Transcript Muscular System Types of Body Movements

Muscular System
Types of Body Movements
600+ skeletal muscles attached to bone or
connective tissue at no less than 2 points
Origin – attached to immovable bone
Insertion – attached to movable bone
MUSCLE MOVES TOWARD ORIGIN
DURING CONTRACTION
Most Common Types of Body
Movements
Flexion (decrease angle)
Extension (increase angle)
Abduction (moving limb away)
Adduction (moving limb toward)
Rotation (move bone along
longitudinal axis)
 Circumduction (combination)
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Common Types of Movement (cont.)
 Pronation (moving palm up to down; forces
radius to cross ulna)
 Supination (moving palm down to up into
anatomical position; radius and ulna
parallel)
 Inversion (turning sole of foot medially)
 Eversion (turning sole of foot laterally)
 Dorsiflexion ( ankle movement/ instep up)
 Plantar flexion (straighten ankle/instep
down)
Types of Muscles
 Movement is result of team of muscles. Whatever team
can do, another team can reverse.
 Prime Mover (agonist) = the muscle (of team) that has
major responsibility for causing a particular movement
 Ex: biceps brachii for elbow flexion
 Antagonist = muscles that oppose or reverse movement
(located opposite side of joint from agonist)
 Ex: triceps brachii antagonizes biceps brachii, but is also
prime mover for forearm extension
 Synergist = muscles that help prime mover
 Add force and reduce undesirable movements
 Fixators = specialized synergists (stabilize)
 Immobilize bone or muscle’s origin (i.e,scapula)
Naming Skeletal Muscle
 Muscles are named on the basis of several
criteria (Look for the hints!)
 Direction of muscle fiber (and fascicles)- in
relation to lines like midline and axis of limb)
 rectus [straight] – run parallel
 oblique –run at a slant
 transversus – at right angles
 Rectus femoris – straight muscle of thigh
 Transversus abdominus
Naming Skeletal Muscle (cont.)
 Relative size of muscle
 maximus [largest] – gluteus maximus
 minimus [smallest]- gluteus minimus
 longus [long]- fibularis longus
 brevis [short] – extensor pollicis brevis
 Number of origins
 Biceps [2], triceps [3], quadriceps [4]
 biceps brachii, triceps brachii, quadriceps
femoris
Naming Skeletal Muscle (cont.)
 Location of muscle’s origin and
insertion
 Ex: intercostal muscle
 “costal” = rib
 runs between the ribs
 Ex: temporalis muscle
 overlies temporal bone
 Ex: sternocleidomastoid muscle
 “sternum” and “clavicle” [origin]
 mastoid process of temporal [insertion]
Naming Skeletal Muscle (cont.)
 Shape of the muscle
 Deltoid = triangular
 Trapezius = trapezoid
 Action of the muscle
 Flexor – flexor digitorum superficialis
 Flexes wrist and middle phalanges
 Extensor – extensor carpi radialis longus
 Action, joint (wrist), lies close to radius of the
forearm, size rel. to other wrist extensors
 Adductor – adductor longus
 Adducts, medially rotates thigh
Muscle Mechanics –Fascicle
Arrangement
 Review muscle force and speed
 Patterns of fascicle arrangement
 Circular – concentric rings (sphincters)
 Orbicularis oculi (eye); orbicularis oris (mouth)
 Convergent – fascicles converge to single tendon of
insertion(triangular or fan-shaped)
 Pectoralis major
 Parallel (& fusiform)– straplike or spindle shaped
 Sartorius (thigh to knee) – longest muscle in body
 Biceps brachii – flexes elbow, supinates forearm
Muscle Mechanics –Fascicle
Arrangement (cont.)
 Pennate – attach obliquely to central
tendon
 Unipennate (one side of tendon) – extensor
digitorum longus (leg)
 Bipennate (from opposite sides of tendon) –
rectus femoris (thigh) [like a feather]
 Multipennate – [like many feathers together]
 Deltoid muscle (shoulder)
Muscle Mechanics –Fascicle
Arrangement (cont.)
 Arrangement determines range of
movement and power
 Parallel = shorten most but not
powerful
 Power depends on total muscle cells
in muscle (more cells=more power)
 Bipennate and multipennate = most
fibers but shorten little & very
powerful
Bone-Muscle Relationships – lever
systems
 Lever systems- partnerships between
muscular and skeletal systems
 Lever – rigid bar that moves on a fixed
point (fulcrum) when force applied
 Applied force (effort) moves a resistance
(load)
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Joints = fulcrums
Bones = levers
Muscle contraction = effort (applied at insertion)
Load = bone + tissues + what is moved with
lever
Bone-Muscle Relationships – lever
systems (cont.)
 Lever operates at mechanical advantage
when load is close to fulcrum and effort is
applied far from fulcrum
 Used to move large load over small distance
(power lever)
 Slower, more stable, strength is priority
 Lever operates at mechanical
disadvantage when load is far from
fulcrum and effort is applied near fulcrum
 Force greater than the load moved (speed lever)
 Force lost, but speed and range of movement
gained
Bone-Muscle Relationships – lever
systems (cont.)
 Lever classes
 First-class lever
 Effort applied at one end of lever; load at other end;
fulcrum between (scissors)
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Lift head off chest
some act at mechanical advantage; others disadvantage
 Second-class lever
 Effort applied at one end; fulcrum at the other end;
load between (wheelbarrow) (uncommon)
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Standing on toes
 Third-class lever
 Effort applied between the load and fulcrum (tweezers)
(act at great speed & mechanical disadvantage)
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Most skeletal muscle