 Here, everybody, Dr. O here. I'm going to go into much more detail about joints and joint structures like bursas and these types of things in the future, but for now I just want to talk about what a typical synovial joint looks like, so this is about as textbook as you're going to get here. The synovial joint is the most common type of joint in the body, so obviously we need to talk about it. So a key characteristic, when I think about a synovial joint in comparison to other joints, right, these two bones are not directly connected by dense fibrous tissue or cartilage there, the presence of that joint cavity is the key. So inside this joint cavity we have this synovial fluid, synovial fluid is very thick, sticky, and it's a lubricating fluid, so it's lubricating the ends of these bones. So the fact that these two bones are not directly connected and they have this lubricating fluid inside this joint cavity is what allows for increased movement compared to the other types of joints we covered like sutures and the gonfosis and these kind of things. So the wall on the outside of a synovial joint is going to be that articular capsule, that is a fibrous connect tissue, but it attaches the bones outside of that joint surface there. The articular cartilage there, which is hyaline cartilage, its job is to prevent friction or wear and tear or rubbing that occurs between these two bones. Now as we age this cartilage will thin and be frayed and once you lose that articular cartilage, that hyaline cartilage, you can then have bone on bone contact and that can lead to arthritis or osteoarthritis. That's very, very common. I saw countless patients with that in the past. So we have the synovial membrane is going to be what produces the synovial fluid that we talked about, this lubricating fluid. We talked about the capsule there being the outside of the joint and we talked about the articular cartilage, which is basically works like Teflon to prevent that sticking and wearing and tearing. Okay, so because of this structure, how it's built, remember that each synovial joint like this one will be classified as a synovial joint, obviously, but will also be classified as a diarthrosis, a freely movable joint. Okay, so that's a typical synovial joint. I hope this helps. Have a wonderful day. Be blessed.