MRI TMJ temporo mandibular jiont Dr Ahmed Esawy

‫الرحيم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬
Dr Ahmed Esawy

RADIOLOGY CHANNEL
IMAGING ORAL BOARD
MRI
TEMPOROMANDIBULAR
JIONT TMJ
Dr Ahmed Esawy

Dr. Ahmed Abdallah Eisawy
MBBS M.Sc MD
Dr Ahmed Esawy

TEMPROMANDIBULAR
JOINT
Dr Ahmed Esawy

TMJ: is a bilateral joints permits the
mandible to move as a unit with
two functional patterns:
• Hinge (inferior portion)
• Translation (superior portion)
(ginglymoarthroidal joint)
(compound joint)
it has four anatomical parts:
1- condyle
2- articular fossa
3- articular disc
4- articular capsule
Dr Ahmed Esawy

Plain Radiography
• Transcranial lateral
Projection
• Submento-vertex view:
– Condylar morphology.
– Relative condylar position
to the horizontal baseline.
– Mandibular asymmetry.
• Postero-anterior view
– Condylar morphology
– Mandibular
deviation.
Dr Ahmed Esawy

Conventional Tomography
• Lateral Tomography
– Shows condylar location in closed and open mouth
– Assesses condylar morphology: size, sclerosis, erosion,
etc…
– Relative size & shape of the glenoid fossa.
• High radiation dose to the eye lens.
• Has been replaced by CT
Dr Ahmed Esawy

Normal Anatomy
Mandibular condyle (head)
Glenoid fossa
Articular tubercle
(eminence)
Dr Ahmed Esawy

Computed Tomography
• Axial & coronal 1-2mm slice thickness
• Sagittal reconstruction is made
through the condyle
3D reconstruction may be
helpful to evaluate positional
relationships between the joint
components
Dr Ahmed Esawy

• MR imaging: modality of choice; with dedicated
surface coils
• Conventional radiology: trauma
• Multisection CT: jaw trauma & concomitant osseous
injuries
• Sonography: internal derangement & inflammation;
with interobserver variability
• Arthrography: replaced by MRI
Dr Ahmed Esawy

MR Imaging
• Protocol: (1.5T)
– STIR replaced T1WI+FS+C
☆ Oblique sagittal— T1 (close+open), T2 (open)
Oblique coronal— T1WI
Dr Ahmed Esawy

• Parasagittal & paracoronal views: angulated
perpendicular & parallel to the axis of the
mandibular condyle
Dr Ahmed Esawy

MRI
• Technique & Equipment:
– Oblique sagittal PD are usually
obtained in closed and open
mouth positions.
– Coronal images may be needed
when a meniscus is suspected
to be displaced far medially or
laterally.
– T2 WI are useful for detection
of joint effusion.
Dr Ahmed Esawy

• The disk is firmly attaching to the capsule and the
condular neck medially and laterally
• Attached to the superior part of the pterygoid
muscle anteromedially
Dr Ahmed Esawy

• Drawing illustrates the anatomy of the TMJ.
• 1 = condyle; 2 = temporal bone, articular eminence;
• 3 = temporal bone, mandibular fossa; 4 = disk, anterior band; 5 = disk, intermediate
zone; 6 = disk, posterior band; 7 = superior retrodiskal layer;
• 8 = inferior retrodiskal layer; 9 =vasculonervous structures10 =capsular superior
attachment 11 = capsular inferior attachment 12 = superior joint space;
• 13 = inferior joint space 14 = superior head of the lateral pterygoid muscle (LPM)
15 = inferior head of the LPM 16 = interpterygoid space; 17 = external auditory
canal
Dr Ahmed Esawy

Temporomandibular disk (sagittal)
1. Anterior band
2. Posterior band
3. Intermediate zone
(inconstant central
water signal intensity)
4. Anterior attachment
5. Posterior attachment
(bilaminar zone)
A P
Dr Ahmed Esawy

Anatomy & Biomechanics
• TMJ
– Mandibular head
– Mandibular fossa
– Articular eminence
– Hyaline cartilage covers the articulating cortical
bone
– Fibrocartilaginous disk: bow-tie shaped, biconcave
morphology
Dr Ahmed Esawy

Temporomandibular Disk
• Anterior and posterior bands: longer in the
mediolateral than in the anteroposterior dimension
• Anterior band: smaller, attaches to articular
eminence, condylar head, & joint capsule
• Posterior band: blends with highly vascularized, loose
connective tissue, the bilaminar zone, and the
capsule
Dr Ahmed Esawy

The meniscus consists of anterior band, thin intermediate zone and a
thicker posterior band.
Posteriorly, the meniscus is attached to the bilaminar zone which
contain a rich vascular bed and neural elements supplying the
meniscus.
Anteriorly it is attached to the lateral pterygoid muscle.
Intermediate
zone
Posterior
band
Anterior
band
Bilaminar
zone
lateral
pterygoid
An integral part of the joint
is the meniscus. It is a
fibrocartilagenous saddle shaped
structure that divides the joint into
separate upper and lower
compartments, each lined by a
synovial membrane.
Dr Ahmed Esawy

Disk Evaluation
• The meniscus of the TMJ is a biconcave
fibrocartilaginous structure located between the
mandibular condyle and the temporal bone
component of the joint.
• Its function is to accommodate a hinging action as
well as the gliding action that occurs between the
temporal bone and the mandible.
• The disk is round to oval, with a thin center
(intermediate zone) that separates thicker peripheral
portions known as the anterior and posterior bands
Dr Ahmed Esawy

Physiologic Joint (closed mouth)
• The disc positioned between the mandibular head
inferiorly and the articular eminence anteriorly and
superiorly
• The posterior band lies within 10˚ of the 12 o’clock
position
• The medial and lateral corners of the disk align with the
condylar borders and do not bulge laterally or medially
Dr Ahmed Esawy

Closed mouth position (sagittal projection)
The posterior band
lies within
10˚(anteriorly) of the
12 o’clock (posteriorly)
position
Dr Ahmed Esawy

Closed mouth view (sagittal)
1. Mandibular head
2. Articular eminence
3. Disk
4. Bilaminar zone
5. Lateral pterygoid muscle
with interposed fat tissue
(5a, superior head; 5b,
inferior head)
6. Superior joint space
7. Inferior joint space
Dr Ahmed Esawy

