Temporomandibular joint/prosthodontic courses

TEMPOROMANDIBULAR
JOINT
www.indiandentalacademy.com

ANATOMY OFANATOMY OF
TEMPOROMANDIBULAR JOINTTEMPOROMANDIBULAR JOINT

IntroductionIntroduction
►It is unique to mammals.It is unique to mammals.
►In other vertebrates the lower jaw isIn other vertebrates the lower jaw is
compoundcompound
►As mammals evolved, the compound lowerAs mammals evolved, the compound lower
jaw was reduced to a single bone( the md)jaw was reduced to a single bone( the md)
bearing teeth and articulate with newlybearing teeth and articulate with newly
developed articulating surface on thedeveloped articulating surface on the
temporal bone. Thus, in phylogenetic terms,temporal bone. Thus, in phylogenetic terms,
the TMJ is a secondary joint.the TMJ is a secondary joint.

Evolution of TMJEvolution of TMJ

►Agnathia- earliest vertibrates; had no md. OnlyAgnathia- earliest vertibrates; had no md. Only
cranial part was presentcranial part was present
►Gnathostome-active vertibrates;anterior gillGnathostome-active vertibrates;anterior gill
arch enlarge and first set gnathostomic jawarch enlarge and first set gnathostomic jaw
►Reptilian stage- movable joint appeared, lowerReptilian stage- movable joint appeared, lower
jaw was made of many bone plates whichjaw was made of many bone plates which
made it movablemade it movable
►Pterygopalatine component- these animalsPterygopalatine component- these animals
developed a shuttting component which coulddeveloped a shuttting component which could
grip the foodgrip the food www.indiandentalacademy.com

►Dentary bone stageDentary bone stage
►Coronoid process stage-dentary boneCoronoid process stage-dentary bone
expanded backwards; it further increases inexpanded backwards; it further increases in
size & gave rise to coronoid process. Theresize & gave rise to coronoid process. There
was opening in the skull roofwas opening in the skull roof
►Dentary squamosal joint- the back end ofDentary squamosal joint- the back end of
the dentary bone came in contact with thethe dentary bone came in contact with the
cranium at the squamosal bone. At this timecranium at the squamosal bone. At this time
condyle of the mandible form.condyle of the mandible form.www.indiandentalacademy.com

Embryology of TMJEmbryology of TMJ
►The TMJ develops initially from widelyThe TMJ develops initially from widely
separated temporal and condylar blastemasseparated temporal and condylar blastemas
that grow towards each otherthat grow towards each other
►The temporal blastemas arises from oticThe temporal blastemas arises from otic
capsulecapsule
►Condylar blastemas arises from theCondylar blastemas arises from the
secondary condylar cartilage of thesecondary condylar cartilage of the
mandiblemandible

►Initially the mesenchyme interveningInitially the mesenchyme intervening
between condylar blastema and temporalbetween condylar blastema and temporal
blastema is differentiated into fibrous tissueblastema is differentiated into fibrous tissue
►During 10During 10thth
week of IU life two cleftsweek of IU life two clefts
develops in the intervened fibrousdevelops in the intervened fibrous
connective tissue, forming the two jointconnective tissue, forming the two joint
cavities and thereby defining thecavities and thereby defining the
interarticular discinterarticular disc

►The inferior compartment forms first (10The inferior compartment forms first (10
week) and the superior compartment startsweek) and the superior compartment starts
to appear at about 11 ½ weekto appear at about 11 ½ week
►Cavitation occur by degradation rather thanCavitation occur by degradation rather than
enzymatic liquefaction or cell deathenzymatic liquefaction or cell death

►Early functional activity of the TMJ providesEarly functional activity of the TMJ provides
biomechanical stresses that producebiomechanical stresses that produce
ischemia in the differentiating tissue of theischemia in the differentiating tissue of the
joint, facilitating condrogenesis in thejoint, facilitating condrogenesis in the
condyle and articular fossacondyle and articular fossa
►Functional pressure contributes to theFunctional pressure contributes to the
contouring of the articulating surfacescontouring of the articulating surfaces

