Muscle · Neck

Splenius cervicis

Musculus splenius cervicis

Splenius cervicis is the deeper, lower partner of splenius capitis. It runs from the spinous processes of the upper-middle thoracic spine upward and outward to the transverse processes of the top three neck vertebrae, so it acts on the neck rather than on the head. Both sides together extend the neck; one side alone turns and side-bends it toward the same side. It is buried under the trapezius, the rhomboids and splenius capitis for almost its whole length, so it is rarely identified on its own — but as a superficial extensor of the neck it shares the load that gets shifted onto this layer when the deep neck flexors are not doing their job.