The primary use of the trapezius muscle is to move the shoulder blades, twist head and neck, stabilize the shoulders, shrug and support the arms.This muscle is also considered as an accessory breathing muscle.
Located at the upper-middle back, the trapezius is one of the widest muscles in the back. It got its name from its shape that resembles a trapezoid. The trapezius is attached from the base of the skull, down to the shoulder blades and to the 12th thoracic vertebra. The muscle is divided into three regions: the superior region, the intermediate region and the inferior region.
The trapezius muscle provides upper posture support and it is both a postural and an active muscle. It aids in breathing by helping expand the upper region of the chest when breathing in. This muscle is often referred to as just traps by bodybuilders and they show the development of this muscle in competitions via the back double bicep and the most muscular pose..