Nerve supply of rhomboides major
**Core Concept**
The rhomboid major muscle is a deep muscle of the back that plays a crucial role in scapular rotation and movement. The nerve supply of this muscle is essential for understanding the motor control and function of the scapular region.
**Why the Correct Answer is Right**
The rhomboid major muscle receives its nerve supply from the dorsal scapular nerve, which is a branch of the brachial plexus. The dorsal scapular nerve arises from the C5 root of the brachial plexus and innervates the rhomboid major and minor muscles, as well as the levator scapulae muscle. This nerve supply allows for coordinated movement of the scapula and is essential for activities such as rowing and lifting.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the rhomboid major muscle does not receive its nerve supply from the long thoracic nerve, which is responsible for innervating the serratus anterior muscle.
**Option B:** This option is incorrect because the nerve supply to the trapezius muscle is primarily from the spinal accessory nerve (cranial nerve XI), not the dorsal scapular nerve.
**Option C:** This option is incorrect because the rhomboid major muscle does not receive its nerve supply from the suprascapular nerve, which primarily innervates the supraspinatus and infraspinatus muscles.
**Clinical Pearl / High-Yield Fact**
The dorsal scapular nerve can be compressed or injured, leading to weakness and atrophy of the rhomboid major and minor muscles, as well as the levator scapulae muscle. This can result in scapular winging and decreased scapular stability.
**Correct Answer: D. Dorsal scapular nerve.**