👉 The retention fluid, also known as synovial fluid, is a viscous liquid found within the cavities of synovial joints. It serves to lubricate and nourish the joint surfaces, reducing friction during movement and providing essential nutrients to the cartilage. This fluid is continuously produced by specialized cells within the joint capsule and is replenished through diffusion from the synovial membrane. It plays a crucial role in maintaining joint health and function by ensuring smooth, pain-free motion and protecting the cartilage from wear and tear.