ACTIVITY 1
1. Muscles: Platysma
Origin: Fascia of the upper thorax (includes: deltoid muscle, the clavicle, and pectoralis major)
Insertion: Lower border of mandible and skin of lower face
Action: Depression of mandible and angle of mouth, tension in the skin of lower face and anterior neck
2. Muscles: Mentalis
Origin: Mandible
Insertion: Skin of chin or the mentolabial sulcus
Action: Elevates and protrudes lower lip and pulls the skin of chin up
3.Muscles: Orbicularis Oris
Origin: Muscle fibers surrounding opening of mouth
Insertion: Skin and mucous membrane of lips
Action: Closes mouth, compresses and protrudes lips during kissing or resists distension when blowing
4. Muscles: Corrugator Supercilii
Origin: Medial end of superciliary arches
Insertion: Skin above middle of supraorbital margin
Action: Wrinkling of forehead, draws eyebrows downward, shields eyes from bright light
5. Muscles: Orbicularis Oculi
Origin: Frontal process of maxilla, nasal part of frontal bone, medial palpebral ligament, and lacrimal bone
Insertion: Medial wall of orbit
Action: Closing of the eyelid, blinking, controls the tear pump mechanism
6. Muscles: Occipitofrontalis
Origin: Frontal belly, muscles of forehead, & skin of eyebrow
Insertion: Frontal belly: Skin superior to supraorbital margin; Occipital belly: epicranial aponeurosis
Action: Retracts scalp, wrinkles skin of forehead, and elevates eyebrows