Final answer:
The term for turning the foot such that the plantar surface faces medially is inversion. It involves movement at the intertarsal joints, not the ankle joint itself.
Step-by-step explanation:
The term that describes turning the foot so the plantar surface faces medially is inversion. Inversion involves the multiple plane joints among the tarsal bones of the posterior foot, specifically the intertarsal joints, and it angles the bottom of the foot toward the midline.
This is different from eversion, which turns the bottom of the foot away from the midline. Both inversion and eversion are important for stabilizing the foot when engaging in activities such as walking, running, or playing sports.