Which muscles is not of much use to you in picking up a cup?

The trapezius muscle is not of much use to you in picking up a cup.

The trapezius muscle is a large muscle that extends from the base of the skull to the middle of the back. It is responsible for moving the shoulder blades and head. While the trapezius muscle can be used to assist in lifting objects, it is not the primary muscle used for this purpose. The biceps brachii muscle, located on the front of the upper arm, is the primary muscle responsible for flexing the elbow and lifting objects.