ACTIVITY 1
Name a muscle that may cause the following facial expression and write down its origin, insertion, and action.
IMAGE 1
- Muscle: Platysma
- Origin: from the deltoid and pectoral region superiorly and medially and ascends to the anterior and lateral aspects of the neck
- Insertion: into the border of the lower mandible
- Action: draws the corners of the mouth inferiorly and widens it; it also draws the skin superiorly when teeth are clenched
IMAGE 2
- Muscle: Mentalis
- Origin: Mandible just inferior to the incisor teeth
- Insertion: Skin of the chin
- Action: Raises and protrudes lower lip as it wrinkles the skin of the chin
IMAGE 3
- Muscle: Orbicularis Oris
- Origin: Maxilla and Mandible near midline
- Insertion: Encircles oral orifice/ skin around the lips
- Action: cause the lips to stick out from the face (i.e., puckering of the lips)
IMAGE 4
- Muscle: Corrugator Supercilii
- Origin: Frontal bone at the medial end of the superciliary arch
- Insertion: Skin above the middle of the supraorbital margin.
- Action: Draws eyebrow medially and inferiorly, creating vertical wrinkles above nose
IMAGE 5
- Muscle: Orbicularis Oculi
- Origin: Arch of frontal bone above nasal 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
IMAGE 6
- Muscle: Occipitofrontalis
- Origin: from the lateral two-thirds of the superior nuchal lines of occipital bone
- Insertion: onto the back end of the galea aponeurotica/ epicranial aponeurosis
- Action: lift eyebrows; fold skin of forehead into horizontal crease