TANILON, Pauline Joy B.
ACTIVITY 1
Name the muscle that may cause the following facial expression and write down its origin, insertion and action.
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 as in pouting; depresses mandible.
2. Mentalis
> Origin: Mandible
> Insertion: Skin of chin.
> Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting.
3. Orbicularis oris
> Origin: Muscle fi bers 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.
4. 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.
5. Orbicularis oculi
> Origin: Medial wall of orbit.
> Insertion: Circular path around orbit.
> Action: Closes eyelids.
6. 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.
References:
Tortora, G. J., & Derrickson, B. (2014). Principles of Anatomy and Physiology (14th ed.). Wiley.