This muscle is considered the most superficial among the muscles covering the upper back, neck and shoulders. In fact, it is just beneath the skin. The trapezius is inserted through acromion, lateral part of the clavicle and scapular spine. Meanwhile, it originates at the spinous process of the 7th cervical vertebra up to the 12th thoracic vertebra, medial superior line of the neck, ligamentum nuchae and at the external protuberance of the occipital bone. The trapezius is innervated by Cranial Nerve XI (accessory nerve) and the nerves branching through C3 and C4.

The upper fibers of the trapezius rotate the scapula upward and elevate the said bone. The middle fibers aid the scapula to adduct or to move towards the medial part of the torso, while the lower fibers assist the upper fibers in rotating the scapula upward and even depresses the scapula. All of these allow us to tilt our head, extend our neck, twist our arms  and shrug our shoulders.