Which middle ear bones derive from the first pharyngeal arch?

Which middle ear bones derive from the first pharyngeal arch?

• A. Malleus and Incus
• B. Stapes and Incus
• C. Malleus and Stapes
• D. All three

Answer: (A)

The first pharyngeal arch forms two of the tiny middle ear bones: the malleus (hammer) and the incus (anvil). These come from Meckel's cartilage within that arch, which shapes in development to produce these two ossicles that connect the eardrum to the inner ear. The stapes (stirrup), on the other hand, arises from Reichert's cartilage of the second pharyngeal arch. So, when asking which bones derive from the first arch, the malleus and incus are the ones that fit. The stapes does not, since it originates from the second arch.

The first pharyngeal arch forms two of the tiny middle ear bones: the malleus (hammer) and the incus (anvil). These come from Meckel's cartilage within that arch, which shapes in development to produce these two ossicles that connect the eardrum to the inner ear. The stapes (stirrup), on the other hand, arises from Reichert's cartilage of the second pharyngeal arch. So, when asking which bones derive from the first arch, the malleus and incus are the ones that fit. The stapes does not, since it originates from the second arch.