Which pharyngeal arch forms the stapes?

• A. First arch
• B. Second arch
• C. Third arch
• D. Fourth arch

Answer: (B)

The stapes comes from the second pharyngeal arch. During development, the skeletal elements of the ears split among arches, with the malleus and incus arising from the first arch, and the stapes arising from Reichert’s cartilage of the second arch. This makes the second arch the source of the stapes, the stirrup-shaped middle-ear bone that transmits vibrations to the inner ear. The first arch does not form the stapes (it forms the malleus and incus), and the third and fourth arches contribute to other head and neck structures (such as parts of the hyoid bone and laryngeal cartilages), not the stapes.