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Articulations Articulations • junction of 2 bones • MOTION

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Articulations Articulations • junction of 2 bones • MOTION Powered By Docstoc
					             Articulations
• junction of 2 bones
• MOTION OCCURS AT A JOINT -- NOT
  AT A LIMB
  – i.e. elbow flexion NOT forearm flexion
      Classification of joints
• Synarthroses - fibrous joint with little or
  no movement
• Amphiarthroses - cartilaginous joints
  with some motion
• Diarthroses - (aka synovial) - freely
  movable joint
         Joint Classification
• based on
  – number of axes of rotation
  – number of planes of motion
  – e.g. uniaxial -- 1 axis of rotation so 1 plane
    of motion
Ball and Socket = Triaxial
  e.g., flexion & extension       Condyloid = Biaxial
internal & external rotation     e.g., flexion & extension
   abduction & adduction       internal & external rotation
                              Pivot = uniaxial
                              e.g., supination
     Hinge = uniaxial
                              & pronation
e.g., flexion and extension
Gliding = no axes
   ‘gliding between
      2 flat bones’
                                        Saddle = biaxial
                                       same as condyloid
                                        but greater ROM


             Ellipsoidal = biaxial
           e.g., flexion & extension
            abduction & adduction
   Structure of Synovial Joint
A - articular (hyaline)
  cartilage (1-7 mm)
  – smooth elastic tissue on
    ends of bone
  – 60-80% water
  – no blood supply
  – absorbs shock,
    distributes force and
    provides a low friction
    surface
     Structure of Synovial Joint
B - fibrous capsule
  – very fibrous collagen
    tissue used to hold bones
    together
C - synovial membrane
  – lines the joint cavity
  – secretes synovial fluid to
    lubricate and provide
    nutrition




   NOTE: B & C combine to form the articular capsule
   or joint capsule
   Structure of Synovial Joint

D - ligaments
  – connect bone-to-bone
  – usually restrict ROM
    at a joint


• tendons (not shown)
  – connect muscle-to-     A* - Joint cavity

    bone
     Other Structures of Synovial
                Joints
• bursa                                  Olecranon
  – small capsules lined with synovial   bursa
    membranes
  – reduces friction between other
    structures in the joint
• tendon sheaths
  – fascia surrounding tendon to
    reduce friction between tendon and
    surrounding structures
                                             Digital
                                             synovial
                                             sheath
Other Structures of Synovial Joints

articular fibrocartilage
  – different from articular cartilage
  – takes the form of a fibrocartilaginous
    disc or partial disc
      • distributes load over joint surface
      • improve fit of articulating surfaces
      • limit slipping of one bone relative to
        other
      • protect periphery of articulation
      • lubricate articulation
      • absorb shock
close-packed vs. loose
packed
close packed
  position
  – maximum contact
    area
  – minimum mobility
  – maximum stability
          Bony Stability (cont.)
• amount of contact area
    Joint Stability - Connective
              Tissue
• ligamentous support
    Properties of Connective
             Tissue
• elasticity
  – ability to return to normal state after stretch
  – elastic limit
     • stretch beyond this limit will cause permanent
       damage
• plasticity
  – stretched too far such that does not return
    to its normal state
     • ligament sprain (worse than bone fracture)
              elastic      Sprains occur in this region
Exercise       limit
will help
                                  plastic
increase
the loads                                   Sprains result
a ligament                                  in decrease of
or tendon                                   joint stability
can sustain



                        deformation (length)
       Joint Stability - Muscles
• muscular
  arrangement
  – ability of muscle to
    provide support
  – muscle fatigue
     • cruciate rupture more
       likely when muscle is
       fatigued
               Mobility
• degree to which an articulation is
  allowed to move before being restricted
  by surrounding tissues
• ROM a.k.a. flexibility
       Stability v. Mobility
• trade-off between stability and
  mobility
   –increase stability decrease
    mobility
   –vice-versa
   Neuromuscular Response to
          Stretching
•Sensory neurons provide feedback on
 the characteristics of the muscle or
 other tissues.

