Certified Surgical Technologist (CST) Practice Exam

The stapes, also known as the stirrup bone, is the ossicle that is situated in the middle ear and plays a crucial role in the auditory system. It is the smallest bone in the human body and connects the incus to the oval window of the cochlea. The primary function of the stapes is to transmit sound vibrations from the incus to the oval window, which then initiates the process of converting these vibrations into fluid waves within the inner ear. This action is essential for the perception of sound.

In contrast, the malleus and incus are the other two ossicles in the middle ear, but they do not directly interface with the oval window. The malleus, often referred to as the hammer, is attached to the tympanic membrane (eardrum), while the incus acts as a bridge between the malleus and stapes. The utricle, on the other hand, is part of the vestibular system in the inner ear, involved in balance rather than hearing, and does not play a role in the conduction of sound vibrations through the middle ear.