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Human Anatomy & Physiology
05A.3 Muscle Concepts
Introduction to Muscle Building
Concept # 1:
Muscles attach to bones through either "tendinous" attachments or
"fleshy" attachments.
Concept # 2:
Muscles must have at least two attachments and must cross at least
one joint.
This muscle has ______ attachments.
Does it cross a joint?
Concept # 3:
Muscles can affect the shape of bones: Wolff's Law
See: http://en.wikipedia.org/wiki/Wolff's_law & look at examples
too.
Concept # 4:
Muscles always "pull" and get shorter.
The attachment that moves (the one 'pulled') is known as the
Insertion and is usually distal.
The attachment that stays put (and pulls the other attachment site
toward it) is known as the Origin and is usually proximal.
Concept # 5:
Muscle attachments are identified.
Concept # 6:
Movement that decreases the angle is known as flexion.
Movement that increase the angle is known as extension.
‘when a muscle moves ventral to ventral it is a FLEXOR!’
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The angle between the ventral sides is decreased.
‘ muscles that move the dorsal side towards the dorsal side are known
as EXTENSORS!’
VENTRAL SIDE has FLEXORS ONLY!
DORSAL SIDE is where EXTENSORS are
located!
The muscle that is pulling is known as the primary mover (agonist).
The muscle that is partially relaxed is known as the antagonist.
Concept # 7:
Muscles work in opposing pairs.
If a muscle can flex (ventral location) a joint, then there is an
opposite muscle on the other side that extends the joint (dorsal
location).
If there is a muscle that rotates a joint one way, then there has
to be a muscle on the opposite side that will rotate the muscle
back
(Example: supinator rotates the palm up and the pronator
rotates the palm down.)
Concept # 8:
Muscle striation/fiber direction point to attachments and show
direction of pull.
Remember to:
Reduce, Recite, Reflect, & Review!
& Study 3 x 5!
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