EMBRYOLOGY OF TMJEMBRYOLOGY OF TMJ
66thth
week I.U.- Condensation of mesenchymeweek I.U.- Condensation of mesenchyme
lateral to Meckel’s cartilagelateral to Meckel’s cartilage
77thth
week- Complete membranous bonyweek- Complete membranous bony
plate albeit fragile isplate albeit fragile is
formed,paralleling and locallyformed,paralleling and locally
enveloping the bilateralenveloping the bilateral
Meckel’s cartilagenous rodsMeckel’s cartilagenous rods
1010thth
week- Bony mandible has recognizable form andweek- Bony mandible has recognizable form and
Meckel’s cartilage begins to resorbMeckel’s cartilage begins to resorb
Lateral Pterygoid muscle During this phase condylar fields develop atLateral Pterygoid muscle During this phase condylar fields develop at
thethe
formed with 2 distinct cranial ends of the mandibleformed with 2 distinct cranial ends of the mandible
headsheads
One head Second toOne head Second to

Disk is supposed 12Disk is supposed 12thth
week- Condylar processes are recognizableweek- Condylar processes are recognizable
to emerge from: and secondary cartilage productionto emerge from: and secondary cartilage production
1) Mesenchyme begins1) Mesenchyme begins
that develops b/wthat develops b/w
developing condyle/ 14developing condyle/ 14thth
week- Endochondral ossification of theweek- Endochondral ossification of the
temporal squama secondary cartilage beginstemporal squama secondary cartilage begins
and Meckel cartilage (Starts centrally Proceeds upwards)and Meckel cartilage (Starts centrally Proceeds upwards)
OR ,OR ,
2) Extension from 202) Extension from 20thth
week- Equilibrium b/w production of cartilageweek- Equilibrium b/w production of cartilage
lateral pterygoid and subsequent replacement by bonelateral pterygoid and subsequent replacement by bone
muscle to malleus (Typical picture of a growing mandible)muscle to malleus (Typical picture of a growing mandible)

DevelopmentDevelopment
►At birth the mandibular fossa is almost flatAt birth the mandibular fossa is almost flat
and bear no articular surfaceand bear no articular surface
►Only after eruption of permanent dentition,Only after eruption of permanent dentition,
at 7 yrs, articular tubercle begins to becomeat 7 yrs, articular tubercle begins to become
prominentprominent
►Its development accelerates until 12 yr ofIts development accelerates until 12 yr of
lifelife

T.M.J- 8T.M.J- 8thth
month fetusmonth fetuswww.indiandentalacademy.com

T.M.J- 4 year old childT.M.J- 4 year old childwww.indiandentalacademy.com

T.M.J- Adult edentulousT.M.J- Adult edentulouswww.indiandentalacademy.com

Bones of the jointBones of the joint
► Bones of TMBones of TM
articulation are thearticulation are the
glenoid fossa aboveglenoid fossa above
(on the under surface(on the under surface
of the squamous partof the squamous part
of the temporal bone)of the temporal bone)
and the condyle belowand the condyle below

Glenoid fossaGlenoid fossa
►is limited-is limited-
►Posteriorly by squamotympanic andPosteriorly by squamotympanic and
petrotympanic fissurepetrotympanic fissure
►Medially-spine of sphenoidMedially-spine of sphenoid
►Laterally-root of zygomatic process ofLaterally-root of zygomatic process of
temporal bonetemporal bone
►Anteriorly- articular eminenceAnteriorly- articular eminence

CondyleCondyle
►Composed of cancellous bone covered by aComposed of cancellous bone covered by a
thin layer of compact bonethin layer of compact bone
►It measures about 20mm from side to side &It measures about 20mm from side to side &
10 mm from before backwards.10 mm from before backwards.
►Articular surface is strongly convexArticular surface is strongly convex
anterioposteriorly and slightly convexanterioposteriorly and slightly convex
mediolaterally i.e condyle is ellipticalmediolaterally i.e condyle is elliptical

Ligaments of joints-Ligaments of joints-
► Capsular ligament with synovialCapsular ligament with synovial
membranemembrane
► Articular discArticular disc
► Lateral or Temporo-mandibular ligamentLateral or Temporo-mandibular ligament
► Accessory ligament- SphenomandibularAccessory ligament- Sphenomandibular
ligament & Stylomandibular ligamentligament & Stylomandibular ligament

