JOINTSSTRUCTURE AND FUNCTION:Joints A “connection” between 2 or more bones A pivot point for bony motion The “features” of the joint help determine The ROM Degrees of freedom Functional potential of the jointAxial Skeleton The Axial Skeleton makes up the central bony axis of the body and is composed of: the skull hyoid bone sternum ribs vertebral column sacrum coccyxAppendicular Skeleton Just as the name suggests, the appendicular skeleton is composed of the appendages or extremities: This includes the supporting structuresBONEANATOMY & FUNCTIONPrimary Types of Tissue Cortical (compact) – outmost portions of bone  Strong Dense Absorptive (forces) Cancellous (spongy) – inner portions of bone Porous Lightens the bone Redistributes forces & is covered by articular cartilageStructural Features of Bone Diaphysis Epiphyses (2) Proximal Distal Articular cartilage –hyaline cartilage Periosteum Medullary canal EndosteumPrimary Types of Bones Five categories Long Sesamoid Irregular Flat ShortsesamoidJoint Classifications SynarthrosisAllows little to no movementSutures in the skull Distal tibiofibular jointSuture linesJoint Classifications Amphiarthrosis Formed by fibro and hyaline cartilage Shock absorbers Allows limited motionJoint Classifications Diarthrosis (Synovial Joints) Contains fluid-filled cavity between 2 or more bones There are 7 categories with 7 common elements!WhatWhySynovial fluid-for joint lubrication & nutritionArticular cartilage-to spread out and absorb forcesArticular capsule-to contain the jointSynovial membrane-to produce the fluid for the jointCapsular ligaments-to limit excessive joint motionBlood vessels-to provide nutrients, permit healing to occur!Sensory nerves-transmit pain and awareness of position (proprioception)Synovial Joint ClassificationsThe structure of the joint determines the functional potential for the joint. Most of the names intentionally resemble functional structures!Hinge CondyloidPivot SaddleEllipsoid PlaneBall-and-SocketHinge JointDegrees of Freedom1Primary MotionsFlexion and extensionMechanical AnalogyDoor hingeAnatomic ExamplesHumero-ulnar joint, interphalangeal jointsPivot JointDegrees of Freedom1Primary MotionsSpinning one member on an axisMechanical AnalogyDoor knobAnatomic ExamplesProximal radioulnar jointElipsoid Joint Degrees of Freedom2Primary MotionsFlex & Ext,ABD & ADDMechanical AnalogyFlattened convex with concave troughAnatomic ExamplesRadiocarpal jointBall & Socket JointDegrees of Freedom3Primary MotionsFlex & Ext, ABD & ADD, IR & ERMechanical AnalogySpherical convex surface & concave cupAnatomic ExamplesGlenohumoral joint and hipPlane JointsDegrees of FreedomVariablePrimary MotionsSlide &/or rotationMechanical AnalogyBook sliding or spinning on a tableAnatomic ExamplesIntercarpal joints intertarsal jointsSaddle JointsDegrees of Freedom2Primary MotionsBilpanar, excluding spinMechanical AnalogyHorseback rider on a saddleAnatomic ExamplesCMC joint of the thumbSternoclavicular jointCondyloid JointDegrees of Freedom2Primary MotionsBiplanar MotionMechanical AnalogySpherical convex surface & concave cupAnatomic ExampleTibiofemoral jointMCP jointConnective Tissue All connective tissues that support the joints of the body are composed of: Fibers There are 3 types of fibers Type I collageno Thick and resist stretchingo Ligaments, tendons & fibrous capsules Type II collegeno Thinner and less stiffo Provide a flexible framework to maintain the shape & consistency of the structures such as hyaline cartilage Elastino Elastic and help prevent injury due to ability to “give” and not breakConnective Tissue All connective tissues that support the joints of the body are composed of: Ground substance Collagen & elastin within a water saturated matrix Cells Responsible for maintenance & repairConnective Tissue: Joint “support”Ground substanceDisperses repetitive forces Water Glycosaminoglycans SolutesCells – “cytes”Cells for maintenance and repair.  Blastocytes,  phagocytesWhy do bones need maintenance & repair?Types of Connective Tissue in Joints Dense Irregular Connective Tissue Binds bones together Makes up ligaments & external joint capsule Type I collagen Injuries- Ruptured Lateral Collateral ligaments in the ankle, instability in the talocrural ligamentTypes of Connective Tissue in Joints Articular Cartilage Resists compressive and shear forces in articular surfaces Covers the ends of articulating surfaces of bones in synovial joints High % type II collagen content which helps to anchor the cartilage to the bone Injuries Wear & tear decreases it’s effectiveness in reducing compression leading to OA and joint pain & inflammation.Types of Connective Tissue in Joints Fibrocartilage Provides support & stabilization to joints, resists compression & shear forces Makes up the intervertebral discs and menisci of the knees Multidirectional bundles of type I collagen Injuries Tearing can cause disruption of the integrity of the structure and pain with loss of functionTypes of Connective Tissue in Joints Bone Forms primary supporting structure of the body & a rigid level to transmit the force of muscle to move & stabilize the body Forms internal levers of musculoskeletal system Specialized arrangement of Type I collagen & framework for hard mineral salts Injuries osteoporosisTypes of Connective tissue1. Dense irregular (attachment points)a. Ligamentsb. Joint capsule2. Articular cartilage (ease of movement)a. Covering at the end of bones of synovial joints3. Fibrocartilage (the shock absorbers)a. Menisci pleural of “meniscus”b. Intervertebral discs4. Bone – (the levers in the musculoskeletal