1. Joints
Joint Fundamentals

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 binding bones together and 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 dense, connective fibrous tissues
There is no joint cavity
Most are immovable
There are three types – sutures, syndesmoses, and gomphoses

6. Fibrous Structural Joints: 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

7. Fibrous Structural Joints: Sutures
Figure 8.1a

8. Fibrous Structural Joints: Syndesmoses
Bones are connected by a fibrous tissue ligament
Movement varies from immovable to slightly variable
Examples include the connection between the tibia and fibula, and the radius and ulna

9. Fibrous Structural Joints: Syndesmoses
Figure 8.1b

10. Name two functions of joints.
Review
Name two functions of joints.
Name three structural classification of joints.
Name three functional classification of joints.
Name three types of fibrous joints.
Where is the most prominent place to find suture joints.
Name one example of Syndesmoses joint.
Joint Fundamentals

11. Fibrous Structural Joints: Gomphoses
The peg-in-socket fibrous joint between a tooth and its alveolar socket
The fibrous connection is the periodontal ligament

12. Cartilaginous Joints
Articulating bones are united by hyaline cartilage or disks of fibrocartilage
Lack a joint cavity
Two types – synchondroses and symphyses

13. Cartilaginous Joints: Synchondroses
A bar or plate of hyaline cartilage unites the bones
Examples include:
Epiphyseal plates of children
Joint between the costal cartilage of the first rib and the sternum

14. Cartilaginous Joints: Synchondroses
Figure 8.2a, b

15. Cartilaginous Joints: 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
Examples include intervertebral joints and the pubic symphysis of the pelvis

16. Cartilaginous Joints: Symphyses
Figure 8.2c

17. Synovial Joints
Those joints in which the articulating bones are separated by a fluid-containing joint cavity
Ends of the bones are covered in hyaline cartilage and the ends are encapsulated by synovial fluid
All are freely movable
Examples – all limb joints, and most joints of the body

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

19. Synovial Joints: General Structure
Figure 8.3a, b

20. Table 8.2.1

21. Table 8.2.2

22. Table 8.2.3

23. Ball-and-Socket Joints
Types of Synovial Joints
Ball-and-Socket Joints
A spherical or hemispherical head of one bone articulates with a cuplike socket of another
Multiaxial joints permit the most freely moving synovial joints
Examples: shoulder and hip joints

24. Ball-and-Socket Joints
Figure 8.7f

25. Condyloid Joints
Oval articular surface of one bone fits into a complementary depression in another
Both articular surfaces are oval
Biaxial joints permit all angular motions
Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints

26. Condyloid Joints
Figure 8.7d

27. Planar Joints
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

28. Planar Joints
Figure 8.5a

29. Hinge Joints Hinge joints
Cylindrical projections of one bone fits into a trough-shaped surface on another
Motion is along a single plane
Uniaxial joints permit flexion and extension only
Examples: elbow and interphalangeal joints

30. Hinge Joints
Figure 8.7b

31. Pivot Joints
Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another
Only uniaxial movement allowed
Examples: joint between the axis and the dens, and the proximal radioulnar joint

32. Pivot Joints
Figure 8.7c

33. Similar to condyloid joints but allow greater movement
Saddle Joints
Similar to condyloid joints but allow greater movement
Each articular surface has both a concave and a convex surface
Example: carpometacarpal joint of the thumb
Joints

34. Saddle Joints
Figure 8.7e