function
Last reviewed 01/2018
Pectoralis major assists in a number of functions:
- medial rotation of the arm
- adductor of the arm, particularly in combination with latissimus dorsi. The sternocostal fibres are the main ones to carry out this function. This movement can be used when the arm is fixed to raise the thorax superiorly, as in climbing.
- extension of the flexed forearm; again, carried out by the sternocostal fibres by virtue of their postion
- flexion of the humerus to the horizontal from the neutral position; mainly carried out by the clavicular fibres
- elevation and lateral deviation of the upper ribs during inspiration. The costal insertions act as accessory muscles of respiration with the arm fixed.