1. Joints 8

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 by Function
A. synarthroses - immoveable (sutures in cranium)
B. amphiarthroses - slightly moveable (tibia-fibula)
C. diarthroses - freely moveable (shoulder joint)

4. 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:
A. Fibrous
B. Cartilaginous
C. Synovial

5. A. Fibrous Structural Joints
The bones are joined by fibrous tissues
There is no joint cavity
Most are immovable
There are three types
a. sutures
b. syndesmoses
c. gomphoses

6. Three Types of Fibrous Joints
a. Sutures
1. between cranial bones
2. very tight, thin layer of connective tissue
3. synostoses - bone replaces connective in adult
b. Syndesmoses
1. very little freedom for movement
2. interosseous membrane/ligament present
c. Gomphoses
1. one part fit tightly into the other
2. periodontal tissue holds parts firmly together
3. example: teeth in the mandible and maxillae

7. Occur between the bones of the skull
-- 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

8. Figure 8.1a

9. Bones are connected by a fibrous tissue ligament
-- 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

10. Figure 8.1b

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

12. B. Cartilaginous Joints
Articulating bones are united by cartilage
Lack a joint cavity
Two types – synchondroses and symphyses

13. Two Types of Cartilaginous Joints
a. Synchondrosis
1. hyaline cartilage --> bone over time
2. example: area between epiphysis & diaphysis of bone
3. example: joint between ribs and sternum
b. Symphysis
1. bones connected by disc of fibrocartilage
2. allows for slight movement (amphiarthrotic)
3. example: pubic symphysis, intervertebral discs

14. A bar or plate of hyaline cartilage unites the bones
-- Synchondroses
A bar or plate of hyaline cartilage unites the bones
All synchondroses are synarthrotic
Examples include:
Epiphyseal plates of children
Joint between the costal cartilage of the first rib and the sternum

15. Figure 8.2a, b

16. Amphiarthrotic joints designed for strength and flexibility
-- 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

17. Figure 8.2c

18. All are freely movable diarthroses
C. Synovial Joints
Those joints in which the articulating bones are separated by a fluid-containing joint cavity
All are freely movable diarthroses
Examples – all limb joints, and most joints of the body

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

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

21. Synovial Joints: Friction-Reducing Structures
Bursae – flattened, fibrous sacs lined with synovial membranes and containing synovial fluid
Common where ligaments, muscles, skin, tendons, or bones rub together
Tendon sheath – elongated bursa that wraps completely around a tendon

22. Synovial Joints: Movement
The two muscle attachments across a joint are:
Origin – attachment to the immovable bone
Insertion – attachment to the movable bone
Described as movement along transverse, frontal, or sagittal planes

23. Synovial Joints: Range of Motion
Nonaxial – slipping movements only
Uniaxial – movement in one plane
Biaxial – movement in two planes
Multiaxial – movement in or around all three planes

24. Types of Synovial Joints
Plane joints
Articular surfaces are essentially flat
Allow only slipping or gliding movements
Only examples of nonaxial joints
Examples: between carpals of the wrist
Figure 8.7a

25. 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

26. Figure 8.7b

27. Pivot joints 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

28. Figure 8.7c

29. Condyloid (Ellipsoidal) 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

30. Figure 8.7d

31. Saddle joints 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

32. Figure 8.7e

33. 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

34. Figure 8.7f

35. Movements of Joints
It is VERY important that you learn the terminology for movements of joints. Muscles act mainly to cause movement or fixation of a joint!!!!!!!

36. Gliding movements Gliding Movements
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

37. Gliding Movement
Figure 8.5a

38. Angular Movement
Flexion — bending movement that decreases the angle of the joint
Extension — reverse of flexion; joint angle is increased
Dorsiflexion and plantar flexion — up and down movement of the foot
Abduction — movement away from the midline
Adduction — movement toward the midline
Circumduction — movement describes a cone in space

39. Angular Movement
Figure 8.5b

40. Angular Movement
Figure 8.5c, d

41. Angular Movement
Figure 8.5e, f

42. The turning of a bone around its own long axis
Rotation
The turning of a bone around its own long axis
Examples
Between first two vertebrae
Hip and shoulder joints
Figure 8.5g

43. Supination and pronation Inversion and eversion
Special Movements
Supination and pronation
Inversion and eversion
Protraction and retraction
Elevation and depression

44. Special Movements
Figure 8.6a

45. Special Movements
Figure 8.6b

46. Special Movements
Figure 8.6c

47. Special Movements
Figure 8.6d

48. Largest and most complex joint of the body
Knee
Largest and most complex joint of the body
Allows flexion, extension, and some rotation
Three joints in one surrounded by a single joint cavity
Femoropatellar
Lateral and medial tibiofemoral joints

