Y khoa, y dược - Joints: Part B

8 Joints: Part BClassification of Synovial JointsSix types, based on shape of articular surfaces:PlaneHingePivotCondyloidSaddleBall and socketPlane JointsNonaxial jointsFlat articular surfacesShort gliding movements Figure 8.7aabcdefNonaxialUniaxialBiaxialMultiaxialaPlane joint (intercarpal joint)Hinge JointsUniaxial joints Motion along a single planeFlexion and extension onlyFigure 8.7bbHinge joint (elbow joint)abcdefNonaxialUniaxialBiaxialMultiaxialPivot JointsRounded end of one bone conforms to a “sleeve,” or ring of another boneUniaxial movement only Figure 8.7ccPivot joint (proximal radioulnar joint)abcdefNonaxialUniaxialBiaxialMultiaxialCondyloid (Ellipsoidal) JointsBiaxial jointsBoth articular surfaces are ovalPermit all angular movementsFigure 8.7ddCondyloid joint(metacarpophalangeal joint)abcdefNonaxialUniaxialBiaxialMultiaxialSaddle JointsBiaxialAllow greater freedom of movement than condyloid jointsEach articular surface has both concave and convex areasFigure 8.7eeSaddle joint (carpometacarpal jointof thumb)abcdefNonaxialUniaxialBiaxialMultiaxialBall-and-Socket JointsMultiaxial jointsThe most freely moving synovial jointsFigure 8.7ffBall-and-socket joint (shoulder joint)abcdefNonaxialUniaxialBiaxialMultiaxialKnee JointLargest, most complex joint of bodyThree joints surrounded by a single joint cavity:Femoropatellar joint:Plane jointAllows gliding motion during knee flexionLateral and medial tibiofemoral joints between the femoral condyles and the C-shaped lateral and medial menisci (semilunar cartilages) of the tibiaAllow flexion, extension, and some rotation when knee is partly flexedPLAYA&P Flix™: Movement at the knee jointFigure 8.8a(a) Sagittal section through the right knee jointFemurTendon ofquadricepsfemorisSuprapatellarbursaPatellaSubcutaneousprepatellar bursaSynovial cavityLateral meniscusPosteriorcruciateligamentInfrapatellarfat pad Deep infrapatellarbursaPatellar ligamentArticularcapsuleLateralmeniscusAnteriorcruciateligamentTibiaFigure 8.8b(b) Superior view of the right tibia in the knee joint, showing the menisci and cruciate ligamentsMedialmeniscusArticularcartilageon medialtibialcondyleAnteriorAnteriorcruciateligamentArticularcartilage onlateral tibialcondyleLateralmeniscusPosteriorcruciateligamentKnee JointAt least 12 associated bursaeCapsule is reinforced by muscle tendons:E.g., quadriceps and semimembranosus tendonsJoint capsule is thin and absent anteriorlyAnteriorly, the quadriceps tendon gives rise to:Lateral and medial patellar retinaculaPatellar ligamentFigure 8.8cQuadricepsfemoris muscleTendon ofquadricepsfemoris musclePatellaLateral patellarretinaculumMedial patellarretinaculumTibial collateralligamentTibiaFibularcollateralligamentFibula(c) Anterior view of right kneePatellar ligamentKnee JointCapsular and extracapsular ligamentsHelp prevent hyperextensionIntracapsular ligaments: Anterior and posterior cruciate ligamentsPrevent anterior-posterior displacementReside outside the synovial cavityFigure 8.8dArticular capsuleOblique poplitealligamentLateral head ofgastrocnemiusmuscleFibular collateralligamentArcuate poplitealligamentTibiaFemurMedial head ofgastrocnemiusmuscleTendon ofsemimembranosusmuscle(d) Posterior view of the joint capsule,including ligamentsPopliteusmuscle (cut)Tendon ofadductor magnus BursaTibial collateralligamentPLAYAnimation: Rotatable kneeFigure 8.8eFibularcollateralligamentPosterior cruciateligamentMedial condyleTibial collateralligamentAnterior cruciateligamentMedial meniscusPatellar ligamentPatellaQuadriceps tendonLateral condyleof femurLateralmeniscusFibulaTibia(e) Anterior view of flexed knee, showing the cruciateligaments (articular capsule removed, and quadricepstendon cut and reflected distally)Figure 8.9LateralMedialPatella(outline)Tibial collateralligament(torn)Medialmeniscus (torn)Anteriorcruciateligament (torn)Hockey puckShoulder (Glenohumeral) JointBall-and-socket joint: head of humerus and glenoid fossa of the scapulaStability is sacrificed for greater freedom of movementFigure 8.10aPLAYAnimation: Rotatable shoulderAcromionof scapulaSynovial membraneFibrous capsuleHyalinecartilageCoracoacromialligamentSubacromialbursaFibrousarticular capsuleTendonsheathTendon oflong headof bicepsbrachii muscleSynovial cavityof the glenoidcavity containingsynovial fluidHumerus(a) Frontal section through right shoulder jointShoulder JointReinforcing ligaments:Coracohumeral ligament—helps support the weight of the upper limbThree glenohumeral ligaments—somewhat weak anterior reinforcementsShoulder jointReinforcing muscle tendons:Tendon of the long head of biceps:Travels through the intertubercular groove Secures the humerus to the glenoid cavityFour rotator cuff tendons encircle the shoulder joint:SubscapularisSupraspinatusInfraspinatusTeres minorPLAYA&P Flix™: Rotator cuff muscles: An overview (a)PLAYA&P Flix™: Rotator cuff muscles: An overview (b)Figure 8.10cAcromionCoracoacromialligamentSubacromialbursaCoracohumeralligamentGreatertubercleof humerusTransversehumeralligamentTendon sheathTendon of longhead of bicepsbrachii muscleArticularcapsulereinforced byglenohumeralligamentsSubscapularbursaTendon of thesubscapularismuscleScapulaCoracoidprocess(c) Anterior view of right shoulder joint capsuleFigure 8.10dAcromionCoracoid processArticular capsuleGlenoid cavityGlenoid labrumTendon of long headof biceps brachii muscle Glenohumeral ligamentsTendon of thesubscapularis muscle ScapulaPosteriorAnterior(d) Lateral view of socket of right shoulder joint,humerus removedElbow JointRadius and ulna articulate with the humerusHinge joint formed mainly by trochlear notch of ulna and trochlea of humerusFlexion and extension onlyPLAYA&P Flix™: Movement at the elbow jointFigure 8.11aArticularcapsuleSynovialmembraneSynovial cavityArticular cartilageCoronoid processTendon ofbrachialis muscleUlnaHumerusFat padTendon oftricepsmuscleBursaTrochleaArticular cartilageof the trochlearnotch(a) Median sagittal section through right elbow (lateral view)Elbow JointAnular ligament—surrounds head of radiusTwo capsular ligaments restrict side-to-side movement:Ulnar collateral ligamentRadial collateral ligamentFigure 8.11bHumerusLateralepicondyleArticularcapsuleRadialcollateralligamentOlecranonprocessAnularligamentRadiusUlna(b) Lateral view of right elbow jointPLAYAnimation: Rotatable elbowFigure 8.11dArticularcapsuleAnularligamentCoronoidprocess(d) Medial view of right elbowRadiusHumerusMedialepicondyleUlnarcollateralligamentUlnaHip (Coxal) JointBall-and-socket jointHead of the femur articulates with the acetabulumGood range of motion, but limited by the deep socket Acetabular labrum—enhances depth of socketPLAYA&P Flix™: Movement at the hip joint: An overviewFigure 8.12aArticular cartilageCoxal (hip) boneLigament ofthe head of the femur (ligamentum teres)Synovial cavityArticular capsuleAcetabularlabrum Femur(a) Frontal section through the right hip jointHip JointReinforcing ligaments:Iliofemoral ligamentPubofemoral ligamentIschiofemoral ligamentLigamentum teresPLAYAnimation: Rotatable hipFigure 8.12cIschiumIliofemoralligamentIschiofemoralligamentGreatertrochanterof femur(c) Posterior view of right hip joint, capsule in placeFigure 8.12dAnterior inferioriliac spineIliofemoralligamentPubofemoralligamentGreatertrochanter(d) Anterior view of right hip joint, capsule