1. Chapter 9: Articulations

2. Articulations Body movement occurs at joints (articulations) where 2 bones connect Body movement occurs at joints (articulations) where 2 bones connect

3. Joint Structure Determines direction and distance of movement (range of motion) Determines direction and distance of movement (range of motion) Joint strength decreases as mobility increases Joint strength decreases as mobility increases

4. What are the major categories of joints, and the structure and function of each category?

5. Functional Classification Table 9–1

6. Structural Classifications Bony Bony Fibrous Fibrous Cartilaginous Cartilaginous Synovial Synovial

7. Synostosis Fused bones, immovable: Fused bones, immovable: –metopic suture of skull –epiphyseal lines of long bones

8. Fibrous Joint Gomphosis – periodontal ligament Gomphosis – periodontal ligament Syndesmosis – interosseous membrane Syndesmosis – interosseous membrane Suture – have fibrous strands Suture – have fibrous strands

9. Cartilagenous Joint Is a rigid cartilaginous bridge between 2 bones: Is a rigid cartilaginous bridge between 2 bones: –epiphyseal cartilage of long bones –between vertebrosternal ribs and sternum

10. What is the basic structure of a synovial joint, and what are the common accessory structures and their functions?

11. Synovial Joints (Diarthroses) Also called moveable joints Also called moveable joints At ends of long bones At ends of long bones Within articular capsules Within articular capsules Lined with synovial membrane Lined with synovial membrane

12. Articular Cartilages Pad articulating surfaces within articular capsules: Pad articulating surfaces within articular capsules: –prevent bones from touching Smooth surfaces lubricated by synovial fluid: Smooth surfaces lubricated by synovial fluid: –reduce friction

13. Synovial Fluid Contains slippery proteoglycans secreted by fibroblasts Contains slippery proteoglycans secreted by fibroblasts

14. Functions of Synovial Fluid 1. Lubrication 2. Nutrient distribution 3. Shock absorption

15. Synovial Joints: Accessory Structures Cartilages Cartilages Fat pads Fat pads Ligaments Ligaments Tendons Tendons Bursae Bursae

16. Cartilages Cushion the joint: Cushion the joint: –fibrocartilage meniscus (articular disc)

17. Fat Pads Superficial to the joint capsule Superficial to the joint capsule Protect articular cartilages Protect articular cartilages

18. Accessory Ligaments Support, strengthen joints Support, strengthen joints Sprain: Sprain: –ligaments with torn collagen fibers

19. Tendons Attach to muscles around joint Attach to muscles around joint Help support joint Help support joint

20. Bursae Pockets of synovial fluid Pockets of synovial fluid Cushion areas where tendons or ligaments rub Cushion areas where tendons or ligaments rub

21. Synovial Joints: Stabilizing Factors Prevent injury by limiting range of motion: Prevent injury by limiting range of motion: –collagen fibers (joint capsule, ligaments) –articulating surfaces and menisci –other bones, muscles, or fat pads –tendons of articulating bones

22. Injuries Dislocation (luxation): Dislocation (luxation): –articulating surfaces forced out of position –damages articular cartilage, ligaments, joint capsule Subluxation: Subluxation: –a partial dislocation

23. What are the dynamic movements of the skeleton?

24. Types of Dynamic Motion Linear motion (gliding) Linear motion (gliding) Angular motion Angular motion Rotation Rotation

25. Linear Motion Pencil maintains vertical orientation, but changes position Pencil maintains vertical orientation, but changes position Figure 9–2a, b

26. Angular Motion Pencil maintains position, but changes orientation Pencil maintains position, but changes orientation Figure 9–2c

27. Circumduction Circular angular motion Circular angular motion Figure 9–2d

28. Rotation Pencil maintains position and orientation, but spins Pencil maintains position and orientation, but spins Figure 9–2e

29. Planes (Axes) of Dynamic Motion Monaxial (1 axis) Monaxial (1 axis) Biaxial (2 axes) Biaxial (2 axes) Triaxial (3 axes) Triaxial (3 axes)

30. Abduction Figure 9–3b, c

31. Abduction Angular motion Angular motion Frontal plane Frontal plane Moves away from longitudinal axis Moves away from longitudinal axis

32. Adduction Angular motion Angular motion Frontal plane Frontal plane Moves toward longitudinal axis Moves toward longitudinal axis

33. Circumduction Circular motion without rotation Circular motion without rotation Angular motion Angular motion Figure 9–3d

34. Rotation Figure 9–4

35. Rotation Direction of rotation from anatomical position Direction of rotation from anatomical position Relative to longitudinal axis of body Relative to longitudinal axis of body

36. Rotation Left or right rotation Left or right rotation Medial rotation (inward rotation): Medial rotation (inward rotation): –rotates toward axis Lateral rotation (outward rotation): Lateral rotation (outward rotation): –rotates away from axis

37. Pronation and Supination Pronation: Pronation: –rotates forearm, radius over ulna Supination: Supination: –forearm in anatomical position

38. Inversion and Eversion Figure 9–5a

39. Inversion and Eversion Inversion: Inversion: –twists sole of foot medially Eversion: Eversion: –twists sole of foot laterally

40. Dorsiflexion and Plantar Flexion Figure 9–5b

41. Dorsiflexion and Plantar Flexion Dorsiflexion: Dorsiflexion: –flexion at ankle (lifting toes) Plantar flexion: Plantar flexion: –extension at ankle (pointing toes)

42. Opposition Thumb movement toward fingers or palm (grasping) Thumb movement toward fingers or palm (grasping) Figure 9–5c

43. Protraction and Retraction Figure 9–5d

44. Protraction and Retraction Protraction: Protraction: –moves anteriorly –in the horizontal plane (pushing forward) Retraction: Retraction: –opposite of protraction –moving anteriorly (pulling back)

45. Elevation and Depression Figure 9–5e

46. Elevation and Depression Elevation: Elevation: –moves in superior direction (up) Depression: Depression: –moves in inferior direction (down)

47. Lateral Flexion Bends vertebral column from side to side Bends vertebral column from side to side Figure 9–5f

48. What are the types of synovial joints, and the relationship of motion to structure?

49. Classification of Synovial Joints by Shape Gliding Gliding Hinge Hinge Pivot Pivot Ellipsoidal Ellipsoidal Saddle Saddle Ball-and-socket Ball-and-socket A Functional Classification of Synovial Joints PLAY