Okay, let's tackle this question about the dorsal scapular nerve. The question is asking which muscles are supplied by this nerve and which one is not. First, I need to recall what the dorsal scapular nerve innervates.

The dorsal scapular nerve, also known as the nerve to the rhomboids, arises from the brachial plexus, specifically from the C5 root. Its main function is to supply the rhomboid major and minor muscles. These muscles are responsible for retracting the scapula. Wait, but there's another muscle sometimes associated with this nerve—could it be the levator scapulae? No, wait, the levator scapulae is innervated by the dorsal scapular nerve as well. Let me confirm that. Yes, the dorsal scapular nerve does supply the rhomboids and the levator scapulae. So, any muscle not listed here would be the exception.

Looking at the options, the question is missing the specific muscles listed as A, B, C, D. But from standard questions, the typical distractors might include the serratus anterior, which is actually supplied by the long thoracic nerve. The trapezius is innervated by the spinal accessory nerve (Cranial nerve XI). So, if the options include trapezius or serratus anterior, those would be the exceptions. Alternatively, the levator scapulae is correct, so if an option includes a different muscle like the pectoralis minor, that's not supplied by the dorsal scapular nerve. But since the question is about the exception, the correct answer would be the muscle not listed among the rhomboids and levator scapulae.

Wait, let me structure this. The core concept is the innervation of the muscles around the scapula. The dorsal scapular nerve supplies the rhomboid major, rhomboid minor, and levator scapulae. So if the options include, say, trapezius or serratus anterior, those are not supplied by this nerve. Therefore, the correct answer would be the option that lists one of those muscles. The clinical pearl here is to remember that the long thoracic nerve supplies the serratus anterior, and the spinal accessory nerve supplies the trapezius. The dorsal scapular nerve is C5, so any muscle not in its distribution is the exception.

**Core Concept**
The dorsal scapular nerve (C5) innervates the rhomboid major, rhomboid minor, and levator scapulae muscles. These muscles stabilize and retract the scapula. Knowledge of brachial plexus anatomy and scapular muscle innervation is critical for diagnosing neurological deficits.

**Why the Correct Answer is Right**
The dorsal scapular nerve arises from the C5 root of the brachial plexus. It supplies the rhomboid major, rhomboid minor, and levator scapulae. These muscles are responsible for scapular retraction (pulling the scapula toward the spine) and elevation (levator scapulae). Any muscle not among these three is **not** supplied by the dorsal scapular nerve. For example, the **trapezius** (innervated by cranial nerve XI) and

✓ Correct Answer: C. Supraspinatus