Which action constitutes the Trendelenburg sign protocol?

Which action constitutes the Trendelenburg sign protocol?

• A. The patient lies supine and performs leg raises.
• B. The patient stands on one leg for several seconds while pelvic alignment is observed from behind.
• C. The patient walks on a treadmill while pelvic tilt is recorded.
• D. The patient stands on both legs and performs toe raises.

Answer: (B)

The action tests hip abductor strength during unilateral stance by watching whether the pelvis stays level when balancing on one leg. When the stance leg's gluteus medius/minimus are weak, they can’t hold the pelvis level, so the pelvis drops on the opposite side. Standing on one leg for several seconds and observing pelvic alignment from behind directly assesses that stabilization, which is why this is the correct protocol for the Trendelenburg sign. The other actions pair with different tests or assessments—lying on the back to raise a leg checks hip flexors, walking with pelvic tilt recording is a gait analysis, and two-leg toe raises assess plantarflexors and overall balance—not the single-leg pelvic stabilization this sign examines.

The action tests hip abductor strength during unilateral stance by watching whether the pelvis stays level when balancing on one leg. When the stance leg's gluteus medius/minimus are weak, they can’t hold the pelvis level, so the pelvis drops on the opposite side. Standing on one leg for several seconds and observing pelvic alignment from behind directly assesses that stabilization, which is why this is the correct protocol for the Trendelenburg sign. The other actions pair with different tests or assessments—lying on the back to raise a leg checks hip flexors, walking with pelvic tilt recording is a gait analysis, and two-leg toe raises assess plantarflexors and overall balance—not the single-leg pelvic stabilization this sign examines.