The splenius cervicis (also known as splenius colli, Latin: musculus splenius cervicis) is a deep muscle of the back, which is located in the back of the neck.
The splenius cervicis originates from the spinous processes of the third to sixth thoracic vertebrae (T3 - T6).
The fibers of the splenius cervicis insert into the transverse process of the atlas (C1), the tip of the transverse process of the axis (C2), and into the posterior tubercle of the third cervical vertebra (C3).
The actions provided by the splenius cervicis are rotation and lateral flexion of the head when acting unilaterally. It extends the head when acting on both sides or bilaterally.
The splenius cervicis is innervated by the lateral branches of the posterior branches (dorsal rami) of the lower cervical spinal nerves that arise from cervical plexus.