Joints
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Articulations of bones
Functions of joints
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Hold bones together
Allow for mobility
Ways joints are classified
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Functionally
Structurally
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Synarthroses
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Amphiarthroses
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Immoveable joints
Slightly moveable joints
Diarthroses
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Freely moveable joints
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Fibrous joints
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Cartilaginous joints
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Generally immoveable
Immoveable or slightly moveable
Synovial joints
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Freely moveable
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Lies between tibia and fibula (interosseous membrane)
Fibula
Fibrous joint
Tibia
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Suture:
• Between flat bones
• Teeth-like projections
• Thin layer of connective tissue connects bones
• Skull
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There are two (2) types of cartilaginous
joints (amphiarthroses):
• Synchondrosis - plate of hyaline cart.
• Symphysis - pad or plate of
fibrocartilage
•
Synchondrosis:
• Bands of hyaline cartilage unite bones
• Epiphyseal plate (temporary)
• Between manubrium and the first rib (costal
cartilages)
Costal cartilage
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Symphysis:
• Pad of fibrocartilage between bones
• Pubic symphysis
• Joint between bodies of adjacent vertebrae
Pubis
Fibrocartilage
disc of
symphysis pubis
Band of
fibrocartilage
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Synovial joints are freely moveable
(diarthroses)
There are six (6) types of diarthroses
There are specific parts of a diarthroses:
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Articular cartilage
Joint cavity
Joint capsule
Synovial membrane
Synovial Bursae
Spongy
bone
Joint cavity filled
with synovial
fluid
Joint
capsule
Synovial
membrane
Articular
cartilage
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Articular cartilage – hyaline cartilage covers the surface
of each bone
Joint capsule – double layered capsule surrounding
cavity
Synovial cavity – space filled w/ synovial fluid
Synovial fluid – viscous lubricating fluid
Reinforcing ligaments – ligaments that strengthen joint
- ligament - joins a bone to another bone
Other joint features:
1.
Fatty pad (hips & knee)
2.
Menisci or articular discs – separate cavity into 2
compartments (ex. Knee, jaw, sternoclavicular)
3.
Bursa – flattened fibrous sacs w/ synovial membrane
and fluid that act as “ball bearings” to prevent friction
on adjacent structures during joint activity.
a. Cushion movement of one body part over another
b. Located between skin and bone (where skin rubs over bone)
and between muscle, tendons, ligaments and bone
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Uniaxial
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Biaxial
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Hinge joint - elbow & knee
Pivot joint - articulation of atlas and axis of cervical vertebra
Saddle joint - thumb
Condylar joint - wrists & knuckles
Multiaxial
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Ball and socket joint - hip & shoulder
Gliding joint - intervertebral discs and between carpals and
tarsals
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Hinge Joint
• Elbow joint
• Between phalanges
Pivot Joint
• Between atlas (C1) and the dens of axis (C2)
dens
atlas
humerus
radius
axis
Hinge joint
Transverse
ligament
Pivot joint
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Saddle Joint
• Between carpal and 1st metacarpal (of thumb)
Condylar Joint
• Between metacarpals and phalanges
• Between radius and carpals
Saddle joint
Condylar joint
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Ball-and-Socket Joint
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Hip joint
Shoulder joint
Gliding Joint
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Between carpals
Between tarsals
Between facets of adjacent vertebrae
Ball and Socket Joint
Gliding Joint
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The shoulder, elbow, and knee are large, freely
moveable joints.
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Ball-and-socket
Head of humerus and glenoid cavity of scapula
• Loose joint capsule
• Bursae
• Ligaments prevent displacement
• Very wide range of movement (circumduction)
Gliding joint
• Between acromion process and clavicle
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•
clavicle
scapula
subdeltoid
bursa
acromion
process
humerus
Joint
capsule
•
Hinge joint
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humerus
Gliding joint
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Trochlea of humerus
Trochlear notch of ulna
Joint capsule
Capitulum of humerus
Head of radius
Joint cavity
radius
Flexion and extension
Many reinforcing
trochlea
ligaments
Stable joint
ulna
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Largest joint
Most complex – 3 joints
• Medial and lateral
condyles of distal end of
femur and
• Medial and lateral
condyles of proximal end
of tibia and
• Femur articulates
anteriorly with patella
Strengthened by many
ligaments and tendons
Menisci separate femur and
tibia
Bursae
femur
synovial
membrane
joint
cavity
prepatellar
bursa
patella
menisci
joint
capsule
tibia
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Joint stiffness is an early sign of aging
Fibrous joints first to change; can strengthen
however over a lifetime
Changes in symphysis joints of vertebral
column diminish flexibility and decrease height
(remember water loss from the IVDs)
Synovial joints lose elasticity
Disuse hampers the blood supply
Activity and exercise can keep joints functional
longer