1. Principle Skeletal Muscles 1
Muscles of Facial Expression, Muscles that Move the Mandible and Muscles that Move the Eyeballs

2. Muscles of Facial Expression
The muscles of facial expression provide humans with the ability to express a wide variety of emotions. The muscles themselves lie within the layers of superficial fascia. The origins are generally in the fascia or bones of the skull and insertions into the skin of the face

3. Occipitofrontalis Front and Occipital Bellies
Front Belly:
Origin – Epicranial Aponeurosis
Insertion – Skin superior to orbit
Action – Draws scalp forward, raises eyebrows and wrinkles skin of forehead horizontally
Occipital Belly
Origin – Occipital and Temporal Bones
Insertion – Epicranial Aponeurosis
Action – Draws scalp backwards

5. Orbicularis Oris Origin – muscle fibers surrounding opening of mouth
Insertion – Skin at corner of mouth
Action – Closes and protrudes lips, compresses lips against teeth and shapes lips during speech

6. Zygomaticus Major Origin – zygomatic bone
Insertion – Skin at angle of mouth and orbicularis oris
Action – Draws corners of mouth outward and upward as in smiling

7. Buccinator Origin – Maxilla and Mandible Insertion – Orbicularis Oris
Action – presses cheeks against teeth and lips, as in whistling; draws corner of mouth laterally, assists in chewing be keeping food between teeth

8. Platysma Origin – Fascia over deltoid and pectoralis major muscles
Insertion – Mandible, muscles around mouth and skin of lower face
Action – Draws outer part of lower lip downward and backward as in pouting; depresses mandible

9. Orbicularis Oculi Origin – Medial wall of orbit
Insertion – Circular path around orbit
Action – Closes eye; wrinkles forehead vertically

10. Levator Palpebrae Superioris
Origin – Roof of Orbit
Insertion – Skin of upper eyelid
Action - Opens Eye

12. Muscles that Move the Mandible
Also known as muscles of mastication because they are used for biting and chewing. These muscles also assist in speech.

13. Masseter Origin – Maxilla and Zygomatic Arch Insertion – Mandible
Action – Elevates and retracts mandible

14. Temporalis Origin – Temporal Bone Insertion – Mandible
Action – Elevates and retracts mandible

15. Medial Pterigoid Origin – Sphenoid bone and maxilla
Insertion – Mandible
Action – elevates and protracts mandible and moves mandible from side to side

16. Lateral Pterygoid Origin – Sphenoid Bone Insertion – TMJ
Action – Protracts mandible, depresses mandible and moves mandible from side to side

17. Muscles that Move the Eyeballs
Movement of the eyeballs are controlled by three pairs of extrinsic muscles. These are among the fastest contracting and most precisely controlled skeletal muscles of the body.

18. Superior Rectus/Inferior Rectus
Origin – Tendinous ring attached to bony orbit around the optic foramen
Insertion – Superior and central part of the eyeball
Action – Moves eyeball upward and medially and rotates its medially
Inferior:
Origin - Tendinous ring attached to bony orbit around the optic foramen
Insertion – Inferior and central part of the eyeball
Action – Moves eyeball downward and medially and rotates it laterally

20. Lateral/Medial Rectus
Origin – Tendinous ring attached to bony orbit around the optic foramen
Insertion – Lateral Side of Eyeball
Action – Moves eyeball laterally
Medial:
Insertion – Medial Side of Eyeball
Action – Moves eyeball medially

22. Superior/Inferior Oblique
Origin – Tendinous ring attached to bony orbit around the optic foramen
Insertion – Eyeball between superior and lateral recti
Action – moves eyeball downward, laterally and rotates medially
Inferior:
Origin – Maxilla
Insertion – eyeball between inferior and lateral recti
Action – moves eyeball upward and laterally and rotates it laterally