Which of the following is a major muscle of the back?

The story behind the answer

Trapezius is a large, superficial back muscle spanning the upper back and neck. It stabilizes the shoulder girdle, elevates the scapula (shrugging), retracts and rotates it, and helps extend the neck. It’s innervated by the spinal accessory nerve (cranial nerve XI). Viewed from both sides, it outlines a trapezoid—hence the name.

The other options aren’t muscles but wrist (carpal) bones: triquetrum, trapezium, and trapezoid. Memory tip: “Traps are muscles you train” (on back day), while the -um/-oid names live in the wrist. Or think T-R-A-P-ezius for the back “TRAPs” bodybuilders talk about.