Wisconsin Esthetics State Board Practice Test

What is the function of the orbicularis oculi muscle?

1. To raise the eyebrows

2. To circle the mouth

3. To open the eyelid

4. To close the eyelid

The correct answer is: To close the eyelid

The orbicularis oculi muscle is primarily responsible for closing the eyelid. It encircles the eye and allows for actions such as blinking and squinting, which are crucial for protecting the eye from irritants, as well as for retaining moisture on the eye’s surface. This muscle's contraction brings the eyelids together, creating a complete closure that is essential for various functions such as sleeping and shielding the eyes from bright lights. In contrast, the other options represent different functions performed by other muscles. Raising the eyebrows is the role of the frontalis muscle, while the muscle that circles the mouth is the orbicularis oris. The opening of the eyelid is achieved by muscles such as the levator palpebrae superioris, not the orbicularis oculi. Thus, the choice aligns accurately with the function of the orbicularis oculi.