What innervates the splenius cervicis muscle?

The splenius cervicis muscle is primarily innervated by the lower cervical spinal nerves. This muscle, located in the posterior neck, is involved in movements such as extending, rotating, and laterally flexing the neck. The specific nerve roots involved in this innervation typically originate from the cervical spine, particularly from C5 to C7, which are classified as lower cervical nerves.

Understanding the anatomical positioning of the splenius cervicis muscle and the corresponding spinal nerves provides insight into its functional role in head and neck movements. The lower cervical spinal nerves are tasked with supplying motor function to this muscle, which explains why this answer is accurate. The proximity and contribution of these nerve roots to the muscle's function highlight their importance in neck movement and stability.