okay so in this video really got classifications of joints or articulations right so an articulation means to connect so technically in the body in articulation is a place for two or more bones meet to form a joint and the functions of these joints are to basically help to give the skeleton some mobility and stability in fact there's an interesting trade-off between mobility and stability because where you have joints where tor bones meet if those bones are at the place where they meet is highly stable then they're probably going to be pretty immobile so that their mobility will be low if they're very stable because you're gonna use a lot of tissue that's tight and strong to hold those bones together well now opposite to this you find that joints that are highly mobile are often the least stable because to make those places where the bones meet moveable requires either the tissue to be soft or you know not a whole lot of tissue holding those bones together so that way they're more stable I'm sorry more mobile so there's actually two classifications of joints we have structural and functional classifications the structural classifications of joints include fibrous cartilaginous and synovial and this is what we're talking about in terms of what they're made of so that we have joints that are made of fibrous tissue like dense regular connective tissue we have joints that are made of cartilage and therefore cartilaginous and we have synovial joints which are the movable joints that are made of a synovial membrane which is a lubrication membrane so in terms of the functional classifications we have three types and this all refers to the degree of movement so we have synarthrosis which are immovable joints and fareth Roces which are slightly movable and the dire throw C's which are freely movable so an example of a synarthrosis or a totally immovable joint would be like the cranial sutures so the places where your cranial bones meet those are Cinar throught ik because they're immovable and we have an Pharisees which are slightly movable an example of this would be like the distal tib Uhler fibular articulation and this is a type of ligament that's slightly movable and then the diarthrotic joints are freely movable in fact all synovial joints are diarthrotic and they're freely movable an example this would be like your shoulder joint or hip joint now the structural classifications are more clear-cut in terms of what they're made of now what's interesting then is we can also make some predictions about how movable a joint is based on what it's made of so for instance most of the fibrous joints are going to be Cinar throught ik and then a lot of the cartilaginous joints are either going to be syn orthotic or an periodic and then we know that all synovial joints are diarthrotic or freely movable