## Core Concept
The superior gluteal nerve innervates the **gluteus medius** and **gluteus minimus muscles**, which are crucial for hip abduction and maintaining the pelvis level during gait. Injury to this nerve leads to weakness of these muscles, resulting in a **Trendelenburg gait** (also known as a waddling gait) and a positive Trendelenburg sign.

## Why the Correct Answer is Right
The patient exhibits a waddling gait and a positive Trendelenburg sign due to the weakness of the gluteus medius and minimus muscles. The Trendelenburg sign is positive when the pelvis sags on the side opposite to the stance leg, indicating weakness of the hip abductors on the stance leg side. This clinical presentation directly correlates with the function of the muscles innervated by the superior gluteal nerve.

## Why Each Wrong Option is Incorrect
- **Option A:** This option does not directly relate to the expected physical findings associated with a superior gluteal nerve injury.
- **Option B:** This option might relate to other types of nerve injuries or muscle weaknesses but does not specifically align with the superior gluteal nerve injury symptoms.
- **Option C:** This option could potentially relate to various neurological or musculoskeletal conditions but does not specifically match the expected outcomes of a superior gluteal nerve injury.

## Clinical Pearl / High-Yield Fact
A key clinical correlation to remember is that a positive Trendelenburg sign and a waddling gait are highly suggestive of **gluteus medius and minimus weakness**, often due to superior gluteal nerve injury. This is a high-yield fact for orthopedic and neurology exams.

## Correct Answer Line
**Correct Answer: D.**

✓ Correct Answer: B. The left side of the pelvis droops or sags when he attempts to stand with his weight suppoed just by the right lower limb.