Question

From outer to inside, the sequence of three bones present in the middle ear of mammals are
A. Malleus, stapes and incus
B. Stapes, malleus, and incus
C. Malleus, incus and stapes
D. Incus, malleus, and stapes

Answer 1

1)The chain of three small bones known as ossicles are responsible for conducting the sound vibration to the inner ear.
2)The malleus is in touch with the eardrum or tympanic membrane.

Complete answer:
Option A: All three of these bones are present in the mid-ear. They start at the end of the outer ear, which is the eardrum. The first bone is the malleus which is in contact with eardrums and receives vibration from them. But stapes is not the bone next to the malleus.
Therefore, this is the incorrect option.

Option B: Stapes is the last bone of ossicles and it is positioned towards the inner ear and is connected to the oval window to the vestibule of the inner ear. Therefore, this is the incorrect option.

Option C: The order of small bones inside the middle ear, from outer to inner is the malleus, incus, and then stapes. Therefore this is the correct answer. Malleus is the outermost and hammer-shaped bone. They receive sound vibration from the eardrum and pass it to the next small bone, which is the incus. Incus is the middle bone and forms a connection between both other bones. Incus means anvil. The third and last bone stapes continue from the incus and transmit the vibrations to the inner ear. Stapes means stirrup.

Option D: Incus is the middle bone among the ossicles. Therefore, this is the incorrect option.

Hence, the correct answer is option (C)

Note: 1)The middle ear bones are named in Latin according to their shape.
2)Ossicles give the eardrums mechanical support and also reduce the area of distribution of sound waves and hence decrease the dampening of them.