These joints are the most common joints in the body and provide free movement between the bones they join.

All synovial joints possess a joint cavity

An articular capsule unites the joint. The capsule spans and encloses the joint cavity.

The joint capsule is lined by a synovial membrane which secretes (makes) synovial fluid.

Synovial fluid provides protection and lubrication for the articular (cartilaginous) lining of the bone ends forming the joint.

Synovial joints are often reinforced by ligamentous bands that may be extrinsic (ie separate from the joint capsule) or intrinsic (ie thickenings of parts of the joint capsule.

In the adult, articular cartilage has no blood vessels, lymph channels, or nerves.

1. Plane Joints(Gliding Joints)

Plane joints can usually only move around one axis (uniaxial). They are made up of flat or curved surfaces sliding past each other.

These joints are capable of limited gliding or sliding movements.

An example of a plane joint is the acromioclavicular joint between the acromion of the scapula and the clavicle. Also, the wrist or ankle.

2. Hinge Joints

Hinge joints are also uniaxial.

Flexion and extension are the only movements available in these joints.

Examples of hinge joints are the elbow and knee.

3. Saddle Joints

Saddle joints permit movement in two planes and are therefore biaxial. These joints permit all motions except rotation.

The opposing surfaces are concave and convex so they have "saddle shaped" articulating surfaces.

An example of a saddle joint is the carpometacarpal joint of the thumb.

4. Condyloid Joints (Ellipsoid)

The shape of the Condyloid (knuckle like) joint allows movement in both the sagittal and coronal planes, therefore they are also biaxial joints.

Examples of condyloid joints are the metacarpophalangeal (knuckle) joints of the hand.

Flexion/Extension and Abduction/Adduction are permitted.

Notice that in these joints there is more movement in the sagittal plane than in the coronal plane.

5. Ball and Socket Joints

Ball and socket joints are the most movable joints in the body. The spherical surface (the "ball") of one bone moves within the deep concave surface (the "socket") of the other bone.

They are multiaxial therefore permitting movement in multiple planes.

Flexion/Extension, Abduction/Adduction, Medial/Lateral Rotation and Circumduction are all available in ball and socket joints.

Double click on the Skeletal image!

The Hip (femoral) , and shoulder joints are good exmaples of these highly mobile joints.

6. Pivot Joints

Pivot joints are designed to allow rotation. Movement therefore occurs about one axis.

Rotation is possible because a rounded process of bone rotates within a ring or sleeve of another.

Examples of pivot joints are the radio-ulnar joint at the elbow and the atlantoaxial joint between the head and neck