The trapezius muscle is a large diamond shaped muscle in your back and neck. It originates on the nuchal ligament and the spinous processes of c6-t12. It inserts on the scapular spine, acromion process, and the distal clavicle. It’s upper fibres act to elevate the shoulder and rotate the glenoid fossa upward. The lower fibres assist this motion. The middle fibres strongly adduct the scapula. This is the most common muscle in the human body to get trigger points. Trigger points in the lateral upper edge refer pain into the lateral neck and temples. Points in the mid and lower parts of the muscle refer pain into the posterior neck and shoulders. Trigger points in this muscle are a common cause of headaches.