2Joints Chapter 9 Joint Classifications Fibrous Joints Cartilaginous JointsSynovial JointsTypes of Movements at Synovial JointsTypes of Synovial JointsFactors Affecting Contact and Range of Motion at Synovial JointsSelected Joints of the BodyAging and JointsArthroplastyMuse Lecture #6
3An Introduction to Articulations Body movement occurs at joints (articulations) where two bones connectJoint StructureDetermines direction and distance of movement (range of motion)Joint strength decreases as mobility increases
4Classification of Joints Two methods of classificationFunctional classification is based on range of motion of the jointStructural classification relies on the anatomical organization of the joint
5Classification of Joints Functional ClassificationsSynarthrosis (immovable joint)No movementFibrous or cartilaginous connectionsMay fuse over timeAmphiarthrosis (slightly movable joint)Little movementDiarthrosis (freely movable joint)More movementAlso called synovial jointsSubdivided by type of motionParty on Arth!
10Classification of Joints Functional ClassificationsSynarthroses (immovable joints)Are very strongEdges of bones may touch or interlockFour types of synarthrotic joints:suturegomphosissynchondrosissynostosis
11Classification of Joints Synarthrotic JointsSutureBones interlockedAre bound by dense fibrous connective tissueAre found only in skullGomphosisFibrous connection (periodontal ligament)Binds teeth to socketsYah can’t chomp without the gomph
12Joints (Fibrous Joints) SuturesOccur only between bones of the skullSyndesmosesPermits slight movementInterosseous membraneBetween the tibia and fibula in the legGomphosesImmovable jointJoint in which a cone-shaped peg fits into a socketArticulations of the teeth with the sockets of the maxillae and mandible
13(b) Syndesmosis Joint held together by a ligament. Fibrous tissue can vary in length, butis longer than in sutures.FibulaTibiaLigamentFigure 8.1b
14Joints (Fibrous Joints) Lack a synovial cavityThe articulating bones are held very closely together by dense irregular connective tissueFibrous joints permit little or no movementThree types of fibrous jointsSuturesSyndesmosesGomphoses
15Classification of Joints Synarthrotic JointsSynchondrosisIs a rigid cartilaginous bridge between two bones:epiphyseal cartilage of long bonesbetween vertebrosternal ribs and sternumSynostosisFused bones, immovable:metopic suture of skullepiphyseal lines of long bones
16Classification of Joints Functional ClassificationsAmphiarthrosesMore movable than synarthrosisStronger than freely movable jointTwo types of amphiarthrosessyndesmosis:bones connected by ligamentssymphysis:bones separated by fibrous cartilage
17Classification of Joints Functional ClassificationsSynovial joints (diarthroses)Also called movable jointsAt ends of long bonesWithin articular capsulesLined with synovial membrane
18Synovial Joints Components of Synovial Joints Articular cartilages Pad articulating surfaces within articular capsules:prevent bones from touchingSmooth surfaces lubricated by synovial fluid:reduce friction
20Synovial Joints Components of Synovial Joints Synovial fluid Contains slippery proteoglycans secreted by fibroblastsFunctions of synovial fluid:lubricationnutrient distributionshock absorption
21Synovial Joints Components of Synovial Joints Accessory structures Cartilages:cushion the joint:Fibrous cartilage pad called a meniscus (articular disc)Fat pads:superficial to the joint capsuleprotect articular cartilagesLigaments:support, strengthen jointssprain: ligaments with torn collagen fibers
22Synovial Joints Components of Synovial Joints Accessory structures Tendons:attach to muscles around jointhelp support jointBursae:pockets of synovial fluidcushion areas where tendons or ligaments rub
23Coracoacromial ligament Subacromial bursa Humerus resting Cavity in bursa containingsynovial fluidBursa rollsand lessensfriction.Humerus headrolls medially asarm abducts.Humerusmoving(b) Enlargement of (a), showing how a bursa eliminates friction where a ligament (or other structure) would rub against a boneFigure 8.4b
24Synovial Joints Factors That Stabilize Synovial Joints Prevent injury by limiting range of motionCollagen fibers (joint capsule, ligaments)Articulating surfaces and menisciOther bones, muscles, or fat padsTendons of articulating bones
25Synovial Joints [INSERT FIG. 9.1a] Figure 9–1a The Structure of a Synovial Joint.
26Synovial JointsFigure 9–1b The Structure of a Synovial Joint.
27Synovial Joints Injuries Dislocation (luxation) Subluxation Articulating surfaces forced out of positionDamages articular cartilage, ligaments, joint capsuleSubluxationA partial dislocation
28Movements Types of Dynamic Motion Planes (Axes) of Dynamic Motion Linear motion (gliding)Angular motionRotationPlanes (Axes) of Dynamic MotionMonaxial (1 axis)Biaxial (2 axes)Triaxial (3 axes)
29MovementsFigure 9–2 A Simple Model of Articular Motion.
30MovementsFigure 9–2 A Simple Model of Articular Motion.
