Science [7 marks Questions]

A synovial joint is a joint which makes connection between two bones consisting of a cartilage lined cavity filled with fluid, which is known as a diarthrosis joint. These are the most flexible type of joint between bones, because the bones are not physically connected and can move more freely in relation to each other. Synovial joints have four main distinguishing features.

Feature	Structure	Function
Ligament	A band of strong fibrous tissue.	To connect bone to bone.
Synovial fluid	A slippery fluid with the consistency of egg-whites that is contained within the joint cavity.	To reduce friction between the articular cartilage in the joint.
Articular cartilage	Glassy-smooth cartilage that is spongy and covers the ends of the bones in the joint.	To absorb shock and to prevent friction between the ends of the bones in the joint.
Joint Capsule	A tough fibrous tissue that has two layers, with the fibrous capsule lying outside the synovial membrane.	The fibrous capsule helps to strengthen the joint, while the synovial membrane lines the joint and secretes synovial fluid.

The point at which two separate bones meet is called a joint Depending on the type of movement they allow, joints can be of three types: fixed, slightly movable and movable joints. 1. Fitted or Immovable joints:
In this type of joint, no movement is possible between the two bones. The structures between the bones of the skull box are examples of immovable joints. 2. Slightly movable joints:
Only very little (partial) movement occurs between the two bones. The joint between a rib and the breast bone or between the vertebrae is the example for slightly movable joint. 3. Freely movable joints:
In this type, varying degree of movements is possible between the two bones forming the joint. There are six major types of movable joints. Condition:
The different types of movable joints are:

Joint	Examples
Ball and Socket	Shoulder Hip
Hinge	Elbow Knee Ankle
Pivot	Spine (Atlas / Axis joint at the top)
Condyloid	Wrist
Gliding	Spine (between the bony processes of the vertebrae)
Saddle	Thumb, shoulder and inner ear.