Chapter 9, part 1

1. Chapter 9, part 1 Articulations

2. Learning Objectives • Contrast the major categories of joints, and explain the relationship between structure and function for each. • Describe the structure of a synovial joint. • Describe the dynamic movements of the skeleton. • List the types of synovial joint, and discuss the relationship of structure to function in each.

3. Learning Objectives • Describe the structure and function of the vertebrae, shoulder, elbow, hip and knee joints. • Describe the relationship between joint strength and mobility. • Describe the effects of aging on the joints.

4. SECTION 9-1A Classification of Joints

5. Articulations • Articulations • Where two bones interconnect • Immovable joints • Synarthroses, or bony • Slightly moveable joints • Amphiarthroses, or fibrous / cartilagenous • Freely moveable joints • Diarthroses, or synovial

6. Synarthroses (immovable joints) • Four major types • Suture = skull bones bound together by dense connective tissue • Gomphosis = teeth bound to bony sockets by periodontal ligaments • Synchondrosis = two bones bound by rigid cartilaginous bridge • Syntosis = two bones completely fused

7. Amphiarthroses (slightly movable joints) • Two major types • Syndesmosis = bones connected by a ligament • Symphysis = bone separated by fibrocartilage

8. Diarthroses (freely movable joints) • Bony surfaces enclosed within articular capsule • Bony surfaces covered by articular cartilage • Bony surfaces lubricated by synovial fluid • Structures include • Menisci • Fat pads • Accessory ligaments • Bursae

9. Figure 9.1 The Structure of a Synovial Joint Figure 9.1

10. SECTION 9-2Articular Form and Function

11. Dynamic motion • Dynamic motion • Linear motion • Angular motion • Rotation • Joints classified based on type of motion permitted • Monaxial • Biaxial • Triaxial

12. Figure 9.2 A Simple Model of Articular Motion Figure 9.2

13. Types of movement • Gliding motion • Two surfaces slide past one another • Angular motion • Flexion, extension, hyperextension • Abduction, adduction • Circumduction

14. Figure 9.3 Angular Movements PLAY Animation: Flexion, Extension, Hyperextension Figure 9.3

15. Rotational movement • Left or right • Medial (internal) or lateral (external) • Pronation or supination in the bones of the forearm only

16. Figure 9.4 Rotational Movements Figure 9.4a,b

17. Figure 9.4 Rotational Movements Figure 9.4c

18. Special movement • Movements of the foot • Inversion and eversion • Plantar flexion and dorsiflexion • Movements of the thumb • Opposition

19. Other movements • Protraction moves a structure anteriorly • Retraction moves a structure posteriorly • Elevation moves a structure superiorly • Depression moves a structure inferiorly • Lateral flexion bends the vertebrae to one side

20. Figure 9.5 Special Movements Figure 9.5

21. Structural classification of joints • Gliding joints permit movement in a single plane • Hinge joints are monaxial joints permitting angular motion in one plane • Pivot joints are monaxial joints that permit rotation • Ellipsoid joints are biaxial joints that pit one bone in an oval depression of another • Saddle joints are biaxial joints with one concave and one convex bone face • Ball-and-socket joints are triaxial joints that permit rotation and other movements

22. Figure 9.6 A Functional Classification of Synovial Joints Figure 9.6

23. Figure 9.6 A Functional Classification of Synovial Joints PLAY Animation: Joint Motion Figure 9.6