The splenius cervicis lies deep to the splenius capitis, running from the mid-thoracic spinous processes to the upper cervical transverse processes. Its actions are identical to the splenius capitis but directed at the cervical vertebrae rather than the skull. Together the two splenius muscles form the primary movers of neck extension and ipsilateral rotation, working against the deep suboccipital muscles for fine head positioning.
| Origin | Spinous processes of T3 through T6 |
|---|---|
| Insertion | Posterior tubercles of the transverse processes of C1 through C3 |
| Nerve Supply | Posterior rami of the lower cervical spinal nerves |
| Blood Supply | Descending branch of the occipital artery |
| Actions | Extension of the neck; Ipsilateral rotation of the neck; Ipsilateral lateral flexion of the neck |
|---|
Acting unilaterally it rotates and laterally flexes the neck to the same side, and bilaterally it extends the cervical spine, making it important for maintaining upright head position during activities requiring sustained forward gaze.
Splenius cervicis trigger points refer pain to the top of the head and behind the eye in a pattern easily confused with tension headache or occipital neuralgia. Whiplash injuries predictably injure the splenius cervicis group alongside the semispinalis and multifidus, producing the diffuse posterior neck pain and stiffness of acute whiplash-associated disorder.
The splenius cervicis is palpable deep to the trapezius in the posterolateral neck, accessible with sustained deep pressure directed anteriorly between the trapezius and the cervical laminar column during resisted neck extension.
Acute tear from whiplash or sudden forceful neck movement producing posterolateral neck pain with restricted rotation, managed conservatively with active mobilisation and progressive rehabilitation.
