The procerus is a small, triangular-shaped muscle located in the forehead region of the face, between the eyebrows. It extends from the nasal bone to the skin of the forehead, just above the eyebrows. The procerus muscle is responsible for pulling the skin between the eyebrows downward and wrinkling the skin of the nose, which can cause the eyebrows to be pulled downward and inward. The procerus muscle works with other facial muscles to produce certain facial expressions, such as frowning or concentration. The procerus muscle is innervated by the buccal branch of the facial nerve (cranial nerve VII) and works in conjunction with other facial muscles to produce a range of facial expressions. Dysfunction or weakness of the procerus muscle can lead to difficulties with facial expressions, such as frowning or wrinkling the nose.