2 neuromuscular proprioceptors:
  MUSCLE SPINDLES &
     GOLGI TENDON ORGANS
               Muscle Spindles
• location:
   – interspersed throughout muscle
     belly
• responds to:
   – muscle length
   – muscle velocity
• causes:
   – autogenic facilitation
   – reciprocal inhibition
              Stretch Reflex
• The muscle spindle is responsible for the stretch
  reflex.
• As a muscle is rapidly stretched, the muscle
  spindle responds by facilitation of the same
  muscle and inhibition of the antagonistic
  muscle.
• This reflex can be seen in the patellar tendon
  tap.
         Golgi Tendon Organ
• location:                                Muscle Fibers
  – near the muscle-tendon
                                GTO
    junction
• responds to:
  – muscle tension
• causes:
  – autogenic inhibition          tendon
  – antagonistic facilitation
GOLGI TENDON ORGAN
           “My Little GTO”
• possibly the critical determinant to maximal
  lifting levels in weight training

• may also be responsible for uncoordinated
  responses in untrained individuals

• response is adapted through training
BALLISTIC                      STATIC
          activate muscle     if static position
          spindles which      achieved slowly then
          elicits a stretch   can minimize muscle
               reflex         spindle response

                              if held for sufficiently
                              long period (~30s) then
                                    can elicit GTO
                                       response


     may result in
     tearing a muscle
  STATIC BETTER THAN BALLISTIC
Spindle response: minimal if performed slowly

GTO response: active stretch of hip extensors
causes GTO to relax hip extensors and to
activate the hip flexors

motive force: actions of the hip flexors

consequences: no negatives -- limited ROM        ACTIVE
limits possibility of injury and exercise       STRETCH
antagonists
Spindle response: minimal if performed slowly

GTO response: passive stretch of hip extensors
causes GTO to relax hip extensors

motive force: external force

consequences: no direct control of ROM thus      PASSIVE
may exceed physiological limits and induce
muscle damage                                    STRETCH
                    Stretching
• Proprioceptive Neuromuscular Facilitation
• PNF
   – alternating contraction - relaxation of agonist &
     antagonist muscles
   – takes advantage of the response of the proprioceptors
   – e.g. hamstrings
      • passive static stretch of hams - relax
      • active maximal concentric action of hams - relax
      • repeat
            Plyometric Training

Plyometric training consists of exercises that rapidly
stretch a muscle followed immediately by a
contraction. They improve power output in the muscle
by:
Neurological Influences: rapidly stretching of the
muscle, which excites the motoneurons via the stretch
reflex.
Structural Influences: involving elastic energy from
the stretch-shortening cycle.
     Arthritis
• Refers to more than 100
different diseases that
affect areas in or around
joints.

• The disease also can
affect other parts of the
body.

• Arthritis causes pain,
loss of movement and
sometimes swelling.

•Affects women more
than men
                            Source: Arthritis Foundation – www.arthritis.org
                        Osteoarthritis
                         20.7 million
                      Mostly after age 45
   Rheumatoid                                           Fibromyalgia
    2.1 million                                          3.7 million
  Mostly women                                          Mostly women




   Juvenile
                                                               Gout
   Arthritis
   285,000                Arthritis                         2.1 million
                                                            Mostly men
 Under age 17




Juvenile Rheumatoid                              Spondylarthropathies
   Arthritis (JRA)                                    412,000
       50,000                Lupus
                            239,000

                                      Source: Arthritis Foundation – www.arthritis.org
 Osteoarthritis (OA), or degenerative
 joint disease, is one of the oldest and
 most common types of arthritis,
 characterized by the breakdown of the
 joint's cartilage. Cartilage is the part of
 the joint that cushions the ends of bones.
 Cartilage breakdown causes pain and
 joint swelling. With time, there will be
 limited joint movement.


