Shoulder muscles are divided in 2 main groups:
  • Shoulder girdle: this group includes the Deltoid, the Supraspinatus, the Infraspinatus, the Teres Major, the Teres Minor and the Subscapularis. 
  • Muscles connecting the shoulder with the thorax: this group is formed by the Pectoralis Major and Pectoralis Minor muscles, Subclavius and Anterior Serratus.

Both groups, together with the back muscles that reach the humerus or the scapula, play a fundamental role in the movements of the shoulder girdle and upper limb.