trapezius muscle tra·pe·zi·us muscle (trə-pē'zē-əs)
A muscle with origin from the superior nuchal line, the external occipital protuberance, the nuchal ligament, the spinous processes of the seventh cervical and thoracic vertebrae, with insertion into the lateral third of the posterior surface of the clavicle, the medial side of the acromion, and the upper border of the spine of the scapula, with nerve supply from the accessory nerve and the cervical plexus, and whose action draws the head to one side or backward and rotates the scapula.
large, superficial muscle at the back of the neck and the upper part of the thorax, or chest. The right and left trapezius together form a trapezium, an irregular four-sided figure. It originates at the occipital bone at the base of the skull, the ligaments on either side of the seven cervical (neck) vertebrae (ligamentum nuchae), and the seventh cervical and all thoracic vertebrae. It is inserted on the posterior of the clavicle (collarbone) and on the spine of the scapula (shoulder blade). Its chief action is support of the shoulders and limbs and rotation of the scapula necessary to raise the arms above shoulder level
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