an articulation is just a joint your skeleton is full of joints it's anywhere that two or more bones meet so there are many different types of joints in the body to organize all these different types you can do that by asking yourself what the function of the joint is what its structure is and then its type let's look at all of these at once might be a little overwhelming at first but we're gonna go through all the functional structural and types of joints beginning with the meeting between your parietal bones okay so at the top of your skull the parietal bones meet up what is the function of that joint that means how much motion do we want do we want the parietal bones to be able to wiggle and wave around a lot like our arms no clearly not so the joint or articulation between the parietal bones is a sin arthrosis it means those joints are synced up they're tightly held together there's no movement there well the structure of this articulation look like if you could pull these out of a cadaver and look at them under a microscope what holds those bones together well it turns out the answer is there are fibers there so we call this a fibrous structural type and then finally what's the specific name for the articulation between the parietal bones what's the sagittal suture the type of joint is a suture you can go through this with all the joints in your body shoulder joints and hip joints wrist and elbow even your tooth sockets holding your teeth in place are a type of joint so let's dive into this terminology and everything is going to be organized in my PowerPoint as in many textbooks starting with the functional type meaning in this image you can see all the types of joints that are sin arthrosis and remember that sin s y n I like to think of that meaning it's synced up like when you plug your iPhone into your computer it syncs your pictures they are together so synarthrosis these are together there's no movement in these joints so then the next question is well how do you make sure there's no movement what is the structural type of joint there well as we already mentioned you can have some fibers in there holding the bones together tightly those are called fibrous joints or you can have some cartilage cartilage can be pretty strong make a pretty tight joint and so that's a cartilaginous articulation sometimes the bones will just fuse right together so the structural type is bony fusion now we can get into even a little bit more detail and name specific joints in the body that exhibit these characteristics meaning a suture is an articulation between bones of the skull in which fibers bind together the bones to make sure that there is no movement in the joint synarthrosis another place you don't want movement is in the articulation between your teeth and your tooth sockets your alveolar processes so a gum Phocis is a type of joint in which you have a fiber called the periodontal ligament ensuring that there's no movement between your teeth and your maxillary bones and your mandible fibers aren't the only thing that can make a nice tight joint cartilage can do it too and we have a name for that it's called a sin condor osis remember sin is when the bones synch up tight and Kandra is cartilage so this is a rigid cartilaginous bridge between two bones and an example shown here is in between these sternum and the ribs synchondrosis finally if you really don't want that joint to move at all you can just fuse those bones together we haven't even talked about this but your frontal bone used to be your frontal bones and they fuse together you can't even see a line or anything they're just perfectly fused together same with the ischium ilium and pubis of your AHS coxa those bones are fused together no evidence remains that they used to be separate bones so those are all a type of sin osto --ss bones have synced up well one has fuse so aust refers to bone and the bones have fused together so all of these are types of synarthrosis articulations with no movement that's good for protecting organs keeping our teeth in our mouths but we need a little bit of movement sometimes amphi arthrosis provide a little bit of movement in the joint I'm still not doing this but a little bit of movement if you want to attach two bones together with a lid in a little bit of movement you can use fibers again and when you do so we call that a syndesmosis when bones are connected by fibers we're talking ligaments here like the ligaments in between the tibia and fibula you cartilage can provide a pretty good articulation again so you can have cartilaginous joints but rather than being a synchondrosis like we saw in the sternum and ribs a non-moving joint sometimes they can move a little like in the case of a synthesis a synthesis is where the bones are separated by a chunk of cartilage not a bridge of cartilage like before but like a pad of cartilage the pubic symphysis great example of a synthesis it even has symphysis in the name but also the intervertebral discs have a pad of cartilage separating those bones and we do have a little bit of movement in between our vertebrae I still haven't got to do this so we need one more type of joint that provides a lot of movement that's gonna be the diarthrosis freely movable joints now things are a little different here because there's not going to be any fibers they're not cartilaginous no bony fusion etc we just have one word for diuresis and that's synovial so all the joints that are diarthrosis have a synovial structure these all provide a wide range of movement these are mostly found at the ends of long bones so meaning my shoulder socket but also by elbow but also my wrist and so on these freely movable joints can't all do this my elbow for example can only go e or it's only moving on one plane and to make sure you understand planes what we're talking about here is basically XY and z how many dimensions can a joint move in or another way to think of it is is like yaw pitch and roll that just means think of a plane a plane can go up like this and down like this and that's one dimension a plane can Bank so that's the second dimension of movement and a plane can spin you don't really want them to if you've seen Top Gun that's called the flat spin that's how goose you know so planes do have that ability go up and down left and right and banking three dimensions so if you think about moving your elbow all my elbow can really do is like lift off and touch down and lift off and touch down it can't move in the other dimensions so that's a mono axial type of viewing there are also biaxial and tri-axial types of synovial joints we're going to get into all that in a separate video let's just mention briefly when I say that these the diarthrosis are all synovial joints they all have synovial fluid so this fluid is inside the joint for lubrication because you know I'm generating a lot of rubbing in my shoulder socket while I do this so I need lubrication I need shock absorption and there are cartilage cells in there that get nourished that get nutrients and oxygen provided through the synovial fluid and we won't talk about this in detail but if you've got some joint issue they'll probably do a joint tap they'll withdraw fluid from that joint to look for blood or white blood cells which might indicate trauma or infection or something so they can use joint fluid as a diagnostic tool it should be relatively clear maybe a little bit yellowish you don't want it cloudier or bloody clearly so what we'll do next is look at a synovial joint in detail so we can better understand all of the structures in the joint that let me do this