The coracobrachialis is the smallest of the three muscles that attach to the coracoid process of the scapula. coracobrachialis ORIGIN: The coracobrachialis is Originates from the coracoid process of the scapula. coracobrachialis INSERTION: The coracobrachialis is inserted on the medial surface of the humerus shaft. coracobrachialisACTION: The coracobrachialis is majorly working for flexion & adduction of the humerus. The coracobrachialis is a synergist of the pectoralis major . coracobrachialis NERVE SUPPLY: The coracobrachialis is supplied by the Musculocutaneous nerve.