Capsular ligamentCapsular ligament
►AboveAbove--
anteriorlyanteriorly- articular tubercle- articular tubercle
posteriorly-posteriorly- squamotympanic fissuresquamotympanic fissure
►BelowBelow-- to the neck of the mandibleto the neck of the mandible
►Above the disc the capsule is loose and belowAbove the disc the capsule is loose and below
the disc it is tautthe disc it is taut
►It is strengthened laterally by TM ligamentIt is strengthened laterally by TM ligament
►The inner aspect of the capsule is lined by aThe inner aspect of the capsule is lined by a
synovial membrane.synovial membrane.www.indiandentalacademy.com

Articular discArticular disc
►Articular disc is interposed between theArticular disc is interposed between the
articular surface of two bones.articular surface of two bones.
►It is an oval, fibrous plate that fuses at itsIt is an oval, fibrous plate that fuses at its
anterior margin with the fibrous capsuleanterior margin with the fibrous capsule
►Medial & lateral corners are directlyMedial & lateral corners are directly
attached to the poles of condyle.attached to the poles of condyle.
►It divide the joint into two comprtment-It divide the joint into two comprtment-
condylodiscal & temporodiscalcondylodiscal & temporodiscal
►Disc is biconcave in saggital section, with aDisc is biconcave in saggital section, with a
thin intermediate zone, a thick anteriorthin intermediate zone, a thick anterior
band, and a thick posterior bandband, and a thick posterior band

►The later is continuous with looseThe later is continuous with loose
fibroelastic portion called as bilaminar zone,fibroelastic portion called as bilaminar zone,
which is highly vascular and innervated. Itswhich is highly vascular and innervated. Its
superior stratum consist of fibrous andsuperior stratum consist of fibrous and
elastic tissue attaches to the posterior wallelastic tissue attaches to the posterior wall
of glenoid fossa and the squamotympanicof glenoid fossa and the squamotympanic
fissure, while the inferior stratum collagenfissure, while the inferior stratum collagen
and nonelastic fibres attaches to the back ofand nonelastic fibres attaches to the back of
md. Condyle.md. Condyle.
► Some fibers of lateral pterygoid attach toSome fibers of lateral pterygoid attach to
the anterior border of disc.the anterior border of disc.

Lateral or TM ligamentLateral or TM ligament
► It blends with the lateral part of fibrous capsuleIt blends with the lateral part of fibrous capsule
and extend downward and backwards from theand extend downward and backwards from the
tubercle of the root of zygoma to the lateraltubercle of the root of zygoma to the lateral
surface and posterior margin of the neck ofsurface and posterior margin of the neck of
mandible.mandible.
► It consist of two parts-It consist of two parts-
1.1. an outer oblique portion- arising from articularan outer oblique portion- arising from articular
eminence to condylar neckeminence to condylar neck
2.2. an inner horizontal portion-from articular eminencean inner horizontal portion-from articular eminence
to lateral pole of condyleto lateral pole of condyle

►It restrict the movement of mandible in threeIt restrict the movement of mandible in three
different planedifferent plane
1.1. By preventing lateral dislocation of one joint,By preventing lateral dislocation of one joint,
it prevents medial dislocation of other.it prevents medial dislocation of other.
2.2. Oblique component limits the amount,ofOblique component limits the amount,of
inferior displacementinferior displacement
3.3. Horizontal component limits posteriorHorizontal component limits posterior
displacementdisplacement

Accessory ligamentAccessory ligament
1.1. SphenomandibulaSphenomandibular- situated medial tor- situated medial to
the capsule separated by considerablethe capsule separated by considerable
gap. The ligament is derived fibrousgap. The ligament is derived fibrous
envelop of meckels cartilage of the firstenvelop of meckels cartilage of the first
branchial arch. It is attached above to thebranchial arch. It is attached above to the
spine of the sphenoid bone and below tospine of the sphenoid bone and below to
the lingual of the mandibular foramenthe lingual of the mandibular foramen
where it is pierced by mylohyoid vesselswhere it is pierced by mylohyoid vessels
and nerves.and nerves.

