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Temporo-mandibular joint

Anatomy and pathology

Bernhard Schuknecht

Medical Radiological Institut Zurich

European Course in Head and Neck Neuroradiology Nov 4‐6, 2020

Anatomy osseous jointMandible : condylar process

Temporal fossa: fossa mandibularis – glenoid fossa concave

articular emenince convex

Articular surface fibrocartilage (type II collagen)

Surface area:  Condylus ‐ glenoid fossa 200 : 420 mm2  (Lang J 1977)

Proc. zygomaticus

Condylus shape variable: Condylar polymorphism

Anatomy: capsule

Capsula articularisrelativ thin, anterior thicker

Membrana fibrosacollagen fibers

Membrana synovialissynovial villi, vessels, nervs

Art. disco‐temporalis Art. disco‐mandibularis

ap lt

Joint capsule u lateral capsular disc attachment

DESS 0.7mm cor

Star Vibe gd 0.5

muscle anterior + posterior joint recess

Anatomy:  disc

• type I collagen ap orientation

• fibrous tissue

• proteoglykan (visco‐elastic)

medial lateral

Function: distribution of loadfriction↓ sliding

2‐ 3mm

1‐2 mm

3‐4mm

M. pterygoid sup. head:  → disc –joint capsuleinf. head:  → condyle

sup head

inf. head

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Anatomy: bilaminar Zone  • Stratum superius: elastic fibers ‐ horizontal

Fiss tymp.‐petrosquamosa + external auditory canal

• Genu vasculosum: vascular spaces, loose connective tissue, fat

• Stratum inferius: fibrous collagen, oblique‐ post. condyle

. 

Left

Right

Ligamentous cause of movement dependent pain

Lt TMJ pain markedly exacerbated during opening ff dental tx

T1gd fs 3mm  closed open 

closed open 

TMJ: principle pats complaints

• painspontaneous, in movement

• noiseclicking, snapping, friction

• limitation of movement

mouth opening, closing. deviation ….

Research Diagnostic criteriafor temporomandibular disorders

3 examiners reliability () :     OPT         CT            MRI

osteoarthritis 0.16 0.71        (0.46)

% agreement pairwise rating:

osteoarthritis 19%        84%         59%

disc displacement w/wo red 0.78/0.94 %

any disc disease 95%

effusion 81%

Ahmad M et al. Oral Surg Oral med Oral patho Oral radiol Endod 2009;107:844‐860

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TMJ protocol/ sequences /planes

Coil 4 chanal diameter 12 cm 1.5 T

t2 trufi sag dynTA 0.36 Measurements 90Voxel Size 0.8x0.8x4.5 mmFoV 150 mm FoV phase 100%Slice thikness 4.5 mmTR 4.65 TE 1.81Flip Winkel 60Time resolution 0.4s

t2 3d DESS cor obl along ascending ramusTA 4.27Voxel size 0.5x0.5x0.7 mmFoV 160 mm FoV phase 100%Slice thickness 0.7 mmTR 19.49 TE 7.09Flip Winkel 25Silces per slab 80

t2 fs Dixon axial including lower jaw ,parotid and sm gland 3.5mm

pd tse corTA 2.32Voxel size 0.3x0.3x0.2 mmFoV 200 mm FoV phase 100%Slice thickness 2 mmTR 2000 TE 14Flip Winkel 180

pd tse sag obliqueTA 3.54Voxel size 0.2x0.2x3 mmFoV 180mm FoV phase 100%Slice thickness 3 mmTR 1990 TE 12Flip Winkel 180

DESS‐ plane 

PD cor obl plane 

pd tse sag obliquet2 trufi sag dyn

CTMROsseous structure of condyle

CT vs MR (4 channel TMJ surface)

compacta = cortical bone + cancellous bone

PD sag obl 3mm 

PD cor obl 2mm 

cor DESS 0.7mm 

adult 

adolescent 15 y 

MR  → cortical + cancellous bone 12y

13.5 y

growth plate

condylolysis

overuse / bone bruise

52y

T1gd fs 3mm  

0.7mm  

cor obl PD 2mm  

changes invisible by CT/CB –CT: 

changes visible by CT/CB –CT→  avoid radiation exposure !

cor DESS 

TMJ : Anatomy and function

closed

open

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Quantification→ anterior disc dislocation

Normal 11:00‐12:00 disco‐ bilaminar

transition zone

Pathologic< 10:30

9:00

7:00

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Anterior disc position10:30‐11:00 

lt closed lt open

Anterior disc dislocation (ADD) with reduction

thickened disco‐bilaminar transition zone, slight effusion disco‐temporal + disco‐mandibulardisc intactlateral capsular attachment maintained (cor obl.)  

