The smallest body in the human body is known as stapes and is located in the middle of the ear. It is also known as the stirrup bone as it looks like a stirrup. It is a movable bone. It is connected to two other bones known as malleus bone and incus bone. These three bones vibrate when sound enters your ear. These vibrations are sent into the inner part of the ear which allows you to hear the sound. These bones are also found in mammals.