Head & NeckSource-checked

Scalene muscles (anterior, middle, posterior)

Scalenus anterior, scalenus medius, scalenus posterior

Pronunciation: skay-LEEN

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

These are deep muscles on the sides of your neck. When they're tight (which is common), they can cause neck stiffness and shoulder tension. They also help you breathe harder during exercise.

Show the advanced explanation

The scalenes are among the most frequently painful and dysfunctional muscles in desk workers because they are constantly recruited for stability against forward-head posture. Tightness in the scalenes can compress the brachial plexus and subclavian vessels, a condition called 'thoracic outlet syndrome' — numbness/tingling into the arm.

Structure & function

Location: Three deep muscles on the sides of the neck, running from the cervical vertebrae down to the ribs. They are not easily visible but are frequently tight in desk workers.
Origin: Transverse processes of the cervical vertebrae (C2–C7).
Insertion: First and second ribs.
Main action(s): Together: assist in neck flexion and lateral flexion. The anterior and middle scalenes also elevate the ribs during breathing (inspiration), especially during heavy or strained breathing.
Joint(s) crossed: Cervical spine (cervical intervertebral joints)
Movement plane: sagittal (flexion), frontal (lateral flexion)
Innervation: Cervical spinal nerves (C3–C8)
In daily movement: Maintain neck posture during sitting and standing; assist in breathing, especially during exertion.
In exercise: Secondary flexors of the neck; prime movers of neck lateral flexion (tilting the ear toward the shoulder).
Commonly confused with: Often lumped together with the sternocleidomastoid, but they are separate, deeper muscles with a different origin and primary action.
Common misconceptions: The scalenes are not primarily for extending the neck — they flex and laterally flex; extension is the job of the posterior muscles.

Exercises that use this muscle

As a primary mover

Isometric neck flexion hold

As a secondary / stabilizer

Gentle neck rotations (secondary)

⚠ Safety note

Scalene tightness is a red flag for poor shoulder posture. Aggressive stretching of a tight scalene can occasionally trigger or worsen arm symptoms; mobility work should be gentle and monitored.

Sources

“The scalenes originate on the cervical vertebrae and insert on the ribs; they assist in neck flexion and lateral flexion, and elevate the ribs in breathing.”

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

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