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Muscle Types & Names. Muscles cause movement primarily @ 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). Muscles. Types of Muscles. Prime mover – muscle with the major
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Muscles cause movement primarily @ 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) Muscles
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)
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 & muscle @ 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 Facial Expression
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* Muscles of mastication (chewing)
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* Neck Muscles
