The muscles that cover the skull are the epicranius muscles. The epicranius muscles are comprised of two muscles: the frontalis muscle and the occipitalis muscle. The muscle located on the forehead is the frontalis muscle, while the occipitalis muscle is located on the right and the left side of the skull on the back side. These two muscles work together to lift the eyebrows and wrinkle the forehead. The frontalis muscle is a thin muscle, which is of quadrilateral form.
The orbicularis occuli muscle is the facial muscle that surrounds the eyelids. Externally, it looks like a ring-like band. It is made up of skeletal muscle fibres. The main function of this muscle is to help the eye to blink. Along with this, these muscles also provide a definite shape to the eye and help in the compression of the tear gland, thus facilitating the flow of tears.
The orbicularis oris muscle encircles the mouth. It provides a definite shape to the lips. These muscles are located between the skin and mucous membrane of the lips. These muscles control the movements originating in the jaw bones of the mouth. They also facilitate various facial expressions and help us to play various musical instruments such as flute, mouth organ, etc.