49. Knee Ligaments and Tendons – Anterior View
Tendon of the quadriceps femoris muscle
Lateral and medial patellar retinacula
Fibular and tibial collateral ligaments
Patellar ligament
Figure 8.8c

50. Knee – Other Supporting Structures
Anterior cruciate ligament
Posterior cruciate ligament
Medial meniscus (semilunar cartilage)
Lateral meniscus

51.        
Figure 8.8b

53. Shoulder (Glenohumeral)
Ball-and-socket joint in which stability is sacrificed to obtain greater freedom of movement
Head of humerus articulates with the glenoid fossa of the scapula

54. Synovial Joints: Shoulder Stability
Weak stability is maintained by:
Thin, loose joint capsule
Four ligaments – coracohumeral, and three glenohumeral
Tendon of the long head of biceps, which travels through the intertubercular groove and secures the humerus to the glenoid cavity
Rotator cuff (four tendons) that encircles the shoulder joint and blends with the articular capsule

55. Synovial Joints: Shoulder Stability  
Figure 8.10a

56. Shoulder Stability 
Figure 8.10b

58. Ball-and-socket joint
Hip (Coxal) Joint
Ball-and-socket joint
Head of the femur articulates with the acetabulum
Good range of motion, but limited by the deep socket and strong ligaments

59. Hip Stability Acetabular labrum Iliofemoral ligament
Pubofemoral ligament
Ischiofemoral ligament
Ligamentum teres
Figure 8.11a

60. Synovial Joints: Hip Stability
Figure 8.11c, d

61. Sprains The ligaments reinforcing a joint are stretched or torn
Partially torn ligaments slowly repair themselves
Completely torn ligaments require prompt surgical repair

62. Cartilage Injuries The snap and pop of overstressed cartilage
Common aerobics injury
Repaired with arthroscopic surgery

63. Dislocations Occur when bones are forced out of alignment
Usually accompanied by sprains, inflammation, and joint immobilization
Caused by serious falls and are common sports injuries
Subluxation – partial dislocation of a joint

64. Inflammatory and Degenerative Conditions
Bursitis
An inflammation of a bursa, usually caused by a blow or friction
Symptoms are pain and swelling
Treated with anti-inflammatory drugs; excessive fluid may be aspirated
Tendonitis
Inflammation of tendon sheaths typically caused by overuse
Symptoms and treatment are similar to bursitis

65. Arthritis
More than 100 different types of inflammatory or degenerative diseases that damage the joints
Most widespread crippling disease in the U.S.
Symptoms – pain, stiffness, and swelling of a joint
Acute forms are caused by bacteria and are treated with antibiotics
Chronic forms include osteoarthritis, rheumatoid arthritis, and gouty arthritis

66. Osteoarthritis (OA)
Most common chronic arthritis; often called “wear-and-tear” arthritis
Affects women more than men
85% of all Americans develop OA
More prevalent in the aged, and is probably related to the normal aging process

67. Osteoarthritis: Course
OA reflects the years of abrasion and compression causing increased production of metalloproteinase enzymes that break down cartilage
As one ages, cartilage is destroyed more quickly than it is replaced
The exposed bone ends thicken, enlarge, form bone spurs, and restrict movement
Joints most affected are the cervical and lumbar spine, fingers, knuckles, knees, and hips

68. Osteoarthritis: Treatments
OA is slow and irreversible
Treatments include:
Mild pain relievers, along with moderate activity
Magnetic therapy
Glucosamine sulfate decreases pain and inflammation

69. Rheumatoid Arthritis (RA)
Chronic, inflammatory, autoimmune disease of unknown cause, with an insidious onset
Usually arises between the ages of 40 to 50, but may occur at any age
Signs and symptoms include joint tenderness, anemia, osteoporosis, muscle atrophy, and cardiovascular problems
The course of RA is marked with exacerbations and remissions

70. Rheumatoid Arthritis: Course
RA begins with synovitis of the affected joint
Inflammatory chemicals are inappropriately released
Inflammatory blood cells migrate to the joint, causing swelling
Inflamed synovial membrane thickens into a pannus
Pannus erodes cartilage, scar tissue forms, articulating bone ends connect
The end result, ankylosis, produces bent, deformed fingers

71. Rheumatoid Arthritis: Treatment
Conservative therapy – aspirin, long-term use of antibiotics, and physical therapy
Progressive treatment – anti-inflammatory drugs or immunosuppressants
The drug Enbrel (made by Amgen in Thousand Oaks) a biological response modifier, neutralizes the harmful properties of inflammatory chemicals

72. Gouty Arthritis
Deposition of uric acid crystals in joints and soft tissues, followed by an inflammation response
Typically, gouty arthritis affects the joint at the base of the great toe
In untreated gouty arthritis, the bone ends fuse and immobilize the joint
Treatment – colchicine, nonsteroidal anti-inflammatory (NSAID’s) drugs, and glucocorticoids