10.2017 rt closed

rt open

9.2020 rt closed rt open

ADD with reduction (2017)

→ ADD without reduction (2020)

10.2017

9.2020

offenrt open

condylar edema

small ant. Recess‐ limitation of mouth opening

rt closed

Movie 

Anterior disc dislocationwithout reduction (=fixed ADD) 

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ltold

RTrecent

fixed ADD: recent vs old + f‐up

effusion‐ disc and bilaminar zone intact

rt closed rt open

bilaminar zone connection lost, osteoarthrosis

10. 2019 10. 2020Lt open  Lt open 

Elongation of lateral capsular attachment

rt closed lateral rt closed medial

Medial disc dislocation (very rare)

lt closed lateral

Posterior disc dislocation (very rare)

Ruptured tendinous insertion + effusion

Disc‐ perforation

closed

open

open

closed

+ posterior disc displacement

acute! pain + effusion – rare but symptomatic !

usually asymptomatic !!! 

Pat SA

PAT SB

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Oct 2013medial

lateral

July 2014 mediallateral

Fixed ADD: pain and clicking oct 2013                        f‐up (for contralat. side) after tx with oral splint

remodelling capacity of bone 

OsteoarthrosisCondylar deconfiguration, joint space ↓

cortical bone thickeninganterior osteophyte, subchondral sclerosis + cystglenoid fossa + articular eminence flattening

rt closed lt closed

usually asymptomatic unless inflamed !!! 

Activated osteoarthrosis

rt closed rt open

Synovial proliferation, slight effusion‐ joint space widening

Synovitis

closed open

effusion + synovial Gd uptake due to  ID = internal derangement /disc displacementosteoarthrosis / autoimmun inflammatory disease

T1 Gd fsT1gd fs

Synoviocytes secrete proinflammatory cytokines (IL1β and TNF α)

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Idiopathic juvenile arthritis

most common rheumatic disease  approximately 1 of 1000 childrenTMJ affected in ~ 50% of patsTx→ control inflammation +prevent joint damage → preserve normal growth 

14 y 

PD T1gd fs

Bilaminar zone

condyle

synovitis

F‐up 17 y arthritis

osteoarthrosis – asymptomatic

PD

courtesy Dr Dr D. Zweifel 

offen

Chondrocalcinosis

tophous ‐ pseudotumoral type

closed

linear or fleck like calcificationsrarely ~ w acute or chronic pain, prevalence 18% (CT) in pats w wrist/ knee ch. 

classical 

Zweifel D, Ettlin D, Schuknecht B Obwegeser O Journal of Oral and Maxillofacial Surgery 2012; 70:60‐67.

Differential D.: osteochondrosis dissecans

Synovial chondromatosis

Cor T2

synovial metaplasia of unclear etiology leading to cartilaginous nodules → break free, mineralize, and even ossify

T2 cor lt

Conclusion

OPG basic diagnostic tool: occlusion dental status„the panoramic does not show detailed abnormalities of the TMJ “

CBT/CT ossoeus Δ: trauma, degenerative, (neoplasm)

MR internal derangement (disc….,perforation, ), ligament Δ : lateral capsular, bilam. zone )effusion, synovial inflammation- metaplasiaosseous changes: growth plate, bonebruise, condylolysis, arthritis (early invisible CT/CBTosteoarthrosis inactive vs active

functional trufi sequ. → TMJ function

Clinical findings and Imaging

→ basis for correct diagnosis and effective Tx !

Decision for choice of correct imagingBased on history, clinical findings and therapeutic consequences

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