Which muscle is primarily involved in shrugging the shoulders?

The trapezius muscle is primarily responsible for shrugging the shoulders due to its anatomical positioning and function. This large, triangular muscle extends from the back of the head down the spine and laterally across the shoulder girdle. When the upper fibers of the trapezius contract, they elevate the scapula, which results in the upward movement of the shoulders, commonly associated with the action of shrugging.

The trapezius also plays a role in other movements, including the rotation and retraction of the scapula, but its ability to specifically elevate the shoulders makes it the key muscle involved in this action. The other muscles listed do not have the same primary function of shoulder elevation; for example, the rhomboid muscle primarily aids in scapular retraction, the latissimus dorsi contributes to arm movements such as extension and adduction, and the pectoralis minor assists in scapular stabilization and movement but is not the main muscle for shrugging.