In a single-leg stance, weakness of the hip abductors causes a pelvic tilt to which side?

• A. Same side
• B. Both sides
• C. No tilt
• D. Opposite side

Answer: (D)

In a single-leg stance, the hip abductors of the stance leg (primarily gluteus medius and minimus) contract to keep the pelvis level in the frontal plane. If these muscles are weak, they can’t counteract gravity, causing the pelvis to drop on the side opposite the stance leg. This contralateral pelvic tilt is the classic presentation (often called a Trendelenburg sign). The tilt wouldn’t occur on the same side, nor on both sides or disappear, because the unsupported side loses stability due to the weak abductors.