Transcript Ch 6 Movements-Muscle Types-Names

Pages 196-203
Muscles and Body Movements
 Movement is attained as a result of a muscle moving
an attached bone
 Muscles are attached to at least two points
1.
2.
Origin: attaches to an immovable/less movable bone
Insertion: attaches to a movable bone
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Muscle
contracting
Origin
Brachialis
Tendon
Insertion
Types of Body Movements
 Flexion
 Decreases the angle of the joint
 Brings two bones closer together
 Typical of bending hinge joints (e.g., knee and elbow) or
ball-and-socket joints (e.g., the hip)
 Extension
 Opposite of flexion
 Increases angle between two bones
 Typical of straightening the elbow or knee
 Extension beyond 180° is hyperextension
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Flexion
Hyperextension
Extension
Flexion
Extension
(a) Flexion, extension, and hyperextension of the shoulder and knee
Hyperextension
Extension
Flexion
(b) Flexion, extension,
and hyperextension
Types of Body Movements
 Rotation
 Movement of a bone around its longitudinal axis
 Common in ball-and-socket joints
 Example: moving the atlas around the dens of axis (i.e.,
shaking your head “no”)
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Rotation
Lateral
rotation
Medial
rotation
(c) Rotation
Types of Body Movements
 Abduction
 Movement of a limb away from the midline
 Adduction
 Opposite of abduction
 Movement of a limb toward the midline
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Abduction
Adduction
Circumduction
(d) Abduction, adduction,
and circumduction
Types of Body Movements
 Circumduction
 Combination of flexion, extension, abduction, and
adduction
 Common in ball-and-socket joints
 Proximal end of bone is stationary, and distal end moves
in a circle
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Abduction
Adduction
Circumduction
(d) Abduction, adduction,
and circumduction
Special Movements
 Dorsiflexion
 Lifting the foot so that the superior surface approaches
the shin (toward the dorsum)
 Plantar flexion
 Depressing the foot (pointing the toes)
 “Planting” the foot toward the sole
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Dorsiflexion
Plantar flexion
(e) Dorsiflexion and plantar flexion
Special Movements
 Inversion
 Turning sole of foot medially
 Eversion
 Turning sole of foot laterally
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Inversion
(f) Inversion and eversion
Eversion
Special Movements
 Supination
 Forearm rotates laterally so palm faces anteriorly
 Radius and ulna are parallel
 Pronation
 Forearm rotates medially so palm faces posteriorly
 Radius and ulna cross each other like an X
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Pronation
(radius rotates
over ulna)
Supination
(radius and ulna
are parallel)
S P
(g) Supination (S) and pronation (P)
Special Movements
 Opposition
 Moving the thumb to touch the tips of other fingers on
the same hand
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Opposition
(h) Opposition
Types of Muscles
 Prime mover— muscle with the major responsibility
for a certain movement
 Synergist— muscle that aids a prime mover in a
movement and helps prevent rotation
 Fixator— stabilizes the origin of a prime mover
 Antagonist— muscle that opposes or reverses a prime
mover
 It is the actions of all muscles involved that provide
smooth, coordinated and precise movement.
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Naming Skeletal Muscles
 Skeletal muscles can be named according to:
 direction of muscle fibers: rectus (straight)
 relative size of the muscle: maximus (largest)
 location of the muscle: temporalis (temporal bone)
 number of origins triceps (three heads)
 location of origin and insertion: sterno (on the
sternum)
 shape of the muscle: deltoid (triangular)
 action: flexor/extensor (flex/extend a bone)
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Figure 6.15 Relationship of fascicle arrangement to muscle structure.
(a)
(b)
(a) Circular
(orbicularis oris)
(e)
(c)
(b) Converent
(pectoralis major)
(d)
(e) Multipennate
(deltoid)
(f)
(g)
(c) Fusiform
(biceps brachii)
(d) Parallel
(sartorius)
(f) Bipennate
(rectus
femoris)
(g) Unipennate
(extensor digitorum
longus)