The main purpose of the trapezius muscle if to stabilize the shoulder blade (scapula); provide a base for the movements of the arm, and to create the shoulder girdle for stability to the upper body.
A number of muscles are involved in shrugging your shoulders, including the latissiumus dorsi, the deltoids, the rhomboids, the scapular muscles, the biceps, the triceps, among others. The primary muscle is the upper trapezius muscle. The secondary muscles are the middle trapezius muscles and the levator scapulae.
scalene muscles
Retraction= Middle trapezius Elevation= Upper trapezius
The trapezius is an upper back/neck muscle and the deltoids are shoulder muscles
The trapezius raises scapulaas when shrugging shoulders, and pulls head backwards.
Trapezius - it elevates and depresses the scapula.
Trapezius 1
The rhomboid muscles and the middle trapezius muscle pull the scapulae medially. These muscles work together to retract and stabilize the scapulae toward the spine.
Trapezius and Latissimus dorsi
The trapezius muscles are the muscles on the dorsal surface that are shaped like a trapezpoid.
The trapezius muscle in humans is a single, large muscle divided into three specific regions based on their functions: the upper trapezius, middle trapezius, and lower trapezius. Each region of the trapezius muscle contributes to different movements of the shoulder and neck.
I would imagine that would be the trapezius muscles.