N3 Anatomy and Physiology AY 2023-2024

1. Name of muscle: 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. Name of muscle: Mentalis

• • Origin: Mandible

  • Insertion: Skin of chin

  • Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting.

3. Name of muscle: 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.

4. Name of 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 as in frowning.

5. Name of muscle: Orbicularis oculi

• • Origin: Medial wall of orbit.

  • Insertion: Circular path around orbit.

  • Action: Closes one eye

6. Name of muscle: 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. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.