ACTIVITY 1
1. Platysma
Origin: Fascia of the upper thorax (including the clavicle, acromial region, pectoralis major, and deltoid muscle)
Insertion: Lower border of mandible, skin of buccal/cheek region, lower lip, modiolus, orbicularis oris, and in some cases, orbicularis oculi
Action: Depresses mandible and angle of mouth, tenses skin of lower face and anterior neck
2. Mentalis
Origin: Incisive fossa of mandible
Insertion: Skin of chin/mentolabial sulcus
Action: Elevates, everts, and protrudes lower lip, wrinkles skin of chin
3. Orbicularis Oris
Origin: Medial aspects of maxilla and mandible, perioral skin and muscles, modiolus
Insertion: Skin and mucous membrane of lips
Action: Closes mouth, compresses and protrudes lips
4. Corrugator Supercilii
Origin: Medial end of superciliary arches, fibers of orbicularis oculi muscle
Insertion: Skin above middle of supraorbital margin
Action: Pull the eyebrows medially and inferiorly
5. Orbicularis Oculi
Origin: Nasal part of frontal bone, frontal process of maxilla, medial palpebral ligament, lacrimal bone
Insertion: Skin of orbital region, lateral palpebral raphe, superior and inferior tarsal plates
Action: Closes eyelids tightly (orbital part), closes eyelids gently (palpebral part), compresses lacrimal sac (deep palpebral part)
6. Occipitofrontalis
Origin: Frontal belly (frontalis), skin of eyebrow, muscles of forehead
Insertion: Epicranial aponeurosis
Action: Elevates eyebrows, wrinkles skin of forehead (frontal belly), retracts scalp (occipital belly)