The top of the foot has occasionally been named the “saddle” as it is thought to resemble the back of the horse where the saddle might be placed. You can notice a distinct deformity or bump that could develop on the top of the feet, which is why this is sometimes termed a Saddle Bone. https://fitofithealth.com/saddle-bone-deformity-throw-the-kitchen-sink-at-it/