| anterior mandible|
| mandibular branch of facial nerve|
elevates and wrinkles skin of chin, protrudes lower lip
The mentalis is a paired central muscle of the lower lip, situated at the tip of the chin. It originates from the mentum and inserts into the chin soft tissue. The primary effect of the mentalis contraction is the upward-inward movement of the soft tissue complex of the chin, which raises the central portion of the lips in turn. In the setting of lip incompetence (the upper and lower lips do not touch each other at rest), the mentalis muscle contraction can bring temporary but strained oral competence.
In conjunction with orbicularis contraction, the mentalis muscle allows the lips to "pout." Externally, mentalis contraction causes wrinkling of the chin skin, as used in expressions of doubt or displeasure. It is sometimes referred to as the "pouting muscle."
Geniospasm is a genetic movement disorder of the mentalis muscle.