Question

The sequence of ear ossicles from outside (tympanum) to inside is
A. Stapes, incus and malleus
B. Malleus, incus and stapes
C. Stapes, malleus and incus
D. Incus, malleus and stapes

Answer 1

Hint: The middle ear has three bones called ossicles or auditory ossicles. They are the smallest bones in the human body. They help in the transmission of sound from the air to the fluid filled labyrinth(cochlea) or inner ear.

Complete Answer:
The tympanic cavity in the middle ear has a chain of three movable bones or ossicles. They are;
1. Malleus: it is the outermost bone and is largest of all the three bones. It transmits the sound vibrations received from the eardrum to stapes through incus. Since it is attached to a tympanic membrane or eardrum, it is more likely to cause hearing loss.
2. Incus: it is in the shape of ‘anvil’, hence it is also called an anvil bone. It is connected to the malleus laterally and transmits the received vibration to stapes medially.
3. Stapes: they help in the transmission of sound vibrations to the inner ear from incus through the oval window.
Malleus is connected with the tympanic membrane of the middle ear. The stapes is attached to the circumference of the fenestra vestibuli. Incus is in between malleus and stapes and is attached to both by delicate articulations. The absence of these bones may result in deafness.

Therefore the correct answer is (B) Malleus, incus and stapes.

Note: The size of the ear ossicles in the infant and the size of the ossicles in adults is almost the same. They can be stored in ossicles banks and can be utilized during ossiculoplasty. To replace the damaged middle ear, ossicles are used as homotografts.