What main actions are produced by the pectoralis major muscle?

The pectoralis major muscle is primarily responsible for several key movements at the shoulder joint, notably shoulder adduction and medial rotation. When the muscle contracts, it pulls the upper arm towards the body’s midline, which is the action of adduction. Additionally, it helps in medially rotating the arm, turning it inward towards the body.

This combination of actions is essential for movements such as pushing, throwing, and lifting, where the arms need to be brought closer to the torso or rotated inward. Understanding the role of pectoralis major in shoulder mechanics is crucial for exercises targeting this muscle, as well as for rehabilitation practices that involve restoring shoulder function.

The other options listed involve movements that the pectoralis major does not primarily facilitate. For instance, shoulder extension, abduction, and elevation are associated with other muscles such as the deltoids and latissimus dorsi, which is why they are not the correct focus for the actions of the pectoralis major.