Certified Surgical Technologist (CST) Practice Exam

Which of the following is an ossicle of the middle ear?

1. Pinna

2. Incus

3. Labyrinth

4. Vestibule

The correct answer is: Incus

The incus is an ossicle of the middle ear, and it plays a crucial role in the process of hearing. The middle ear contains three tiny bones known as ossicles: the malleus, incus, and stapes. These bones are essential for transmitting sound vibrations from the eardrum to the inner ear. The incus, often called the anvil, acts as a lever that helps facilitate this transfer of sound energy, working in conjunction with the other ossicles to amplify the vibrations. In contrast, the pinna is the outer ear structure that helps funnel sound waves into the ear canal. The labyrinth refers to the complex structure of the inner ear, which is involved in hearing and balance but is not a bone. The vestibule is a part of the inner ear that helps with balance and spatial orientation, not directly related to the ossicles of the middle ear. Understanding the specific roles and locations of these anatomical structures helps clarify the distinction between them and highlights the importance of the incus in auditory function.