1. Articulating your body
Joints
Articulating your body

2. Joints (Articulations)
Weakest parts of the skeleton
Articulation – site where two or more bones meet
Functions of joints
Give the skeleton mobility
Hold the skeleton together

3. Classification of Joints: Structural
Structural classification
focuses on the material between bones
Whether or not a joint cavity is present
The three structural classifications are:
Fibrous
Cartilaginous
Synovial

4. Classification of Joints: Functional
Functional classification is based on the amount of movement allowed by the joint
The three functional classes of joints are:
Synarthroses – immovable
Amphiarthroses – slightly movable
Diarthroses – freely movable

5. Fibrous Structural Joints
The bones are joined by fibrous tissues
There is no joint cavity
Most are immovable
There are three types
Sutures
Syndesmoses
gomphoses

6. Sutures
Figure 8.1a

7. Sutures Occur between the bones of the skull
Comprised of interlocking junctions completely filled with connective tissue fibers
Bind bones tightly together, but allow for growth during youth
In middle age, skull bones fuse and are called synostoses

8. Syndesmoses
Figure 8.1b

9. Syndesmoses Bones are connected by a fibrous tissue ligament
Movement varies from immovable to slightly variable

10. Gomphoses
The peg-in-socket fibrous joint between a tooth and its alveolar socket
The fibrous connection is the periodontal ligament

11. Cartilaginous Joints Articulating bones are united by cartilage
Lack a joint cavity
Two types – synchondroses and symphyses

12. Synchondroses
Figure 8.2a, b

13. Synchondroses A bar or plate of hyaline cartilage unites the bones
All synchondroses are synarthrotic

14. Symphyses
Figure 8.2c

15. Symphyses
Hyaline cartilage covers the articulating surface of the bone and is fused to an intervening pad of fibrocartilage
Amphiarthrotic joints designed for strength and flexibility

16. Synovial Joints
Those joints in which the articulating bones are separated by a fluid-containing joint cavity
All are freely movable diarthroses
Examples – all limb joints, and most joints of the body

17. General Structure Synovial joints all have the following
Articular cartilage
Joint (synovial) cavity
Articular capsule
Synovial fluid
Reinforcing ligaments

18. General Structure
Figure 8.3a, b

19. Friction-Reducing Structures
Bursae – flattened, fibrous sacs lined with synovial membranes and containing synovial fluid
Common where ligaments, muscles, skin, tendons, or bones rub together
Tendon sheath – elongated bursa that wraps completely around a tendon

20. Friction-Reducing Structures
Figure 8.4

21. Range of Motion Nonaxial – slipping movements only
Uniaxial – movement in one plane
Biaxial – movement in two planes
Multiaxial – movement in or around all three planes

22. Stability Determined by: Ligaments Muscle tone is accomplished by:
Articular surfaces
shape determines what movements are possible
Ligaments
unite bones and prevent excessive or undesirable motion
Muscle tone is accomplished by:
Muscle tendons across joints acting as stabilizing factors
Tendons that are kept tight at all times by muscle tone

23. Range of Motion Nonaxial Uniaxial Biaxial Multiaxial
slipping movements only
Uniaxial
movement in one plane
Biaxial
movement in two planes
Multiaxial
movement in or around all three planes

24. Gliding Movements
One flat bone surface glides or slips over another similar surface
Examples – intercarpal and intertarsal joints, and between the flat articular processes of the vertebrae

25. Gliding Movement
Figure 8.5a

26. Angular Movement Flexion Extension
bending movement that decreases the angle of the joint
Extension
reverse of flexion; joint angle is increased

27. Angular Movement
Figure 8.5b

28. Knee

29. Angular Movement
Figure 8.5c, d

30. Angular Movement Dorsiflexion and plantar flexion Abduction Adduction
up and down movement of the foot
Abduction
movement away from the midline
Adduction
movement toward the midline
Circumduction
movement describes a cone in space

31. Angular Movement
Figure 8.5e, f

32. Rotation The turning of a bone around its own long axis Examples
Between first two vertebrae
Hip and shoulder joints
Figure 8.5g

33. Special Movements Supination and pronation Inversion and eversion
Protraction and retraction
Elevation and depression
Opposition

34. Special Movements
Figure 8.6a

35. Special Movements
Figure 8.6b

36. Special Movements
Figure 8.6c

37. Special Movements
Figure 8.6d

38. Special Movements
Figure 8.6e