A Answers (1)
National Academy of Sports Medicine answeredThe two primary muscles in the upper back include the trapezius and, although usually considered more of a shoulder muscle, the rear deltoid. The trapezius, because it has different sections (upper, middle, and lower), can perform a variety of functions. Generally, the trapezius can squeeze the shoulder blades together, move the shoulder blades down toward the thighs, and elevate or raise the shoulder blades up toward the ears, such as in a shrug. The rear deltoid works together with the trapezius and other mid/upper-back muscles to coordinate movement of the upper arm with the shoulder blades. The rear deltoid is a critical muscle for shoulder health because along with the rotator cuff, it is one of the few muscles that connects the upper arms to the shoulder blades.