in place Temporomandibular Joint (TMJ)Mandibular condyle articulates with the temporal boneTwo types of movementHinge—depression and elevation of mandibleGliding—e.g. side-to-side (lateral excursion) grinding of teethMost easily dislocated joint in the bodyFigure 8.13aZygomatic processMandibular fossaArticular tubercleInfratemporal fossaExternalacousticmeatusArticularcapsuleRamus ofmandible Lateralligament (a) Location of the joint in the skullFigure 8.13bArticularcapsuleMandibularfossaArticular discArticulartubercleSuperiorjointcavityInferior jointcavityMandibularcondyleRamus ofmandible Synovialmembranes(b) Enlargement of a sagittal section through the jointFigure 8.13cLateral excursion: lateral (side-to-side) movements of the mandibleOutline ofthe mandibularfossaSuperior viewCommon Joint InjuriesSprainsThe ligaments are stretched or tornPartial tears slowly repair themselvesComplete ruptures require prompt surgical repairCartilage tearsDue to compression and shear stressFragments may cause joint to lock or bindCartilage rarely repairs itselfRepaired with arthroscopic surgeryFigure 8.14TornmeniscusCommon Joint InjuriesDislocations (luxations)Occur when bones are forced out of alignmentAccompanied by sprains, inflammation, and joint immobilizationCaused by serious falls or playing sports Subluxation—partial dislocation of a jointInflammatory and Degenerative ConditionsBursitisAn inflammation of a bursa, usually caused by a blow or frictionTreated with rest and ice and, if severe, anti-inflammatory drugsTendonitisInflammation of tendon sheaths typically caused by overuseSymptoms and treatment similar to bursitisArthritis>100 different types of inflammatory or degenerative diseases that damage jointsMost widespread crippling disease in the U.S.Symptoms; pain, stiffness, and swelling of a jointAcute forms: caused by bacteria, treated with antibioticsChronic forms: osteoarthritis, rheumatoid arthritis, and gouty arthritisOsteoarthritis (OA)Common, irreversible, degenerative (“wear-and-tear”) arthritis85% of all Americans develop OA, more women than menProbably related to the normal aging processOsteoarthritis (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 sulfateRheumatoid Arthritis (RA)Chronic, inflammatory, autoimmune disease of unknown cause Usually arises between age 40 and 50, but may occur at any age; affects 3 times as many women as menSigns and symptoms include joint pain and swelling (usually bilateral), anemia, osteoporosis, muscle weakness, and cardiovascular problemsRheumatoid Arthritis RA begins with synovitis of the affected jointInflammatory blood cells migrate to the joint, release inflammatory chemicals Inflamed synovial membrane thickens into a pannusPannus erodes cartilage, scar tissue forms, articulating bone ends connect (ankylosis)Figure 8.15Rheumatoid Arthritis: TreatmentConservative therapy: aspirin, long-term use of antibiotics, and physical therapyProgressive treatment: anti-inflammatory drugs or immunosuppressants New biological response modifier drugs neutralize inflammatory chemicalsGouty ArthritisDeposition of uric acid crystals in joints and soft tissues, followed by inflammationMore common in men Typically 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 alcoholLyme DiseaseCaused by bacteria transmitted by the bites of ticksSymptoms: skin rash, flu-like symptoms, and foggy thinkingMay lead to joint pain and arthritisTreatment: antibioticsDevelopmental Aspects of JointsBy embryonic week 8, synovial joints resemble adult jointsA joint’s size, shape, and flexibility are modified by use Advancing 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 problemsJointsLigaments