Splenius capitis
Musculus splenius capitis
Also known as: splenius, splenius cervicis
A broad, bandage-like muscle of the back of the neck. It runs from the nuchal ligament and upper thoracic spines to the mastoid process, and it extends and rotates the head to the same side.
Overview
Splenius capitis (from splenion, a bandage) wraps obliquely around the deeper neck muscles. It arises from the lower half of the nuchal ligament and the spinous processes of C7–T3/T4 and runs upward and laterally to the mastoid process and the lateral third of the superior nuchal line, deep to SCM. Its companion, splenius cervicis, continues lower down (T3–T6 spines) to the transverse processes of C1–C3. Splenius forms part of the floor of the posterior triangle, where it lies between SCM and levator scapulae.
Acting together, the two sides extend the head and neck. Acting alone, one side laterally flexes the neck and rotates the face to the same side, working with the opposite SCM. Splenius belongs to the intrinsic (epaxial) back muscles and is therefore supplied by dorsal rami.
Anatomy
- Origin
Inferior half of the nuchal ligament and the spinous processes of C7–T3 (T4).
- Insertion
Mastoid process and the lateral third of the superior nuchal line.
- Action
Bilaterally: extends the head and neck. Unilaterally: laterally flexes the neck and rotates the face to the same side.
- Innervation
Dorsal rami of the middle cervical spinal nerves.
- Nerve roots
C2–C4 (dorsal rami)
- Arterial supply
Muscular branches of the occipital artery; transverse cervical artery.
- Relations
Covered by trapezius, SCM and the rhomboids (inferiorly). Covers the semispinalis capitis and the suboccipital region.
Function
- Extends the head and neck (bilaterally)
- Rotates the face to the same side and laterally flexes the neck (unilaterally)
Clinical significance
Whiplash
Sudden flexion–extension of the neck strains splenius and the other posterior neck muscles, causing neck pain and stiffness. Muscle spasm is a common source of cervicogenic headache.
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.