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The Temporomandibular Joint-The Temporomandibular Joint-Anatomy/PhysiologyAnatomy/PhysiologyEvaluation/TreatmentEvaluation/Treatment

Lori Steinley P.T., M.S.Lori Steinley P.T., M.S.

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AnatomyAnatomy

TemporomandibularTemporomandibularjoint (TMJ)joint (TMJ)•• Temporal boneTemporal bone

•• MandibleMandible

•• Relationship with boneyRelationship with boneylandmarks on skulllandmarks on skull

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CondyleCondyle Medial/lateralMedial/lateral

measurementmeasurementtwice thetwice theanterior/posterioranterior/posterior•• Not pure hingeNot pure hinge

movementmovement•• Rotation withRotation with

translation forwardtranslation forward

AttachmentsAttachments•• CollateralCollateral

ligaments-ligaments-medial/lateralmedial/lateral

•• Further anteriorFurther anterior––temporalistemporalisinsertion oninsertion oncoronoid processcoronoid process

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DiscDisc

CharacteristicsCharacteristics•• Posterior portionPosterior portion

thickestthickest

•• IntermediateIntermediateportionportion

In contact withIn contact withcondylecondyle

ThinnestThinnest

Avascular, aneuralAvascular, aneural

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DiscDisc

AttachmentsAttachments•• Posterior ligamentPosterior ligament

ElasticElastic

Passive-tensionPassive-tensiontissuetissue

•• Lateral pterygoid-Lateral pterygoid-Superior fibersSuperior fibers

•• Capsule-Capsule-anterior/posterioranterior/posterioronlyonly

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Normal disc movementNormal disc movement Moves as unit withMoves as unit with

condylecondyle Held in place on condyleHeld in place on condyle

by ligaments (collateralsby ligaments (collateralsand posterior)and posterior)

First 11 mm of opening,First 11 mm of opening,disc stationary, whiledisc stationary, whilecondyle rotatescondyle rotates

>11 mm, disc and>11 mm, disc andcondyle translate forwardcondyle translate forward

Disc rotates backward byDisc rotates backward bytension of posteriortension of posteriorligamentligament

Condyle always in contactCondyle always in contactwith intermediate portionwith intermediate portion

Opening door analogyOpening door analogy1010

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CapsuleCapsule

SynovialSynovialmembranemembrane•• Produces synovialProduces synovial

fluidfluid

•• Lubrication andLubrication andmetabolic exchangemetabolic exchangefor avascular jointfor avascular jointtissue (disc)tissue (disc)

TemporomadibularTemporomadibularligamentligament

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Muscles-TemporalisMuscles-Temporalis Origin-temporal fossa,Origin-temporal fossa,

superior to zygomatic archsuperior to zygomatic archinsertion-coronoid processinsertion-coronoid processof mandibleof mandible

Anterior, middle andAnterior, middle andposterior fibersposterior fibers

Elevation of mandibleElevation of mandible

Posterior fibers-retrusion,Posterior fibers-retrusion,and deviation to same sideand deviation to same side

Postural musclePostural muscle

Large muscle 53% of totalLarge muscle 53% of totalmass of elevatorsmass of elevators

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TemporalisTemporalis

Referral pattern-Referral pattern-temple, alongtemple, alongeyebrow, behindeyebrow, behindthe eye or upperthe eye or upperteethteeth

Perpetual clencherPerpetual clencher

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Muscles-MasseterMuscles-Masseter Origin-zygomatic archOrigin-zygomatic arch

insertion-mandibularinsertion-mandibularangle and ramusangle and ramus•• Sling with medialSling with medial

pterygoidpterygoid•• Together make up 57%Together make up 57%

of cross section ofof cross section ofelevators-power chewerelevators-power chewer

Synergist withSynergist withtemporalis fortemporalis forelevation but alsoelevation but alsoretrudes jaw, lateralretrudes jaw, lateraldeviation to same sidedeviation to same side

