1. Chapter 8 Joints of the Skeletal System
Joint- site where two bones come together
Articulation – functional junctions between bones
FUNCTIONS OF JOINTS:
Articulations
Junctions between bones
Binds parts of skeletal system together
Makes bone growth possible
Permit parts of the skeleton to change shape during childbirth
Enable body to move in response to skeletal muscle contraction
8-2

2. Classification of Joints
Structural Classification
Synovial Joints
Bones separated by a
joint cavity
most complex
allow free movement
hip, knee, shoulder
Fibrous Joints
Bones held together by connective tissues
between bones in close contact
skull sutures and teeth
no joint cavity
Functional Classification
Cartilaginous Joints
Bones held together by cartilage
pubic symphysis and invertebral discs
no joint cavity
Synarthrotic
immovable
Amphiarthrotic
slightly movable
Diarthrotic
freely movable
8-3

3. Fibrous Joints 3 Types Syndesmosis Suture Gomphosis Syndesmosis
long fibers connect bones
amphiarthrotic
distal ends of tibia and fibula
8-4

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
8-5

5. Cartilaginous Joints 2 Types Synchondrosis Symphysis Synchondrosis
bands of hyaline cartilage unite bones
epiphyseal plate (temporary)
between manubrium and first rib
synarthrotic
8-6

6. Cartilaginous Joints Symphysis pad of fibrocartilage between bones
pubis symphysis
joint between bodies of vertebrae
amphiarthrotic
8-7

7. Synovial Joints Diarthrotic – move freely joint cavity joint capsule
articular cartilage
Osteoarthritis
synovial fluid
reinforcing ligaments
fatty pads
menisci
bursae – flattened fibrous sacs that prevent friction
8-8

8. Synovial fluid A lubrication fluid within the joint cavity
Functions of SF:
Reduces friction between cartilages of 2 bones
Nourishes cartilage of the joint
Contains phagocytes
Provides “weeping lubrication”

9. Types of Synovial Joints
Condyloid (ellipsoid) Joint
permit all angular movement, except rotation
between metacarpals and phalanges
knee
Ball-and-Socket Joint
all angular movement
hip
shoulder
8-9

10. Types of Synovial Joints
Gliding (plane) Joint
cartilaginous joints
intervertebral discs
between carpals and tarsals
Hinge Joint
permit flexion and extension
only
elbow
between phalanges
8-10

11. Types of Synovial Joints
Pivot Joint
permit rotation
between proximal ends of radius and ulna
Saddle Joint
between carpal and metacarpal of thumb
8-11

12. General Types of Movements
1. Gliding movements – when flat bones surfaces glide or slide over one another
2. Angular movements – changes in angles between bones (synovial joints)
3. Special Movements – at special joints

13. Gliding Movements Occur at cartilaginous joints Examples:
Intervertebral disc
Sternoclavicular joint

14. Angular Movements abduction/adduction dorsiflexion/plantarflexion
flexion/extension/hyperextension
8-12

15. Angular Movements
rotation/circumduction
8-13

16. Special Movements supination/pronation eversion/inversion
protraction/retraction
elevation/depression
supination/pronation
8-14

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
8-15

18. Shoulder Joint
8-16

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
8-17

20. Elbow Joint
8-18

21. Hip Joint ball-and-socket joint head of femur acetabulum
heavy joint capsule
many reinforcing ligaments
less freedom of movement than shoulder joint
8-19

22. Hip Joint
8-20

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
flexion/extension/little rotation
strengthened by many ligaments and tendons
menisci separate femur and tibia
bursae
8-21

24. Knee Joint
8-22

26. Life-Span Changes
Joint stiffness is an early sign of aging (next slide)
Regular exercise can prevent stiffness
Fibrous joints first to strengthen over a lifetime. Sutures during infancy
Ligaments lose their elasticity and become tightly crossed linked.
Changes in symphysis joints of vertebral column diminish flexibility and decrease height
Synovial joints start to lose elasticity in 30’s. Affects range of motion and can upset balance, contributing to more falls later in life.
8-23

28. Joint Disorders Sprains
damage to cartilage, ligaments, or tendons associated with joints
forceful twisting of joint (slide)
Bursitis
inflammation of a bursa
overuse of a joint
Arthritis
inflamed, swollen, painful joints
over 100 types of arthritis
involves cartilage, bone, muscles, tendons, ligaments,
and nerves
10% of the population
no cure
8-24

30. Types of Arthritis
Rheumatoid Arthritis – the synovial membranes of the joints and connective tissues grow abnormally to form a layer in the joint capsule.
- this layer grows into the articular surface, destroying cartilage and fusing bones of the joint.
Osteoarthritis – degenerative joint disease, occurs in people in their 70’s.
- more common in overweight people
- exercise can prevent this disease

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