TMJ Abnormalities Flashcards
describe mandibular condyle
cylindrical
2cm mediolateral
variable shape
angled 15-33 degrees with sagittal plane
temporal component of TMJ - implication for?
formed by squamous portion
posterior – glenoid / madnibualr fossa
anterior - articular emninence and tubercle
- WHERE YOU WILL MOST LIKELY SEE OSTEOARTHRITIS
where will you see artheroarthritis in TMJ?
anterior portion at the articular eminence and tubercle
interarticular disc - describe
avascular fibrous connective tissue
which part is thicker in the disc
thicker anterior band
thinner in middle and VERYT HICK POSTERIOR BAND
- also thicker medially than laterally
displacement in what direction?
medio-anterior
where does interarticular disc (meniscus) attach?
to the condylar poles both medially and laterally
Retrodiscal tissues aka
posterior disc attachment
Retrodiscal tissue describe
well-innervated and may be the cause of paon in the case of anterior disc displacement
VASCULAR
- expands in volume via venous distension
superior vs inferior aspects of Retrodiscal tissues
sueprior - very flexible
inferior - not as flexible
when to image the TMJ?
- supplements clinical inforamtion
- osseous abnormalities
- conservative tx has failed
- symptoms are worsening
- history of significant trama, dysfunctin, alteration in ROM, nerve abnormalities, changes in occlusion
TMJ imaging modalities
- PANO
- CBCT
- MDCT
- MRI
MDCT and TMJ imaging?
see soft tissue – but CANOT VISUALIZE THE DISC
MRI of disc?
FLUID IS MORE NOTICEABLE
- provides contrast for disc and other SOFT TISSUE structures
MRI of disc?
FLUID IS MORE NOTICEABLE
- provides contrast for disc and other SOFT TISSUE structures
condylar hyperplasia
developmental abnormality that results in ENLARGED and occasionally deformed condylar head
- possible enlarged glneoid fossa, condylar neck, ramus and body
female >male
age less than 20
self-limiting
mandibular assymetry
normal cortical thickness and trabecular pattern – condylar head and neck may bend forward or lateral
differential diagnosis with condylar hyperplasia
tumor – more irregular like osteochondroma
coronoid hyperplasia presents as
elongated coronoid process, extending at least 10mm above the inferior rim of the zygomatic arch
male > female
often bilateral and can contact the posterio surface of zygomatic arch, restricting condylar translation
bifid condlye is what?
anatomical VARIANT
- developmental depression or notch in teh superior condylar surface
- more of an anomoly and cannot say pathiology
- usually incidental finding
- occasionally TMD symptoms
- more often unilateral and can be anterio-posterior or mediolateral
bifid condlye is what?
anatomical VARIANT
- developmental depression or notch in teh superior condylar surface
- more of an anomoly and cannot say pathiology
- usually incidental finding
- occasionally TMD symptoms
- more often unilateral and can be anterio-posterior or mediolateral
describe disc displacement
direction most likely to occur?
abnormally positioned disc relative to the condylar and temporal components of the TMJ
MOST COMMONLY ANTERIOR
- but can be antero-medially, medially, or anterior-laterally displaced
can interfere with function, cause pain, or be asympotmatic
- POPPING, CLICKING,
- crepitus (sign of degeneration)
- decreased ROM
- may be locking
normal appearance of the disc usually look?
liek a bow-ties
at 11 or 12 o-clock
disc deformities and perforatin
long-term displacement leads to loss of normal shape
- may be impossible to identify
- perforations occur most commonly in retrodiscal tissue
- not reliable on MRI
- bone to bone contact of osseous componenets is suggestive of perforation or displacement
DJD aka
inflammatory?
osteoarthritis
not considered inflammatory but signs are kind of liekt hat
describe DJD
breakdown of articulating fibrocartilage leading to deterioration of teh osseouos structures
non-inflammatory
bone erosion as well as new bone formation (osteophytes and sclerosis)
- incidence increases with age and females more likely than males
DJD occurs where?
most likely where things are occluding
- anterior glenoid fossa- posterior articualr eminence
6 signs of DJD
- flattening?