RelationsRelations::► Laterally:Laterally:
* Lateral pterygoid muscle* Lateral pterygoid muscle
► Posteriorly:Posteriorly:
* Auriculotemporal nerve* Auriculotemporal nerve
► Anteriorly:Anteriorly:
* Maxillary artery* Maxillary artery
► Inferiorly:Inferiorly:
* Inferior alveolar nerve and vessels entering* Inferior alveolar nerve and vessels entering
mandibular foramenmandibular foramen
* A lobule of parotid gland* A lobule of parotid gland
► Medially:Medially:
* Medial pterygoid* Medial pterygoid
* Chorda tympani nerve* Chorda tympani nerve
* Wall of pharynx with fat and pharyngeal veins* Wall of pharynx with fat and pharyngeal veins
intervening.intervening. www.indiandentalacademy.com

StylomandibularStylomandibular ligament- formed byligament- formed by
the thickening of the deep cervical fasciathe thickening of the deep cervical fascia
and extends from the tip of the styloidand extends from the tip of the styloid
process of temporal bone to the angle ofprocess of temporal bone to the angle of
mandible. Sometimes the ligament ismandible. Sometimes the ligament is
pierced by the cervical part of facial artery.pierced by the cervical part of facial artery.
It separates the parotid gland from theIt separates the parotid gland from the
submandibular gland.submandibular gland.

Blood supplyBlood supply ::
► Vascular supply to the joint is profuseVascular supply to the joint is profuse
► Every vessel within a radius of some three centimetersEvery vessel within a radius of some three centimeters
contributes branches to the joint capsule.contributes branches to the joint capsule.
► Major arterial donationsMajor arterial donations
► Posteriorly:Posteriorly:
* The large superficial temporal artery* The large superficial temporal artery
* Maxillary artery* Maxillary artery
► Anteriorly:Anteriorly:
* The smaller posterior deep temporal* The smaller posterior deep temporal
* Masseteric* Masseteric
* Lateral pterygoid terminals* Lateral pterygoid terminalswww.indiandentalacademy.com

Nerve supply :Nerve supply :
► TheThe Mandibular nerveMandibular nerve ((the third and major division of thethe third and major division of the
fifth cranial nervefifth cranial nerve))
► Three branchesThree branches from the mandibular nerve are foundfrom the mandibular nerve are found
sending terminals to the joint capsulesending terminals to the joint capsule
 The largest is the Auriculotemporal nerve which supplies:The largest is the Auriculotemporal nerve which supplies:
the posterior medial lateral partsthe posterior medial lateral parts
 The next in size is a branch from the Masseteric nerve.The next in size is a branch from the Masseteric nerve.
andand
 A more variable branch from the posterior Deep TemporalA more variable branch from the posterior Deep Temporal
nervenerve
supply:supply:
the anterior parts of the jointthe anterior parts of the joint

► Relations of TMJ-Relations of TMJ-
1.1. lateral- skin and fasciae, parotid gland, temporallateral- skin and fasciae, parotid gland, temporal
branches of fascial nervebranches of fascial nerve
2.2. medial- tympanic plate separates the joint frommedial- tympanic plate separates the joint from
internal carotid artery, spine of sphenoid, with theinternal carotid artery, spine of sphenoid, with the
upper end of sphenomandibular ligament attachedupper end of sphenomandibular ligament attached
to it, auricular & cordatympani nerve, middleto it, auricular & cordatympani nerve, middle
meningeal arterymeningeal artery
3.3. anterior- lateral pterygoid, masseteric nerve andanterior- lateral pterygoid, masseteric nerve and
vesselsvessels
4.4. posterior- parotid gland separates the joint fromposterior- parotid gland separates the joint from
the external auditory meatus, superficial temporalthe external auditory meatus, superficial temporal
vessels, auriculotemporal nervevessels, auriculotemporal nerve
5.5. inferior- maxillary artery and vein.inferior- maxillary artery and vein.

