What type of joints are primarily surrounded by synovial fluid?

Synovial joints are the type of joints primarily surrounded by synovial fluid. This fluid is crucial for the function of these joints as it acts as a lubricant, reducing friction between the articular cartilages of the bones during movement. The presence of synovial fluid allows for a greater range of motion, which is characteristic of synovial joints, including the knee, elbow, and shoulder. Additionally, synovial joints are enclosed within a joint capsule that is lined with synovial membrane, which produces this fluid, further highlighting the role of synovial fluid in promoting joint health and mobility.

In contrast, fibrous joints, found in areas such as the skull, do not contain a joint cavity or synovial fluid. Cartilaginous joints, like those between the vertebrae, also lack synovial fluid and instead have cartilage providing support and stability. Immovable joints, which refer to joints that do not permit movement, also do not have synovial fluid as they are typically formed by fibrous or cartilaginous structures. Therefore, the unique characteristics of synovial joints, including the presence of synovial fluid, make them distinct from the other types of joints.