The trapezius muscle is a broad, triangular skeletal muscle in the upper back. It extends from the occipital bone and the spinous processes of the cervical and thoracic spine to the shoulder blade and collarbone.
Functionally, it is divided into three sections: pars descendens (descending part), pars transversa (transverse part) and pars ascendens (ascending part). Together they control the raising, lowering, rotation and retraction of the shoulder blade and stabilise the shoulder girdle. In everyday life, the trapezius plays a central role in head posture and overhead arm movements.