Synovial membraneSynovial membrane
► The capsule is lined on its inner surface by a synovialThe capsule is lined on its inner surface by a synovial
membrane.membrane.
► Membranes has fold of villi which protrude into theMembranes has fold of villi which protrude into the
joint cavity. These folds increases in number with agejoint cavity. These folds increases in number with age
and also more prominent in the joint affected byand also more prominent in the joint affected by
pathologic process.pathologic process.
► The synovial membrane is responsible for theThe synovial membrane is responsible for the
production of synovial fluid, which is characterized byproduction of synovial fluid, which is characterized by
well defined physiological properties of viscosity,well defined physiological properties of viscosity,
elasticity and plasticity,elasticity and plasticity,
► Synovial fluid contains a small population of varyingSynovial fluid contains a small population of varying
cell types such as monocytes, lymphocytes, freecell types such as monocytes, lymphocytes, free
synovial cells and occasionally PMN.synovial cells and occasionally PMN.www.indiandentalacademy.com

►The chemical composition of synovial fluidThe chemical composition of synovial fluid
indicated that it is dialysate of plasma withindicated that it is dialysate of plasma with
added protein & mucin. Its functions are-added protein & mucin. Its functions are-
1.1. To provide liquid environment for the jointTo provide liquid environment for the joint
surfacesurface
2.2. Lubrication to increase efficiency & reduceLubrication to increase efficiency & reduce
erosionerosion

Biomechanics of TMJBiomechanics of TMJ
►Tmj is a compound jointTmj is a compound joint
►One joint system is between condyle andOne joint system is between condyle and
disc. As the disc is tightly bound to thedisc. As the disc is tightly bound to the
condyle by lateral & medial discal ligaments,condyle by lateral & medial discal ligaments,
only rotation of the disc on the articularonly rotation of the disc on the articular
surface of the condyle is possiblesurface of the condyle is possible
►Second system is between condyle-discSecond system is between condyle-disc
complex with mandibular fossa. As the disccomplex with mandibular fossa. As the disc
is not tightly attached to the articular fossa,is not tightly attached to the articular fossa,
translation is also possibletranslation is also possible

►Stability of the joint is maintained byStability of the joint is maintained by
constant activity of the muscle that pullconstant activity of the muscle that pull
across the joint. Even in resting state, theseacross the joint. Even in resting state, these
muscles are in a state of contraction calledmuscles are in a state of contraction called
tonustonus
►As the muscle activity increases, theAs the muscle activity increases, the
condyle is increasingly forced against thecondyle is increasingly forced against the
disc and the disc against the fossa, resultingdisc and the disc against the fossa, resulting
in an increase in interarticular pressure andin an increase in interarticular pressure and
thus disc space narrowsthus disc space narrows

► As pressure increases , the condyle seats itself onAs pressure increases , the condyle seats itself on
the thinner intermediate zone of the disc, howeverthe thinner intermediate zone of the disc, however
when the pressure is decreased the thickerwhen the pressure is decreased the thicker
posterior portion of the disc is rotated to fill theposterior portion of the disc is rotated to fill the
spacespace
► Posterior border of the disc is attached to thePosterior border of the disc is attached to the
retrodiscal lamina; which is composed of elasticretrodiscal lamina; which is composed of elastic
connective tissue. When the mouth is closed, theconnective tissue. When the mouth is closed, the
elastic traction is minimal, however duringelastic traction is minimal, however during
opening, the superior retrodiscal lamina becomeopening, the superior retrodiscal lamina become
increasingly stretched,creating increased force toincreasingly stretched,creating increased force to
retract the discretract the disc
► Thus retrodiscal lamina retracts the discThus retrodiscal lamina retracts the disc
posteriorly on the condyleposteriorly on the condyle

►The superior lateral pterygoid muscle pullThe superior lateral pterygoid muscle pull
the disc anteriorlythe disc anteriorly
►In the resting closd joint position the anteriorIn the resting closd joint position the anterior
force will exceed the posterior elasticforce will exceed the posterior elastic
tractiontraction

MANDIBULAR MOVEMENTS ANDMANDIBULAR MOVEMENTS AND
ROLE PLAYED BY MUSCLESROLE PLAYED BY MUSCLES
► Elevation of mandibleElevation of mandible
 TheThe temporalistemporalis elevates the coronoid processelevates the coronoid process
 Masseter and medial pterygoidMasseter and medial pterygoid elevate the angle ofelevate the angle of
mandiblemandible
 Lateral pterygoid relaxes as muscles exert upwardLateral pterygoid relaxes as muscles exert upward
tractiontraction
► Depression of mandibleDepression of mandible
 Lateral pterygoidLateral pterygoid exerts a forward pull on neck ofexerts a forward pull on neck of
mandiblemandible
 Sup. HeadSup. Head of lateral pterygoid pulls articular discof lateral pterygoid pulls articular disc
down of articular tubercledown of articular tuberclewww.indiandentalacademy.com