Closed mouth view (coronal)
1. Mandibular head
2. Articular fossa
3. Disk
4. Medial attachment
5. Lateral attachment
8. Lateral pterygoid muscle
Dr Ahmed Esawy

Physiologic Joint (open mouth)
• The disk slides into a position between the madibular
head and articular eminence
• The loose tissue of the bilaminar zone allows the
remarkable range of motion
• The attachments of the disk prevent luxation during
opening
• The disk does not move in the coronal plane when
the joint is intact
Dr Ahmed Esawy

Open mouth view (sagittal)
1. Mandibular head
5. Disk
6. Bilaminar zone
7. Lateral pterygoid
muscle with
interposed fat tissue
Dr Ahmed Esawy

Open position of normal TMJ
a— sagittal; b— coronal
1. Mandibular head
3. Disk
4. Bilaminar zone
muscle
Dr Ahmed Esawy

• Sagittal oblique spin-
echo T1-weighted
magnetic resonance
(MR) image obtained in
the closed-mouth
position shows the
normal TMJ.
Dr Ahmed Esawy

When the mouth closes:
The head of mandible sits in the fossa at rest,
thick posterior band of the meniscus lies
immediately above the condyle
When the mouth opens:
two distinct motions occur at the joint:
The first motion is rotation around a
horizontal axis through the condylar heads
The second motion is anterior translation.
The condyle and meniscus (by the
contraction of lateral pterygoid) move
together anteriorly beneath the articular
eminence
Dr Ahmed Esawy

Closed position of normal TMJ
a— sagittal; b— coronal
1. Mandibular head
2. Articular fossa
3. Disk
4. Bilaminar zone
muscle
Dr Ahmed Esawy

Drawings illustrate TMJ function. (a) Initial closed-mouth position. (b) At the beginning of the
open-mouth position, the digastric muscle forces the condyle downward. The condyle then
rotates in the lower joint space, and condylar displacement begins when the jaw is opened
beyond 20–25 mm. Retrodiskal ligaments stabilize the disk.
(c) Condylar protraction (maximum open-mouth position). Involvement of the inferior LPM is
basic to this step, and the superior LPM can displace the disk, probably to maintain joint
congruence. The superior retrodiskal layer prevents complete abnormal displacement. (d)
Progression to the maximum clenching position. The inferior LPM is normally very active in this
phase as well.
Dr Ahmed Esawy

• Superior belly of lateral pterygoid musle
– Originates from the greater sphenoid wing and
inserts on the the disk
– Plays a key role in upholding the physiologic
position of the disk as it pulls the disk forward
when the jaw is opened
Dr Ahmed Esawy

sagittal MR imaging
• the meniscus appears as a biconcave structure with
homogeneous low signal intensity
• the bilaminar zone demonstrates intermediate signal
intensity.
• The posterior band and retrodiskal tissue are best
depicted in the open-mouth position , slightly
hyperintense, more frequently hypointense in patients
with disk disease
• Typically, the anterior band and the intermediate zone
are hypointense , lies immediately in front of the condyle
and the junction of the bilaminar zone
Dr Ahmed Esawy

• Morphologic features of the
normal disk. (a) On a sagittal
oblique gradient-echo T2-
weighted MR image (closed-
mouth position), the anterior and
posterior bands are thick and the
intermediate zone (arrow) is thin,
creating a biconcave disk shape.
(b) Sagittal oblique gradient-echo
T2-weighted MR image (open-
mouth position) more clearly
depicts the posterior band and
retrodiskal tissue (arrow). These
anatomic entities are best depicted
in the open-mouth position.
Dr Ahmed Esawy

MRI
• MRI of normal TMJ:
– Disc Biconcave
– Posterior band superior to the
condyle
– In open mouth:
• Thin zone lies between condyle &
tubercle
• Posterior band articulates against
posterior surface of the condyle
Dr Ahmed Esawy

Lateral pterygoid muscle raphe
Lower head of lateral pterygoid muscle
Anterior band of articular disc
Posterior band of articular disc
Posterior disc attachment
Dr Ahmed Esawy

Articular disc
Dr Ahmed Esawy

MRI and autopsy
sections: upper row
oblique sagittal MRI,
asymptomatic
volunteer: left lateral,
middle medial, right
opened mouth
Dr Ahmed Esawy

Retrodiskal layers
• retrodiskal layers (superior and inferior) and vasculonervous structures
constitute an anatomic area called retrodiskal tissue, or the bilaminar
zone. The inferior retrodiskal layer is made up of collagen fibers, and the
superior retrodiskal layer consists of elastic fibers
• These retrodiskal layers play an important role in normal disk
displacement.
• Improvements in MR imaging currently allow detailed depiction of these
structures and related pathologic changes. Rupture of superior retrodiskal
layer fibers may produce significant disk instability.
Dr Ahmed Esawy

• Normal retrodiskal tissue.
• (a) Sagittal oblique gradient-echo
T2-weighted MR image (closed-
mouth position) clearly depicts
the retrodiskal layers (arrow).
These structures play an
important role in normal disk
movement and can easily be
visualized at MR imaging.
• (b) Sagittal oblique spin-echo
proton-density–weighted MR
image (open-mouth position)
shows the superior retrodiskal
layer (arrow) between the
posterior band and the
mandibular fossa.
Dr Ahmed Esawy

Temporomandibular Joint Disk
Position Assessed at Coronal
MR Imaging
Dr Ahmed Esawy

• (a, b) Schematic illustrations of left TMJ measurements in (a) closed-mouth and
(b) opened-mouth positions. a = longest mediolateral distance of condyle, b =
line perpendicular to a and tangential to condyle, c = line parallel to b and
tangential to disk, = distance between b and c at lateral aspect of joint, =
distance between b and c at medial aspect of joint, l = lateral, m = medial.
Dr Ahmed Esawy

• Two-dimensional coronal oblique of TMJ in closed-mouth position in
20-year-old female . Both the medial (left *) and the lateral (right *)
edges of the TMJ disk are medial to the condyle (c).Dr Ahmed Esawy

• Two-dimensional coronal oblique MR of TMJ in opened-mouth position in female
Both the medial edge (black *) and the lateral edge (white *) are medial to the
condyle (c). These findings combined with those in emphasize the medial shift of
the TMJ disk. Dr Ahmed Esawy

Age changes of theTMJ:
1- Flattened condyle
2- osteoporosis of the condyle bone.
3- Thickning of the fibrous covering of the condyle.
4- Thinning of the cartilagenous zone of condyle.
5- Thinning of the disc
6- Fibrotic synovial folds
7- Thickening of the b.v. walls
8- Decrease the number of nerves
Dr Ahmed Esawy

