N3 Anatomy and Physiology AY 2023-2024

Activity 1

1. Platysma

   1. Origin: Fascia over deltoid and pectoralis major muscles.

   2. Insertion: Skin superior to supraorbital margin.

   3. Action: Draws scalp anteriorly, raises eyebrows, and wrinkles the skin of the forehead horizontally as in look of surprise.

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 the 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. Occipitofrontalis (Frontal belly)

   1. Origin: Epicranial Aponeurosis

   2. Insertion: Skin superior to supraorbital margin.

   3. Action: Draws scalp anteriorly, raises eyebrows, and wrinkles the skin of the forehead horizontally as in look of surprise.

References:

Tortora, G. J., & Derrickson, B. H. (2017). Principles of Anatomy & Physiology. Wiley.