Activity 1
Bien Troy B. Torres
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
- Insertion: mandible, muscles of the mouth, skin of lower face
- Action: depresses the mandible, draws outer lower lip part posteriorly and inferiorly.
2. MENTALIS
- Origin: mandible
- Insertion: skin of the chin
- Action: elevates and protrudes lower lip and pulls the skin of the chin.
3. ORBICULARIS ORIS
- Origin: muscle fibers surrounding the opening of the mouth
- Insertion: skin at the corner of the mouth
- Action: closes and protrudes the lips, compresses lips against teeth, shapes lips.
4. CORRUGATOR SUPERCILII
- Origin: medial end of superciliary arch of the frontal bone
- Insertion: skin of eyebrows
- Action: wrinkles skin of forehead vertically, draws eyebrows inferiorly.
5. ORBICULARIS OCULI
- Origin: medial wall of orbit
- Insertion: skin around eyes
- Action: closes the eyes.
6. OCCUPITOFRONTALIS
- Origin: epicranial aponeurosis
- Insertion: skin superior to supraorbital margin
- Action: raises the eyebrows, draws scalp anteriorly, wrinkles skin of forehead horizontally.