1. Chapter 8 Joints of the Skeletal System
Articulations
Functional junctions between bones
Bind parts of skeletal system together
Make bone growth possible
Permit parts of the skeleton to change shape during childbirth
Enable body to move in response to skeletal muscle contraction

2. Classification of Joints
Fibrous Joints
dense connective tissues connect bones
between bones in close contact
synarthrotic
immovable
amphiarthrotic
slightly movable
diarthrotic
freely movable
Cartilaginous Joints
hyaline cartilage or fibrocartilage connect bones
Synovial Joints
most complex
allow free movement
held together by a fluid filled joint cavity

3. Fibrous Joints 3 Types Syndesmosis Suture Gomphosis Syndesmosis
a sheet or bundle of fibrous tissue connects bones
amphiarthrotic
lies between tibia and fibula

4. Fibrous Joints Suture between flat bones synarthrotic
thin layer of connective tissue connects bones
Gomphosis
cone-shaped bony process in a socket
tooth in jawbone
synarthrotic

5. Cartilaginous Joints 2 Types Synchondrosis Symphysis Synchondrosis
bands of hyaline cartilage unite bones
epiphyseal plate (temporary)
between manubrium and first rib
synarthrotic

6. Cartilaginous Joints Symphysis pad of fibrocartilage between bones
pubis symphysis
joint between bodies of adjacent vertebrae
amphiarthrotic

7. Synovial Joints diarthrotic joint cavity synovial fluid joint capsule
synovial membrane
bursae

8. General structure of a synovial joint
Articular cartilage covers ends of bones
Spongy bone usually beneath cartilage
Subchondral plate between bone and cartilage that absorbs shock
Joint capsule strengthened by ligaments that hold bones together
Synovial membranes secretes a clear viscous synovial fluid

9. Synovial fluid moistens, provides nutrients, and lubricates articular surfaces
Some areas have villi to increase surface area
Menisci divide some synovial joints into compartments
Some joints have fluid filled bursae
Bursae are usually located between the skin and underlying bony prominances

10. Bursae cushion and aid movement of tendons over bony parts
Bursae are named according to their locations

11. Types of Synovial Joints
Ball-and-Socket Joint
hip
shoulder
Widest range of motion
Condyloid Joint
between metacarpals and phalanges
Wide range of movement but not rotation

12. Types of Synovial Joints
Gliding Joint (Plane)
between carpals
between tarsals
Permits sliding and twisting
Hinge Joint
elbow
between phalanges
Moves in one plane only

13. Types of Synovial Joints
Pivot Joint
between proximal ends of radius and ulna
Permits rotation
Saddle Joint
between carpal and metacarpal of thumb
Permits variety of movement

14. Types of Joint Movements
abduction/adduction
dorsiflexion/plantarflexion
flexion/extension/hyperextension

15. Types of Joint Movements
rotation/circumduction
supination/pronation

16. Types of Joint Movements
eversion/inversion
protraction/retraction
elevation/depression

17. Shoulder Joint ball-and-socket head of humerus
glenoid cavity of scapula
loose joint capsule
bursae
ligaments prevent displacement
very wide range of movement

18. Shoulder Joint

19. Elbow Joint hinge joint gliding joint flexion and extension
trochlea of humerus
trochlear notch of ulna
gliding joint
capitulum of humerus
head of radius
flexion and extension
many reinforcing ligaments
stable joint

20. Elbow Joint

21. Hip Joint ball-and-socket joint head of femur acetabulum of coxa
heavy joint capsule
many reinforcing ligaments
less freedom of movement than shoulder joint

22. Hip Joint

23. Knee Joint largest joint – most complex
medial and lateral condyles of distal end of femur
medial and lateral condyles of proximal end of tibia
femur articulates anteriorly with patella
modified hinge joint (2 condyloids & gliding)
flexion/extension/little rotation
strengthened by many ligaments and tendons
menisci separate femur and tibia
bursae

24. Knee Joint

25. Life-Span Changes Joint stiffness is an early sign of aging
Fibrous joints first to change; can strengthen over a lifetime
Changes in symphysis joints of vertebral column diminish flexibility and decrease height
Synovial joints lose elasticity
Disuse hampers the blood supply
Activity and exercise can keep joints functional longer

26. Clinical Application Joint Disorders Sprains
damage to cartilage, ligaments, or tendons associated with joints
forceful twisting of joint
overstretching
Bursitis
inflammation of a bursa
overuse of a joint

27. Arthritis inflamed, swollen, painful joints Rheumatoid Arthritis
autoimmune disorder
synovial membrane thickens forming a mass called a pannus
articular cartilage is damaged and bones may
fuse together (bony ankylosis)
systemic disorder often affecting the skin, eyes,
lungs, blood vessels, and heart

28. Osteoarthritis Most common type
Degenerative and usually occurs with aging
Articular cartilage softens and disintegrates
slowly
Joints become painful with restricted movements

29. Lyme Arthritis Bacterial infection passed in a tick bite
Causes intermittent arthritis of several joints several weeks after initial infection
Symptoms first appear as a rash, fatigue, flulike aches and pains
Treated with antibiotics
May be difficult to diagnose

30. Normal hand

31. Bony Ankylosis of the hand

32. Osteoarthritis – most common type
articular cartilage wears away placing stress
on the subchondral plate
degenerative disorder caused by aging
If a joint is immobilized for a long period of time the articular cartilage may soften and degenerate
Arthroscopy is used to examine a joint – blue box page 271