ClassificationofJoints• Criteria– Howbonesarejoinedtogether– Degreeofmobility
• Minimumcomponents– 2articulatingbones– Interveningtissue
• FibrousCTorcartilage
• Categories– Synarthroses– nomovement– Amphiarthrosis– slightmovement– Diarthrosis– freelymovable
SynarthrosisSutures
• Foundonlyinskull• Immovablearticulation• FlatbonesjoinedbythinlayeroffibrousCT• Types– Serrate– Squamous(lap)– Plane
SynarthrosisSutures
• Serrate• Serratededgesofboneinterlock
• Twoportionsoffrontalbones
• Squamous(lap)• Overlappingbeveledmarginsformssmoothline
• Temporalandparietalbones
• Plane• Jointformedbystraight,nonoverlappingedges
• Palatineprocessofmaxillae
SynarthrosisSchindylesis
• Immovablearticulation• Thinplateofboneintocleftorfissureinaseparationofthelaminaeinanotherbone
• Articulationofsphenoidboneandperpendicularplateofethmoidbonewithvomer
SynarthrosisGomphosis
• Immovablearticulation• Conicalprocessintoasocket
• Articulationofteethwithalveoliofmaxillarybone
• Periodontalligament=fibrousCT
SynarthrosisSynchondrosis
• Cartilagenousjoints– Ribsjoinedtosternumbyhyalinecartilage
• Synostoses– Whenjointossifies– Epiphysealplatebecomesepiphysealline
Amphiarthrosis
• Slightlymoveablearticulation• Articulatingbonesconnectedinoneoftwoways:– Bybroadflattenedfibro-cartilagediscs• Fibrocartilage• Symphisis
– Byinterosseusligaments• Syndesmosis
AmphiarthrosisSyndesmosis
• Twobonesjoinedbyinterosseousmembrane
• Example– Radioulnarjoint– Tibulofibularjoint
Diarthrosis
• Synovialjoints• Freelymovable• Types– Hinge– Gliding– Pivot– Saddle– Condyloid– Ballandsocket
GeneralAnatomy• Articularcartilage
– Hyalinecartilage– Coversendsofbones
• Jointcapsule– Enclosesjointcavity– Retainssynovialfluid– Twoparts
• Fibrouscapsule• Synovialmembrane
• Synovialfluid– Producedbyfibroblasts– Lubricatesjoint– Nourishesarticularcartilage– Removeswaste– Containsalbuminandhyaluronic
acid
GeneralAnatomy
• Meniscus– Cartilagesthatdonotcross
joint– Foundinknee– Shockabsorbers– Guidemovementofbone– Stabilizejoint
• AccessoryStructures– Tendon– Ligaments– Bursae(pl.)
• Fibroussacfilledwithsynovialfluid
TemperomandibularJoint
• Articulardisc– Fibrocartilagepad
crossesjointcapsule– Foundin
temporomadibularandradioulnarjoints
DiarthrosesHingeJoints
• Monaxial• Articulationbetweenconcaveandconvexsurfaces
• Locations– Knee– Elbow– Betweenphalanges
DiarthrosesGlidingJoints
• Biaxial• Articularsurfacesflatorslightlyconcaveandconvex
• Sidetosideorback/forthmotionwithslightrotation
• Locations– Betweencarpals– Betweentarsals
DiarthrosesPivotJoints
• Monaxial• Conicalbonefitsintoadepression
• Rotationaroundacentralaxis
• Locations– Radius/ulna– Atlas/axis
DiarthrosesSaddleJoints
• Eacharticularprocessisconcaveinonedirection,convexinanother
• Amodifiedcondyloidarticulationwithawiderrangeofmovement
• Locations– Betweenthetrapeziumand
1stmetacarpal– Betweenthemalleusand
incus
DiarthrosesCondyloidJoints
• Biaxial• Convexsurfaceisovalshaped
• Up/down,sidetosidemovements
• Locations– Radius/carpals– Metacarpals/phalanges
DiarthrosesBallandSocketJoints
• Multiaxial• Greatestrangeofmovementofallsynovialjoints
• Roundedconvexsurfacewithacuplikecavity
• Locations– Shoulder– Hip
MovementsofSynovialJointsMovementTerminology
• Flexion,Extension,andHyperextension• Abductionandadduction• Elevationanddepression• Protractionandretraction• Lateralandmedialexcursion• Circumduction• Rotation• Supinationandpronation• Oppositionandreposition• Dorsiflexionandplantarflexion• Inversionandeversion
Flexion,Extension,andHyperextension
• Flexion– Decreaseintheangleofthejoint– Usuallyinasagittalplane– Ex)bendingtheelbow
• Extension– Straightensjointandreturnsbodyparttoanatomicalposition
– Ex)straightentheelbow• Hyperextension– Extensionofjointbeyond180o
– Ex)lookingupwardattheceiling
AbductionandAdduction,ElevationandDepression
• Abduction– Movementawayfromthemedianplane– Ex)Raisingarm
• Adduction– Movementtowardthemedianplane– Ex)Loweringarm
• Elevation– Movementthatraisesbonevertically– Ex)shruggingshoulders
• Depression– Movementthatlowersbonevertically– Ex)loweringmandibletoopenmouth
Protraction,Retraction,LateralandMedialExcursion
• Protraction–Movementofboneforwardonahorizontalplane– Ex)thrustingpelvisforward
• Retraction–Movementofboneposteriorly
• Lateralandmedialexcursion– Lateral:Sidewaysmovementrightorleft–Medial:Movementbacktomidline– Ex)sidetosidegrindingofteeth
CircumductionandRotation,SupinationandPronation
• Circumduction– Movementconscribesaconicalspace– Ex)windingupforapitch
• Rotation– Boneturnsonitslongitudinalaxis– Ex)twistingatwaist
• Supination(forearmonly)– Rotationofforearmsothatpalmfacesforwardorupward
• Pronation(forearmonly)– Rotationofforearmsothatpalmfacestowardrearordownward
OppositionandReposition,DorsiflexionandPlantarFlexion
• Opposition–Movementofthumbtowardfingertips
• Reposition–Movementofthumbbacktoanatomicalpositionparalleltoindexfinger
• Dorsiflexion– Upwardmovementoffoot
• Plantarflexion– Steppingdownward
InversionandEversion
• Inversion– Turningsolesoffeetinwardmediallytowardeachother
• Eversion– Turingsolesoffeetoutwardawayfromeachother
LeverSystems
• Components1. Rigidrod:thestationarybone2. Effort• appliedforce:suppliedbymusclecontraction
3. Fulcrum• pivotpoint:joint
4. Resistance• theloadmovedbytheappliedforce• themovableboneandanythingattached
FirstClassLevers
• Fulcrumpositionedbetweeneffortandresistance
• Jointworkslikeasee-saw
• Example– atlanto-occipitaljoint(nodding)
SecondClassLevers
• Resistancepositionedbetweentheeffortandfulcrum
• Jointworkslikeawheelbarroworcrowbar
• Example– contractionofthecalfmusclestoelevatethebody
ThirdClassLevers
• Effortpositionedbetweenthefulcrumandresistance
• Mostcommon• Jointworkslikeforceps• Example– elbowjoint