The trapezius is a large, flat sheet of muscle located on the upper and middle portion of the back.
The trapezius originates on the base of the skull, the ligament of the neck, and the spinous processes of the seventh cervical to the twelfth thoracic vertebrae.
It inserts along a curved line on the outer third of the posterior border of the clavicle, the top of the acromium, and the upper border of the spine of the scapula.
Rotates the scapula, pulls the scapula toward the spinal column, and pulls the shoulders down. The very uppermost portion of the trapezius elevates the scapula.