What is the primary action of the coracobrachialis muscle?

The primary action of the coracobrachialis muscle is best described as adducting, extending, and stabilizing the shoulder joint. This muscle originates from the coracoid process of the scapula and inserts onto the humerus, functioning primarily to bring the arm closer to the body during adduction. Additionally, it helps with shoulder flexion and stabilization, particularly when the arm is in a raised position or during movements that require control of the shoulder joint.

Understanding this muscle's role is crucial for comprehending shoulder mechanics and for rehabilitation strategies following shoulder injuries, as its actions contribute significantly to the overall function and stability of the shoulder girdle.