Mentalis is so named because it is associated with thinking or concentration, although the justification for this view is lacking. It also has been said to express doubt. It originates in the part of the mandible below the front teeth and inserts into the skin of the chin, and acts to push the chin boss upwards, wrinkling it and curving the lips upward in an inverted U.

Mentalis is innervated by the zygomatic branch of the facial nerve (VII) and is supplied with blood by the facial artery.