31Movements Types of Movements at Synovial Joints Terms describe Plane or direction of motionRelationship between structures
32Movements Types of Movements at Synovial Joints Linear motion Also called glidingTwo surfaces slide past each other:between carpal or tarsal bones
33Movements Angular Motion Flexion Extension Angular motion Anterior–posterior planeReduces angle between elementsExtensionIncreases angle between elements
41Movements Types of Movement at Synovial Joints Rotation Direction of rotation from anatomical positionRelative to longitudinal axis of bodyLeft or right rotationMedial rotation (inward rotation):rotates toward axisLateral rotation (outward rotation):rotates away from axis
45Movements Types of Movements at Synovial Joints Special movements Inversion:twists sole of foot mediallyEversion:twists sole of foot laterallyDorsiflexion:flexion at ankle (lifting toes)Plantar flexion:extension at ankle (pointing toes)Plant your feet
46Movements Special Movements at Synovial Joints Opposition Thumb movement toward fingers or palm (grasping)ProtractionMoves anteriorlyIn the horizontal plane (pushing forward)RetractionOpposite of protractionMoving anteriorly (pulling back)
47Movements Special Movements at Synovial Joints Elevation Depression Moves in superior direction (up)DepressionMoves in inferior direction (down)Lateral flexionBends vertebral column from side to side
50Movements Classification of Synovial Joints by Shape Gliding Hinge PivotEllipsoidSaddleBall-and-socketA Functional Classification of Synovial Joints
51Movements Gliding Joints Hinge Joints Pivot Joints Flattened or slightly curved facesLimited motion (nonaxial)Hinge JointsAngular motion in a single plane (monaxial)Pivot JointsRotation only (monaxial)
52MovementsFigure 9–6 Movements at Synovial Joints.
53Movements Ellipsoid Joints Saddle Joints Ball-and-Socket Joints Oval articular face within a depressionMotion in two planes (biaxial)Saddle JointsTwo concave, straddled (biaxial)Ball-and-Socket JointsRound articular face in a depression (triaxial)
54MovementsFigure 9–6 Movements at Synovial Joints.
55Movements A joint cannot be both mobile and strong The greater the mobility, the weaker the jointMobile joints are supported by muscles and ligaments, not bone-to-bone connections
56Intervertebral Articulations C2 to L5 spinal vertebrae articulateAt inferior and superior articular processes (gliding joints)Between adjacent vertebral bodies (symphyseal joints)
57Intervertebral Articulations C2 to L5 spinal vertebrae articulateIntervertebral discs:pads of fibrous cartilageseparate vertebral bodiesanulus fibrosus:tough outer layerattaches disc to vertebraenucleus pulposus:elastic, gelatinous coreabsorbs shocks
61Intervertebral Articulations Six Intervertebral LigamentsInterspinous ligamentConnects spinous processesSupraspinous ligamentConnects tips of spinous processes (C7 to sacrum)Ligamentum nuchaeContinues supraspinous ligament (C7 to skull)
62Intervertebral Articulations Damage to Intervertebral DiscsSlipped discBulge in anulus fibrosusInvades vertebral canalHerniated discNucleus pulposus breaks through anulus fibrosusPresses on spinal cord or nerves
63Intervertebral Articulations Figure 9–8a Damage to the Intervertebral Discs.
64Intervertebral Articulations Figure 9–8b Damage to the Intervertebral Discs.
65Intervertebral Articulations Movements of the Vertebral ColumnFlexionBends anteriorlyExtensionBends posteriorlyLateral flexionBends laterallyRotationTurning
69Joints (Selected Joints of the Body) Temporomandibular JointCombined hinge and planar joint formed by the mandible and the temporal boneOnly movable joint between skull bonesOnly the mandible moves
70Lateral excursion: lateral (side-to-side) movements of the mandible Superior viewOutline ofthe mandibularfossaLateral excursion: lateral (side-to-side) movements of themandibleFigure 8.13c
71(a) Location of the joint in the skull Mandibular fossaArticular tubercleZygomatic processInfratemporal fossaExternalacousticmeatusLateralligamentArticularcapsuleRamus ofmandible(a) Location of the joint in the skullFigure 8.13a
72(b) Enlargement of a sagittal section through the joint Articular discArticulartubercleMandibularfossaSuperiorjointcavityArticularcapsuleSynovialmembranesMandibularcondyleRamus ofmandibleInferior jointcavity(b) Enlargement of a sagittal section through the jointFigure 8.13b
73The Shoulder Joint Also called the glenohumeral joint Allows more motion than any other jointIs the least stableSupported by skeletal muscles, tendons, ligamentsBall-and-socket diarthrosisBetween head of humerus and glenoid cavity of scapula
74The Shoulder Joint Socket of the Shoulder Joint Glenoid labrumDeepens socket of glenoid cavityFibrous cartilage liningExtends past the boneProcesses of the Shoulder JointAcromion (clavicle) and coracoid process (scapula)Project laterally, superior to the humerusHelp stabilize the joint
75The Shoulder Joint Shoulder Ligaments Shoulder Separation Glenohumeral CoracohumeralCoraco-acromialCoracoclavicularAcromioclavicularShoulder SeparationDislocation of the shoulder joint
77The Shoulder JointFigure 9–9a The Shoulder Joint.
