Part of the With What family

Splenius cervicis

The lower half of the splenius pair, attaching to the neck vertebrae rather than the skull.

Type
Muscle
Region
Neck
Standard name
m. splenius colli
Origin
Spinous processes of the third to sixth thoracic vertebrae
Insertion
Posterior tubercles of the transverse processes of the upper two or three cervical vertebrae
Actions
neck extensionneck rotationneck sidebending
Verify
TA2 2274 TA98 A04.3.02.104

What it is

A narrow muscle running upward and outward from the upper thoracic spine to the transverse processes of the top cervical vertebrae, lying alongside and below splenius capitis with the same fibre direction.

The distinction between the two is where they end: capitis reaches the skull, cervicis stops at the neck vertebrae.

What it does

The same actions as splenius capitis — extension of the neck with both sides, rotation and side-bending towards its own side with one — but applied to the cervical spine rather than to the head on top of it.

What loads it

Holding the head and neck up, and resisted neck extension and rotation.

What is commonly got wrong about it

That it is separable from splenius capitis in practice. They share a fibre direction and are loaded together in every neck movement.

That neck muscles need dedicated training. They work continuously supporting the head. There are contexts where dedicated neck training is reasonable — contact sport among them — but it is not a general requirement.