The orbicularis oculi is a circular muscle that surrounds the eye and is responsible for closing the eyelids. It comprises three parts: the palpebral part, the orbital part, and the lacrimal part. The palpebral part is responsible for gentle eyelid closure, while the orbital part is responsible for forceful closure, such as during blinking or squinting. The lacrimal part is located near the inner corner of the eye and helps drain tears into the tear ducts. The orbicularis oculi muscle is innervated by the facial nerve (cranial nerve VII). It is essential for protecting the eye from foreign objects, regulating tear production, and conveying emotions through facial expressions such as winking, blinking, or closing the eyes in a smile.