Damage to which of the following will cause a positive Trendelenburg sign?
**Core Concept**
The Trendelenburg sign is a clinical test used to assess the integrity of the hip abductors, particularly the **gluteus medius** and **gluteus minimus** muscles. Damage to these muscles or their innervation can lead to a positive Trendelenburg sign. The **superior gluteal nerve** is responsible for innervating these muscles.
**Why the Correct Answer is Right**
A positive Trendelenburg sign is characterized by a pelvis that tilts downwards on the side of the standing leg, indicating weakness of the hip abductors on that side. This occurs when the **gluteus medius** and **gluteus minimus** muscles are weakened or damaged, causing the pelvis to sag on the contralateral side. The **superior gluteal nerve** plays a crucial role in this process.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not directly relate to the hip abductors or their innervation.
**Option B:** This option is also incorrect as it is not directly involved in the Trendelenburg sign.
**Option C:** This option is incorrect because, although it is related to the hip, it is not the primary structure responsible for the Trendelenburg sign.
**Why Each Wrong Option is Incorrect (Continued)**
**Option D:** This option is incorrect because it is not directly related to the hip abductors or their function.
**Clinical Pearl / High-Yield Fact**
The Trendelenburg sign is an important clinical test for assessing hip abductor function and can be used to diagnose conditions such as **gluteus medius** tears or **superior gluteal nerve** damage. A positive sign can also indicate **lumbar disc herniation** or **piriformis syndrome**.
**Correct Answer:** Correct Answer: D. Gluteus medius.