2. Joints
A joint is the site of meeting of two or more bones.
Joints are classified into three types (depending on the material that hold the articular bones together):

3. Fibrous joints
Sutures: only seen in between the skull bones and they frequently ossify with age).
Syndesmosis:
Inferior tibiofibular joint (no movement in this joints and never ossify).
Interosseous membrane connecting bones of forearm & leg.
Gomphosis: in the joints between the teeth and jaws. Each tooth is connected to the socket by periodontal membrane.

4. Cartilaginous joints
Primary cartilaginous: these are temporary joints, in which the bones are connected by hyaline cartilage that ossifies with age. No movement is possible. This type is seen in:
Epiphyseal plate connecting epiphysis and metaphysis.
1st sternocostal joint between 1st costal cartilage and sternum.

5. Cartilaginous joints
Secondary cartilaginous: the bones are connected by disc of fibrocartilage, which rarely ossifies with age. A small amount of movement is possible. These joints are seen in the joints of midline of body:
Intervertebral discs
Symphysis pubis
Manubriosternal junction

6. Synovial joints
are held together by fibrous capsule & characterized by presence of joint cavity. Synovial joints are freely movable and represent most joints of the body.
The capsule is lined by synovial membrane that secretes lubricating fluid (synovial fluid) for the articular surfaces.
Articular ends are covered by hyaline cartilage.
The capsule is thickened in certain parts to form ligaments, which provide strength and flexibility to the joint.

7. Synovial Joints Allow considerable movement
Most joints that unite bones of axial and peripheral skeleton
Articular cartilage and disks
Joint cavity and capsule
Synovial membrane and fluid
Bursae

8. Types of synovial joints
Variety
Shape
Movement
Example
Plane
flat articulating surfaces
allow gliding or sliding movement
Acromio-clavicular J.
Intercarpal js.
Intertarsal js..
Uniaxial
(allow movement around one axis only)
Hinge
- concave surface with convex surface
- movement occurs around transverse axis
- flexion & extension
Elbow J.
Inter-phalangeal Js.
Pivot
- bony pivot surrounded by a ring
- movement occurs around vertical axis
- pronation & supination
- rotation
Radioulnar Js.
Atlantoaxial Js.
Biaxial
(allow movements around two axis)
Ellipsoid
- oval convex surface fits into an ellipsoid concavity
- movement occurs around 2 axes perpendicular to each other
- abduction & adduction
Wrist J.
Metacarpo-phalangeal Js.
Saddle
- both articular surfaces are concavo-convex
- movement in 2 axes like ellipsoid J. with slight rotation
- slight rotation
Carpo-metacarpal J. of thumb
Multiaxial
(allow move-ment around multiple axes)
Ball & socket
head of one bone fits into a cup-like concavity of other bone
circumduction
Shoulder J.
Hip J.

10. Types of Movement Flexion and Extension Angular Flexion and Extension
Abduction and Adduction
Circular
Rotation
Circumduction
Flexion and Extension

11. Abduction and Adduction

12. Rotation and Pronation and Supination

13. Circumduction

14. Special Movements Unique to only one or two joints Types
Elevation and Depression
Protraction and Retraction

15. Elevation and Depression

16. Protraction and Retraction

17. Points to Remember
A joint or articulation is a meeting between two bones and does not necessarily imply movement
A joint can be classified according to its structure
Synovial joints are the most complex
Specific terms are used to describe the movements of joints that are freely movable.
Commonly grouped in opposing pairs that move a part of the body in relation to the anatomical position.