2JointsNow that we know all of the bones we need to look at the joints of the skeletonJoints, also called articulations, have two main functionsThey hold bones together securelyThey give the rigid skeleton mobility
3Classification of joints Joints are commonly classified in two mannersFunctionally -- how they workStructurally -- how they are constructed and shaped.
4Functional Classification The functional classifications focus on the amount of movement allowed by the jointsWith this system we have 3 main categoriesSynarthrosesAmphiarthrosesDiarthroses
5Synarthroses Synarthroses joints are joints that are immoveable Most commonly located in the axial skeletonEx: joints of the large bones of the cranium like the tempro-parietal joint
6Amphiarthroses Amphiarthroses are joints that are slightly movable. These joints, like synarthroses are mostly located in the axial skeleton where rigidity is important to the function of the bones.
7Diarthroses Diarthroses are joints that are freely movable These are mostly found in the appendicular skeleton, whose main function is mobility and manipulation.
8Structural Classification We can also classify the joints by there structural classificationsWe also have 3 structural classificationsFibrousCartilaginousSynovial
9Fibrous JointsFibrous joints are joints that are united by fibrous tissueThe best examples of this type of joint are the sutures in the skullIn sutures we have the jagged edges bound tightly together with connective tissue fibers
10Fibrous joints Sutures are not the only place for fibrous joints There are some places where the connecting fibers are larger and longer to allow more “give”These are called syndesmosesAn example is between the distal end of the fibula and tibia
11Cartilaginous Joints These are the joints connected by cartilage Examples of this type of joint are usually slightly moveableThe joints between the vertebrae are cartilaginous joints
12Synovial JointsSynovial joints are those in which the articulating surfaces are seperated by a joint cavity containing synovial fluidAll Synovial joints have 4 distinguishing features.
13Features of synovial joints Articular cartilageFibrous articular capsuleJoint CavityReinforcing Ligaments
14Types of synovial joints There are 6 types of synovial jointsPlaneHingePivotCondyloidSaddleBall-and-Socket
15Plane Joint A plane joint can be seen in your carpals It moves very limitedly
16Hinge jointA hinge joint can be found in your humerus where it connects to the ulnaThis allows motion similar to a hinge of a door
17Pivot jointPivot joints can be found in your radius and ulna as well as your vertebraeThey allow for twisting motion
18Condyloid jointCondyloid joints provide motion to the sides like a joystickAn example would be your metacarpals and metatarsals
19Saddle jointA saddle joint is shaped like a saddle and provide for motion back and forth and side to sideAn example would be where your metacarpal 1 meets your carpals
20Ball and socket jointBall and socket joints provide the most movement out of all the jointsThey allow for nearly 360 degrees of rotationThey can be found in the heads of your humerus and femur