Disorders of the TMJ:
1- limitation of movement:
- temporary
- permanent
2- dislocation
3- pain
4- hyperplasia
5- neoplasm
6- loose bodies in the TMJ
Dr Ahmed Esawy

These age changes lead to:
-Decrease in the synovial fluid formation
-Impairment of motion due to decrease in the
disc and capsule extensibility
-Decrease the resilience during mastication due
to chondroid changes into collagenous
elements
-Dysfunction in older people
Dr Ahmed Esawy

patients of TMJ disease divided into 3 groups according severity of
clinical manifestation and we found that:
Group I. EARLY cases who presented with painless clicking with No
restricted motion.
Group II. INTERMEDIATE group who presented with frequent pain,
joint tenderness, headaches, locking restricted motion and painful
chewing.
Group III. LATE cases who presented with trismus, joint crepitus
and marked chronic pain.
Clinical manifestations were evaluated and registered and were
correlated to the degree of ADD in MRI.
Dr Ahmed Esawy

• Category 0 (Normal disc position)
• Category I (Partial anterior disc displacement with
reduction (PADDWR))
• Category II (Partial anterior disc displacement without
reduction (PADDWOR))
• Category III (Complete anterior disc displacement
with reduction (CADDWR))
• Category IV (Complete anterior disc displacement without
reduction (CADDWOR))
According to the degree of anterior disk
displacment (ADD) our series was classified into 4
categories
Dr Ahmed Esawy

• Category 0
• Normal disc position (the thin intermediate
zone interposed between the condyle and the
adjacent temporal bone, wherever the two
bones are most closely apposed to one
another regardless of whether or not the
mouth was open or closed)
Dr Ahmed Esawy

normal TMJ MR showing normal meniscus (m) posterior and superior to condyle (C) -- the
articular eminence (E) and auditory canal (AC) are also shown
Dr Ahmed Esawy

Drawing of normal temporomandibular joint showing
normal relationship between temporal fossa, disk, and
mandibular condyle.
(A) A closed-mouth sagittal image shows mandibular
condyle articulating with temporal fossa. The disk is
at the 11 o'clock position.
(B) An open-mouth sagittal image illustrates normal
translation of disk and condyle. The condyle is
positioned at the apex of the articular eminence
Dr Ahmed Esawy

T1-Weighted sagittal magnetic resonance images in (a) closed- and
(b) open-mouth positions showing normal disc positions (arrows)
Dr Ahmed Esawy

A 20-year-old woman with a normal
temporomandibular joint.
(A) A closed-mouth sagittal T1-weighted image
shows a normal relationship of the mandibular
condyle (large arrow), the disk (small arrow) at
the 11 o'clock position, the temporal fossa
(arrowhead), and the articular eminence (curved
arrow).
(B) Open-mouth sagittal T1-weighted image shows
normal translation of the disk (small arrow) and
condyle (large arrow) at the apex of the articular
eminence (arrowhead).
Dr Ahmed Esawy

Sagittal oblique spin-echo proton-
density–weighted MR image (closed-
mouth position) shows the disc in its
normal position between the condyle
and temporal bone and centred in the
intermediate zone (arrow).
Sagittal oblique spin-echo proton-density–
weighted MR image (open-mouth position)
shows that the disc has maintained its normal
position during condylar movement (arrow).
Dr Ahmed Esawy

• Category I: Partial anterior disc displacement
with reduction (PADDWR); disc displaced
anteriorly in closed mouth up to the posterior
band interposed between the two most
closely apposed cortical bone surfaces of the
condyle and eminence with disc reduction to
normal location in open mouth position
Dr Ahmed Esawy

weighted MR image (closed-mouth position)
shows partial anterior disc displacement
with intermediate signal of degeneration (large
arrow) and anterior osteophyte of the condyle
(small arrow).
shows that the disc has maintained its normal
position during condylar movement (arrow).
Dr Ahmed Esawy

Internal Derangements
• General orthopedic term implying a mechanical fault that
interferes with the smooth action of a joint
• The most common internal derangement is disc displacement
Clinical Features
• Clicking sounds from joint (s)
• Restricted or normal mouth opening capacity
• Deviation on opening
• Pain
Dr Ahmed Esawy

Disk Displacement
Unidirectional multidirectional
Vertical axis
Anterior
posterior
transverse axis
medial
lateral
Antero-lateral
Antero-medial
Postero-lateral
Postero-medial
anterior
displacement
with reduction.
anterior
displacement
without reduction.
Dr Ahmed Esawy

Disk Displacement
• May be uni- or multidirectional
– Unidirectional anterior and multidirectional anterolateral and
anteromedial displacements are the most common type
– Unidirectional transverse and posterior displacements are rare
Dr Ahmed Esawy

• Assessment of disk position
– Both sagittal and coronal images
– The jaw is firstly assessed in the closed position
• Whether displaced disks relocate to a physiologic
position during jaw opening or stay displaced is an
important issue in the grading and prognosis
– Stay displaced: more likely to develop disk degeneration
and rupture
– Disc may have normal (biconcave) or deformed morphology
Dr Ahmed Esawy

Unidirectional Disk Displacement
• Anterior & posterior disk displacements are diagnosed
on sagittal images by using the position of posterior
band as a discriminator
– Posterior band is ventral to the 11 clock position
– Posterior displacment when posterior band is
displaced posteriorly and exceeds 1 o'clock position
• Medial and lateral displacements: the coronal plane
– Normally do not extend beyond the border of the
condylar head. Bulging disk displacement
Dr Ahmed Esawy

• Partial displacement— the disk continues to stay in
contact with the regular articular surface of the condylar
head . lower prevalence of symptoms than full
displacement
• Complete displacement— the relationship lost
findingsDirection of displacment
Posterior band is ventral to the 11 clock
position
Anterior disk displacment
Posterior band is dorsal to the 13 (1) clock
position
posterior disk displacment
Medial attachment and disk bulge medial to
the medial border of the mandibular head
medial disk displacment
Lateral attachment and disk bulge lateral to
The lateral border of the mandibular head
lateral disk displacment
Dr Ahmed Esawy

