A joint structure is the point where two or more bones meet in the body. Joints allow for movement and flexibility, enabling activities like walking, bending, and lifting. They can be classified into different types, such as hinge joints, which allow movement in one direction, and ball-and-socket joints, which permit a wider range of motion. The main components of a joint include cartilage, which cushions the bones, and synovial fluid, which lubricates the joint to reduce friction. Ligaments connect bones to each other, while tendons attach muscles to bones, playing a crucial role in joint stability and movement.