1. Joints (Articulations)

2. Ligaments Connect bone to bone
Composed of dense connective tissue that contains collagen and elastin fibers
Cannot be regenerated naturally
Some ligaments allow movement while others limit or prevent movements
Some ligaments also function in stability and reinforcement.
Ligaments gradually strain when under tension and return to their original position
Some people have more elastic ligaments which results in hypermobility.

4. Joints (Articulations)
Sites where 2 or more bones meet.
2 functions:
Hold bones together securely
Give the rigid skeleton mobility

5. Joints are classified in 2 ways:
Functionally: amount of movement
Structurally: how bones are articulated

6. Functional
Synarthroses: immovable
Amphiarthroses: slightly moveable
Diarthroses: freely moveable

7. Synarthroses & Amphiarthroses joints are found in the axial skeleton and make up regions that function in protection
Diarthroses joints are found in the limbs of the appendicular and make up regions that function in movement.

8. Structural
Fibrous: immovable
Cartilaginous: slightly moveable
Synovial: freely moveable

9. Fibrous
Fibrous tissue forms joints
Short connecting fibers form sutures in the skull
Long connecting fibers are called syndesmoses which allow for more give are found in the connection of the tibia to fibula.
Gomphoses are immovable joints in the shape of a socket (teeth)

10. Cartilaginous Bones are connected by fibrocartilage
Slightly moveable examples:
Pubic symphysis of the pelvis
Intervertebral disks of the spinal column
Immovable (synchondroses) examples:
Epiphyseal plates
Joints between the first ribs and the sternum

11. Synovial Joint cavity containing synovial fluid
All joints of the limbs
All have 4 features:
Articular hyaline cartilage at the ends of bones
Articular capsule
Joint cavity that contains synovial fluid
Reinforcing ligaments

12. Synovial Cont. May have bursae & tendon sheaths
Both are bags of lubricant that reduce friction
Bursae: flattened sac of synovial fluid; common where ligaments, muscles, skin, tendons, or bones rub together.
Tendon sheath: elongated bursae the wraps completely around a tendon

13. Types of Synovial Joints
Shapes of articulating bone surfaces determine the movements that are allowed.
Plane
Hinge
Pivot
Condylar
Saddle
Ball & Socket

15. Plane Articular surfaces are flat
Only short slipping or gliding movements are allowed
There is no rotation around any axis
Intercarpal joints of the wrist

16. Hinge
Cylindrical end of one bone fits into a trough shaped surface of another
Movement is allowed in one plane
Elbow, knee, ankle, joints between phalanges of fingers

17. Pivot Rounded end of a bone fits into a sleeve or ring of a bone
A rotating bone turns around its long axis. The bone rotates around another bone
Radioulnar joint and between the atlas and axis of the vertebral column.

18. Condylar
Knuckle like
Egg shaped surface of one bone fits into an oval cavity of another
Allow movement of bone from side to side and back and forth
Bone cannot rotate
Knuckle (between metacarpals and phalanges) joints

19. Saddle Each surface has concave and convex areas just like a saddle
Same movements as condylar
Joint between carpal and metacarpal of the thumb

20. Ball and Socket
Spherical head of one bone fits into a round socket of another.
Allows movement in all directions
Most freely moving
Shoulder and Hip