What is the primary function of the splenius capitis muscle?

The primary function of the splenius capitis muscle is to facilitate both extension and rotation of the neck. This muscle is located at the back of the neck, and its fibers run obliquely toward the higher parts of the vertebrae. When the splenius capitis contracts, it allows for the head to be tilted backward (extension) and also enables the rotation of the head to the same side as the muscle that is contracting.

This dual functionality is crucial for many movements associated with head and neck positioning, such as looking upwards and turning the head towards the shoulder. Understanding the actions of these muscles is important when considering neck mobility and overall spinal health.

The other options highlight movements that do not primarily involve this specific muscle. Lateral flexion of the spine and flexion of the cervical spine involve different muscle groups, while stabilization of the head is more about maintaining posture rather than the active movements the splenius capitis supports.