To explain how orthotics function, it is important to understand the mechanics of walking. With each step, the vertical axis of the heel ideally should land almost perpendicular to the ground, with a slight inclination of only a few degrees toward the outside of the heel. From there, the weight is distributed progressively toward the lateral (outside) side of the foot. As the little (or fifth) toe starts to touch the ground, the arch of the foot should flatten slightly, shifting the body’s weight toward the medial (inside) side of the foot. The heel then should start to lift off the ground, shifting the weight to the medial forefoot, principally the ball of the foot and the big toe.