The traps
Trapezius · musculus trapezius
A large diamond-shaped muscle across your upper back and neck that shrugs and steadies the shoulders.
What it does
The trapezius spreads from the base of the skull down the spine to the middle back, and out to the collarbone and shoulder blade. Its upper fibres shrug the shoulders, its middle fibres pull the shoulder blades together and its lower fibres draw them down.
Surprising fact
The left and right trapezius together form a trapezium shape, which is how the muscle got its name.
Why it matters
Stress and long desk sessions keep the upper trapezius tense, which is why that is where people carry knots and why a shoulder rub feels so good.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.