Arthrology- thestudyofthestructureandfunctionofjointsJoint-anylocationwheretwoormorebonesarticulate.

Articulation- asynonymforjoint.

Articulations Bio230-Dr.CarlaSweet

Classificationofjoints

A. StructuralClassification-focusesonthematerialbindingthebonestogetherandwhetherornotaJOINTCAVITYispresent.1.FibrousJoints- herethebonesarejoinedtogetherbyFibrousTissue(denseconnectivetissue).Nojointcavity.

ex.thethesuturesbetweenbonesoftheskull,veryshortdenseconnectivetissuefibers(collagen),holdthebonestogether.2.Cartilaginousjoints- thebonesareheldtogetherbyCartilage.Nojointcavity.ex.fibrocartilage ofsymphsis pubisandintervertebral discs.3.SynovialJoints- thearticulatingbonesareseparatedbyafluidcontainingjoint

cavity.

B.FunctionalClassification-basedontheamountofmovementallowedatthejoint.1.Synarthrosis=nomovement2.Amphiarthrosis =slightlymovablejoints3.Diarthrosis=freelymovablejoints

Examples:1.Suture2.Gomphosis-Betweentheteethandjaws

Synarthrosis- immovablejoints&nojointcavityHereBonesareheldtightlytogetherbydense(fibrous)connectivetissue.

Ex.–symphysis pubis-intervertebral disks

Amphiarthrosis- slightlyimmovablejoints&nojointcavityHereBonesunitedbycartilage

Diathrosis-freelymoveable&haveasynovialjointcavity

Examples:•shoulder•elbow•wrist•hip•thumb•ankle•knee

Featuresofasynovialjoint1. Articular Cartilage2. Synovial(joint)Cavity3. Articular Capsule(2layers)

a.Outerlayer=fibrouslayer,madeofdenseirregularC.T.Continuouswithperiosteum.b.Innerlayer=synovialmembrane(looseC.T.)Coversallinternaljt.surfacesnotcoveredbycartilage.

4. SynovialFluid(madebythesynovialmembrane)

5.ReinforcingLigaments

Featuresofasynovialjoint

Otherstructuresusuallypresentinsynovialjoints:1.Meniscus- (foundinknees)2.Bursa- (multiplelocations)3.Tendonsheaths

Bursae-(plofbursa)foundthroughoutthebody;largestintheshoulder,elbow,knee,andhipjoints.

Tendonsheaths-Modifiedbursathatsurroundcertaintendons.Foundwheretendonscrossjoints(exwrist&ankles)

ankle

Menisci(pluralofmeniscus)-cushionsoffibrocartilage

Bursae andtendonsheathsarebagsoflubricantthatreducefrictionatsynovialjoints

MovementsofSynovialJoints

Movementsofvariousjoints

Flexion = decreases the angle between bones, brings bones closer together.

Extension = reverse of flexion.

Hyperextension = moving beyond anatomical position.

hyperextension not seen in elbow or knee.

Angularmovementsincreaseordecreasetheanglebetweentwobones.Thesemovementsinclude:Flexion/Extension,Abduction/Adduction andCircumduction

Flexion/Extensioncanoccurinthefollowingjoints:Neck,shoulder,elbow,wrist,fingers,trunk,hip,knee,ankleandtoesBesureyoucandemonstratethesemovementsateachjointlocationlistedabove.

Abduction- movingawayfromtheanatomicalpositionintheFrontalplane.

Adduction- returningtotheanatomicalpositionintheFrontalplane.

The terms abduction and adduction refer to the ACTION, NOT THE APPENDAGE that you are moving (you can abduct and adduct your shoulder, legs at the hip joint, your fingers and wrists. Be sure you can demonstrate these movements)

ABDUCTION:ADDUCTION

Wrist Abduction (aka Radial flexion) = tilting the hand towards the thumb (towards the radius)

Wrist Adduction (aka Ulnar flexion) = tilting hand towards the pinky finger (towards the ulna)

Abduction of the FINGERS is when you spread your fingers apart, Adduction is when you bring your fingers back together.

In terms of your fingers:

Flexion = curling fingers (like a fist)

Extension = pointing your fingers

Circumduction = 1 end of thejoint remains stationary, the otherend makes a CIRCLE.

Only in a ball and socket joint(shoulder & hip)

Rotation=themovementofabodypartarounditsownaxis.ThinkC1:C-2!Shakinghead“no”.Otherexamplesbelowatshoulder&hip.

Movementsofballandsocketjoint

Your shoulder (ball and socket) is a good example of a joint that is “multiarticulate”

The ball and socket allows for:

Abduction & adduction of the arm (flap your arms like a bird , jumping jacks)

•Flexion of the arm (extending to shake a hand or open a door)

•Rotation of the arm (sweeping your desk)

In terms of ANKLE movements

Dorsiflection = lift toes/foot up

towards shin

(standing on your heels)

Zero position = feet flat on the

ground, standing up

Plantar flexion = pointing toes/foot

down (standing on your toes)

In terms of your FEETInversion= only happens in feet, when the foot is turned so the sole is facing inward.

