For ease of study this section of simple anatomy can be divided into four sections:

1. A general description of a joint.
2. The difference between fixed and movable joint.
3. The structure of a movable joint.
4. The main types of movable joints.

Joint:

or articulation, is the connection made between bones in the body.

For your examination you will need to remember two classifications of joints:

• Synarthrodial joints: Immovable joints, for example the joints of bones in the skull.
• Diarthrodial joints: Movable joints, for example the joints found in knee, elbow and shoulder.

The most common type of diarthrodial joints are the synovial joints, which are held together by ligaments and have a complex internal structure composed of:

• Synovial membrane
• Synovial fluid
• Bones
• Cartilage
• Fibrocartilage

Fibrocartilage contributes to a joint’s construction by adding strength and elasticity.

Examination Tip:

• For your examination you will have to remember the main type of movable joints. A good way to do this is to start at the neck and move down through the body showing an example of each joint:

Pivot joint – the vertebrae of the neck

Ball and socket joint – the shoulder joint

Gliding joint – the shoulder blade

Hinge joint – the elbow

Condyloid joint – the wrist

Saddle joint – the thumb

If you remember the types of joint in this way, it will help to demonstrate that you not only know the types of joint, but also know their location.

The ways in which a joint moves:

• Pivot joint:  Associated with rotational movements.
• Ball and socket joint: Can move in all directions.
• Gliding joint: Allows the bones to glide past one another and can be the only motion permitted.
• Hinge joint: Motion in one direction, forward or backwards.
• Condyloid joint and saddle joint: Both can move around two axis.

Certain joints can fall into more than one category.