Mentalis
The mentalis muscle ( " Chin muscle ") is a skin muscle of the head. It rises on the front part of the lower jaw and radiates into the skin of the chin. As a mimic muscle it causes a wrinkling of the chin and pushes the lower lip upward. In humans, this expression is to be found mainly in discontent and doubt, which is why the muscle is referred to as " Schmoll muscle ". The muscle is innervated by the seventh cranial nerve, the facial nerve (VII).
A genetic disorder on chromosome 9 locus q13 - q21 leads to involuntary twitching of the mentalis muscle ( Geniospasmus ). This harmless in itself malfunction has mainly social significance.
An involuntary contraction of the mentalis muscle in brushing the ball of the thumb ( thenar ) the same side is regarded as a primitive reflex (so-called Palm Omen Taler reflex) and is equipped with atrophic brain processes (including in dementia ) associated.