• Drawings (sagittal oblique views)
illustrate disk displacement in the
closed-mouth position. (a) A
pathologic condition is
considered to be present if the
angle between the posterior
band and the vertical orientation
of the condyle (twelve o’clock
position) exceeds 10°.
(b)recommendation that anterior
disk displacement of up to 30° be
considered normal to better
correlate disk displacement with
clinical symptoms of TMJ
dysfunction.
Dr Ahmed Esawy

displaced meniscus anteriorly (arrows, m) anterior to the condyle (C) and auditory
canal (AC) and beneath the articular eminence (E)
Dr Ahmed Esawy

Indirect signs of internal derangement include large joint
effusion
rupture of retrodiscal layers
thickening of lateral pterygoid muscle attachment
osteoarthritic changes.
Dr Ahmed Esawy

Category II: Partial anterior disc displacement
without reduction (PADDWOR)
disc displaced anteriorly in closed mouth as
described in category I, that maintained
displaced with mouth opening
Dr Ahmed Esawy

weighted MR image (closed-mouth
position) shows (flattened shape) partial
anterior disc displacement (arrow).
shows that the disc remains partially
displaced from its normal location (arrow),
associated with Grade I joint effusion.
Dr Ahmed Esawy

Partial anterior disk displacement
Sagittal MR image of
closed jaw— the
posterior band is at 10
o’clock position
Dr Ahmed Esawy

lateral sections central sections open-mouth
Partial anterior disc
displacement at baseline
Dr Ahmed Esawy

• (a) closed-mouth position) shows a
disk (arrow) in its normal position
between the condyle and temporal
bone and centered in the
intermediate zone.
(b) (open-mouth position) shows that the disk
(arrow) returns back has maintained its normal
position during condylar movement. This
interposition of the disk prevents abnormal contact
between osseous joint surfaces.
Normal disk mobility
Dr Ahmed Esawy

Internal Derangement
• anterior displacement when the mouth is closed, the
meniscus is sandwitched between the anterior aspect of
condyle (anterior to the superior portion of the condyle ) and
the eminence.
• When the mouth is opened the displaced posterior band will
usually return to its normal position as the condyle reaches a
certain point. This is termed anterior displacement with
reduction.
 In opened mouth position disc may be in a normal position
(“with reduction”) or continue to be displaced (“without
reduction”)
Dr Ahmed Esawy

Category III: Complete anterior disc
displacement with reduction (CADDWR);
disc displaced anteriorly in closed mouth
up to no disc substance interposed
between the two most closely apposed
cortical bone surfaces of the condyle and
eminence with disc reduction to normal
location in open mouth position
Dr Ahmed Esawy

shows (thickened shape) complete
anterior disc displacement (arrow) and
associated joint effusion in
both upper and lower joint recesses.
shows that the disc (arrow) has maintained its
normal position during condylar movement.
Dr Ahmed Esawy

• Anterior disk displacement with
reduction.
(open-mouth position) shows that the disk
(arrow) has returned to its normal position
between the condyle and the temporal bone.
This return movement generally produces a
clicking or popping noise
(a) Sagittal oblique gradient-echo T2-weighted
MR image (closed-mouth position) shows an
anteriorly displaced disk (arrow).
Sagittal T2
Dr Ahmed Esawy

• Disk displacement with reduction:
posterior
posterior
Dr Ahmed Esawy

T1-Weighted sagittal magnetic resonance images in (a) closed- and (b) open-mouth
positions showing anterior disc displacement with reduction (arrows)
Dr Ahmed Esawy

Category IV: Complete anterior disc
displacement without reduction
(CADDWOR) disc displaced anteriorly in
closed mouth as described in category III,
that maintained displaced with mouth
opening
Dr Ahmed Esawy

shows complete anterior disc displacement
(arrow).
shows that the disc remains displaced from its
normal location (arrow) and cortical erosion
of the condyle (small arrow). Note the marked
restricted mobility of the condyle apex where
it translates to less than the apex of the
articular eminence.
Dr Ahmed Esawy

• Anterior disk displacement
without reduction.
(b) the open-mouth position, the disk (arrow)
remains displaced from its normal location
(a) (closed-mouth position) shows a disk
(arrow) displaced from its normal location.
Sagittal T2-
Dr Ahmed Esawy

• Disk displacement without reduction:
Dr Ahmed Esawy

T1-Weighted sagittal magnetic resonance images in (a) closedand
(b) open-mouth positions showing anterior disc displacement without reduction (arrows)
Dr Ahmed Esawy

Unidirectional complete anterior
disk displacement
Sagittal MR image with
the jaw closed—
• Disk deformity
• Condyle deformity
due to OA changes
Dr Ahmed Esawy

Complete anterior disc displacement
Open-mouth MRImedial section Autopsy
Dr Ahmed Esawy

Multidirectional Disk Displacement
• Combination of signs of unidirectional disk displacement
• Careful interpretation of sagittal and coronal images
• Impossibility of identifying the complete disk in a single
coronal or sagittal image
Dr Ahmed Esawy

Anterolateral disk displacement
a, sagittal b, coronal
a, anterior displacement (complete) and deformity of the disk
b, the disk bulges laterally beyond the lateral condylar contourDr Ahmed Esawy

Sagittal T1-weighted magnetic resonance image in open-mouth position shows condylar
hypermobility (white arrow) and posterior displacement of articular disc (black arrow)
Dr Ahmed Esawy

Posterior disc displacement
posterior
posterior
Dr Ahmed Esawy

Normal disc morphology is biconcave structure in sagittal
images with homogenous low signal intensity. Disc
deformities including thickening , irregularity , flattening,
folded , degeneration , and perforation were reported
Disc morphology
Dr Ahmed Esawy

weighted MR images (closed-mouth position)
show abnormal disc morphology:
(a) shows intermediate signal of degeneration
within the disc (arrow).
Shows fattened, irregular disc with complete
anterior displacement (arrow) associated with
osteoarthritic changes and joint effusion
Dr Ahmed Esawy

Shows ballooning of posterior disc band with
complete anterior displacement (arrow)
associated with osteoarthritic
changes and joint effusion
Shows perforated disc with complete anterior
displacement (arrow) associated with
osteoarthritic changes (cortical erosion and
irregular articular surface of the condyle and
small anterior osteophyte)
Dr Ahmed Esawy

(a) (closed-mouth position) shows a displaced
disk (arrow) that has lost its typical biconcavity,
having become crumpled and irregular.
(b) (closed-mouth position) obtained in a
different patient shows a pathologic displaced
disk with a rounded shape (arrow).
Sagittal T2-
Abnormal morphologic features of the disk.
Anterior disk
displacement
Dr Ahmed Esawy

