1. Section 1 – Classification of Joints (pp. 248-249)
Ch 8 – The Joints
Section 1 – Classification of Joints
(pp )

2. *Joints are the weakest parts of the skeleton
Articulation
- site where two or more bones come together
- known as a joint
Functions of joints
- Hold skeleton together
- give skeleton mobility
*Joints are the weakest parts of the skeleton

3. Functional Classification of Joints
Based on amount of movement allowed:
1) Synarthrosis
- Generally immovable
2) Amphiarthrosis
- Immovable or slightly movable
3) Diarthrosis
- Freely movable

4. Structural Classification of Joints
Based on material binding bones together:
- Fibrous Joints
- Cartilaginous Joints
- Synovial Joints
*Also involves whether or not joint cavity is present

5. Section 2 – Fibrous Joints (pp. 249-250)
Ch 8 – The Joints
Section 2 – Fibrous Joints (pp )

6. Fibrous Joints Fibrous Joints
- bones joined by dense fibrous connective tissue
- no joint cavity
- most are synarthroses (immovable)
- Examples
1) Sutures
2) Syndesmoses
3) Gomphoses

7. Fibrous Joints – Sutures
- rigid, interlocking joints
- short connective tissue fibers
- allow for growth during youth
- ossify during middle age
- only found in the skull

8. Fibrous Joints – Syndesmoses
- bones connected by ligaments
- immovable to slightly moveable
Examples
*Distal tibiofibular joint
*Interosseous connection
between radius & ulna

9. Fibrous Joints – Gomphoses
- peg-in-socket joints; teeth
- tooth held in by periodontal
ligament

10. Section 3 – Cartilaginous Joints (pp. 250-251)
Ch 8 – The Joints
Section 3 – Cartilaginous Joints
(pp )

11. Cartilaginous Joints Cartilaginous Joints
- bones connected by cartilage
- no joint cavity
Two types:
1) Synchondroses
2) Symphyses

12. Cartilaginous Joints – Synchondroses
- bar or plate of hyaline cartilage binds bones together
- all are synarthroses (immovable)
Examples:
1) Epiphyseal plates
2) Joint between sternum & first rib

13. Cartilaginous Joints – Symphyses
- strong, flexible amphiarthroses (limited movement)
- act as shock absorbers
Examples:
1) Intervertebral joints
2) Pubic symphysis (pelvis)

14. Section 4 – Synovial Joints (pp. 251-253)
Ch 8 – The Joints
Section 4 – Synovial Joints (pp )

15. Synovial Joints Synovial Joints
- all are diarthrotic (freely moveable)
- bones separated by fluid-containing joint cavity
- lubricated by synovial fluid
- include all limb joints; most joints of the body

16. Features of Synovial Joints
Distinguishing features:
1) Articular cartilage
- hyaline cartilage that covers the end of bones
- decreases friction
2) Joint cavity filled with synovial fluid
3) Articular capsule
- strengthens joint
- prevents bones from being pulled apart
4) Synovial fluid
- thick, very slippery fluid that lubricates joint
- thins out as it warms up w/ joint activity

17. Features of Synovial Joints
Distinguishing features:
5) Reinforcing ligaments
- help to strengthen & hold joint together
6) Rich nerve & blood vessel supply
- nerve fibers detect pain & monitor joint position/stretch
- capillary beds help produce synovial fluid

18. Synovial Joints

19. Synovial Joints

20. Synovial Joints

21. Synovial Joints

22. Features of Synovial Joints
Structures associated w/ synovial joints:
1) Bursae
- Flattened, fibrous sacs filled w/ synovial fluid
- Provide cushioning
- Act as “ball bearings” where ligaments, muscles, skin,
tendons, & bones rub together

23. Features of Synovial Joints
Structures associated w/ synovial joints:
2) Tendon sheath
- Elongated bursa that wraps around tendon
- Protection for tendon

24. Stabilizing Synovial Joints
Factors involved in stabilizing synovial joints:
1) Shape of articular surface
- determines what movements are possible
- only plays minor role in stability
2) Number of ligaments & their location
- prevent excessive & undesirable motion
- more ligaments = more strength
- limited stability due to inability to stretch; snap easily
3) Muscle tone
- most important stabilizing factor
- keeps tendons that cross a joint taut

