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Upper BackSource-checked

Trapezius

Trapezius

Pronunciation: truh-PEE-zee-us

Simplified back view showing the diamond-shaped trapezius over the upper back and neck, the rhomboids between the shoulder blades, and the broad latissimus dorsi fanning up from the lower back.
Upper back — trapezius, rhomboids, and latissimus dorsi (simplified). A beginner-level schematic of the major upper-back muscles: trapezius, rhomboids, and latissimus dorsi.
Illustration: Anatomy Learning Platform (original) · CC0-1.0 (public domain dedication)

For beginners

A big back-of-the-neck-and-shoulders muscle that moves your shoulder blades up, together, and down, and helps you reach overhead.

Show the advanced explanation

Its three functional regions form a force couple with the serratus anterior to upwardly rotate the scapula — essential for pain-free overhead motion.

Structure & function

Location
The large diamond-shaped muscle of the upper back and neck.
Origin
Base of the skull and spinous processes of the cervical and thoracic vertebrae.
Insertion
Clavicle, acromion, and spine of the scapula.
Main action(s)
Moves and stabilizes the scapula: upper fibers elevate, middle fibers retract, lower fibers depress; together they help upwardly rotate the scapula for overhead reaching.
Joint(s) crossed
Scapulothoracic and acromioclavicular articulations
Movement plane
multiple
Innervation
Accessory nerve (CN XI) and cervical nerves C3–C4
In daily movement
Shrugging, carrying loads, and positioning the shoulder blade for reaching.
In exercise
Key stabilizer/mover in rows, shrugs, and overhead work; supports posture under load.
Commonly confused with
Its upper fibers are often confused with the deltoid or the levator scapulae.
Common misconceptions
Not just the 'shrug muscle' at the top — its middle and lower fibers are vital for shoulder-blade control.

Exercises that use this muscle

As a primary mover

As a secondary / stabilizer

⚠ Safety note

Chronic upper-trap tension is common with stress and desk posture; balance with mid/lower-trap strengthening.

Sources

“The trapezius stabilizes and moves the scapula (elevation, retraction, depression, upward rotation).”

Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.5 Muscles of the Pectoral Girdle and Upper Limbs

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

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