Question

Which of the following is anvil-shaped ear ossicle?
A. Incus
B. Malleus
C. Stapes
D. Humerus

Answer 1

Hint: Together three bones in the middle ear are called ear ossicles.The three bones that form ear ossicles are incus, malleus and stapes. These three bones are connected to each other in a chain-like fashion.

Complete Answer:
- Incus bone lies in the middle of three ear ossicles and is attached to malleus on the outer side and to stapes on the inner side. The incus bone is anvil-shaped (anvil is an instrument, commonly used by cobblers).
- Out of the three ear ossicles, malleus is the outer one. The handle of Malleus is attached to the inner side of the tympanic membrane. Malleus is a hammer shaped bone.
- The third bone in line of this chain is the stapes which is stirrup-shaped. The stapes is attached to another membrane called the oval window fenestra ovalis. The oval window acts like the 'door' to the inner ear.
- Humerus is a long bone of the upper arm that is connected with the rib cage by the shoulder girdle or pectoral girdle. Humerus is cylindrical and round headed bone. So humerus is not the answer because it is not a part of an ossicles.

So the correct answer is Option (A).

Note: Ear ossicles act in concert as a lever system, increasing the force of the vibration. The sound vibrations when strike the eardrum, it sets the vibrations to stapes and stapes transfers vibrations to the inner ear. However these ear ossicles not only transfer the sound vibrations, but also increase the intensity of the sound. Therefore, the ear ossicles present in the middle ear increase the efficiency of transmission of sound waves to the inner ear.