Chewing-first muscleChewing-first muscleto activateto activate

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MasseterMasseter

Referral pattern-Referral pattern-lower jaw, molarlower jaw, molarteeth and gum,teeth and gum,maxilla, lowermaxilla, lowerportion ofportion ofmandible, templemandible, templeeyebrow and toeyebrow and toear (externally)ear (externally)

““SinusitisSinusitis””

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Muscles-Medial PterygoidMuscles-Medial Pterygoid Origin-inner surface ofOrigin-inner surface of

lateral pterygoid platelateral pterygoid plate(under lateral(under lateralpterygoid) insertion-pterygoid) insertion-ramus of mandible byramus of mandible bythe anglethe angle

Elevation, protrusionElevation, protrusionand lateral deviationand lateral deviationto opposite sideto opposite side

Close relationship withClose relationship withlateral pterygoidlateral pterygoid

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Medial PterygoidMedial Pterygoid Referral pattern-Referral pattern-

posterior mandible,posterior mandible,mouth, below andmouth, below andbehind TMJ includingbehind TMJ includingear (internally)-notear (internally)-notteethteeth

Stuffiness in ear dueStuffiness in ear dueto tensor veli palatinito tensor veli palatinimuscle unable to pushmuscle unable to pushmedial pterygoid outmedial pterygoid outof the way to dilateof the way to dilatethe Eustachian tubethe Eustachian tube

Swallowing difficult asSwallowing difficult asrestriction inrestriction inprotrusion of jawprotrusion of jaw 2020

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Muscles-Lateral PterygoidMuscles-Lateral Pterygoid

Origin-lateralOrigin-lateralpterygoid plate ofpterygoid plate ofsphenoid,sphenoid,insertion-condylarinsertion-condylarneck, ramus ofneck, ramus ofmandible and discmandible and disc

Elevation,Elevation,protrusion, lateralprotrusion, lateraldeviation todeviation toopposite side (alsoopposite side (alsoinitial opening)initial opening)

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Lateral PterygoidLateral Pterygoid Referral pattern-Referral pattern-

zygomatic arch, TMJzygomatic arch, TMJ

Major myofascialMajor myofascialsource of painsource of pain

Cause disc and jaw toCause disc and jaw tobe unable to return tobe unable to return tonormal restingnormal restingpositionposition

Malocclusion of teethMalocclusion of teeth

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Muscles-DigasticMuscles-Digastic Origin-mastoidOrigin-mastoid

notch(posterior)-notch(posterior)-symphysis of mandiblesymphysis of mandible(anterior) insertion-join(anterior) insertion-joinby a common tendon toby a common tendon tothe hyoid bonethe hyoid bone

Depression and retrusionDepression and retrusionof jawof jaw

Less forceful movement-Less forceful movement-assisted with long leverassisted with long leverarm and gravityarm and gravity

Active with swallowing andActive with swallowing andcoughingcoughing

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DigastricsDigastrics

Referral pattern-Referral pattern-behind mandiblebehind mandibletowards back oftowards back ofear, lower incisorsear, lower incisors

Rarely in spasmRarely in spasmdue to forwarddue to forwardhead posturehead posture(stretch weakness-(stretch weakness-Kendall)Kendall)

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Disc DisorderDisc DisorderInternal DerangementInternal Derangement

Abnormal relationshipAbnormal relationshipof the articular disc toof the articular disc tothe mandibularthe mandibularcondyle, fossa andcondyle, fossa andarticular eminencearticular eminence

Review of normalReview of normalbiomechanics-condylebiomechanics-condylealways in contact withalways in contact withintermediate portionintermediate portionof discof disc

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Disc DisorderDisc DisorderInternal DerangementInternal Derangement

Disc is passiveDisc is passivestructure held in placestructure held in placeby the collateralby the collateralligaments and theligaments and theposterior ligament,posterior ligament,with movementwith movementdictated by lateraldictated by lateralpterygoidpterygoid

Posterior ligament isPosterior ligament iselastic so whenelastic so whenstretched allows discstretched allows discto move medially andto move medially andanteriorlyanteriorly

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