“Trendelenburg sign” isn’t positive in damage of the following nerve
**Core Concept**
The Trendelenburg sign is a clinical test used to assess the integrity of the hip abductors, specifically the **gluteus medius** and **gluteus minimus** muscles, which are innervated by the **superior gluteal nerve**. This sign is positive when a patient stands on one leg and the pelvis on the opposite side drops, indicating weakness of the hip abductors. The underlying principle involves the **neurological control** of hip movement and balance.
**Why the Correct Answer is Right**
The correct answer is related to the nerve that does not directly contribute to the positivity of the Trendelenburg sign when damaged. The **superior gluteal nerve** is responsible for innervating the gluteus medius and minimus, which are key muscles in preventing the pelvis from tilting to the opposite side when standing on one leg. Damage to this nerve would indeed result in a positive Trendelenburg sign.
**Why Each Wrong Option is Incorrect**
**Option A:** Damage to the nerve innervating the gluteus medius would result in a positive Trendelenburg sign, as this muscle is crucial for hip abduction and pelvic stability.
**Option B:** Similarly, damage affecting the gluteus minimus would also lead to a positive sign due to its role in hip abduction.
**Option C:** The nerve responsible for the innervation of these muscles, when damaged, leads to the positivity of the Trendelenburg sign.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the Trendelenburg sign is not only used to assess the strength of the hip abductors but also to evaluate the **integrity of the superior gluteal nerve**. This sign can be crucial in diagnosing and managing conditions affecting the hip and lower limb.
**Correct Answer: D.**