1. Joints
= Articulations

2. Joints
Articulations are where 2 or more bones meet.

3. Classification of Joints

4. Classified according to movement or function:
1. synarthroses - immovable
ex: cranial bones, sutures

5. 2. amphiarthroses - slightly movable
ex: ribs with vertebrae

6. diarthroses –
freely movable
ex: elbow, knee

7. sutures - only between bones of the skull
a type of fibrous joint - joined by fibrous tissue

8. Synovial Joints

9. Synovial Joints
articulating bones are separated by a fluid-filled cavity
all are freely movable

10. Synovial Joints Structure:
articular cartilage - smooth, hyaline
joint cavity –
fluid-filled space
articular capsule - double fibrous membrane
synovial fluid - prevents cartilage erosion, lubricates
reinforcing ligaments

11. Bursa - between bone and ligaments, muscle, skin, or tendons
- flattened fibrous sacs
- prevents rubbing against bone

12. tendons –
connect muscle to bone, fibrous tissue

13. ligaments –
connect bone to bone, fibrous tissue

14. Types of Synovial Joints

15. hinge - single plane motion
ex: knee, elbow, fingers

16. pivot – rotation
ex: atlas and axis, radioulna

17. saddle - move in 4 directions
ex: carpalmetacarpal of thumb only

18. ball and socket - movement in all axis ex: shoulder, hip

19. Plane or gliding joints movement limited, either up and down or left and right
ex: sternum and clavicle, between vertebrae, carpals, tarsals

20. condyloid –
angular motion
ex: knuckles

21. Types of Synovial Joints
hinge - single plane motion, ex: knee, elbow, fingers
pivot - rotation, ex: atlas and axis, radioulna
saddle - move in 4 directions, ex: carpalmetacarpal of thumb only
ball and socket - movement in all axis, ex: shoulder, hip
plane/ gliding joints - movement limited, either up/down or left/right, ex: sternum/ clavicle, between vertebrae, carpals, tarsals
condyloid - angular motion, ex: knuckles

22. Types of Angular Movements

23. flexion - decreases angle, brings bones together
dorsiflexion - foot up (toes up)

24. extension - increases angle
hyperextension - beyond upright position (head), exception knee towards back of body

25. abduction - away from midline
adduction - toward midline

26. circumduction - distal end moves in circle, throwing a baseball

27. rotation - around own axis, turning head

28. Types of Angular Movements
flexion - decreases angle, brings bones together
dorsiflexion - foot up (toes up)
extension - increases angle
hyperextension - beyond upright position (head), exception knee towards back of body
abduction - away from midline
adduction - toward midline
circumduction - distal end moves in circle, throwing a baseball
rotation - around own axis, turning head

29. Joint Injuries

30. Sprains ligaments stretched or torn
heals slowly because of poor vascularity
if completely torn, must be repaired surgically

31. Dislocations
when bones are forced out of normal position of joint cavity
bone ends must be reduced (realigned) like a fracture

32. Cartilage Injuries
most are tearing of knee menisci from fall or severe twisting
cartilage is avascular and will not be able to repair itself

33. arthroscopy allows surgeon to view interior of joint through small incision
damaged cartilage is removed, ligament repaired
does not severely impair movement but joint less stable