Trapezius is a major muscle of the back.
The trapezius is a large paired surface muscle in trapezoid shape.
It runs from the occipital bone to the lower thoracic vertebrae of the spine (and laterally to the scapula spine). It moves the scapula and supports the arm.
The trapezius has 3 functional parts:
- An upper part which supports the weight of the arm
- A middle region, which retracts the scapula, and
- A lower part which medially rotates and depresses the scapula.