What is the action of the coracobrachialis muscle?

The coracobrachialis muscle plays a significant role in the movement of the humerus at the shoulder joint. Its primary actions include flexion and adduction of the humerus. This muscle originates from the coracoid process of the scapula and inserts on the medial aspect of the humerus.

When activated, the coracobrachialis muscle pulls the humerus forward and toward the body, facilitating flexion, which involves raising the arm in front of the body. Additionally, its function in adduction allows the arm to be brought closer to the midline, making it essential for various movements that require bringing the arm inward.

Understanding the action of the coracobrachialis is crucial for evaluating shoulder mechanics, rehabilitation after injuries, and planning interventions in orthotics and prosthetics that involve upper limb function.