Synovial fluid , synovia (from the Greek. Sýn - together and lat. Ovum - an egg) is a thick elastic mass filling the joint cavity. Normally transparent or slightly yellowish. In the body, it performs the function of intraarticular lubrication, preventing friction of articular surfaces and their wear; participates in maintaining the normal ratio of articular surfaces in the joint cavity, increases their mobility; provides nutrition for articular cartilage; serves as an additional shock absorber. The fluid is produced by the synovial membrane of the joint and fills its cavity [1] .
Content
Composition
Synovial fluid consists of two main components - liquid and protein-polysaccharide. A fluid is essentially a blood plasma . The main element providing the visco-elastic properties of the synovial fluid is hyaluronan - a polysaccharide from the glycosaminoglycan group. Hyaluronan provides stabilization of the structure of proteoglycans, which in complex form molecules of complex structure and large molecular weight. These molecules are deposited inside the collagen structure of the cartilage , ensuring its elasticity [2] .
Function
When loaded from the deep layers of the cartilage through the pores and spaces between the fibers, a liquid is released to lubricate it. With a decrease in load, the fluid goes back inside the cartilage . Therefore, articular cartilage glides almost without friction even with significant physical exertion (the so-called “enhanced lubrication”).
A lack of synovial fluid worsens gliding and causes creaking of the joint. There are situations when the synovial fluid is secreted in sufficient quantities, but its quality suffers as a result of a lack of certain constituent elements - glucosamine and chondroitin . Various disorders in the process of synovial fluid synthesis are often accompanied by various joint lesions, such as osteoarthritis , etc.