Download Articulations aka. Joints

Essentials of Human Anatomy & Physiology
Elaine N. Marieb
Seventh Edition
Articulations aka. Joints
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Fundamental Functions
 Hold bones together
 Allow for mobility
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.43
Classification of Joints
 Overall classification is based on 3 criteria:
Highlight these in your notes
 Amount of motion allowed
 Type of material that binds bones
together
 Presence or absence of joint capsule
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.43
Classification
 Functionally – based on amount of motion
allowed
 Synarthroses, amphiarthroses, diarthroses
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.43
Functional Classification of Joints
 Synarthroses – immovable joints
 Amphiarthroses – slightly moveable
joints
 Diarthroses – freely moveable joints
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.44
Where in the Body?


Diarthroses found in limbs where mobility
is important
Synarthroses and amphiarthroses are
found in the axial skeleton where
security/strength and protection of organs
is important
Structural Classification of Joints
 Structural – based on type of material that
binds joint together and on
presence/absence of joint capsule
 Fibrous
 Cartilaginous
 Synovial
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.44
Structural Classification of Joints
 Fibrous joints (Synarthroses)
 Generally immovable - Synarthrotic
 No joint capsule
 Joined by fibrous connective tissue
 Examples:
 Sutures
 Syndesmoses
 Gomphoses
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.45
Sutures


Occur between bones of the skull
Edges of bone interlock and fuse
Syndesmoses


Connected by
ligament or
interosseous
membrane (longer
connecting fibers = a
little more “give”)
Examples:


Distal tibiofibular joint
Down the length of
the radius and ulna
Gomphoses

Tooth held by the periodontal ligament
into the mandible/maxilla socket
Cartilaginous Joints (Amphiathroses)
 Immovable or slightly moveable
 Joined by cartilage
 No joint capsule
 Examples:
 A. Symphyses
 B. Synchondroses
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.45
Symphyses
 Pad or plate of FIBROcartilage – slightly
movable
 Examples
 Pubic
symphysis
 Intervertebral
joints
 Sternal angle
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.27b, c
Slide 5.47
Synchondroses


Connected by bar or plate of HYALINE
cartilage
Examples:


Epiphyseal plate
Costal cartilages to ribs
Synovial Joints (Diarthroses)
 Freely moveable
 Articulating bone ends are
separated by a joint cavity
completely filled with synovial
fluid
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.45
Synovial Joint Structure
Articular cartilage (hyaline cartilage) covers the
ends of bones to cushion & protect
 Joint surfaces are enclosed by a double layered
articular capsule (joint capsule)
 Fibrous capsule – outer capsule – continuous
with periosteum
 Synovial membrane – inner lining – continuous
with articular cartilage.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.49
Synovial Joint Structure


Synovial membrane – secretes synovial
fluid into the joint cavity
 Synovial fluid lubricates the joint
surfaces to reduce friction. It also
nourishes the articular cartilage through
diffusion of substances
Ligaments reinforce the joint
 Intracapsular, extracapsular, capsular
Sports Application



Synovial fluid becomes less viscous (thick)
when it is warm. This allows the joint to
move more freely.
Just another reason to warm up before
you stretch and do other activities.
Just like the oil in your car needs to warm
up so it can lubricate the car parts!
Structures Associated with the
Synovial Joint
 Bursae –
 flattened fibrous sacs lined with synovial membrane and
filled with synovial fluid
 Located where ligaments, muscle, skin, tendons and
bone rub together to reduce friction (knee & elbow)
 False (develop at areas of high friction) vs true (born
with)
 Tendon sheath
 Elongated bursa that wraps around a tendon
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.50
Inflammatory Conditions
 Bursitis – inflammation of a bursa usually
caused by a blow or friction caused by
excessive & repetitive exercise.
 Tendonitis – inflammation of tendon sheaths
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.53
Synovial Joint Structure

Miscellaneous
structures


Fatty pads – located
between fibrous
capsule & synovial
membrane or bone
Menisci –
Fibrocartilage pads –
subdivide cavity and
improve stability/fit
The Synovial Joint
sp-Joints.url
Figure 5.28
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.51
Types of Synovial Joints Based on
Shape
Figure 5.29a–c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Types of Synovial Joints Based on
Shape
sp-Joints.url
Figure 5.29d–f
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Examples of Synovial Joints

Non axial – aka plane – gliding motion


Examples: intercarpal, intertarsal
Uniaxial – one plane of motion


Hinge: elbow, knee, interphalangeal, talus with tibia
Pivot: atlantoaxial, proximal radioulnar
Examples of Synovial Joints

Biaxial – two planes of motion


Condyloid: metacarpophalangeal, atlantooccipital, radiocarpal
Saddle: carpometacarpal joints of thumbs
only
Examples of Synovial Joints

Multiaxial – universal motion

Ball & socket: hip, shoulder
Synovial Joint Movements
Movements




Get together in groups
Define each motion in words – starting on
p.268
Act out each motion
Create a “Cheer” that uses the motions &
their names to help you remember them.
Stability of Joints



