What Is the Trapezius Muscle? Trapezius muscles are large, paired, triangular muscles in the back of your neck and upper back. They extend down your back, but they’re mostly involved in the movements ...

A trapezius strain is a muscle or tendon injury that limits movement and strength in the arms. It occurs when the fibers are stretched beyond their typical limit. In severe cases, it can lead to a ...

The trapezius muscle starts right below the skull, runs down the neck and across the shoulders, and then continues down the spine in a “V” shape. It works to stabilize your shoulders and upper back.