25. Section 5 – Movements Allowed by Synovial Joints (pp. 253-259)
Ch 8 – The Joints
Section 5 – Movements Allowed by
Synovial Joints (pp )

26. Movement of Synovial Joints
General types of movement:
1) Gliding movements
- simplest joint movements
- one flat bone surface slips/glides over another

27. Movement of Synovial Joints
General types of movement:
2) Angular movements
- increase or decrease angle between two bones
Examples:
a) Flexion
- decrease the angle of joint
b) Extension
- increase the angle of joint
c) Hyperextension
- excessive extension beyond normal range of motion

28. Movement of Synovial Joints
General types of movement:
2) Angular movements
- increase or decrease angle between two bones
Examples:
d) Abduction
- movement away from midline
e) Adduction
- movement toward midline
f) Circumduction
- circular motion; cone-shaped

29. Movement of Synovial Joints
General types of movement:
3) Rotation
- turning of a bone around its own long axis
Examples:
a) between C1 (atlas) & C2 (axis) vertebrae
b) rotation of humerus & femur

30. Movement of Synovial Joints
Special Movements:
1) Movements of radius around ulna
a) Supination
- turning palm forward (into anatomical position)
b) Pronation
- turning palm backward

31. Movement of Synovial Joints
Special Movements:
2) Movements of the foot
a) Dorsiflexion
- movement of toes upward
b) Plantar flexion
- movement of toes downward

32. Movement of Synovial Joints
Special Movements:
2) Movements of the foot
c) Inversion
- turning sole of foot medially
d) Eversion
- turning sole of foot laterally

33. Movement of Synovial Joints
Special Movements:
3) Non-angular movements in a transverse plane
a) Protraction
- anterior movement of body part
b) Retraction
- posterior movement of body part

34. Movement of Synovial Joints
Special Movements:
4) Elevation
- lifting a body part superiorly
5) Depression
- moving a body part inferiorly

35. Movement of Synovial Joints
Special Movements:
6) Opposition of thumb
- touching thumb to tips of other fingers

36. Section 6 – Types of Synovial Joints (pp. 259)
Ch 8 – The Joints
Section 6 – Types of Synovial Joints
(pp. 259)

37. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
1) Plane Joints
- flat articular surfaces
- short, gliding movements

38. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
2) Hinge Joints
- flexion & extension only
- resembles a mechanical hinge

39. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
3) Pivot Joints
- rounded end of one bone conforms to a “sleeve” or ring of
another bone

40. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
4) Condyloid Joints
- both articulating surfaces are oval
- permit all angular movements

41. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
5) Saddle Joints
- each articular surface has both concave & convex areas
- both surfaces shaped like saddles
- allow greater freedom of movement than condyloid joints

42. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
6) Ball-and-Socket Joints
- spherical head of 1 bone articulates w/ socket of another
- most freely moving of all synovial joints

43. Section 7 – Selected Synovial Joints (pp. 259-264 & 268-269)
Ch 8 – The Joints
Section 7 – Selected Synovial Joints
(pp & )

44. Selected Synovial Joints
Knee Joint
- largest, most complex joint of the body
Three joints in one:
1) Femoropatellar joint
- plane joint
- allows gliding motion of patella over femur during flexion
2 & 3) Tibiofemoral joint (lateral & medial combined)
- primarily acts like a hinge permitting flexion & extension
- formed by femoral condyles & C-shaped lateral/medial menisci of the tibia
A&P Flix™: Movement at the knee joint

45. Selected Synovial Joints

46. Selected Synovial Joints
Knee Joint
- at least 12 associated bursae
- articular capsule only present on sides & back of knee
- front side reinforced by quadriceps tendon/patellar ligament

47. Selected Synovial Joints
Knee Joint – Ligaments
- 3 different kinds of ligaments stabilize & strengthen joint from the OUTSIDE
1) Fibular & tibial collateral ligaments
- 1 on each side of knee
- work to prevent lateral & medial rotation
2) Oblique popliteal ligament
- stabilizes posterior (back) aspect of knee
3) Arcuate popliteal ligament
- reinforces the joint capsule posteriorly

