The trapezius muscle runs from the side of your neck to the top of your shoulder. If you move your shoulder straight up, it is the trapezius doing the work.
Trapezius - it elevates and depresses the scapula.
The trapezius is an upper back/neck muscle and the deltoids are shoulder muscles
Neck, Shoulder and Vertebrae
The trapezius muscle is located in the shoulder. It supports the weight of the arm while also retracting and rotating the shoulder blade. Problems with the trapezius can cause poor poise and posture.
The trapezius muscle allows you to elevate your shoulder. The trapezius muscle resembles a diamond-shaped quadrilateral. Its main function is to stabilize and move the scapula.