Orbicularis oculi muscle is a sphincter muscle that encircles the eye and is responsible for closing and opening the eyelids. It is a thin, circular muscle that is located in the subcutaneous tissue of the eyelids.
Location
The orbicularis oculi muscle is located in the eyelids and surrounds the orbit of the eye. It is divided into two parts: the orbital part, which is located in the upper eyelid, and the palpebral part, which is located in the lower eyelid. The orbital part of the orbicularis oculi muscle is responsible for elevating the eyelid, while the palpebral part is responsible for depressing the eyelid.
Structure
The orbicularis oculi muscle consists of a number of fascicles, or bundles, of muscle fibers that are arranged in a circular fashion around the eye. These fascicles are connected to the skin and underlying structures of the eyelid, including the tarsal plate, a thin plate of dense connective tissue that provides support to the eyelid. The orbicularis oculi muscle is innervated by the facial nerve, which supplies the motor impulses needed for its contraction.
Function
The primary function of the orbicularis oculi muscle is to close the eyelids. This is important for protecting the eye from dust, dirt, and other irritants, as well as for keeping the eye moist and lubricated. The orbicularis oculi muscle also plays a role in facial expression, as it is responsible for wrinkling the skin of the forehead and around the eye when we squint or raise our eyebrows.
Clinical significance
Problems with the orbicularis oculi muscle can lead to a number of eye-related issues. For example, weakness or paralysis of the orbicularis oculi muscle can cause difficulty in closing the eyelids, leading to dryness and irritation of the eye. In severe cases, this can lead to corneal ulceration, a painful condition in which the surface of the eye becomes inflamed and ulcerated.
Additionally, abnormalities in the orbicularis oculi muscle can cause problems with facial expression. This can lead to difficulties in communication and social interactions, as well as problems with self-esteem and self-confidence.