(c) (closed-mouth position) obtained in a third
patient shows a flattened displaced disk
(arrow).
(d (closed-mouth position) obtained in a
another patient demonstrates perforation of
the intermediate zone of the disk (arrow).
Abnormal morphologic features of the disk
Anterior disk
displacement
Dr Ahmed Esawy

Sagittal T1-weighted magnetic resonance image in open-mouth position shows high signal
intensity in superior belly of lateral pterygoid muscle indicating fatty replacement (arrow). Note
the anterior displacement and biconvex deformity of articular disc (arrowhead)
Dr Ahmed Esawy

• Disk Deformity:
– Chronic displacement leads to
deformity of the disc leading
to:
• Loss of the normal biconcave
morphology
• Thickening of its posterior band
• Irregular folding of its anterior
band
Significant for clinical
management as a
deformed disc cannot be
surgically repositioned.
Dr Ahmed Esawy

• (a) Sagittal T2-weighted MR image
(closed-mouth position) shows
significant disk displacement. The
intermediate zone is clearly beyond the
condyle, and the angle between the
posterior band (dashed line) and vertical
(solid line) is close to 50°.
(b) Sagittal oblique gradient-echo T2-weighted
MR image (closed-mouth position) obtained in
a different patient clearly depicts anteromedial
disk displacement. The disk (arrow) appears to
be "floating" by itself, and the condyle is no
longer visualized.
Abnormal disk displacement in TMJ dysfunction
Dr Ahmed Esawy

Normal disk mobility
Translation of the condyle
Dr Ahmed Esawy

• the posterior band (arrow)
remains close to the
mandibular fossa. Opening
of the jaw in this case was
seriously limited.
Stuck disc occurs when the disc fails to displace
in open or closed mouth position and becomes
fixed to the temporal bone due to adhesion.
closed-
mouth
open-mouth
Dr Ahmed Esawy

• Posterior disk displacement.
(a) (closed-mouth position)
shows a posterior band
displaced posteriorly.
• Sagittal T2
• (b) obtained in the open-
mouth position, the posterior
band (arrow) remains
displaced. The jaw was nearly
locked in this case.
Dr Ahmed Esawy

Translation of the condyle
Condyle translation was assessed in PD sagittal oblique images
in open mouth position as follows;
1-apex of the condyle translates to less than the apex of the articular eminence,
2-apex of the condyle translates to the apex of the articular eminence, which
is a position many authors consider normal,
3-apex of the condyle translates beyond the apex of the articular eminence
Dr Ahmed Esawy

Sagittal oblique spin-echo proton-
density–weighted MR images (open-
mouth position) show the translation
of the condyle in relation to the
articular eminence (a) the apex of the
condyle (arrow head) translates to
the apex of the articular eminence
(asterisk), which is considered
normal.
Shows complete
anterior disc
displacement
without reduction
and restricted
mobility of the
condyle i.e., the
apex of the condyle
(arrow head)
translates to less
than the apex of
the articular
eminence
(asterisk).
Shows normal disc position with hypermobility
of the condyle i.e. the apex of the condyle
(arrow head) translates beyond the apex of the
articular eminence (asterisk). Dr Ahmed Esawy

Sagittal T2 fat sat
Closed Note both the
mandibular condyle and
fibrocartilaginous disc
sitting in the fossa.
Sagittal T2 fat sat
Open Note the disc and
condyle translating forward
out of the fossa
Dr Ahmed Esawy

Coronal MR image of closed jaw
Right : slight medial disk displacement
Left : slight lateral disk displacement
Dr Ahmed Esawy

Lateral disc displacement and normal bone
Coronal MR image
Dr Ahmed Esawy

• Lateral Disk displacement :
Coronal MR image
Dr Ahmed Esawy

Coronal T1-weighted magnetic resonance image in closed-mouth
position shows lateral displacement of articular disc (arrow)
Dr Ahmed Esawy

Medial disc displacement
Oblique coronal MRIcoronal MRI
Coronal MR image
Dr Ahmed Esawy

Recapture of Displaced Disk
• Recapture
– Displaced disks regain their normal position during jaw
opening
– Synonym: Reduction
– Indicates the attachments and capsule are less
compromised
• Open jaw image allows further evaluation of the soft
tissue structures
– Rupture of diskal attachments— more severe, at risk for
developing sequelae
Dr Ahmed Esawy

Unidirectional anterior disk
displacement without recapture
Sagittal MR image
(2800/15) with the jaw
open—
• the anteriorly
displaced disk does not
relocate with deformity
Dr Ahmed Esawy

Anterolateral disk displacement with
complete recapture
Coronal (closed)
Lateral bulging of the
disk
Sagittal (open)
The disk is in normal
position
Sagittal (closed)
Anterior displacement of
the disk
Dr Ahmed Esawy

Sagittal T1
Recapture
Open mouth
Sagittal T1
Anterior dislocation
closed mouth
Dr Ahmed Esawy

Sagittal T1
anterior dislocation - closed Sagittal T1
No Recapture
Open mouth
Dr Ahmed Esawy

Thickening of an LPM Attachment
• two parts of the LPM
• the superior LPM and the inferior LPM
• pseudomeniscus sign," or thickening of the
posterior meniscal attachment that occurs in
some patients with an anteriorly displaced
meniscus
Dr Ahmed Esawy

shows normal disc position (large arrow) and
normal thickness of inferior LPM insertion
(small arrow).
shows complete anterior disc displacement
(arrow) and thickened inferior LPM insertion
(arrow head), compared with (a).
thickness of LPM
Dr Ahmed Esawy

Normal LPM. (a) Sagittal oblique spin-echo
proton-density–weighted MR image (closed-
mouth position) shows a thin attachment of
the inferior LPM (arrow) just below the disk
MR image (closed-mouth position) shows a
thin attachment of the superior LPM (arrow)
just in front of the disk
Dr Ahmed Esawy

(c) Sagittal oblique gradient-echo T2-weighted
MR image (closed-mouth position) shows the
thin insertional area of the inferior LPM
(arrow).
(d) On a sagittal oblique gradient-echo T2-
weighted MR image obtained in the open-
mouth position, the insertional area of the
inferior LPM (arrow) has increased due to
contraction of the muscle during this phase.
Normal LPM
Dr Ahmed Esawy

