1. Chapter 9: Articulations

2. Articulations Body movement occurs at joints where 2 bones connect
Articulation = joints; site where two or more bones meet

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

4. Anatomical/Structural Classification of Joints (based on connecting material
Fibrous: bones joined by fibrous CT with no space
Cartilaginous: bones joined by pad or bridge of cartilage
Synovial: bones separated by fluid-filled cavity, surrounded by CT

5. Structural Classification
Table 9–2

6. Physiological/Functional Classifications of Joints: (based on the amount of movement)
Synarthrosis: immovable joints
- No movement
- Fibrous or cartilaginous connections
Amphiarthrosis: slightly moveable joint
- Little movement
Diarthrosis: freely moveable joint
- More movement
- always synovial connections

7. What common characteristics do typical synarthrotic and amphiarthrotic joints share?
joint capsules filled with fluids
non-restricted movement of bony regions
bony regions separated by fibrous connective tissue
articular cartilages and bursae

8. Synarthroses (Immovable Joints)
Are very strong
Edges of bones may touch or interlock
4 Types of Synarthrotic Joints
Suture
Gomphosis
Synchondrosis
Synostosis

9. 1. Synarthoroses * Immoveable Strength Synotosis: fused bones
- Suture of skull and epiphyseal lines of long bones
Suture: interlocked bones, sealed with dense CT
- Found only in the skull
Gomphosis: tooth in alveolar socket, held by peridontal ligament
- Binds teeth to sockets
Synchrondrosis: hyaline cartilage bridge between bones
- Epiphyseal cartilage of long bones and between
vertebrosternal ribs and sternum

10. 2. Amphiarthroses * Slightly Moveable, strength with some mobility
Syndesmosis: bones connected by ligament
Symphasis: bones separated by pad of fibrocartilage

11. 3. Diarthorses = Synovial Joints
Great mobility, less strength and stability
At ends of long bones
Within articular capsules
Lined with synovial membrane

12. Features of Synovial Joints
Articular Cartilage
Synovial Cavity
Articular Capsule
Synovial Fluid
Accessory Structures
- Meniscus, fat pad, accessory ligaments, tendons, bursa, synovial tendon sheath

13. (a)
(b)
Synovial
ligament
Bursa
ibia
Femur
Patella
Articular cartilage
Fat pad
Joint capsule
Meniscus
Joint cavity
Intracapsular ligament
Quadriceps tendon
Patellar ligament T
Marrow cavity
Spongy bone
Periosteum
Synovial membrane
Articular capsule
Joint cavity (containing
synovial fluid)
Compact bone

14. 1. Articular Cartilages Hyaline cartilage
No perichondrium or periosteum
Pad articulating surfaces within articular capsules:
prevent bones from touching
Smooth surfaces lubricated by synovial fluid:
reduce friction

15. Features of Synovial Joints
Synovial cavity:
Space between/around opposing bones
Has synovial fluid
Articular Capsule: 2 layers
Outer
dense irregular connective tissue, continuous with periosteum
Inner
synovial membrane (areolar CT), covers inside surface of cavity except articular cartilage, secretes synovial fluid

16. 4. Synovial Fluid
filtrate from blood plasma + hyaluronic acid from fibroblasts
* Functions:
1. Lubrication
2. Nutrient distribution: diffusion
medium
3. Shock absorption

17. Synovial Joints: Accessory Structures
Cartilages (Meniscus)
Fat pads
Ligaments
Tendons
Bursae
Synovial Tendon Sheath

18. Synovial Joints: Accessory Structures
Meniscus:
fibrocartilage pad = articular disc
Subdivides cavity or changes shape of articular surface, limits range of motion
Cushion the joint
Fat Pad:
Adipose
Superficial to joint capsule,
Function: protection and space filler

19. Synovial Joints: Accessory Structures
Accessory Ligaments:
Dense regular connective tissue
Either part of capsule, inside joint, or outside capsule
Function: support and strengthen joint
Sprain: Ligaments with torn collagen fibers
Tendons:
Attach muscle to bone
Function: Add stability to the joint

20. Synovial Joints: Accessory Structures
Bursa:
Synovial fluid filled pocket
Function: reduces friction
Cushion areas where tendons or ligaments rub
Synovial Tendon Sheath:
- Tubular bursa around a tendon

21. Synovial Joints: Stabilizing Factors
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. Functional Classification
Table 9–1

23. synarthrosis; gomphosis symphysis; sutural synchondrosis; synostosis
In a newborn infant, the large bones of the skull are joined by fibrous connective tissue. Which type of joints are these? The bones later grow, interlock, and form immovable joints. Which type of joints are these?
synarthrosis; gomphosis
symphysis; sutural
synchondrosis; synostosis
syndesmosis; sutural

24. Why would improper circulation of synovial fluid lead to the degeneration of articular cartilages in the affected joint?
Synovial fluid nourishes articular cartilage.
Blood flow follows synovial fluid circulation.
Articular cartilage is composed of synovial fluid.
Both A and B.

