N3 Anatomy and Physiology AY 2023-2024

ACTIVITY 1

1. Platysma
   1. Origin: Fascia over deltoid and pectoralis major muscles.
   2. Insertion: Mandible, blends with muscles around the angle of mouth, and skin of lower face.
   3. Action: Draws outer part of lower lip inferiorly and posteriorly as in pouting; depresses mandible.
2. Mentalis
   1. Origin: Mandible.
   2. Insertion: Skin of chin.
   3. Action: Elevates and protrudes lower lip and pulls skin of chin up, as in pouting.
3. Orbicularis oris
   1. Origin: Muscle fibers surrounding opening of mouth.
   2. Insertion: Skin at corner of mouth.
   3. Action:  Closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech.
4. Corrugator supercilii
   1. Origin: Medial end of superciliary arch of frontal bone.
   2. Insertion: Skin of eyebrow
   3. Action: Draws eyebrow inferiorly and wrinkles skin of forehead vertically as in frowning.
5. Orbicularis oculi 
   1. Origin: Medial wall of orbit.
   2. Insertion: Circular path around orbit
   3. Action: Closes eye.
6. Frontal belly of the occipitofrontalis 
   1. Origin: Epicranial aponeurosis.
   2. Insertion: Skin superior to supraorbital margin.
   3. Action: Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise.

REFERENCE(S):

Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy and physiology (15th ed.). Wiley Custom Learning Solutions. https://handoutset.com/wp-content/uploads/2022/05/Principles-of-anatomy-and-physiology-Wiley-2017-Derrickson-Bryan-H._-Tortora-Gerard-J..pdf