The mentalis muscle is a paired muscle located at the lower end of the chin, and acts as the main muscle of the lower lip. This muscle originates from the mandible, and provides stability to the lower lip to allow it to perform the function of pouting. It causes protrusion of the lower lip and elevates the skin of the chin. As the lower lip is raised, it results in elevation and wrinkling of the chin's skin. The mentalis is so named because of its association with emotional and thoughtful facial expressions. The zygomatic facial nerve innervates this muscle, and the facial artery is its source of blood supply. It is generally not associated with any facial problems, but in rare cases, it may result in medical disorders. One of the movement disorders caused by the mentalis muscle is geniospasm. This is a benign condition that usually begins in childhood, and may occur due to genetic factors. This can be a socially excluding condition for the patient, and may require proper medical care.