Abnormal LPM. (a) Sagittal oblique
gradient-echo T2-weighted MR
image (closed-mouth position) of a
symptomatic TMJ shows complete
disk displacement.
MR image (closed-mouth position) of the
contralateral asymptomatic TMJ shows subtle
disk displacement. The insertional areas of the
superior (arrowhead) and inferior (arrow)
LPMs are markedly thinner than those in the
symptomatic TMJ (cf a).
Dr Ahmed Esawy

Double disk sign. (a) Sagittal oblique gradient-echo T2-
weighted MR image (closed-mouth position) of a
symptomatic TMJ shows complete disk displacement. The
thick insertional area of the inferior LPM (arrow) is parallel to
the disk (arrowhead), creating the double disk sign.
MR image (closed-mouth position) of a
symptomatic TMJ in a different patient
demonstrates severe internal derangement
(arrowhead). A thick inferior LPM attachment
(arrow) is again seen. The double disk sign
must be recognized to distinguish between
disk and muscle attachment. Dr Ahmed Esawy

Sequelae of Internal Derangement
• Disk displacement indicates damage to the
attachments, capsule, and ligaments of TMJ
• Compromised structural integrity  functional
disturbance
• A process of degeneration to osteoarthritis may be
initiated
Dr Ahmed Esawy

• Active stages
– Synovitis, effusion, & bone marrow edema
• Advanced stages
– Joint space narrowing, subchondral sclerosis & cyst
formation, contour irregularity, osteophyte formation
– Neovascularity & remodeling of the disk (deformity,
rupture, & SI changes)
Dr Ahmed Esawy

Osteoarthritis
Definition
 Non-inflammatory focal degenerative disorder of
synovial joints, primarily affecting articular cartilage
and sub-condylar bone; initiated by deterioration
of articular soft-tissue cover and exposure of bone.
Clinical Features
 Crepitation sounds from joint(s)
 Restricted or normal mouth opening capacity
 Pain or no pain from joint areas and/or of
mastication muscles
 Occasionally, joints may show inflammatory signs
 Women more frequent than men
Dr Ahmed Esawy

TMJ osteoarthritis changes
Narrowing of the joint space.
fattening of the articular surface
subcortical sclerosis or cyst
surface erosion
Osteophytes ( arise only from the anterior margin
of the condyle)
generalized sclerosis for the condylar head
Flattening of the articular eminence
subcortical sclerosis,
Surface erosions for the fossa
Dr Ahmed Esawy

anteriorly displaced and deformed, degenerated disc and irregular
cortical outline with osteophytosis and sclerosis of condyle .
Dr Ahmed Esawy

Advanced osteoarthritis and anterior disc
displacement, with joint effusion
Dr Ahmed Esawy

Anterior disk displacement with osteoarthritis
Sag
Cor
Closed position
1. Condyle with areas of
bone marrow edema
2. Articular fossa
3. Displaced disk
4. Effusion
5. Subchondral cyst
Dr Ahmed Esawy

Osteoarthritic changes in four different patients.
(a) Sagittal oblique gradient-echo T2-weighted MR
image (closed-mouth position) obtained in a
patient with internal derangement shows
condylar flattening (arrow).
MR image (open-mouth position) obtained in a
patient with internal derangement without
reduction clearly depicts an osteophyte
(arrow).
Osteoarthritis
Dr Ahmed Esawy

(c) Sagittal oblique spin-echo T2-weighted MR
image (closed-mouth position) obtained in a
patient with internal derangement shows
condylar erosion (arrow).
(d) Sagittal oblique gradient-echo T2-weighted
MR image (open-mouth position) obtained in a
patient with internal derangement without
reduction demonstrates a condylar
osteophyte, flattening, sclerosis, and erosion
(arrow), all of which are signs of osteoarthritic
changes ( a–c).
Osteoarthritis
Dr Ahmed Esawy

– Degenerative (Osteoarthritis)
• X-ray
– Narrowing of the joint space
anteriorly with slight sclerosis
– Small osteophyte arise from
the anterior margin of the
articular surface of the
condyle
Dr Ahmed Esawy

– Degenerative (Osteoarthritis)
• MRI
– A low signal large osteophyte
associated with anterior
displaced meniscus.
Dr Ahmed Esawy

Sagittal T1-weighted magnetic resonance image in open-mouth position of
osteoarthritic joint shows osteophyte formation (arrowhead) and anterior displacement
and folded deformity of articular disc (arrow)
Dr Ahmed Esawy

• Different grading systems have been developed to
describe the degree of internal derangement and
osteoarthritis
• The most simple to differentiate partial and total disk
displacement is on the basis of the position of the
disk relative to the condylar head and articular
eminence
Dr Ahmed Esawy

Grading System according to Wilkes
Grading System according to Vogl and Abolmaali
Dr Ahmed Esawy

Joint effusion was assessed on T2WI manifesting as area of hyperintensity, which was
divided into 3 grades .
Grade 0: None (no bright signal in either joint space).
Grade I: Slight effusion (a bright signal in either joint space that conforms to
the contours of the disc, fossa/articular eminence, and or condyle).
Grade II: Frank effusion (a bright signal in either joint
space that extends beyond the osseous contours of fossa/articular
eminence, and or condyle and has a convex configuration
in the anterior or posterior recesses.
Dr Ahmed Esawy

Joint effusion
Joint effusion. On a sagittal
oblique gradient-echo T2-
weighted MR image obtained
in the closed-mouth position,
joint fluid (arrow) clearly
delineates the shape of the
disk between the upper and
lower joint spaces
"arthrographic effect" . This
phenomenon is best seen on
T2-weighted images.
gadolinium-enhanced MR imaging of the TMJ
may allow clear differentiation between the
proliferating synovium, which enhances, and
joint effusion, which does not. This technique
can be useful if rheumatic inflammatory joint
disease associated with joint effusion is
suspectedDr Ahmed Esawy

Sagittal T2-weighted magnetic resonance image shows fl uid effusion in superior joint cavity
(arrow) and anterior displacement and folded deformity of articular disc (arrowhead)
Dr Ahmed Esawy

Sagittal T2-weighted magnetic resonance image in open-mouth position shows fl uid
effusion in the superior joint space (arrows) and high signal intensity in the glenoid fossa
indicating retodiskitis (arrowhead) Dr Ahmed Esawy

Other findings related to internal derangement
• Joint effusion
• Avascular necrosis &
bone oedema
• Osteoarthritis
Dr Ahmed Esawy

