Which tiny bone in the middle ear is shaped like a stirrup?

Which tiny bone in the middle ear is shaped like a stirrup?

• A. Stapes
• B. Malleus
• C. Incus
• D. Cochlea

Answer: (A)

In the middle ear, three tiny bones pass vibrations from the eardrum to the inner ear, acting like a tiny lever system. The one shaped like a stirrup is the stapes. It’s the smallest bone in the body, and its footplate fits into the oval window of the cochlea, so vibrations are transferred into the fluid-filled inner ear. This setup amplifies the pressure because the eardrum has a larger surface area than the oval window. The other two bones—the malleus (hammer) and the incus (anvil)—work together with the stapes to move these vibrations along. The cochlea is part of the inner ear, not a middle-ear bone.

In the middle ear, three tiny bones pass vibrations from the eardrum to the inner ear, acting like a tiny lever system. The one shaped like a stirrup is the stapes. It’s the smallest bone in the body, and its footplate fits into the oval window of the cochlea, so vibrations are transferred into the fluid-filled inner ear. This setup amplifies the pressure because the eardrum has a larger surface area than the oval window. The other two bones—the malleus (hammer) and the incus (anvil)—work together with the stapes to move these vibrations along. The cochlea is part of the inner ear, not a middle-ear bone.