What are the different classes of synovial joints called?

Synovial joints, also known as diarthroses, are the most common and most movable type of joint in the body. They are categorized into six different classes based on their shape and the movement they allow. These classes are:

1. Pivot Joints: These allow for rotation around an axis. An example is the joint between the first and second vertebrae of the neck that allows the head to move back and forth.

2. Hinge Joints: These joints act like a door hinge, allowing flexion and extension in just one plane. Examples include the elbow and the interphalangeal joints of the fingers.

3. Saddle Joints: These joints allow movement in two planes, flexion/extension and abduction/adduction. An example is the thumb joint.

4. Plane Joints: These joints allow for gliding or sliding movements, and are found between the tarsal bones of the feet and the carpal bones of the hands.

5. Condyloid Joints: These joints allow for movement in two planes without rotation. An example is the wrist joint.

6. Ball and Socket Joints: These joints allow for the greatest range of motion, with movement in multiple planes and rotation. Examples include the shoulder and hip joints.