Head & NeckSource-checked

Splenius capitis

Pronunciation: SPLEN-ee-us kuh-PIT-iss

Simplified front and lateral view of the neck showing the sternocleidomastoid on the sides, the scalenes deeper within, and the upper trapezius connecting the neck to the shoulders. The cervical vertebrae are shown as a central axis. — Head & neck — sternocleidomastoid, scalenes, splenius, and upper trapezius (simplified). A beginner-level schematic of the neck's primary muscles: sternocleidomastoid, scalenes, splenius capitis, and upper trapezius.
Illustration: Anatomy Learning Platform (original) · CC0-1.0 (public domain dedication)

For beginners

This muscle on the back of your neck extends your head backward (like tilting your chin up) and helps rotate your head. It's one of the main muscles that holds your head upright.

Show the advanced explanation

The splenius capitis is a short, powerful extensor that works in concert with the upper trapezius to support the head. A weak or inhibited splenius capitis (common in forward-head posture) leads to reliance on overactive upper trapezius and neck tension.

Structure & function

Location: A muscle on the back-upper side of the neck, running from the upper thoracic spine up to the base of the skull. It's one of the primary neck extensors.
Origin: Spinous processes of the thoracic vertebrae (T1–T4) and the ligamentum nuchae (a ligament that runs down the back of the neck).
Insertion: Mastoid process and superior nuchal line of the temporal bone (same insertion region as the upper trapezius).
Main action(s): Extends the head and neck (tilts the chin upward); rotates the head to the same side (right splenius capitis rotates the head right).
Joint(s) crossed: Cervical spine (cervical intervertebral joints and atlantoaxial joint)
Movement plane: sagittal (extension), transverse (rotation)
Innervation: Dorsal rami of cervical spinal nerves (C3–C4)
In daily movement: Holding the head upright, especially when looking upward (like when reading a high screen).
In exercise: Prime mover of neck extension; active during any posture-correcting movement that involves pulling the chin back.
Commonly confused with: Sometimes grouped with the 'upper trapezius' even though they are distinct muscles with different origins and actions.
Common misconceptions: The splenius capitis does NOT rotate the head to the opposite side — it rotates to the SAME side (unlike the SCM).

Exercises that use this muscle

As a secondary / stabilizer

Chin tuck and nod (secondary)
Gentle neck rotations (secondary)

⚠ Safety note

Overuse of the splenius capitis to compensate for weak deep cervical flexors can create chronic upper-neck tension and headaches. Balanced neck training (flexion and extension, not just extension) is key.

Sources

“The splenius capitis originates on the thoracic spine and ligamentum nuchae, inserts on the mastoid process, and extends and rotates the head.”

Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.6 Muscles of the Head, Neck, and Spine

Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19