1. PLATYSMA
Origin: Fascia over deltoid and pectoralis major muscles.
Insertion: Mandible, blends with muscles around angle of mouth, and skin of lower face.
Action: The platysma muscle helps in depressing the lower lip, pulling the corners of the mouth downward, and tightening the skin of the neck. It is involved in expressions like grimacing and tension in the neck during emotional responses.
2. MENTALIS
Origin: The mentalis muscle originates from the mental protuberance of the mandible (chin).
Insertion: It inserts into the skin of the chin.
Action: The mentalis muscle primarily protrudes and wrinkles the skin of the chin. It is involved in activities like pouting and wrinkling the chin.
3. ORBICULARIS ORIS
Origin: Muscle fibers surrounding opening of mouth.
Insertion: Skin at corner of mouth.
Action: The orbicularis oris is a sphincter muscle of the lips. It allows for the closure and puckering of the lips, aiding in various facial expressions and functions like kissing and whistling.
4. CORRUGATOR SUPERCILLI
Origin: Medial end of superciliary arch of frontal bone.
Insertion: Skin of eyebrow.
Action: The corrugator supercilii muscle is responsible for drawing the eyebrows medially and downward, resulting in vertical wrinkles between the eyebrows. It contributes to facial expressions of concentration, frowning, or anger.
5. ORBICULARIS OCULI
Origin: Medial wall of orbit.
Insertion: Circular path around orbit.
Action: The orbicularis oculi is responsible for closing and squinting the eyes. It protects the eyes from bright light and foreign objects and is involved in facial expressions like blinking and winking.
6. OCCIPITOFRONTALIS
Origin: Frontal Belly - Epicranial aponeurosis ; Occipital Belly - Occipital bone and mastoid process of temporal bone.
Insertion: Frontal Belly - Skin superior to supraorbital margin ; Occipital Belly - Epicranial aponeurosis.
Action: The frontalis part of occipitofrontalis raises the eyebrows and wrinkles the forehead, while the occipitalis part fixes the galea aponeurotica in place. Together, these muscles are involved in facial expressions, such as raising the eyebrows in surprise or curiosity and wrinkling the forehead.
References:
The Ultimate Resource for Healthcare Professionals & Medical Students. TeachMeAnatomy. (n.d.). https://teachmeanatomy.info/
Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy and physiology. Wiley Custom Learning Solutions.