They are located laterally to the transverse processes between prevertebral muscles from the medial side and vertebral (m. scalenus, m. levator scapulae, m. splenius cervicis) from lateral side.
The splenius capitis is deep to sternocleidomastoideus at the mastoid process, and to the trapezius for its lower portion.
The broad-surfaced occipital region at the back of the skull provides a large attachment area for the splenius capitis muscles of the neck.
It is bounded in front by the scalenus medius and behind by splenius cervicis.