Which muscle covers the back of the neck and the upper middle region of the back?

The trapezius muscle is a large, superficial muscle that spans the upper back and neck. It plays a crucial role in moving, rotating, and stabilizing the shoulder blade, as well as extending the neck. Covering the back of the neck and the upper middle region of the back, the trapezius is shaped somewhat like a trapezoid, hence its name. This muscle has three distinct parts: the upper, middle, and lower fibers, each of which contributes to different movements and functions related to the shoulders and head position.

In contrast, muscles such as the latissimus dorsi primarily affect the lower back and sides, involved in movements such as pulling and lifting. The serratus anterior is located on the side of the ribcage and primarily facilitates the movement of the shoulder blade, while rhomboid muscles are situated between the shoulder blades and are responsible for retracting the scapula. The trapezius distinctly covers the area specified in the question, making it the appropriate choice for the muscle that encompasses the back of the neck and the upper middle region of the back.