Final answer:
The anatomical structures that must be present on a 45-degree semi-supinated wrist are the superficial anterior compartment and the superficial posterior compartment of the forearm.
Step-by-step explanation:
The anatomical structures that must be present on a 45-degree semi-supinated wrist include the superficial anterior compartment of the forearm and the superficial posterior compartment of the forearm. The superficial anterior compartment of the forearm consists of muscles that bend the wrist toward the body and tilt the hand to the side away from the body. The superficial posterior compartment of the forearm consists of muscles that straighten the wrist away from the body and tilt the hand to the side away from the body.