Question

The gluteus medius muscle is supplied by which nerve?

• A. Superior gluteal nerve
• B. Inferior gluteal nerve
• C. Nerve to obturator internus
• D. Nerve to quadratus femoris

Hint:

The nerve above piriformis that also causes a Trendelenburg sign when injured.

Answer 1

The Correct Option is A

Step 1: Recall the gluteal nerve supply. The superior gluteal nerve (L4, L5, S1) leaves the pelvis above the piriformis through the greater sciatic foramen. The inferior gluteal nerve (L5, S1, S2) leaves below the piriformis.

Step 2: Match nerve to muscle. The superior gluteal nerve supplies the gluteus medius, gluteus minimus and tensor fasciae latae. The inferior gluteal nerve supplies only the gluteus maximus.

Step 3: So the gluteus medius is supplied by the superior gluteal nerve. Damage to this nerve weakens hip abduction and causes a positive Trendelenburg sign, where the pelvis drops on the unsupported side during walking.

Step 4: Exclude the rest. The inferior gluteal nerve supplies gluteus maximus, the nerve to obturator internus and the nerve to quadratus femoris supply those small lateral rotators, none of which is the gluteus medius.

Step 5 (second part of the original question): The arterial supply of the gluteus medius is from the superior gluteal artery, which accompanies the superior gluteal nerve above the piriformis, not the inferior gluteal, obturator or any ilioinguinal vessel.

The answer is A. Superior gluteal nerve.