N3 Anatomy and Physiology AY 2023-2024

Answers:

1. Platysma

• Origin - Fascia over deltoid and pectoralis major muscles.

• Interaction - 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

• Interaction - Skin of chin

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

3. Orbicularis oris

• Origin - Muscle fibers surrounding opening of mouth

• Interaction - 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.

• Interaction - Skin of eyebrow

• Action - Draws eyebrow inferiorly and wrinkles skin of forehead vertically as in frowning.

5. Orbicularis oculi

• Origin - Medial wall of orbit

• Interaction - Circular path around orbit

• Action - Closes eye

6. Occipitofrontalis (frontal belly)

• Origin - Epicranial aponeurosis

• Interaction - 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.