Sagittal T2-weighted magnetic resonance image shows fl uid accumulation in superior
joint space (arrowhead) and increased signal intensity of the condylar head indicating
bone marrow edema (arrow)
Dr Ahmed Esawy

shows normal intact superior (large
arrow) and inferior (small arrow) retrodiscal
layers
Sagittal oblique T2-weighted MR image (open-
mouth position) shows thickening of superior
retrodiscal layer (large arrow) and normal
inferior retrodiscal layer (small arrow).
RETRODI DISKAL LAYER INTEGRITY
Dr Ahmed Esawy

• Abnormal retrodiskal tissue.
• (a) Sagittal oblique spin-echo proton-
density–weighted MR image (open-
mouth position) obtained in a patient
with internal derangement without
reduction shows rupture of the fibers
of the superior retrodiskal layer
(arrow), resulting in loss of union
with the posterior band.
• (b) Sagittal oblique gradient-echo T2-
weighted MR image (closed-mouth
position) obtained in a different
patient again depicts rupture of the
fibers of the superior retrodiskal layer
(arrow).
Retrodiskal Layer
Rupture
Dr Ahmed Esawy

Sagittal T1-weighted magnetic resonance image in closed-mouth position shows anteriorly
displaced articular disc (arrow) and a hypointense band in the retrodiscal region
(arrowhead) indicating thickening of posterior discal attachment “pseudo disc sign”
Dr Ahmed Esawy

Sagittal T1-weighted magnetic resonance image in closed-mouth position shows anteriorly
displaced disc (arrow). Note the low signal intensity of lateral pterygoid tendon is parallel to the
disc, giving a “double disc sign” Dr Ahmed Esawy

Direct and Indirect MR Imaging Signs of
TMJ Dysfunction
Dr Ahmed Esawy

Progression of TMJ Dysfunction as Seen at
MR Imaging
Dr Ahmed Esawy

Imaging after Treatment
• To detect corrected position of the displaced
disc
• To detect post-operative complication e.g.
– Intra-articular adhesions
– Erosion following implants
before after
Dr Ahmed Esawy

Trauma
• Mandibular fractures:
– Car accidents – 75%
– Falls and sporting accidents – the rest
• Condylar process fractures:
– 25~50% mandibular fractures
– Falls and sporting accidents – majority
• Classifiication
– Condylar neck – low, medium, high
– Condylar head – extra- or intracapsular
Dr Ahmed Esawy

Classification of condylar process fractures
Nondisplaced fractures
Displaced fractures: typically displaced medially due to traction of
lateral pterygoid m. Dr Ahmed Esawy

• Evaluation of the type and grade of displacement of
bony structures is essential for treatment planning
– Angle between mandibular head & ramus
– Degree of contraction in the vertical plane (influences
occlusion)
– Transverse displacement, position of the fractured head…
Dr Ahmed Esawy

• Conventional radiography, panoramic radiography –
first-line dianostic tool
• CT – method of choice for assessment and grading of
facial trauma
• MR – identify posttraumatic disc dislocation &
rupture and injury to attachments, capsule, cartilage,
& ligaments in the pretherapeutic evaluation
Dr Ahmed Esawy

Bilateral medially displaced fractures
Fracture of the mandibular neck
Small fragments on the right (coronal CT)
Dr Ahmed Esawy

1. Nondisplaced fracture of
the right zygomatic
process
2. Vertical condylar head
fracture on the right
3. Comminuted, displaced
condylar head fracture on
the left
Dr Ahmed Esawy

• Trauma
– Condylar neck fracture is
common.
– CT & MRI are helpful in
cases of intracapsular
fractures
Dr Ahmed Esawy

Arthritis
Definition
• Inflammation of synovial membrane characterized by
edema, cellular accumulation, and synovial proliferation
(villous formation).
Clinical Features
• Swelling of joint area, not frequently seen in TMJ
• Pain (in active disease) from joints
• Restricted mouth opening capacity
• Morning stiffness, in particular stiff neck
• Dental occlusion problems; “my bite doesn’t fit”
• Crepitation due to secondary osteoarthritis
Dr Ahmed Esawy

• Arthritis
– Inflammatory arthritis (rheumatoid)
– Degenerative ( osteoarthritis)
– Septic (rare)
Dr Ahmed Esawy

Inflammation
• TMJ: synovia-lined joint
– Synovial arthropathies predominantly rheumatoid
arthritis
– Rare with gout, psoriatic arthritis, ankylosing
sondylitis, SLE, juvenile chronic arthritis, CPPD
deposition
Dr Ahmed Esawy

• No distinction between different forms of synovial
arthropathy with MR imaging
– Synovitis with tissue swelling, edema, effusion
– Joint space narrowing, cartilage destruction, erosions,
marrow edema
– Formation of granulation tissue and pannus typically
occurs in the ―bare areas‖ near the capsular insertion
Dr Ahmed Esawy

Miscellaneous Conditions involving TMJ
– Inflammatory (Rheumatoid Arthritis)
• Very common, with rare significant symptoms.
• Erosions of articular surface of the condyle may be
extensive.The articular fossa usually remain normal
• Coronal T2WI images are valuable.
• Other diseases as SLE, systemic sclerosis, psoriasis,
juvenile chronic arthritis, pigmented villonodular
synovitis, enteropathic arthritides can affect the
TMJ but they are rare.
Arthritis
Dr Ahmed Esawy

– Inflammatory (Rheumatoid Arthritis)
• Erosion of the condyle is marked
• Hypertrophic synovium
Arthritis
Dr Ahmed Esawy

Rheumatoid arthritis.
After 1 yearDr Ahmed Esawy

Rheumatoid arthritis.A MRI shows completely destroyed disc, replaced
by fibrous or vascular pannus and cortical punched-out erosion (arrow)
with sclerosis in condyle.
Dr Ahmed Esawy

Inflammed TMJ in rheumatoid arthritis
Sag STIR
1. Synovitis &
inflammation of
surrounding tissue
2. Small volume of
intracapsular fluid in
superior joint space
3. Partial anterior disk
displacement
Dr Ahmed Esawy

Inflammed TMJ in rheumatoid arthritis
T1(400/15) T1+C
Slight enhancement of the bilaminar zone after
contrast administration
Dr Ahmed Esawy

