Author: Dr Peter de Souza
Last modified: 14 November 2022

The pectoralis major muscle is a thick fan-shaped muscle which arises from the sternum and medial clavicle, inserting onto the lateral lip of the intertubercular sulcus of the humerus.


  • Medial 1/2 of clavicle
  • Anterior surface of sternum
  • Costal cartilages 1-7
  • Aponeurosis of external oblique


  • Proximal humerus (lateral intertubercular groove)


  • Adduction humerus
  • Medial rotation humerus
  • Flexion of the humerus


  • Medial and lateral pectoral nerves

Blood Supply

  • Pectoral branch of the thoracoacromial trunk