Which nerves innervate the splenius cervicis?

• A. Dorsal rami of cervical nerves.
• B. Ventral rami of thoracic nerves.
• C. Dorsal rami of lumbar nerves.
• D. Spinal accessory nerve.

Answer: (B)

Splenius cervicis, a deep back muscle, is innervated by the dorsal rami of the spinal nerves in the cervical region. These dorsal rami carry motor fibers to the intrinsic back muscles and supply them from their posterior branches, typically from the middle cervical nerves (roughly C4–C8). The ventral rami of thoracic nerves supply anterior and lateral trunk muscles and intercostals, not the deep extensors of the neck. The dorsal rami of lumbar nerves serve the lower back, not the neck. The spinal accessory nerve innervates trapezius and sternocleidomastoid, not the splenius cervicis.