1. 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 (pouting)
- Depresses mandible
2. Mentalis
Origin: Mandible
Insertion: Skin of chin
Action:
- Raises and extends lower lip
- Lifts skin of chin up (pouting)
3. Orbicularis oris
Origin: Muscle fibers surrounding opening of mouth
Insertion: Skin at corner of mouth
Action:
- Closes and protrudes lips (kissing)
- Squeezes lips against teeth
- Shapes lips during speech
4. Corrugator supercilii
Origin: Medial end of superciliary arch of frontal bone
Insertion: Skin of eyebrow
Action:
- Lowers the eyebrow
- Longitudinally furrows the skin on the forehead (frowning)
5. Orbicularis oculi
Origin: Medial wall of orbit
Insertion: Circular path around orbit
Action: Closes eye
6. Occipitofrontalis (frontal belly)
Origin: Epicranial aponeurosis
Insertion: Skin superior to supraorbital margin
Action:
- Pulls the scalp forward
- Raises eyebrows
- Horizontally wrinkles the forehead skin (surprised look)