1. Muscular System
Ch 11

2. Origin- fixed point of attachment; for biceps brachii O= clavicle and humerus
Insertion- moveable, usually crosses a joint; O= radius
Prime mover- - muscle group responsible for producing particular movement
Antagonist- works opposite of prime mover
Synergist-reduces undesirable or unnecessary movement
Contraction of a muscle crossing 2 or more joints would
cause movement of all if synergists weren’t there to
stabilize it
Ex. make a fist without bending wrist
Fixator- specialized synergist- helps maintain posture; ex. muscles of the back fix scapula

4. Lever Systems Lever systems:
lever - rod that moves at the fulcrum (fixed point)
fulcrum (F) typically the joint moving
Resistance (R)- gravity pulling on body
Effort (E)- muscle contraction
Movement occurs when E > R
First class levers - E F R
Second class levers - F R E
Third class levers - F E R . . (most common)

5. Lever Systems
1st class lever
2nd class lever
3rd class lever

6. biceps (flexor) triceps (extensor) triceps (extensor) Antagonistic
Muscles
triceps
(extensor)
biceps
(flexor)

7. Naming Skeletal Muscles
Direction of muscle fibers- straight, transverse
Size of muscles- maximus, minimus, longus, brevis
Location- frontalis, temporalis, occipitalis
# of origins- biceps, triceps, quadriceps
location of muscles origin and insertion-
sternoclediomastoid- O= sternum and clavicle, I =
mastoid process of temporal bone
shape of muscle- deltoid- triangle shape, trapezius-
trapezoid shape
action of muscle- adductor muscle (adducts, brings
in thigh)

8. Frontal
Obicularis oculi
Temporalis
Obicularis oris
Masseter
Sternoclediomastoid

17. Masseter sternocledeomastoid Frontalis aponerosa Orbicularis oculi
temporalis
zygomaticus
Orbicularis oris
Masseter
sternocledeomastoid