48. Selected Synovial Joints
Knee Joint – Ligaments
- 2 different kinds of ligaments stabilize & strengthen joint from the INSIDE
1) Anterior Cruciate Ligament (ACL)
- prevents forward sliding of the tibia on the femur
- works to stop hyperextension of the knee
2) Posterior Cruciate Ligament (PCL)
- prevents backward sliding of the tibia
Most knee strength/stability is a direct result of heavy reinforcement by muscle tendons…
Greater strength & tone of muscles = less chance of injury!
Animation: Rotatable knee

49. Selected Synovial Joints
Temporomandibular Joint (TMJ)
- “jaw joint”
- mandibular condyle articulates with temporal bone
- most easily dislocated joint in the body…even by deep yawns
Two types of movement:
1) Hinge – depression & elevation of the mandible
2) Gliding – side-to-side grinding of teeth

50. Section 8 – Homeostatic Imbalances (pp. 269-271)
Ch 38 – The Joints
Section 8 – Homeostatic Imbalances
(pp )

51. (if not repaired, inflammation will turn ligament to mush!)
Common Joint Injuries
Sprains
- ligaments are stretched or torn
- partial tears slowly repair themselves
- complete ruptures require prompt surgical repair
(if not repaired, inflammation will turn ligament to mush!)
Cartilage tears
- due to compression & sudden direction change
- cartilage fragments may cause joint to lock or bind
- cartilage is avascular & unable to repair itself
- must be repaired by arthroscopic surgery

52. Common Joint Injuries Dislocations (luxations)
- occur when bones are forced out of alignment
- accompanied by sprains, inflammation, & joint immobilization
- repeat dislocations more likely b/c ligaments become stretched

53. Inflammatory Joint Conditions
Bursitis
- Inflammation of bursa
- Usually caused by sharp hit or friction
- treated with rest, ice, & anti-inflammatory drugs
Tendonitis
- Inflammation of tendon sheath
- caused by overuse of joint

54. Inflammatory Joint Conditions
Arthritis
- Inflammatory/degenerative disease of joints
- Over 100 types
- Most widespread, crippling disease in U.S.
- Symptoms = pain, stiffness, & swelling of joint
- Acute forms caused by bacteria; treated w/ antibiotics
- Chronic forms: Osteoarthritis, Rheumatoid arthritis, & Gouty arthritis

55. Forms of Arthritis Osteoarthritis
- Most common, chronic arthritis; irreversible
- Probably related to normal aging process; wear & tear
- 85% of all Americans will develop OA; women over men
- Cartilage destroyed faster than replaced in overworked joints
- Exposed bone ends thicken, enlarge, form bone spurs, & restrict movement

56. Forms of Arthritis

57. Forms of Arthritis Rheumatoid Arthritis
- Autoimmune disorder…immune system attacks joints
- Symptoms begin w/ bilateral inflammation of joint
- Usually arises between age 40-50; 3 times more likely in women
- Often leads to deformities

58. Forms of Arthritis

59. Forms of Arthritis Rheumatoid Arthritis - Treatment
1) Conservative therapy
- aspirin, long-term antibiotics, & physical therapy
2) Progressive therapy
- anti-inflammatory drugs or immunosuppressants

60. Forms of Arthritis Gout
- Inflammation caused by urate crystals found in blood of
people who have difficulty processing proteins
- More common in men
- If untreated, bone ends may fuse & immobilize joint
- Treatment = drugs that help process crystals; lots of water

61. Section 9 – Developmental Aspects (pp. 272)
Ch 8 – The Joints
Section 9 – Developmental Aspects
(pp. 272)

62. Developmental Aspects
Joint Development
- by embryonic week 8, synovial joints resemble adult joints
- size, shape, flexibility of joint modified by use
As you age…
- ligaments, tendons shorten & weaken
- intervertebral discs become more likely to herniate
- most people have some degree of OA by age 70
**Exercise that puts joints through full range of motion is key to delaying joint problems!