1. Muscle: Platysma
Origin: Fascia over deltoid and pectoralis major muscles.
Insertion: Mandible, blends with muscles around angle of mouth, and skin of lower face.
Action: Draws outer part of lower lip inferiorly and posteriorly as in pouting; depresses mandible.
2. Muscle: Mentalis
Origin: Mandible.
Insertion: Skin of chin.
Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting.
3. Muscle: Orbicularis oris
Origin: Muscle fibers surrounding opening of mouth.
Insertion: Skin at corner of mouth.
Action: Closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech.
4. Muscle: Corrugator supercilii
Origin: Medial end of superciliary arch of frontal bone.
Insertion: Skin of eyebrow.
Action: Draws eyebrow inferiorly and wrinkles skin of forehead vertically as in frowning.
5. Muscle: Orbicularis oculi
Origin: Medial wall of orbit.
Insertion: Circular path around orbit.
Action: Closes eye.
6. Muscle: Frontal belly
Origin: Epicranial aponeurosis.
Insertion: Skin superior to supraorbital margin.
Action: Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise.
REFERENCE:
Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.