• Origin

Clavicle, sternum, and costal cartilages of upper ribs

• Insertion

Greater tubercle and intertubercular sulcus of humerus

• Agonist(s)

- Anterior fibers: clavicular head - Upper fibers of serratus anterior, sternocostal head - Pectoralis minor; Sternocostal fibers - Upper fibers of serratus anterior

• Antagonist(s)

- Posterior fibers: Latissimus dorsi, teres major, and posterior fibers of deltoid

• Function

Adducts and medially rotates arm; clavicular head: flexes arm; sternocostal head: extends flexed arm