right we'll begin section nine by looking at how joints are classified so what is a joint it's basically a connection between either two or more bones or cartilage and bone or teeth and Bone we can classify joints structurally and functionally if you classify them structurally you're going to look at whether or not they have a cavity and what type of Conn connective tissues are involved in the joint if you're looking at them functionally you're really only considering how much movement occurs at that joint so in your structural classification we're looking at what material composes the joint and whether or not there is a cavity in the joint there are three structural classifications fibrous cartilagenous and synovial so if it's a fibrous joint it's held together by fibrous connective tissue we can classify those fibrous joints two ways by their movement um they could either be a sinosis which has little or no movement or amphiarthrosis which has a little bit of movement um but your fius joints are never going to be freely movable um so in terms of synarthrosis or areas that have little or no movement um those would be sutures in the skull what we call synes mosis which uh includes the inner oous membranes between the radius and Ola of the forearm and the tibia and fibula of the lower leg or what we call a gomphosis which is where the teeth attach into the um bone of the mandible or the maxela and then if you have amphiarthrosis now these are not really movable joints but they do allow a bit of movement that would include your intervertebral discs um you can obviously flex your backbone somewhat uh and then the puic symphysis where the two pelvic bones meet in the anterior portion uh that's somewhat movable there's a hormone called relaxin that is produced during pregnancy that makes that joint even more movable um to allow for childbirth um cartilagenous joints on the other are held together by cartilage um some of your cartilagenous joints will transition to Bone uh with age and lose their Mobility so when we classify our cartilagenous joints they can be sondros or synarthrosis or arthroses and those terms are interchangeable those are cartilagenous joints that are joined by highin cartilage um and the reason they're called synarthrosis is because they're immovable they don't move at all uh examples the epipal or growth plate of long bones before it oif or the first sternocostal joint where the first ribs meet the sternum um also symphysis like the puic symphysis this is categorized as a secondary cartilagenous joint it's technically fibrocartilage so symphyses are both fibrous joints and cartilagenous Joints um but they do allow a little movement like the pubic symphysis then finally you have synovial joints sovial joints are those that allow for free movement between bones these are the ones that you probably think of like your elbow your knee your shoulder um now with a cial joint these the bones that articulate are going to be covered with articular cartilage and that's to protect the ends of the bones there's also a cavity found in synovial joints you'll see a large C or you'll see a distinct synovial cavity between the bones cobal joints are also going to be surrounded by accessory ligaments because cobal joints are freely movable they are also less stable uh in terms of joints the more movable the more movement that you get the less stability you have because the joints are going to be held together by ligaments and tendons and those tend to be less stable so examples of synovial joints hip knee shoulder elbow right now if you look at functional classifications remember that's only based on movement so you have synarthroses these have no movement examples are sutures in the skull and the synes mosis the gomphosis which is where the teeth um the roots of the teeth set in the bones of the maxilla and mandible and then you have inner oous membranes between the radius andula and the forearm and the tibia and fibula in the lower leg then you have Ani arthrosis and these do allow a little bit of movement examples pubic symphysis invertebral discs and finally you have diarthroses and these are your typical sovial joints uh they're freely movable hip knee shoulder elbow are examples