The splenius capitis muscle is a large, flat muscle located in the posterior (back) region of the neck. It originates at the spinous processes of the upper thoracic and lower cervical vertebrae, and inserts into the superior nuchal line and the mastoid process of the temporal bone. The splenius capitis muscle is one of the muscles that make up the posterior neck muscles, and is located deep to the trapezius muscle.

The main function of the splenius capitis muscle is to extend the head and neck at the upper cervical vertebral joints. This movement is essential for activities such as looking upwards and turning the head to the side, and helps to provide stability and support for the head and neck. The splenius capitis muscle also helps to rotate the head and neck, and assist in lateral flexion (bending to the side) of the neck.

Receives signals from two points: