The mentalis muscle is a small, paired muscle located in the chin region of the face. It extends from the mandible (lower jaw) to the skin of the chin and is responsible for elevating and wrinkling the skin of the chin. The mentalis muscle also helps to protrude the lower lip and provides support to the lower lip during speech and facial expressions. The mentalis muscle is innervated by the marginal mandibular branch of the facial nerve (cranial nerve VII). It works with other facial muscles to produce a range of facial expressions. Dysfunction or weakness of the mentalis muscle can lead to difficulties with speech, eating, and facial expressions, such as frowning or pouting.