Final answer:
Internal (medial) rotation of the humerus will roll the humeral head anteriorly and press the coracoacromial ligament forward, bringing it closer to the surface.
Step-by-step explanation:
The action that will roll the humeral head anteriorly, pressing the coracoacromial ligament forward, is internal (medial) rotation of the humerus. This rotation is part of shoulder joint movements. When the humerus internally rotates, the head of the humerus moves anteriorly, which would bring structures like the coracoacromial ligament closer to the surface of the shoulder, making it more prominent. This is different from the coracohumeral ligament, which runs from the coracoid process of the scapula to the anterior humerus and is also an intrinsic ligament of the shoulder joint.