What action does the stapedius muscle perform?

The stapedius muscle plays a crucial role in the auditory system, specifically in the protection of the inner ear from loud sounds. When the stapedius muscle contracts, which occurs in response to loud noises, it functions to reduce the movement of the stapes bone (one of the tiny bones in the middle ear). This contraction effectively dampens the transmission of sound vibrations to the inner ear, preventing potential damage to the delicate hair cells responsible for hearing.

By limiting the amplitude of sound waves that reach the inner ear during exposure to loud sounds, the stapedius muscle acts as a protective mechanism, helping to maintain hearing health and prevent noise-induced hearing loss. This protective response is often referred to as the acoustic reflex, demonstrating how our body instinctively reacts to loud auditory stimuli.

The other answers relate to functions that do not accurately describe the primary role of the stapedius muscle, which is specifically about protection and not amplification, frequency perception, or supporting structures of the auditory system.