Name the muscle that may cause the following facial expression and write down its origin, insertion and action.
1. Platysma
Origin: It originates in the skin and fascia of infraclavicular and supraclavicular regions.
Insertion: The insertion site is located in the base of the mandible, lower lip, and orbicularis oris.
Action: Pulling angles of mouth laterally as well as superiorly, depresses the mandible.
2. Mentalis
Origin: It originates in the anterior aspect of the mandible.
Insertion: The site of insertion is located on the skin of the chin.
Action: Protrusion of the lower lip, elevation and wrinkling of the skin of the chin.
3. Orbicularis oris
Origin: It originates in the medial aspect of the maxilla, mandible, and modiolus.
Insertion: The site of insertion is located in the skin that surrounds the lips.
Action: Closing of the mouth and motion of kissing.
4. Corrugator supercilii
Origin: It originates at the medial end of the supraorbital ridge.
Insertion: The site of insertion is located in the skin of the forehead that is near to the eyebrow.
Action: Wrinkling of forehead, draws eyebrows downward, shields eyes from bright light.
5. Orbicularis oculi
Origin: It originates from the nasal portion of the frontal bone, the frontal process of the maxilla, and the medial palpebral ligament to the lacrimal crest and bone.
Insertion: The insertion site of this facial muscle includes the skin overlying the circumference of the orbit, the orbital spectrum, the temporal aspect of the orbit, and also inferiorly towards the cheek.
Action: Closing of the eyelid, blinking, controls the tear pump mechanism.
6. Occipitofrontalis
Origin: It originates from occipital and frontal belly (occipital bone, epicranial aponeurosis).
Insertion: The insertion site is located in the epicranial aponeurosis.
Action: Raises eyebrows, wrinkles forehead, draw scalp posteriorly.
References:
https://geekymedics.com/category/osce/clinical-examination/msk/