Muscles _____, they don't ______
pull/push
pull push
What are 3 factors that decide the name of skeletal muscle
Muscle location: bone or body region with which muscle associated
▪ Example: temporalis (over temporal bone)
▪ Muscle shape: distinctive shapes
▪ Example: deltoid muscle (deltoid = triangle)
▪ Muscle size
▪ Example: maximus (largest), minimus (smallest), longus (long)
Direction of muscle fibers or fascicles
▪ Example: rectus (fibers run straight), transversus (fibers run at right angles), and
oblique (fibers run at angles to imaginary defined axis)
▪ Number of origins
▪ Example: biceps (two origins) and triceps (three origins)
Location of attachments: named according to point of origin and
insertion (origin named first)
▪ Example: sternocleidomastoid attaches to sternum and clavicle, with insertion on
mastoid process
▪ Muscle action: named for action they produce
▪ Example: flexor or extensor
▪ Several criteria can be combined
▪ Example: extensor (extends) carpi (wrist) radialis (radius) longus (length is long)
What are fascicles?
bundles of muscle fibers enclosed in the perimysium.
Fascicles determine muscle’s range of motion
▪ Amount of movement when muscle shortens
▪ Fascicles determine muscle’s power
▪ Long fibers more parallel to long axis shorten more; usually not powerful
▪ Power depends on number of muscle fibers
▪ Bipennate, multipennate muscles have most fibers → shorten little but are powerful
What are the components of a lever system
Lever: rigid bar (bone) that moves on a fixed point called fulcrum (joint)
▪ Effort: force (supplied by muscle contraction) applied to lever to move resistance
(load)
▪ Load: resistance (bone + tissues + any added weight) moved by the effort
What are the three main functional groups?
1. Prime mover (agonist)
▪ Major responsibility for producing specific movement
▪ 2. Antagonist
▪ Opposes or reverses particular movement
3. Synergist helps prime movers
▪ Adds extra force to same movement
▪ Reduces undesirable or unnecessary movement
What gives the Gluteus maximus it's name
gluteal region large size
What are the most common types of fascicle arrangements.
Most common patterns are circular, convergent, parallel, fusiform, and
pennate
What is the difference between mechanical disadvantage and advantage.
Mechanical advantage (power lever): load is close to fulcrum, with
effort far from fulcrum
▪ Small effort can move large load
▪ Mechanical disadvantage (speed lever): load is far from fulcrum, with
effort close to fulcrum
▪ Load moved rapidly over large distance; offers wider range of motion
A muscle that crosses the anterior side produces ______ in upper body muscles
flexion
Why do the biceps and triceps have the bi and tri prefixes
They have 2 and 3 heads/ origin points
give an example of a circular arranged muscles
orbicularis oris or oculi
Describe a first class lever
fulcrum is between load and effort
seesaw or scissors
A muscle that crosses the medial side produces ______
Am muscle that crosses the lateral sdie produces_______
Adduction, Abduction
What about the biceps femoris muscle gives it its name.
2 heads located on the femur
What type of fascicle arrangement does the biceps brachii have
fusiform
What is an example of a 1st class lever in the body
neck extension
when you perform elbow flexion with a supinated palm what is the prime movers, the synergist, and the antagonist muscle.
brachialis,
brachioradialis biceps brachii,
triceps brachii, anconeus
What gives the Rectus abdominus it's name
Rectus-fibers run straight
transverse- fibers run horizontally
What is a pennate fascicle arrangement, and what are the three types of them and give an example of each type
Pennate: short fascicles attach obliquely to central tendon running
length of muscle (example: rectus femoris)
▪ Three forms
▪ Unipennate: fascicles attach only to one side of tendon (example: extensor digitorum
longus)
▪ Bipennate: fascicles insert from opposite sides of tendon (example: rectus femoris)
▪ Multipennate: appears as feathers inserting into one tendon (example: deltoid)
What kind of lever is the biceps brachii muscle curling a dumbell
class 3