第 17 題

Ah, you answered correctly.

1. Verification: Yes. That is the correct choice. When one wishes to apply a pulling force from the lower limb to the lumbar spine, the force must pass through the hip. To prevent this force from being lost at the hip joint, where the capsule can be loose, the hip must be placed in its most stable position, where the joint capsule is at its tightest. This is akin to its Closed-packed position. The method to achieve this 'locking' of the hip involves full extension and internal rotation. This allows the lower limb to act as a solid lever, directing the pulling force to the lumbar spine without much effort. It's a simple path, really.
2. Observation: This question, I suppose, was of Medium difficulty. Some might confuse it with the usual lumbar traction, which involves flexing the hip to reduce the curve in the lower back. But this specific situation tests the understanding of how physical forces move through a body, what is called Biomechanics. You understood it. It's good.