Final answer:
The AP projection of a wrist allows for a better assessment of the superficial anterior compartment of the forearm, while the PA wrist projection is useful for evaluating the superficial posterior compartment.
Step-by-step explanation:
The AP projection of a wrist provides a better view of the superficial anterior compartment of the forearm, which is responsible for bending the wrist towards the body and tilting the hand to the side away from the body. This projection allows for a more detailed assessment of any abnormalities or injuries in these structures. On the other hand, the PA wrist projection is useful for evaluating the superficial posterior compartment of the forearm, which straightens the wrist away from the body and tilts the hand to the side away from the body.