Activity 1
Week 3
by GEORGETTE E. ZALDIVAR
Name the muscle that may cause the following facial expression and write down its origin, insertion, and action.
- PLATYSMA
- Origin: Fascia over the deltoid and pectoralis major muscles.
- Insertion: Mandible, blends with muscles around the angle of the mouth and the skin of the lower face.
- Action: Draws the outer part of the lower lip inferiorly and posteriorly, as in pouting; depresses the mandible and tenses the skin of the anterior neck.
- MENTALIS
- Origin: Mandible.
- Insertion: Skin of chin.
- Action: Elevates and protrudes lower lip and pulls the skin of chin up, as in pouting.
- ORBICULARIS ORIS
- Origin: Muscle fibers surrounding the opening of the mouth
- Insertion: Skin at the corner of the 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 the frontal bone.
- Insertion: Skin of eyebrow.
- Action: Draws eyebrow inferiorly and wrinkles skin of the forehead vertically as in frowning.
- ORBICULARIS OCULI
- Origin: Medial wall of the orbit.
- Insertion: Circular path around the orbit.
- Action: Closes eyelids tightly (orbital part), closes eyelids gently (palpebral part), compresses lacrimal sac (deep palpebral part)
- 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 the look of surprise.
REFERENCE:
Tortora, G. J., & Derrickson, B. (2014). Muscles of the Head That Produce Facial Expression. In G. J. Tortora, & B. Derrickson, Principles of Anatomy and Physiology (pp. 337-338). Hoboken, NJ: Wiley.