1.
Muscle: Platysma
Origin: Fascia over deltoid and pectoralis major muscles
Insertion: mandible, blends with muscles around angle of mouth, skin of lower face
Action: Depresses mandible, draws outer part of lower lip inferiorly and posteriorly
2.
Muscle: Mentalis
Origin: Mandible
Insertion: Skin of chin
Action: Lower lip protruding and elevating, skin chin pulling up which leads to wrinkles of the chin
3.
Muscle: Orbicularis Oris
Origin: muscle fibers surrounding the opening of the mouth
Insertion: skin at corner of the mouth
Action: Lip closing and protruding, compressing lips against teeth, shaping 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 (frowning)
5.
Muscle: Orbicularis Oculi
Origin: medial wall of orbit
Insertion: circular path around orbit
Action: closing of the eyes
6.
Muscle: Occipitofrontalis
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. & Derrickson, B.(2012). Principles of anatomy and physiology. John Wiley & Sons