Articular surfaces: shallow vs. deep
Muscle tone is the MAJOR factor that
determine joint stability. Bigger muscles
= bigger tendons = bigger bone
attachment points (Wolff’s law)
Ligaments: more ligaments = equal more
stability (also the amount of stress on the
ligament)
Shoulder Joint
Shoulder Joint





Most freely movable but most least stable
Ball & socket joint
Glenoid labrum: rim of fibrocartilage that
deepens glenoid cavity
Reinforcing ligaments primarily on anterior
aspect
Muscle tendons are most important in
stabilty
Shoulder Joint

Superstabilizer of joint
is the tendon of the
long head of the
biceps brachii muscle
Shoulder Joint

Rotator cuff


Other fused tendons
for stability
Can be stretched &
injured during
vigorous circumduction
Shoulder Joint

Dislocates inferiorly/anteriorly due to
weakness of reinforcements
Elbow Joint


Very stable hinge
joint
Main portion of joint
is trochlea with
semilunar notch
Elbow Joint

3 important ligaments
Medial collateral
 Lateral collateral
 Annular ligament – encloses the radial
head for stability during pronation &
supination


Several tendons cross joint to provide
stability
Ligaments of Elbow
Hip Joint

Less movable but very stable




Large muscles & ligaments
Deep socket
Acetabular labrum enhances depth of
socket
Hip displacements are rare due to the
stability of the joint – It takes great force
to dislocate a hip joint
Hip Joint
Hip Socket

3 main ligaments



Iliofemoral
Pubofemoral
ischiofemoral
Hip Joint


These ligaments are arranged so that the
head of the femur is actually screwed
deeper into the socket upon standing
Ligamentum teres contains a small artery
that supplies nutrients to the head of the
femur. Any damage to this artery can
lead to severe arthritis
Hip Joint

This is the most common joint replaced.
The Knee
Knee Joint Structure



Largest joint in body - Very complex
Joint is only partially enclosed by capsule
– capsule is absent anteriorly – This
increases the flexibility of the knee
Contains 10 bursae (& maybe additional
false bursa)
Knee Bursae
Menisci

C-shaped fibrocartilage – deepen articular
cartilage
Menisci



Increases lateral stability
Absorbs shock
Only attached at outer margin so loose
ends are frequently torn in sports injuries
Reinforcement

Extracapsular – help stabilize entire joint





Patellar ligament
Lateral collateral – critical in preventing lateral
angular motion
Medial collateral – critical in preventing medial
angular motion
Oblique popliteal
Arcuate popliteal
Intracapsular


Help prevent displacement of articular
surfaces
Anterior cruciate




Attached to the anterior tibia
Prevents overextension
Taut when knee is extended
Posterior cruciate



Attached to the posterior tibia
Prevents overflexion
Taut when knee is flexed
Stability



The knee is strongly reinforced by
muscles, tendons, and ligaments
BUT relatively unprotected by muscle
Muscle strength is very important for
stability – bigger muscles = bigger
tendons that help to stabilize
Muscles
Anterior Knee Structure
Structures Most Often Injured



Medial Meniscus
Medial Collateral Ligament
Anterior Cruciate Ligament


This ligament is tight (taut) when the joint is
extended
The posterior ligament is tight when the joint
is flexed – so it is harder to injure
Homeostatic Imbalances

Sprains



Stretched & torns ligaments
Heal slowly due to poor vascularity of
cartilage
Dislocations or Subluxation must be
reduced
Arthritis
Main definition: synovial
membrane thickening and
decrease in synovial fluid
production
Osteoarthritis



Define: Chronic Degenerative (non
inflammatory)
Who affected: aged
Symptoms:

Erosion of articular cartilages, contact of bone
surfaces, bone spurs form that enlarge the
bone ends, joint motion restricted, stiffness &
pain
Osteoarthritis


Major symptom: crepitus: crunching noise
made by affected joints resulting from
contact of roughened articular surfaces
Treatment: analgesics, bedrest, moderate
exercise
Ostearthritis
Rheumatoid Arthritis



Define: autoimmune disorder, chronic
inflammatory
Who affected: women age 40+ (also a
juvenile version)
Symptoms: bilateral, remissions &
exacerbations, synovial membrane
thickens & fluid production decreases,
cartilage & bone may eventually be
eroded away
Rheumatoid Arthritis


Pannus: abnormal tissue that clings to
articular cartilage – may cause joint fusion
known as ANKYLOSIS
Treatments: drug therapy, cold & hot
packs, mild exercise to prevent fusion,
joint replacement
Rheumatoid arthritis
Rheumatoid Arthritis
Gouty Arthritis




Define: Hyperurecemia – buildup of sodium
urate crystals
Most commonly affected: men
Symptoms: usually single joint – swollen &
painful
Treatments: drug therapy if continual, cold pack
& analgesics, watch diet (liver, kidney, sardines,
anything high in purines), avoid alcohol and
excessive Vitamin C
Gouty Arthritis
Gout
Extra Terms


Ankylosing Spondylitis: variation of
rheumatoid arthritis – affects men –
progresses superiorly along spine causing
spinal fusion
Synovitis: inflammation of synovial
membrane of a joint causing swelling &
joint movement limitation