Note: Good day, class! My apologies for posting my answers in this forum discussion so late. I was setback last week by an illness that lasted for six days. I had informed our professors about this health condition and provided them with a medical clearance. I kindly ask for your consideration and understanding. Thank you.
1. Muscle: Platysma
- Origin: Deep fascia over pectoralis major and deltoid
- Insertion: Body of mandible and angle of mouth
- Action: Depresses mandible and angle of mouth
2. Muscle: Mentalis
- Origin: Body mandible to roots (anterior to roots of inferior incisors)
- Insertion: Skin of chin (mentolabial sulcus)
- Action: Elevates and protrudes lower lip; elevates skin of chin (showing doubt)
3. Muscle: Orbicularis Oris
- Origin: Maxilla, mandible, and skin
- Insertion: Encircles oral orifice
- Action: Compresses lips together
4. Muscle: Corrugator supercilii
- Origin: Superciliary arch
- Insertion: Skin of eyebrow
- Action: Vertical wrinkles of forehead, as in frowning
5. Muscle: Orbicularis Oculi
Palpebral part
- Origin: Medial palpebral ligament
- Insertion: Lateral palpebral raphe
- Action: Closes eyelids and dilates lacrimal sac
Orbital part
- Origin: Medial palpebral ligament and adjoining bone
- Insertion: Loops return to origin
- Action: Throws skin around orbit into folds to protect eyeball
6. Muscle: Occipitofrontalis
- Origin: Occipital belly - Highest nuchal line of occipital bone and Frontal belly - Skin and superficial fascia of eyebrows
- Insertion: Epicranial aponeurosis
- Action: Moves scalp on skull and raises eyebrows
References:
Moore, Keith Leon, Dalley, Arthur F, Agur, Anne M. R. (2014). Clinically oriented anatomy (7th). Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins.
Snell, Richard S. (2012). Clinical anatomy by regions (9th). Baltimore, MD: Wolters Kluwer/Lippincott Williams & Wilkins.
Tortora, G., & Derrickson, B. (2012). Principles of ANATOMY & PHYSIOLOGY (13th ed.). John Wiley & Sons, Inc.