A synovial joint is a type of joint in the body that allows for a wide range of movement. These joints are characterized by a fluid-filled space called the synovial cavity, which is surrounded by a capsule made of connective tissue. The fluid, known as synovial fluid, lubricates the joint, reducing friction and providing nourishment to the cartilage. Common examples of synovial joints include the knee, elbow, and shoulder. These joints can be classified into different types based on their movement capabilities, such as hinge joints (like the elbow) and ball-and-socket joints (like the shoulder). Synovial joints play a crucial role in enabling flexibility and mobility in the human body.