The muscles of facial expression are a group of muscles that enable humans to convey emotions through facial movements. These muscles are primarily located beneath the skin of the face and are responsible for actions such as smiling, frowning, and raising eyebrows. They are innervated by the facial nerve (cranial nerve VII), which allows for precise control over facial expressions. These muscles include the orbicularis oculi, which helps close the eyes, and the zygomaticus major, which elevates the corners of the mouth to create a smile. Other important muscles include the frontalis, responsible for raising the forehead, and the platysma, which contributes to expressions of surprise or fear. Together, they play a crucial role in non-verbal communication.