ActionsActions

►Protrusion of mandibleProtrusion of mandible
 Lateral pterygoid contractsLateral pterygoid contracts
►Retrusion of mandibleRetrusion of mandible
 Posterior fibers ofPosterior fibers of TemporalisTemporalis with help ofwith help of
Mylohyoid, Digastric & Geniohyoid draw theMylohyoid, Digastric & Geniohyoid draw the
mandible backwardsmandible backwards
►Lateral shift of mandibleLateral shift of mandible
 contraction ofcontraction of lateral pterygoidlateral pterygoid on left side willon left side will
cause the mandible to deviate to right sidecause the mandible to deviate to right sidewww.indiandentalacademy.com

Clinical considerationsClinical considerations
1.1. Developmental disturbances of TMJDevelopmental disturbances of TMJ
• aplasia of mandibular condyleaplasia of mandibular condyle
• hypoplasia of mandibular condylehypoplasia of mandibular condyle
• hyperplasia of mandibular condylehyperplasia of mandibular condyle
• hyperplasia of coronoid processhyperplasia of coronoid process
2.2. Traumatic disturbance of TMJTraumatic disturbance of TMJ
• luxation & subluxationluxation & subluxation
• ankylosisankylosis
• injury to menisciinjury to menisci
• fracture of condylefracture of condylewww.indiandentalacademy.com

3.3. Inflammatory disturbances of TMJInflammatory disturbances of TMJ
• arthritis due to a specific infectionarthritis due to a specific infection
• rhematiod arthritisrhematiod arthritis
• osteoarthritisosteoarthritis
4.4. Neoplastic disturbance of TMJ-Neoplastic disturbance of TMJ-
5.5. Extraarticular disturbance of TMJExtraarticular disturbance of TMJ
► Myofacial pain dysfunction syndromeMyofacial pain dysfunction syndrome

Aplasia –Aplasia –
►A failure of development of mandibularA failure of development of mandibular
condyle, which may be unilateral/bilateral. Ifcondyle, which may be unilateral/bilateral. If
unilateral- obvious facial asymmetry & bothunilateral- obvious facial asymmetry & both
occlusion & mastication may be altered. Aocclusion & mastication may be altered. A
shift of mandible towards affected side alsoshift of mandible towards affected side also
occur.occur.
► Its treatment is osteoplasty.Its treatment is osteoplasty.

Hypoplasia- aquired/ congenitalHypoplasia- aquired/ congenital
►. Acquired can be due to forcep delivery that. Acquired can be due to forcep delivery that
cause traumatic birth injury and X-raycause traumatic birth injury and X-ray
radition over TMJ area for t/t of skin lesionsradition over TMJ area for t/t of skin lesions
such as hemangioma or birth marks.such as hemangioma or birth marks.
►Treatment is cartilage or bone transplantTreatment is cartilage or bone transplant


Hyperplsia-Hyperplsia-
►Due to chronic inflammation. Leading toDue to chronic inflammation. Leading to
slowly progressive elongation of the faceslowly progressive elongation of the face
with deviation of chin away from affectedwith deviation of chin away from affected
side.side.
► Treatment is resection of condyleTreatment is resection of condyle

Luxation & subluxationLuxation & subluxation
► Dislocation of joint occurs only in oneDislocation of joint occurs only in one
direction,i.e.forward. The mandibular head isdirection,i.e.forward. The mandibular head is
displaced from articular tubercle to thedisplaced from articular tubercle to the
infratemporal fossa by sudden spasm of lateralinfratemporal fossa by sudden spasm of lateral
pterygoid muscle during wide opening of mouth,pterygoid muscle during wide opening of mouth,
as in yawning.as in yawning.
► The dislocation is reduced by exerting downwardThe dislocation is reduced by exerting downward
traction of the ramus of md to release the spasmtraction of the ramus of md to release the spasm
of massater. Simultaneously, the chin is elevatedof massater. Simultaneously, the chin is elevated
to throw the head of the mandible in properto throw the head of the mandible in proper
position.position.

