Activity 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 lips inferiorly and posteriorly, depresses mandible
- Mentalis
- Origin: Mandible
- Insertion: Skin of chin
- Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting
- 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
- 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
- Orbicularis oculi
- Origin: Medial wall of orbit
- Insertion: Circular path around orbit
- Action: Closes eye
- Occipitofrontalis (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., & Derrickson, B. (2012). Principles of ANATOMY & PHYSIOLOGY (13th ed.). John Wiley & Sons, Inc.