Psoriatic arthropathy. Oblique coronal and oblique sagittal
CT images show punched-out erosion in lateral part of
condyle (arrow).
Psoriatic arthropathy. MRI shows contrast enhancement
within bone erosion and in joint space, consistent with thickened
synovium/pannus formation. Openmouth
MRI shows reduced condylar translation but normally
located disc (and normal bone in this section)
Dr Ahmed Esawy

Inflammatory arthritis
Dr Ahmed Esawy

Bone Marrow Abnormalities
Definition
• Bone marrow edema: serum proteins within
marrow interstitium surrounded by normal
hematopoietic marrow.
• Osteonecrosis: complete loss of
hematopoietic marrow.
Dr Ahmed Esawy

Imaging Features
•Abnormal signal on T2-weighted image from
condyle marrow: increased signal indicates
marrow edema; reduced signal indicates
marrow sclerosis or fibrosis
•Combination of marrow edema signal and
marrow sclerosis signal in condyle most reliable
sign for histologic diagnosis of osteonecrosis
•Marrow sclerosis signal may indicate advanced
osteoarthritis without osteonecrosis, or
osteonecrosis
Dr Ahmed Esawy

Ankyloses
Definition
Fibrous or bony union between joint
components.
Dr Ahmed Esawy

Growth Disturbances (Anomalies)
Definition
Abnormal growth of mandibular condyle; overgrowth,
undergrowth, or bifid appearance.
Dr Ahmed Esawy

NormalTMJ
Condylar Hypoplasia
Condylar hypoplasia and
facial asymmetry
Dr Ahmed Esawy

• Developmental anomalies
1- Hypoplasia of the Condyle
• Unilateral or bilateral
• Unilateral cases is sequel of trauma or
infection result in mandibular asymmetry
• Bilateral cases are developmental, result in
very small mandible (bird face)
Dr Ahmed Esawy

• Developmental anomalies
2- Hyperplasia of the Condyle
• Rare
• Unknown etiology, always unilateral
• Generalized enlargement of the condylar head
• High activity in scintigram
Dr Ahmed Esawy

• Developmental
anomalies
2- Hyperplasia of the Coronoid process:
• Bilateral enlarged coronoid process extends
above the zygomatic arch.
• The anterior margin of both coronoid
processes are in face-to-face contact with
the posterior aspect of the zygomatic bone
in the open mouth position.
Dr Ahmed Esawy

Inflammatory or Tumor-like Conditions
Calcium Pyrophosphate Dehydrate Crystal
Deposition Disease (Pseudogout)
Dr Ahmed Esawy

Benign Tumors
Synovial Chondromatosis
• Benign tumor characterized by cartilaginous metaplasia of
synovial membrane, usually in knee, producing small
nodules of cartilage, which essentially separate from
membrane to become loose bodies that may ossify.
Dr Ahmed Esawy

Synovial Chondromatosis
Dr Ahmed Esawy

– Synovial chondromatosis
Tumours & Tumour-like conditions
Dr Ahmed Esawy

The disc-condyle relationship appears normal but the condyle-disc complex is displaced
inferiorly (a and b). Significant bony changes are not evident. The T2-weighted image (c)
shows an extremely large amount of synovial fluid visible as a high signal intensity that
expands the joint capsule. Arrow = loose body.
Synovial chondromatosis
Dr Ahmed Esawy

The disc-condyle relationship appears more or less normal but the condyle-disc complex is
displaced inferiorly. Loose bodies are not visible in these cuts.
Dr Ahmed Esawy

An extremely large amount of synovial fluid and several hypointensive loose bodies are visible
in the superior joint space (a). The calcified loose bodies are visible also on the CT image (b).
The outline of the joint capsule in the MRI picture (a) is marked by the white triangles, while
the arrows show the loose bodies in the CT image (b). C = condylar head.
Dr Ahmed Esawy

This image does not show a capsular expansion although the superior joint space is
largely filled with synovial fluid (high signal intensity, white arrow). C = condylar
head.
Dr Ahmed Esawy

The disc-condyle relationship appears normal (a and b), but the disc is displaced superiorly (b)
because the inferior joint space is affected. The T2-weighted image (c) shows a very large
amount of synovial fluid with remarkable capsular expansion of the inferior joint space
Dr Ahmed Esawy

– Simple bone cyst
Dr Ahmed Esawy

Osteochondroma
Definition
Benign tumor characterized by normal bone and
cartilage, near growth zones.
Dr Ahmed Esawy

– Osteochondroma
Dr Ahmed Esawy

Malignant Tumors
Osteosarcoma mandible; 18-year old femaleDr Ahmed Esawy

Malignant tumor, mandible; 70- year-old male
with metastasis from lung cancer
Dr Ahmed Esawy

1-limitation of mandibular movement: due to:
a-intracapsular causes:
Infective arthritis
Juvenile arthritis
Traumatic arthritis
Intracapsular condyle fracture
b-pericapsular causes:
Irradiation
Dislocation
Condylar neck fracture
Infection of adjacent tissues
Dr Ahmed Esawy

c-muscular:
Tmj dysfunction syndrome
Myalgia due bruxism
Haematoma from ID block
Tetanus
d-Others:
Oral submucous fibrosis
Systemic sclerosis
Zygomatic & maxillary fracture
Drugs
Craniofacial anomalies involving the joint
Dr Ahmed Esawy

Limitation of TMJ movements:
Temporary persistent
(trismus) (ankylosis)
Dr Ahmed Esawy

3-Pain in or around the joint: due to:
• injury
• infection & inflammation
• vascular disease e.g: cranial arteritis
• muscle spasm e.g: pain dysfunction syndrome
• rheumatoid & other arthritis
• salivary gland disease e.g: parotid neoplasm
• ear disease e.g: otitis media, externa
Dr Ahmed Esawy

4-Hyperplasia:
Is rare unilateral overgrowth of the condyle.
It causes: facial asymmetry, deviation of the jaw to the
unaffected side on opening and crossbite.
Treated by:
-If it is stabilized at the end of puberty --- corrective
osteotomies to restore occlusion & facial asymmetry
-If it is still active --- intracapsular condylectomy
Dr Ahmed Esawy

5-Neoplasms: (rare):
• osteochondroma
• osteoma
• chondroma
Dr Ahmed Esawy

6-Loose bodies in the TMJ: (rare):
• osteochondritis disssecans:
due to trauma
• synovial chodromatosis
benign neoplasm
Dr Ahmed Esawy

MRI TMJ temporo mandibular jiont Dr Ahmed Esawy

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