AnkylosisAnkylosis
►Hypomobility; mouth opening is less thanHypomobility; mouth opening is less than
5mm. It can be unilateral/ bilateral.5mm. It can be unilateral/ bilateral.
►Ankylosis can be due to trauma, infectionAnkylosis can be due to trauma, infection
and inflammationand inflammation
► In complete ankylosis there is bony fusionIn complete ankylosis there is bony fusion
of the condyle with the articulating surfaceof the condyle with the articulating surface
of the glenoid fossa with absolute limitationof the glenoid fossa with absolute limitation
of motion.of motion.
►There is usually somewhat greater motion inThere is usually somewhat greater motion in
fibrous ankylosis than in bony ankylosis.fibrous ankylosis than in bony ankylosis.

►In intra articular ankylosis the jointIn intra articular ankylosis the joint
undergoes progressive destruction of theundergoes progressive destruction of the
meniscus and flattening of the mandibularmeniscus and flattening of the mandibular
fossa, thickening of the head of the condylefossa, thickening of the head of the condyle
and narrowing of the joint space.and narrowing of the joint space.
►Treatment is osteotomy.Treatment is osteotomy.

Injury to menisciInjury to menisci
►Most common cause is malocclusion,Most common cause is malocclusion,
characterized by pain , clicking & crepitationcharacterized by pain , clicking & crepitation
in joint area.in joint area.
►Treatment is – malocclusion should beTreatment is – malocclusion should be
corrected, immobilization & meniscectomycorrected, immobilization & meniscectomy

Fracture of condyleFracture of condyle
►The thinness of the bone in the articularThe thinness of the bone in the articular
fossa is responsible for the fracture if thefossa is responsible for the fracture if the
mandibular head is driven into fossa by amandibular head is driven into fossa by a
heavy blow. In such cases injury to the brainheavy blow. In such cases injury to the brain
& duramatar have been reported& duramatar have been reported

Arthritis due to specific infection-Arthritis due to specific infection-
►its most common cause is by directits most common cause is by direct
extention of infection into the joint as aextention of infection into the joint as a
result of an adjacent cellulites orresult of an adjacent cellulites or
osteomylitis. Such an extention may followosteomylitis. Such an extention may follow
dental infections, infection of parotid or evendental infections, infection of parotid or even
facial or ear infection.facial or ear infection.

Rheumatoid arthritis-Rheumatoid arthritis-
►Characterized by the inflammation ofCharacterized by the inflammation of
synovial tissue accompained by infilterationsynovial tissue accompained by infilteration
of lymphocytes and plasma cellsof lymphocytes and plasma cells
►Result in destruction of angular surface ofResult in destruction of angular surface of
the joint and may be accompained bythe joint and may be accompained by
fibrous ankylosisfibrous ankylosis
►In early stage there is joint pain but in laterIn early stage there is joint pain but in later
stage there is restriction in movements ofstage there is restriction in movements of
lower jawlower jaw

MPDS-MPDS-
►Indicates a dysfunction in TMJ.Indicates a dysfunction in TMJ.
► It is characterized by-masticatory muscleIt is characterized by-masticatory muscle
tendernesstenderness
►Limited opening of mandibleLimited opening of mandible
►Joint soundsJoint sounds
►PainPain
►More common in femalesMore common in females

BIBLIOGRAPHYBIBLIOGRAPHY
 The Journal of Anatomical Society of IndiaThe Journal of Anatomical Society of India
Vol 49; No.2; December 2000.Vol 49; No.2; December 2000.
 Gray’s Anatomy 34Gray’s Anatomy 34thth
editionedition
 Oral Histology; Development, Structure andOral Histology; Development, Structure and
Function; A.R. Ten Cate; 3Function; A.R. Ten Cate; 3rdrd
editionedition
 Textbook of Anatomy; W.H.Hollinshead; 2Textbook of Anatomy; W.H.Hollinshead; 2ndnd
IndianIndian
edition; 1967edition; 1967
 Facial Growth; Enlow and Poston; 3Facial Growth; Enlow and Poston; 3rdrd
editionedition
 Colour Atlas of Human Anatomy; Mc Minn; 3Colour Atlas of Human Anatomy; Mc Minn; 3rdrd
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 Prosthodontic Treatment for edentulous patients;Prosthodontic Treatment for edentulous patients;
Boucher; 11Boucher; 11thth
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 Varied Links on InternetVaried Links on Internet

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