1. Joints and Movement

2. Articulations = Joints
Functional junctions between bones
Bind parts of the skeletal system
Make bone growth possible
Permit skeletal change during childbirth
Enable movement in response to muscle contraction
Skeleton Review Video

3. 3 Types of Cartilage

4. Classification of Joints
Classification based on the type of tissue that binds the bones:
Fibrous joints
Cartilaginous joints
Synovial joints
Classification according to degree of movement possible:
Immovable (synarthrotic)
Slightly movable (amphiarthrotic)
Freely movable (diarthrotic)

5. Fibrous Joints Dense CT with many collagenous fibers
Lie between bones that are in close contact
3 types:
Syndesmosis – bones bound by long fibers of CT (interosseous ligament); may be twisted
amphiarthrotic
Suture – only between flat bones of the skull
Synarthrotic
Gomphosis – joint between tooth and socket; periodontal ligament

6. Fibrous Joints

7. Cartilaginous Joints (Amphiarthrotic)
Consist of hyaline or fibrocartilage
2 types:
Synchondrosis – bands of hyaline cartilage
Epiphyseal plate
Costal cartilage
Symphysis – pad of fibrocartilage that allows limited movement
Intervertebral disks
Symphysis pubis
Slightly movable (amphiarthrotic)

8. Cartilaginous Joints (amphiarthrotic)

9. Synovial Joints (Diarthrotic)
Articular cartilage (hyaline cartilage) covers the ends of bones
A fibrous articular capsule encloses joint surfaces
A joint cavity is filled with synovial fluid
Ligaments reinforce the joint
Most joints in the body are synovial

10. Synovial Joint Structure (Diarthrotic)
Articular cartilage – hyaline cartilage; resists wear and minimizes friction
Subchondral plate – somewhat elastic bone located under the articular cartilage
Absorbs shocks and helps protect joint from stresses
May fracture from excessive stress from obesity or athletic activities

11. Synovial Joint Structure continued…
Joint capsule – has 2 distinct layers:
Outer layer consists of dense CT whose fibers attach to the periosteum
Flexible enough to allow movement but strong enough to hold the joint together
Ligaments – bundles of strong, tough cartilaginous fibers that reinforce the joint capsule
Synovial membrane – inner layer of the joint capsule
Shiny, vascular lining of loose CT only a few cells thick
Covers all surfaces within the the joint capsule except the articular cartilage

12. Synovial Joint Structure continued…
Synovial cavity – area enclosed by the joint capsule
Synovial fluid – clear fluid secreted by the synovial membrane that moistens and lubricates the joint cavity and supplies nutrients to the cartilage

13. Synovial Joint Structure continued…
Menisci – fibrocartilage disks that partially or completely divide the joint into compartments between the articular surfaces
Bursae – flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid. Common where ligaments, muscles, skin, tendons, or bones rub together.
Knee Replacement Surgery

14. Ball-and-Socket Joints
Bone with a globular head articulates with the cup-shaped cavity of another bone
Widest range of motion and rotation
Examples – hip, shoulder

15. Condyloid Joints Ovoid condyle fits elliptical cavity
Wide range of motion, but no rotation
Examples – metacarpals and phalanges

16. Gliding (plane) Joints
Nearly flat or slightly curved articulating surfaces
Allow sliding (back and forth) and twisting movements
Examples – within the wrist and ankle, between vertebrae, sacroiliac joint, between ribs and sternum

17. Hinge Joints
Convex surface of one bone joins concave surface of another bone
Movement in one plane only
Examples – elbow, phalanges

18. Pivot Joints
Cylindrical surface of one bone rotates within a ring of bone
Allows rotation only
Examples – proximal radius and ulna, atlas and axis

19. Saddle Joints
Bones with concave and convex regions on articulating surfaces
Allows movement in 2 planes
Example – trapezium and metacarpal 1 (thumb)

20. Joints Review (8:11)

21. Types of Ordinary Body Movements
Flexion
Decreases the angle of the joint
Brings two bones closer together
Typical of hinge joints like knee and elbow
Extension
Opposite of flexion
Increases angle between two bones

22. Types of Ordinary Body Movements
Rotation
Movement of a bone around its longitudinal axis
Common in ball-and-socket joints
Example is when you move atlas around the dens of axis (shake your head “no”)

23. Types of Ordinary Body Movements
Abduction
Movement of a limb away from the midline
Adduction
Opposite of abduction
Movement of a limb toward the midline

24. Types of Ordinary Body Movements
Circumduction
Combination of flexion, extension, abduction, and adduction
Common in ball-and-socket joints

25. Special Movements Dorsiflexion Plantar flexion
Lifting the foot so that the superior surface approaches the shin
Plantar flexion
Depressing the foot (pointing the toes)

26. Special Movements Inversion Eversion Turn sole of foot medially
Turn sole of foot laterally

27. Special Movements Supination Pronation
Forearm rotates laterally so palm faces anteriorly
Pronation
Forearm rotates medially so palm faces posteriorly

28. Special Movements Opposition
Move thumb to touch the tips of other fingers on the same hand

29. Joint Movements Protraction Retraction Elevation Depression
moving a part forward
Retraction
moving a part backward
Elevation
raising a part, shrug the shoulder
Depression
lowering a part, droop the shoulder

30. Shoulder Joint
Ball and socket joint made up of the rounded head of the humerus and the glenoid cavity of the scapula.
The joint capsule is loose. Muscles and tendons reinforce the joint.
Shoulder joint is capable of a wide range of movements including flexion, extension, abduction, adduction, rotation, and circumduction.

31. Shoulder Joint
Ligaments: coracohumeral ligament, glenohumeral ligaments, transverse humeral ligament, and glenoid labrum
Bursae: subscapular, subdeltoid, subacromial, subcorocoid bursae

32. Coracoacromial Ligament
Coracoclavicular Ligament

34. Knee Joint The knee is the largest and most complex synovial joint.
It consists of the medial and lateral condyles at the proximal end of the tibia. The femur articulates with the patella.
The joint capsule is thin and strengthened by muscles and tendons.

35. Knee Joint
Ligaments of the knee joint: patella, oblique popliteal, arcuate popliteal, tibial collateral (MCL), fibular collateral ligament (LCL), anterior cruciate ligament (ACL) strengthen the joint capsule.
Cruciate ligaments prevent displacement of articulating surfaces.
Two fibrocartilaginous menisci separate the articulating surfaces.

38. Life-Span Changes
Joint stiffness occurs due to a change in collagen structure.
Fibrous joints strengthen over a lifetime.

39. Life-Span Changes
Synchondrosis disappear over time as part of skeletal growth and development.
Symphysis joints may lose water and flexibility may decrease.