What is the Smallest Muscle in Your Body?

The smallest muscle in the human body is the stapedius, a tiny skeletal muscle located in the middle ear. It measures just over one millimeter in length, though some detailed anatomical studies suggest it can range from about 6 to 11 mm in size when including its full extent. The stapedius attaches to the stapes bone (the smallest bone in the body) and is responsible for dampening vibrations, thereby protecting the inner ear from loud sounds.

• Function: The stapedius is part of the acoustic reflex—it contracts reflexively in response to loud noises, stabilizing the stapes and preventing excessive movement that could damage the delicate structures of the inner ear. This helps prevent hearing loss from sudden loud sounds.
• Nerve supply: It is innervated by the nerve to stapedius, a branch of the facial nerve.
• Clinical significance: If the stapedius is paralyzed (which can happen with facial nerve disorders), the acoustic reflex is lost, leading to a condition called hyperacusis, where normal sounds are perceived as painfully loud.