trapezius

noun

tra·​pe·​zi·​us trə-ˈpē-zē-əs 

tra-

plural trapezii trə-ˈpē-zē-ˌī 

tra-

also trapeziuses

: a large flat triangular superficial muscle of each side of the upper back

Examples of trapezius in a Sentence

Recent Examples on the Web

And your lower trapezius muscles weaken and strain against the upward pull, leading to backaches and pain around the scapulae. —Dana Santas, CNN Money, 2 Oct. 2025

To be a real man, according to this content, young adolescent boys are expected to be tall and broad-shouldered with bulging biceps, pronounced trapezius muscles, and washboard abs. —Ashleigh N. Deluca, Parents, 4 Sep. 2025

In addition to getting units placed in her forehead, Schroeder, 37, also gets injections in the trapezius muscles in her upper back. —Starr Bowenbank, People.com, 10 July 2025

His second spot was noticed a year later on his back, in the area of his left upper trapezius muscle. —Alyssa Goldberg, USA Today, 12 May 2025

Word History

Etymology

New Latin, from trapezium; from the pair on the back forming together the figure of a trapezium

First Known Use

circa 1704, in the meaning defined above

Medical Definition

trapezius

noun

tra·​pe·​zi·​us trə-ˈpē-zē-əs, tra- 

plural trapezii -zē-ˌī  also trapeziuses

: a large flat triangular superficial muscle of each side of the upper back that arises from the occipital bone, the ligamentum nuchae, and the spinous processes of the last cervical and all the thoracic vertebrae, is inserted into the outer part of the clavicle, the acromion, and the spine of the scapula, and serves chiefly to rotate the scapula so as to present the glenoid cavity upward