Which nerve innervates levator scapulae, with contributions from C3-C4?

Which nerve innervates levator scapulae, with contributions from C3-C4?

• A. Spinal accessory nerve
• B. Long thoracic nerve
• C. Dorsal scapular nerve (C5) with contributions from C3-C4
• D. Thoracodorsal nerve

Answer: (C)

Levator scapulae is mainly supplied by the dorsal scapular nerve, which comes from the C5 root and travels with the rhomboids to the muscle. In some people, small branches from the cervical plexus (C3–C4) also contribute fibers to this muscle, giving it the extra C3–C4 input. This combination—dorsal scapular nerve with possible C3–C4 contributions—explains why that option is the best choice for innervation. The other nerves listed are associated with different muscles: the spinal accessory nerve innervates trapezius (and sternocleidomastoid), the long thoracic nerve innervates serratus anterior, and the thoracodorsal nerve innervates latissimus dorsi.

Levator scapulae is mainly supplied by the dorsal scapular nerve, which comes from the C5 root and travels with the rhomboids to the muscle. In some people, small branches from the cervical plexus (C3–C4) also contribute fibers to this muscle, giving it the extra C3–C4 input. This combination—dorsal scapular nerve with possible C3–C4 contributions—explains why that option is the best choice for innervation. The other nerves listed are associated with different muscles: the spinal accessory nerve innervates trapezius (and sternocleidomastoid), the long thoracic nerve innervates serratus anterior, and the thoracodorsal nerve innervates latissimus dorsi.