Articulations junction of 2 bones MOTION OCCURS AT A JOINT -- NOT AT A LIMB –i.e. elbow flexion NOT forearm flexion

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

Condyloid = Biaxiale.g., flexion & extension

internal & external rotation

Ball and Socket = Triaxiale.g., flexion & extension

internal & external rotationabduction & adduction

Hinge = uniaxiale.g., flexion and extension

Pivot = uniaxiale.g., supination& pronation

Gliding = no axes‘gliding between

2 flat bones’

Saddle = biaxialsame as condyloidbut greater ROM

Ellipsoidal = biaxiale.g., flexion & extensionabduction & 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 JointB - 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-

bone

A* - Joint cavity

Other Structures of Synovial Joints

• bursa– small capsules lined with synovial

membranes– reduces friction between other

structures in the joint

• tendon sheaths– fascia surrounding tendon to

reduce friction between tendon and surrounding structures

Olecranon bursa

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 position– maximum contact

area

– minimum mobility

– maximum stability

close-packed vs. loose packed

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)

deformation (length)

load

elas

tic

plastic

elasticlimit

Sprains occur in this region

Sprains resultin decrease ofjoint stability

Exercisewill helpincreasethe loadsa ligamentor tendoncan sustain

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:– near the muscle-tendon

junction

• responds to:– muscle tension

• causes:– autogenic inhibition– antagonistic facilitation

tendon

Muscle Fibers

GTO

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

STATICBALLISTICactivate musclespindles whichelicits a stretch reflex

may result intearing a muscle

if static positionachieved slowly thencan minimize musclespindle response

if held for sufficientlylong period (~30s) then can elicit GTO

response

STATIC BETTER THAN BALLISTIC

ACTIVESTRETCH

Spindle response: minimal if performed slowly

GTO response: active stretch of hip extensorscauses GTO to relax hip extensors and toactivate the hip flexors

motive force: actions of the hip flexors

consequences: no negatives -- limited ROMlimits possibility of injury and exerciseantagonists

PASSIVESTRETCH

Spindle response: minimal if performed slowly

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

motive force: external force

consequences: no direct control of ROM thusmay exceed physiological limits and inducemuscle damage

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

Arthritis

Osteoarthritis20.7 million

Mostly after age 45Rheumatoid2.1 million

Mostly women

Fibromyalgia3.7 million

Mostly women

Gout2.1 million

Mostly men

Spondylarthropathies412,000

JuvenileArthritis285,000

Under age 17

Juvenile RheumatoidArthritis (JRA)

50,000 Lupus239,000


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.


• 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.

Rheumatoid Arthritis (RA) – a systemic disease that affects the entire body.


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

Location of “Tender Points”

• 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.


Arthritis Treatments

Medicines(e.g., analgesics, NSAIDS,

DMARDS, Disease ModifyingAnti-Rheumatic Drugs)

Physical/Occupational Therapy• recommend and teach prescribed muscle strengthening and range-of-motion exercises• teach non-medication ways to control pain• suggest ways to make everyday and work activities easier

RestMore rest and less activity are needed during flares and the

opposite is true during periods of improvement.

Surgeryjoint replacement

Use of Heat or ColdHelpful before and after exercise

Many respond better to cold packs than to heat

Diet• Lack of vitamins associated with progression of OA of the knee • Connection between obesity and OA of the knee• Diet high in Omega 3 fatty acids may help reduce inflammation in RA• In general, people with arthritis are urged to maintain a balanced diet and stay close to their ideal weight.

Joint ProtectionCareful use of joints to limit the pressure on the

involved jointSimple and inexpensive devices available

Exercise(see next slide)


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.


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Articulations junction of 2 bones MOTION OCCURS AT A JOINT -- NOT AT A LIMB –i.e. elbow flexion NOT forearm flexion