Muscle Types & Names

Muscles Muscles cause movement the joints Muscles can attach to the body in 3 ways: -directly to the bone -by tendons (cords of connective tissue) -by an aponeurosis (sheet of connective tissue)

Types of Muscles  Prime mover – muscle with the major responsibility for a certain movement  Antagonist – muscle that opposes or reverses a prime mover

Types of Muscles  Synergist – muscle that aids a prime mover in a movement and helps prevent rotation  Fixator – stabilizes the origin of a prime mover

Naming of Skeletal Muscles  Direction of muscle fibers Example: rectus (straight)  Relative size of the muscle Example: maximus (largest)

Naming of Skeletal Muscles  Location of the muscle Example: many muscles are named for bones (e.g., temporalis)  Number of origins Example: triceps (three heads)

Naming of Skeletal Muscles  Location of the muscles origin and insertion Example: sterno (on the sternum)  Shape of the muscle Example: deltoid (triangular)  Action of the muscle Example: flexor and extensor (flexes or extends a bone)

Muscles of the Head (Face/Neck)

Muscles of Facial Expression Frontalis: Origin - cranial aponeurosis Insertion - skin of eyebrows Action - raises eyebrows

Muscles of Facial Expression Orbicularis oculi: Origin - frontal bone & maxilla Insertion - tissue around eyes Action - blinks and closes eyes; squinting *spincter muscle of eyelids*

Muscles of Facial Expression Zygomaticus Origin - zygomatic bone Insertion - skin & corner of lips Action - raises corner of mouth (smiling muscle) *extends diagonally from corner of mouth to cheekbone*

Muscles of Facial Expression Orbicularis oris Origin - mandible & maxilla Insertion - skin & muscle around mouth Action - closes mouth, purses and protrudes lips (kissing muscle) *encircles mouth; sphincter muscle of lips with fiber that run in many different directions*

Muscles of mastication (chewing) Masseter Origin - zygomatic arch of temporal bone Insertion - mandible Action - closes jaw & elevates mandible *extends across jawbone*

Muscles of mastication (chewing) Temporalis Origin - temporal bone Insertion - mandible Action - closes jaw & elevates mandible *fan-shaped muscle over temporal bone*

Muscles of mastication (chewing) Buccinator: Origin - maxilla and mandible near molars Insertion - orbicularis oris Action - compresses cheek (as in whistling & sucking); holds food between teeth during chewing *principal muscle of cheek; runs horizontally, deep to masseter*

Neck Muscles Sternocleidomastoid Origin - sternum & clavicle Insertion - mastoid process of temporal bone Action - flexes neck forward; rotates head *two-headed muscle located deep to platysma on anterolateral surface of neck*

Neck Muscles Platysma Origin - connective tissue covering superior chest muscles Insertion - tissue around the mouth Action - depresses the mandible, pulls corners of mouth inferiorly (frowning muscle) *thins, sheet-like superficial muscle, plays a role in facial expression*

Head and Neck Muscles

The End!