Activity 1:
1). Platysma
a. Origin: Fascia over deltoid and pectoralis major muscles. Subcutaneous tissue of infraclavicular and supraclavicular regions
b. Insertion: Base of Mandible, blends with muscles around the angle of the mouth and the skin of the lower face.
c. Action: Draws the outer part of the lower lip inferiorly and posteriorly, as in pouting; depresses the mandible. Tenses the skin of inferior face and neck.
2). Mentalis
a. Origin: Body of Mandible
b. Insertion: Skin of chin
c. Action: Elevates and protrudes lower lip and pulls the skin of chin up
3). Orbicularis oris
a. Origin: Medial maxilla and mandible; Muscle fibers surrounding the opening of the mouth
b. Insertion: Skin at the corner of the mouth or mucous membrane of the lips
c. Action: Closes and protrudes lips, as in kissing; compresses lips against teeth and shapes lips during speech; resists distension when blowing
4). Corrugator supercilii
a. Origin: Medial end of superciliary arch of the frontal bone
b. Insertion: Skin of eyebrow; Skin superior to the middle of supraorbital margin
c. Action: Draws eyebrow medially and inferiorly which wrinkles skin of the forehead vertically as in frowning
5). Orbicularis oculi
a. Origin: Medial wall of the orbit; Medial palpebral ligament
b. Insertion: Circular path around the orbit
c. Action: Closes eyelids
6). Occipitofrontalis
a. Origin: Occipital belly (occipital bone) and frontal belly (epicranial aponeurosis)
b. Insertion: Skin superior to supraorbital margin
c. Action: Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in the look of surprise.