Normal synovial joint structure: cartilage, synovium and synovial fluid
How articular cartilage carries load without blood vessels or nerves, what the synovium makes, why normal synovial fluid has under 200 cells/µL and no fibrinogen, how joints are lubricated, and how these explain synovial fluid results, cartilage that won't heal and where joint pain comes from.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Synovial (diarthrodial) joints have hyaline cartilage on the bone ends, a capsule lined by synovium, and a small volume of synovial fluid (knee about 1 to 4 mL).
- Cartilage is avascular, aneural and alymphatic. Chondrocytes make up only 1 to 5% of its volume and depend on diffusion, which is why cartilage barely repairs.
- Synovium has no basement membrane, so synovial fluid is a plasma dialysate plus hyaluronan and lubricin. Small molecules like glucose match plasma; big ones like fibrinogen are kept out.
Loading the rest of the note…
Finished reading?
Sources
- Kelley and Firestein's Textbook of Rheumatology (11th ed.)Elsevier (Firestein, Budd, Gabriel, Koretzky, McInnes, O'Dell, 2021), 2021
- The biology of lubricin: near frictionless joint motionMatrix Biology (Jay and Waller, 2014;39:17-24), 2014
- Does this adult patient have septic arthritis?JAMA (Margaretten et al., 2007;297:1478-1488), 2007
- Therapeutic Guidelines: RheumatologyAU/NZTherapeutic Guidelines Ltd
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy