1. Joints

2. Joints
Now that we know all of the bones we need to look at the joints of the skeleton
Joints, also called articulations, have two main functions
They hold bones together securely
They give the rigid skeleton mobility

3. Classification of joints
Joints are commonly classified in two manners
Functionally -- how they work
Structurally -- how they are constructed and shaped.

4. Functional Classification
The functional classifications focus on the amount of movement allowed by the joints
With this system we have 3 main categories
Synarthroses
Amphiarthroses
Diarthroses

5. Synarthroses Synarthroses joints are joints that are immoveable
Most commonly located in the axial skeleton
Ex: joints of the large bones of the cranium like the tempro-parietal joint

6. Amphiarthroses Amphiarthroses are joints that are slightly movable.
These joints, like synarthroses are mostly located in the axial skeleton where rigidity is important to the function of the bones.

7. Diarthroses Diarthroses are joints that are freely movable
These are mostly found in the appendicular skeleton, whose main function is mobility and manipulation.

8. Structural Classification
We can also classify the joints by there structural classifications
We also have 3 structural classifications
Fibrous
Cartilaginous
Synovial

9. Fibrous Joints
Fibrous joints are joints that are united by fibrous tissue
The best examples of this type of joint are the sutures in the skull
In sutures we have the jagged edges bound tightly together with connective tissue fibers

10. Fibrous joints Sutures are not the only place for fibrous joints
There are some places where the connecting fibers are larger and longer to allow more “give”
These are called syndesmoses
An example is between the distal end of the fibula and tibia

11. Cartilaginous Joints These are the joints connected by cartilage
Examples of this type of joint are usually slightly moveable
The joints between the vertebrae are cartilaginous joints

12. Synovial Joints
Synovial joints are those in which the articulating surfaces are seperated by a joint cavity containing synovial fluid
All Synovial joints have 4 distinguishing features.

13. Features of synovial joints
Articular cartilage
Fibrous articular capsule
Joint Cavity
Reinforcing Ligaments

14. Types of synovial joints
There are 6 types of synovial joints
Plane
Hinge
Pivot
Condyloid
Saddle
Ball-and-Socket

15. Plane Joint A plane joint can be seen in your carpals
It moves very limitedly

16. Hinge joint
A hinge joint can be found in your humerus where it connects to the ulna
This allows motion similar to a hinge of a door

17. Pivot joint
Pivot joints can be found in your radius and ulna as well as your vertebrae
They allow for twisting motion

18. Condyloid joint
Condyloid joints provide motion to the sides like a joystick
An example would be your metacarpals and metatarsals

19. Saddle joint
A saddle joint is shaped like a saddle and provide for motion back and forth and side to side
An example would be where your metacarpal 1 meets your carpals

20. Ball and socket joint
Ball and socket joints provide the most movement out of all the joints
They allow for nearly 360 degrees of rotation
They can be found in the heads of your humerus and femur