Eversion= happens only in the feet, when the foot is turned so the sole is outward.

Supination =ONLY for FOREARM, when

you turn your forearm so that the palms

face forward or ventral (anatomical position).

Pronation = ONLY for the forearm, when

you turn your forearm so that the palm

faces posterior or dorsal.

Pronation brings the radius across the ulna

so the two bones form an X.

Supination:Pronation- refertomovementsofradiusaroundtheulna

Elevation = is the upward movement of a body part

Depression = moving the elevated part inferiorly.

Ex, Shrugging shoulder, opening and closing mouth (mandible)

SpecialMovements

Opposition:Foundonlyinthethumbjoint.Allowsthethumbtotouchtheotherfingersinthesamehand.Thisuniqueactioniswhatmakesthehumanhandabletograspandmanipulateobjects.Humanshave“OpposableThumbs”

PROTRACTION =themovementofabodypartanteriorly (themandibleandthescapula)RETRACTION=isthemovementofabodypartposteriorly (mandibleandthescapula).

retraction protraction

BallandSocket:Triaxial joint-permitsmovementinallthreeplanes.Roundedconvexsurfacewithcuplikecavity.Ex.Shoulder&hipAllow- flexion:extension

-adduction:abduction-circumduction-internal(medial)rotation:external(lateral)rotation

TypesofSynovialJoints(6)

HingejointSurfaceofoneboneconcavetheotherconvexMonoaxial-movementinoneplane

Onlyallow- flexion:extension

Ex.Knee,elbowandinterphalangeal joints

Pivotjoint:limitedtorotationaroundacentralaxis.(monoaxial)ex.- atlas&axis

-proximalarticulationofradiusandulna

Condyloid Joint(akaellipsoidaljoint)-Theovalsurfaceofonebonefitsintothedepressionofanotherbonebiaxial(canmoveintwoplanes).Allows- Flexion:extension andabduction:adduction

examples:radiocarpaljoint(wristjt.),metacarpophalangealjoints2-5

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radiocarpal joint metacarpophalangeal joint

è -------------Lunate

SaddleJoint- foundonlyinthethumb(firstcarpometcarpal joint)Allowforextensiveangularmotion(nottruerotation).Classifiedasabiaxial“plus”jt.Allows- flexion:extension;abduction:adduction

andthumbopposition.

RememberThethumbswingsfromthetrapezium.Allowsforthumbopposition

Plane(Gliding)Joint- -gliding(sliding)indifferentplanes.Examples:1.Sternoclavicular jt.2.Acromioclavicularjoint3.intercarpal joints4.Sacroiliacjoint

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Theshoulderjoint(Glenohumeral joint)Howit“hangs”together.Asynovialjointwithlotsofligamentsandbursae.

bursae

Stabilityhasbeensacrificedtoprovidethemostfreelymovingjointinthebody.

Hipjointandit’sligaments.Deepsocket(acetabulum),andligamentsprovidesstrength&stabilitytoHipJoint.

Hip:asynovialjoint

SynovialJointofhip

KneejointSynovialjointwithitsLigaments,bursae,menisci

Kneestructurestoknow!- Medial(tibial)andLateral(fibular)collateral

ligaments.- - AnteriorandPosteriorcruciateligaments)are

insidethearticularcapsule)- Medialmeniscus;lateralmeniscus- Articularcartilage- Quadricepstendon- Patellarligament

UnhappyTriade:Ruptured:1.AnteriorCruciateLigament(ACL)2.MedialCollateralLigament(MCL)and3.Medialmeniscus.

Commonsportsinjury

CommonsportsInjury

ClinicalJoints

Whatdoyouseewrongwithx-raybelow?

Normal

Calcific tendenitis iscommonlyseenabouttheshoulder.Thetypicalappearanceisthatofsmallfocalglobsofamorphouscalcification,usuallyseenaroundthesupraspinatus tendon.

Normalshoulder

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BoneonBone;Toseeatotalkneereplacementsurgery(notforthefaint)goto:https://www.broadcastmed.com/orthopedics/4919/videos/computer-assisted-total-knee-replacement

Rheumatoidarthritis- anautoimmunediseasethatoccurswhenthebody’simmunesystemattacksthecartilageandmembraneofthejoint..Asthediseaseprogressesthejointcavityiseliminatedandthearticulatingbonesfuse.Resultsinpainfuldisfigurationofthejointandlossofjointfunction.

A32yearoldwomanwhonoteddecreasedflexioninherrightkneewithposteriorfullnessabout3yearsago.Shehadassociatedmildkneepain.Herpasthistorywasnoncontributory.Thephysicalexamdemonstratedpopliteal fullnessanddecreasedkneeflexionfrom0- 50degrees.

Bursitisacommonproblem!

Osteoarthritisofthespine

LooseJoints!

Next----OntotheMuscularSystem!