8Joints (Articulations)Functional Classification of JointsStructural Classification of JointsFibrous JointsFibrous Joints: SuturesSlide 7Fibrous Joints: SyndesmosesSlide 9Fibrous Joints: GomphosesSlide 11Cartilaginous JointsCartilaginous Joints: SynchondrosesSlide 14Cartilaginous Joints: SymphysesSlide 16Synovial JointsSlide 18Slide 19Slide 20Slide 21Slide 22Slide 23Synovial Joints: Friction-Reducing StructuresSlide 25Slide 26Slide 27Stabilizing Factors at Synovial JointsSynovial Joints: MovementSynovial Joints: Range of MotionSummary of Characteristics of Body JointsSlide 32Slide 33Slide 34Slide 35Movements at Synovial JointsSlide 37Gliding MovementsSlide 39Angular MovementsSlide 41Slide 42Slide 43Slide 44Slide 45RotationSlide 47Special MovementsSlide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59PowerPoint® Lecture Slides prepared by Janice Meeking, Mount Royal CollegeC H A P T E RCopyright © 2010 Pearson Education, Inc.8 Joints: Part ACopyright © 2010 Pearson Education, Inc.Joints (Articulations)•Articulation—site where two or more bones meet•Functions of joints:•Give skeleton mobility•Hold skeleton togetherCopyright © 2010 Pearson Education, Inc.Functional Classification of Joints •Based on amount of movement allowed by the joint•Three functional classifications:•Synarthroses—immovable •Amphiarthroses—slightly movable •Diarthroses—freely movableCopyright © 2010 Pearson Education, Inc.Structural Classification of Joints •Based on material binding bones together and whether or not a joint cavity is present•Three structural classifications:•Fibrous•Cartilaginous •SynovialCopyright © 2010 Pearson Education, Inc.Fibrous Joints•Bones joined by dense fibrous connective tissue•No joint cavity•Most are synarthrotic (immovable)•Three types:•Sutures•Syndesmoses•GomphosesCopyright © 2010 Pearson Education, Inc.Fibrous Joints: Sutures•Rigid, interlocking joints containing short connective tissue fibers•Allow for growth during youth•In middle age, sutures ossify and are called synostosesCopyright © 2010 Pearson Education, Inc.Figure 8.1aDensefibrousconnectivetissueSutureline(a) Suture Joint held together with very short,interconnecting fibers, and bone edgesinterlock. Found only in the skull.Copyright © 2010 Pearson Education, Inc.Fibrous Joints: Syndesmoses•Bones connected by ligaments (bands of fibrous tissue)•Movement varies from immovable to slightly movable•Examples: •Synarthrotic distal tibiofibular joint•Diarthrotic interosseous connection between radius and ulnaCopyright © 2010 Pearson Education, Inc.Figure 8.1bFibulaTibiaLigament(b) Syndesmosis Joint held together by a ligament.Fibrous tissue can vary in length, but is longer than in sutures.Copyright © 2010 Pearson Education, Inc.Fibrous Joints: Gomphoses•Peg-in-socket joints of teeth in alveolar sockets•Fibrous connection is the periodontal ligamentCopyright © 2010 Pearson Education, Inc.Figure 8.1cRoot oftoothSocket ofalveolarprocessPeriodontalligament(c) Gomphosis “Peg in socket” fibrous joint. Periodontalligament holds tooth in socket.Copyright © 2010 Pearson Education, Inc.Cartilaginous Joints•Bones united by cartilage•No joint cavity•Two types:•Synchondroses•SymphysesCopyright © 2010 Pearson Education, Inc.Cartilaginous Joints: Synchondroses•A bar or plate of hyaline cartilage unites the bones•All are synarthroticCopyright © 2010 Pearson Education, Inc.Figure 8.2aEpiphysealplate (temporaryhyaline cartilagejoint)Sternum(manubrium)Joint betweenfirst rib andsternum(immovable)(a) SynchondrosesBones united by hyaline cartilageCopyright © 2010 Pearson Education, Inc.Cartilaginous Joints: Symphyses•Hyaline cartilage covers the articulating surfaces and is fused to an intervening pad of fibrocartilage•Strong, flexible amphiarthrosesCopyright © 2010 Pearson Education, Inc.Figure 8.2bFibrocartilaginousintervertebraldiscPubic symphysisBody of vertebraHyaline cartilage(b) SymphysesBones united by fibrocartilageCopyright © 2010 Pearson Education, Inc.Synovial Joints•All are diarthrotic•Include all limb joints; most joints of the bodyCopyright © 2010 Pearson Education, Inc.Synovial JointsDistinguishing features:1. Articular cartilage: hyaline cartilage2. Joint (synovial) cavity: small potential spaceCopyright © 2010 Pearson Education, Inc.Synovial JointsDistinguishing features:3. Articular (joint) capsule: •Outer fibrous capsule of dense irregular connective tissue•Inner synovial membrane of loose connective tissueCopyright © 2010 Pearson Education, Inc.Synovial JointsDistinguishing features:4. Synovial fluid: •Viscous slippery filtrate of plasma + hyaluronic acid •Lubricates and nourishes articular cartilageCopyright © 2010 Pearson Education, Inc.Figure 8.3PeriosteumLigamentFibrouscapsuleSynovialmembraneJoint cavity(containssynovial fluid)Articular (hyaline)cartilageArticularcapsuleCopyright © 2010 Pearson Education, Inc.Synovial JointsDistinguishing features:5. Three possible types of reinforcing ligaments:•Capsular (intrinsic)—part of the fibrous capsule•Extracapsular—outside the capsule•Intracapsular—deep to capsule; covered by synovial membraneCopyright © 2010 Pearson Education, Inc.Synovial JointsDistinguishing features:6. Rich nerve and blood vessel supply:•Nerve fibers detect pain, monitor joint position and stretch•Capillary beds produce filtrate for synovial fluidCopyright © 2010 Pearson Education, Inc.Synovial Joints: Friction-Reducing Structures•Bursae:•Flattened, fibrous sacs lined with synovial membranes •Contain synovial fluid•Commonly act as “ball bearings” where ligaments, muscles, skin, tendons, or bones rub togetherCopyright © 2010 Pearson Education, Inc.Figure 8.4bCoracoacromialligamentSubacromialbursaCavity inbursa containingsynovial fluidBursa rollsand lessensfriction.Humerus headrolls medially asarm abducts.(b) Enlargement of (a), showing how a bursaeliminates friction where a ligament (or otherstructure) would rub against a boneHumerusresting HumerusmovingCopyright © 2010 Pearson Education, Inc.Synovial Joints: Friction-Reducing Structures•Tendon sheath:•Elongated bursa that wraps completely around a tendonCopyright © 2010 Pearson Education, Inc.Figure 8.4aAcromionof scapulaJoint cavitycontainingsynovial