• Most commonly affects middle-aged and older people
• Range from very mild to very severe
• Affects hands and weight-bearing joints (e.g., knees, hips, feet and back).
• OA is not an inevitable part of aging, although age is a risk factor
• Obesity may lead to osteoarthritis of the knees
• Joint injuries due to sports, work-related activity or accidents may be at
increased risk of developing OA.
                                              Source: Arthritis Foundation – www.arthritis.org
  Rheumatoid Arthritis (RA)
   – a systemic disease that
    affects the entire body.




• Characterized by the inflammation of the membrane lining the joint, which
causes pain, warmth, redness and swelling.
• The inflamed joint lining, the synovium, can invade and damage bone and
cartilage.
• Inflammatory cells release enzymes that may digest bone and cartilage.
• The involved joint can lose its shape and alignment, resulting in pain and
loss of movement.
• The disease usually begins in middle age, but can start at any age, and
affects two to three times more women than men.
                                          Source: Arthritis Foundation – www.arthritis.org
                                                 Location of “Tender Points”



Fibromyalgia syndrome is a condition
with generalized muscular pain and
fatigue that is believed to affect
approximately 3.7 million people.



• The name fibromyalgia means pain in the muscles and the fibrous
connective tissues (the ligaments and tendons). The condition is known
as a syndrome because it is a set of signs and symptoms that occur
together.

• Fibromyalgia mainly affects muscles and their attachments to bones.
Although it may feel like a joint disease, it is not a true form of arthritis
and does not cause deformities of the joints. Fibromyalgia is, instead, a
form of soft tissue or muscular rheumatism.
                                          Source: Arthritis Foundation – www.arthritis.org
     Medicines                       Use of Heat or Cold                                  Rest
 (e.g., analgesics, NSAIDS,          Helpful before and after exercise       More rest and less activity are
DMARDS, Disease Modifying                  Many respond better                needed during flares and the
   Anti-Rheumatic Drugs)                to cold packs than to heat          opposite is true during periods of
                                                                                      improvement.




       Surgery                                                                    Exercise
     joint replacement                                                         (see next slide)
                                Arthritis Treatments
                                                                            Joint Protection
                                                                 Careful use of joints to limit the pressure on the
                                                                                   involved joint
                                                                    Simple and inexpensive devices available



                                                                                  Diet
      Physical/Occupational Therapy                        • Lack of vitamins associated with progression of
      • recommend and teach prescribed muscle              OA of the knee
      strengthening and range-of-motion exercises          • Connection between obesity and OA of the knee
      • teach non-medication ways to control pain          • Diet high in Omega 3 fatty acids may help reduce
      • suggest ways to make everyday and work             inflammation in RA
      activities easier                                    • In general, people with arthritis are urged to
                                                           maintain a balanced diet and stay close to their
                                                           ideal weight.


                                                         Source: Arthritis Foundation – www.arthritis.org
                                                Exercise
• Proper exercises performed on a daily basis are an important part of arthritis treatment.
• Exercise to help reduce weight can help prevent osteoarthritis in the knee.
• Proper exercise helps build and preserve muscle strength, keep joints flexible and help protect
joints from further damage.
                                        Two categories of exercise:
• Therapeutic -- Prescribed by a doctor, physical therapist or an occupational therapist. These exercises are
based on individual needs and are designed to reach a certain goal.
• Recreational -- Includes any forms of movement, amusement or relaxation that refreshes the body and
mind. These exercises add to a therapeutic program, but do not replace it.
                                         Three types of exercises:
•Range-of-motion -- Moving a joint as far as it comfortably will go and then stretching it a little further.
Range-of-motion exercises are designed to increase and maintain joint mobility that will decrease pain and
improve function.
•Strengthening -- Increases muscle strength to stabilize weak joints. These exercises use the muscle
without moving the joint.
•Endurance -- This type of exercise includes walking, swimming, bicycling, jogging, dancing and skiing.
These dynamic forms of exercise increase endurance, whereas range-of-motion and strengthening do not.
The most common risk in exercising is injury to joints and muscles. This usually happens from exercising
too long or too hard, especially if a person has not been active for some time.




                                                          Source: Arthritis Foundation – www.arthritis.org

				
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