A joint is a place where bones come together. It is the joints, together with the muscles, which make movements of body parts possible.

At a joint, the ends of the bones are covered with cartilage. This material is similar to bone, but is softer and more flexible. Your ears and the end of your nose are made of cartilage. The cartilage acts as a cushion between the bones and helps prevent the bones from grinding against one another. A fluid called synovial fluid is also found at a joint. This fluid acts as a lubricant (like oil in an engine) and helps make smoother movement at the joint possible.

Problems with the skeletal system can develop when the cartilage begins to break down or when there is a reduction or increase of the fluids found at the joint. These conditions can be studied in more detail in the Injury Section of this project.

The circled areas on the skeletal map below represent four kinds of joints found in the human body. The four kinds of joints are ball and socket, hinge, gliding and immovable. Click on one of the joints from the map to see how movement is possible.

Click on one of the joints from the map to see how movement is possible.