25. Joint Injuries Sprain: damage to ligament Bursitis:
Some collagen torn, slow to heal
Bursitis:
Inflammation of a bursa due to trauma, infection, or repetitive motion
** Synovial joints stabilized by articular capsule and accessory structures to restrict mobility:
Increase Mobility = Decrease Stability = Increase chance of
dislocation

26. Injuries Luxation: Subluxation: Dislocation Joint Displacement
articulating surfaces forced out of position
Joint Displacement
Usually damages articular cartilage, ligaments, and joint capsule
Pain receptors in all CT of the Joint, except articular cartilage, to prevent actions
Subluxation:
Partial dislocation
Displacement beyond usual anatomical limitation
“Double Jointed”

27. The dynamic movements of the skeleton.

28. Movements at Synovial Joints
Linear Movements:
Gliding: slight movement in any direction
Angular Movements: one plane of motion
Flexion: reduce angle in frontal plane
Extension: increase angle in frontal place
Hyperextension: extension past anatomical position
Abduction: move away from longitudinal axis in
sagittal plane
Adduction: move toward longitudinal axis in
Circumduction: move in loop without rotation
Rotational Movements: turn on axis
Medial Rotation: turn in toward body
Lateral Rotation: turn out away from body

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

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

31. Circumduction
Circular angular motion
Figure 9–2d

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

33. Angular Motion: Flexion
Figure 9–3a

34. Angular Movement: Flexion Vs. Extension
Angular motion
Anterior–posterior plane
Reduces angle between elements
Extension
Increases angle between elements

35. Angular Motion: Abduction Vs. Adduction
Figure 9–3b, c

36. Abduction Vs. Adduction
Angular motion
Frontal plane
Moves away from longitudinal axis
Adduction:
Moves toward longitudinal axis

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

38. Special and Specific Motion
Inversion: turn sole inward
Eversion: turn sole outward
Dorsiflexion: lift toes
Plantar flexion: lift heal
Opposition: thumb across palm
Pronation: medial rotation of radius
Superination: lateral rotation of radius
Protraction: move anterior (toward front)
Retraction: move posterior (toward back)
Elevation: move superior (toward head)
Depression: move inferior (toward feet)

39. Inversion and Eversion
Figure 9–5a

40. Dorsiflexion and Plantar Flexion
Figure 9–5b

41. Ranges of Motion Monaxial: movement in 1 plane
Biaxial: movement in 2 planes
Triaxial: movement in 3 planes
Multiaxial: gliding joints, all directions

42. When you do jumping jacks, which lower limb movements are necessary?
flexion and extension
abduction and adduction
flexion and abduction
plantar flexion and eversion

43. The types of synovial joints, and the relationship of motion to structure.

44. Classification of Synovial Joints by Shape
Gliding
Hinge
Pivot
Ellipsoidal
Saddle
Ball-and-socket

45. Gliding/Plane Joints Flattened or slightly curved faces
Slide in any direction
Figure 9–6 (1 of 6)

46. Hinge Joints Cylindrical projections in trough-shaped surface
Angular motion in a single plane (monaxial)
Figure 9–6 (2 of 6)

47. Pivot Joints Round projection in ring shaped depression
Rotation only (monaxial)
Figure 9–6 (3 of 6)

48. Ellipsoidal Joints Oval articular facet within an oval depression
Motion in 2 planes (biaxial)
Figure 9–6 (4 of 6)

49. Saddle Joints 2 concave faces into convex Straddled (biaxial)
Figure 9–6 (5 of 6)

50. Ball-and-Socket Joints
Spherical head into cup-like socket
Round articular face in a depression (triaxial)
Figure 9–6 (6 of 6)

51. KEY CONCEPT A joint can’t be both mobile and strong
The greater the mobility, the weaker the joint
Mobile joints are supported by muscles and ligaments, not bone-to-bone connections

52. How the vertebrae in the vertebral column articulate.

53. Intervertebral Articulations
Figure 9–7

54. Damage to Intervertebral Discs
Figure 9–8

55. Damage to Intervertebral Discs
Slipped disc:
bulge in anulus fibrosus
invades vertebral canal
Herniated disc:
nucleus pulposus breaks through anulus fibrosus
presses on spinal cord or nerves

56. Articulations and Movements of the Axial Skeleton
Table 9–3 (1 of 2)

57. Articulations and Movements of the Axial Skeleton
Table 9–3 (2 of 2)

58. The Elbow Joint
Figure 9–10

59. The Hip Joint
Figure 9–11b, c

60. The Knee Joint
Figure 9–12a, b

61. Articulations of the Appendicular Skeleton
Table 9–4 (1 of 2)

62. Articulations of the Appendicular Skeleton
Table 9–4 (2 of 2)

63. The effects of aging on articulations, and the most common clinical problems.

64. Age Related Changes Rheumatism: Arthritis:
Pain and stiffness of skeletal system
Arthritis:
Rheumatism of synovial joints, caused by damage to articular cartilage
Osteoarthritis:
- Age 60+, cumulative wear and tear erodes cartilage
Rheumatoid Arthritis:
- Autoimmune attack, chronic inflammation and damage to joint
- Ankylosis: ossification of the joint due to untreated RA
Gouty Arthritis:
Crystals of uric acid from nucleic acid metabolism form in synovial fluid, damage cartilage
Due to metabolic disorders