78The Shoulder JointFigure 9–9b The Shoulder Joint.
79The Elbow Joint A stable hinge joint With articulations involving humerus, radius, and ulna
80The Elbow Joint Articulations of the Elbow Humero-ulnar joint Largest articulationTrochlea of humerus and trochlear notch of ulnaLimited movementHumeroradial joint:Smaller articulationCapitulum of humerus and head of radius
84The Hip Joint Also called coxal joint Strong ball-and-socket diarthrosisWide range of motion
85The Hip Joint Structures of the Hip Joint Ligaments of the Hip Joint Head of femur fits into itSocket of acetabulumWhich is extended by fibrocartilaginous acetabular labrumLigaments of the Hip JointIliofemoralPubofemoralIschiofemoralTransverse acetabularLigamentum teres
89The Knee Joint A complicated hinge joint Transfers weight from femur to tibiaArticulations of the knee jointTwo femur–tibia articulationsAt medial and lateral condylesOne between patella and patellar surface of femur
90The Knee Joint Menisci of the Knee Medial and lateral menisci Fibrous cartilage padsAt femur–tibia articulationsCushion and stabilize jointGive lateral supportLocking kneesStanding with legs straight:“locks” knees by jamming lateral meniscus between tibia and femur
91The Knee Joint Seven Ligaments of the Knee Joint Patellar ligament (anterior)Two popliteal ligaments (posterior)Anterior and posterior cruciate ligaments (inside joint capsule)Tibial collateral ligament (medial)Fibular collateral ligament (lateral)
99Aging Rheumatism Arthritis Osteoarthritis A pain and stiffness of skeletal and muscular systemsArthritisAll forms of rheumatism that damage articular cartilages of synovial jointsOsteoarthritisCaused by wear and tear of joint surfaces, or genetic factors affecting collagen formationGenerally in people over age 60
100Developmental Aspects of Joints By embryonic week 8, synovial joints resemble adult jointsA joint’s size, shape, and flexibility are modified by useAdvancing years take their toll on joints:Ligaments and tendons shorten and weakenIntervertebral discs become more likely to herniateMost people in their 70s have some degree of OAExercise that coaxes joints through their full range of motion is key to postponing joint problems
101Aging Rheumatoid Arthritis Gouty Arthritis An inflammatory condition Caused by infection, allergy, or autoimmune diseaseInvolves the immune systemGouty ArthritisOccurs when crystals (uric acid or calcium salts)Form within synovial fluidDue to metabolic disorders
102Rheumatoid Arthritis RA begins with synovitis of the affected joint Inflammatory blood cells migrate to the joint, release inflammatory chemicalsInflamed synovial membrane thickens into a pannusPannus erodes cartilage, scar tissue forms, articulating bone ends connect (ankylosis)
104Gouty ArthritisDeposition of uric acid crystals in joints and soft tissues, followed by inflammationMore common in menTypically affects the joint at the base of the great toeIn untreated gouty arthritis, the bone ends fuse and immobilize the jointTreatment: drugs, plenty of water, avoidance of alcohol
105Aging Joint Immobilization Bones and Aging Reduces flow of synovial fluidCan cause arthritis symptomsTreated by continuous passive motion (therapy)Bones and AgingBone mass decreasesBones weakenIncreases risk of hip fracture, hip dislocation, or pelvic fracture
106Joints (Arthroplasty) Joints may be replaced surgically with artificial jointsMost commonly replaced are the hips, knees, and shouldersHip ReplacementsPartial hip replacements involve only the femurTotal hip replacements involve both the acetabulum and head of the femurKnee ReplacementsActually a resurfacing of cartilage and may be partial or totalPotential complications of arthroplasty include infection, blood clots, loosening or dislocation of the replacement components, and nerve injury
109Osteoarthritis (OA)Common, irreversible, degenerative (“wear-and-tear”) arthritis85% of all Americans develop OA, more women than menProbably related to the normal aging process
110Osteoarthritis (OA)More cartilage is destroyed than replaced in badly aligned or overworked jointsExposed bone ends thicken, enlarge, form bone spurs, and restrict movementTreatment: moderate activity, mild pain relievers, capsaicin creams, glucosamine and chondroitin sulfate
111Lyme Disease Caused by bacteria transmitted by the bites of ticks Symptoms: skin rash, flu-like symptoms, and foggy thinkingMay lead to joint pain and arthritisTreatment: antibiotics
112Integration with Other Systems Bone RecyclingLiving bones maintain equilibrium betweenBone building (osteoblasts)And breakdown (osteoclasts)Factors Affecting Bone StrengthAgePhysical stressHormone levelsCalcium and phosphorus uptake and excretionGenetic and environmental factors
113Integration with Other Systems Bones Support Body SystemsThe skeletal systemSupports and protects other systemsStores fat, calcium, and phosphorusManufactures cells for immune systemDisorders in other body systems can causeBone tumorsOsteoporosisArthritisRickets (vitamin D deficiency)
114Integration with Other Systems Figure 9–13 Functional Relationships between the Skeletal System and Other Systems.
115Integration with Other Systems Figure 9–13 Functional Relationships between the Skeletal System and Other Systems.