Trapezius muscle

In human, trapezius muscle or trapezius is a large muscle that extends longitudinally on the upper portion of a human spine. Its functions are to move the scapulae and support the arm.
The trapezius has three functional regions: the superior region, which supports the weight of the arm; the intermediate region, which retracts the scapulae; and the inferior region, which rotates and depresses the scapulae.
Exercising.
The upper portion of the trapezius can be developed by elevating the shoulders. Middle fibers are developed by pulling shoulder blades together. The lower part can be developed by drawing the shoulder blades downward while keeping the arms almost straight and stiff.