What is the primary function of the orbicularis oris muscle?

The orbicularis oris muscle primarily surrounds the mouth and is responsible for forming the lips. This muscle is essential for several functions, including the ability to pucker the lips, close the mouth, and articulate speech sounds. Its circular arrangement around the oral cavity allows it to control lip movement crucial for eating, speaking, and expressing emotions through facial expressions. Understanding the unique role of this muscle is important in dental nursing, as it relates to oral health, communication, and the overall aesthetics of the face.