- some people jsut have that though - reduced joint space
- sclerosis
- formation - osteophyte
- formation of bone - subchondral cyst
- usually small / round / W-D - erosion
- right on the surface of the joint
what may be first sifgn of DJD
flattening
symptoms of osteoarthritis is usually?
pain within the joint and crepitits
DD with DJD
- inflammatory arthritis (rheumatoid) - more erosice
2. benign tumor - more scleortic (osteoma or osteochondroma)
rheumatoid arthritis
synovial membrane inflammation in several joints
affects TMJ in half of patients
RA looks?
jigaw pattern?
- fribrous ankylosis
generalized osteopenia of the TMJ with synovial inflammation
very erosive
can occur from secondary DJD
fibrous anklylosis occurs with ?
RA
RA DD importance of what ?
medical history
Juvenile arthrosis aka?
idiopathic condylar resorption
or
cheerleader syndrome
idiopathic condylar resorption looks? who usually gets it ?
“toad-stool” appearance
females – younger
treatment for juvenile arthrosis? (ICR)
surgery
- to fix disc and correct plane of occlusion
juvenile idopathic arthritis looks? who gets it
even younger than IRC –
“bird-face” and open bite
major things to note about septic arthritis
- unilateral
- redness and swelling
3.
defintion of effusion
influx of fluid into the joint
may be associated with trauma (hemarthrosis) disc displacement or arthritis
typical TMD symptoms and fluid in the ear, tinnitus, hearing difficulties, difficulty occluding post teeth
condylar disloction presents as?
usually locked open
- condyle
fracture look for
discontiuity in cortical outlines or overlapping
ankylosis two types
fibrous or osseous / bony
fibrous - jigsaw
fibrous ankylosis
irregular, narrow oint space and jigsaw puzzle
bony ankylosis
joint space is obliterated by osseous bridge
- degenerative changes
most common benign tumor
osteochondroma
- radio-opaque
loss of cortex on condyle in younger?
not a pathological sign for anything – they take longer to develop
Pano and CBCT and MT for TMJ?
Pano - gross disease
CT - hard tissue (ossseeous changes)
MCT- hard tissue plus soft tissues
**MRI FOR DISC AND FLUID (EFFUSION)
developmental hyperplasia of condyle DD?
osteochondroma (most common benign tumor in jaw)
but developmental will STOP after puberty and is usually more unilateral and ‘regular enlargment’
pronounced antegonial notch seen in?
condylar HYPO-plasia
downward bowing of the inferior border?
HYPER- plasia of condylar
hypo and hyperplasia of condyle tend to be?
unilateral – whereas coronoid hyperplasia (10mm above the inferior rim of zygomatic arch) may be bilateral
effusion / fluid in the joint is early sign of?
DJD – degenerative joint disease
DJD AKA
osteoarthritis
sign of eroding condyles?
anterior OPEN bite
– like seen in RA which is more likely to cause erosion than DJD
sign of fibrous ankylosis?
jig saw looking of the condylar and eminence – with erosion
vs osseous ankylosis – bone on bone
RA vs osteoarthritis
multiple joints involved and severe erosions think RA
severe erosion in young patient (before age 16) think
Juvenile idiopathic arthritis
- bird face appearance
sign of juvenile arthrosis
“toad-stool appearance” of condylar head and flattened
septic arthritis signs?
unilateral and from infection / inflammation
with PERIOSTEAL REACTION - like double contour
redness, lymphadonopathy, fevere malaise
synovial chondromatosis looks? what is it?
little pebbles within the synovial membrane
BENIGN tumor – one of most common affecting the TMJ
chondromatosis vs chondroCALCINOIS
CALCIONIS – finer more evenly distributed tadio-opacities
condylar dislocation usually?
way anterior to the eminence
most common benign tumor of jaw
osteochondroma
- mixed appearance
location of osteochondrom
almost looks like a large osteophyte
- Radio-opaque
chondrosarcoma is
location?
malignant
condyle
anterior mandible
mandibular symphysisi
malignant tumors more likely to be intrinisc or extrinisic?
EXTRINSIC
- Like they metastisize here
- look for PATHOLOGICAL FRACTURES
‘common’ malignant tumors that metastisize to the jaw
breast, lung, kidney, thyroid, prostate, colon, multiple myeloma
salivary gland tumors
