- Platysma
Origin: Fascia over deltoid and pectoralis major muscles.
Insertion: Mandible
Action: Moves the outer lower lip down and back, like in a pout, and lowers the jaw.
- Depressor Labii Inferioris
Origin: Mandible
Insertion: Skin of lower lip.
Action: Aids in drawing the lower lip downward
- Orbicularis Oris
Origin: Muscle fibers encircling the mouth's opening.
Insertion: Skin at corner of mouth.
Action: Closes and protrudes lips; compresses lips against teeth; and shapes the lips during speech.
- Corrugator Supercilii
Origin: The inner part of the brow ridge on the frontal bone.
Insertion: Skin of eyebrow.
Action: Draws eyebrows inferiorly and wrinkles the skin of the forehead vertically.
- Orbicularis Oculi
Origin: Medial wall of orbit.
Insertion: Circular path around orbit.
Action: Responsible for squinting, closing, and winking of the eyes.
- Occipitofrontalis
Origin: Epicranial aponeurosis
Insertion: Skin superior to supraorbital margin.
Action: Draws the scalp anteriorly, elevates the eyebrows, and creates horizontal wrinkles on the forehead (look of surprise/fright).