The smallest bone in the human body is the stapes bone, which is one of the three tiny bones in the middle ear. These three bones, collectively known as the ossicles, play a crucial role in the transmission of sound vibrations from the eardrum to the inner ear. The stapes bone, also called the stirrup bone, is approximately 0.1 inches (2.5 millimeters) in length and resembles a stirrup used in horseback riding, hence its name. Despite its small size, the stapes bone has an important function in the human auditory system.