Synovial fluid is found in joint cavities and provides lubrication and nutrition to cartilage. It is composed of hyaluronic acid, lubricin, and other substances. Type B synovial cells secrete hyaluronic acid to give synovial fluid its viscosity. Synovial fluid analysis examines characteristics like clarity, viscosity, cell count, proteins, enzymes, and other biomarkers to diagnose conditions like infection, inflammation, or crystal-induced arthritis. The analysis is an important tool to identify joint diseases and guide appropriate treatment.