed don’t fit as the primary abductors. The piriformis mainly acts as a lateral rotator of the hip and only assists with abduction when the hip is flexed. The gluteus maximus is chiefly an extender and external rotator of the hip, with only minor, auxiliary involvement in abduction. The tensor fasciae latae does help with abduction, but its primary roles are flexion and medial rotation, so the strongest and most consistent abducting action comes from the gluteus medius.