Pelvic drop during the swing phase of gait is most commonly due to weakness of which muscle group?

• A. Gluteus medius
• B. Iliopsoas
• C. Hamstrings
• D. Quadriceps

Answer: (A)

Pelvic stability during gait is controlled mainly by the hip abductors, especially the gluteus medius, on the stance leg. As you step and the body weight bears on one limb, the gluteus medius contracts to pull the pelvis level and prevent it from dropping to the opposite side. When this muscle is weak, the pelvis can no longer stay level, so it drops toward the swinging leg side during the stance phase, which is most noticeable in the part of the gait cycle where that leg is weight-bearing. The gluteus medius is the primary muscle responsible for this stabilization, making weakness here the most common cause of pelvic drop. The other muscles listed—iliopsoas, hamstrings, and quadriceps—are not the main stabilizers of the pelvis in the frontal plane during stance, so weakness in them would not typically produce this specific pelvic drop.