1. Platysma muscle
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. Depressor labii inferioris muscle
Origin: Mandible
Insertion: Skin of lower lip
Action: Depresses (lowers) lower lip.
3. Orbicularis oris muscle
Origin: Muscle fibers surrounding opening of mouth.
Insertion: Skin at corner of mouth.
Action: Closes and protudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech.
4. Corrugator supercilii muscle
Origin: Medial end of superciliary arch of frontal bone.
Insertion: skin of eyebrow.
Action: Drwas eyebrow inferiorly and wrinkles skin of forehead vertically as in frowning
5. Orcularis oculi Muscle
Origin: Medial wall of orbit
Insertion: Circular path around orbit
Action: closes eye
6. Occipitofrontalis frontal belly muscle
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.
References: Tortora, G. J., & Derrickson, B. (2017). Principle of Anatomy and Physiology (15th ed., pp. 341-342)