Which movement involves the big toe being turned down while the arch is in and the sole is up on the outside?

The movement described refers to eversion, which specifically involves the turning of the sole of the foot outward away from the midline of the body. When the big toe is turned down, it indicates that the arch of the foot is positioned inward, while the outer edge of the foot and its sole are elevated. This is a characteristic action of eversion, as it enhances stability across the lateral side of the foot during various activities.

Inversion, in contrast, would involve the sole turning inward toward the midline, which does not fit the scenario presented. Dorsiflexion refers to bringing the toes closer to the shin, which does not apply since the question describes the big toe being turned downward. Plantarflexion involves pointing the toes away from the shin, typically lifting the heel off the ground, which also does not align with the described movement of turning the big toe down and elevating the outer sole.

Therefore, the correct understanding of eversion being related to the movement of the foot aligns with the specifics of the question, leading to the conclusion that eversion is the movement characterized by the big toe being turned down while the arch is in and the sole is up on the outside.