The synovial cavity is a small space found within synovial joints, which are the most common type of joint in the human body. This cavity is filled with synovial fluid, a thick liquid that lubricates the joint, reducing friction between the articulating bones. This fluid also provides nutrients to the cartilage, helping to maintain joint health. Synovial joints, such as the knee and elbow, allow for a wide range of motion due to their unique structure. The synovial cavity is surrounded by a joint capsule, which is made up of connective tissue that helps stabilize the joint while allowing flexibility.