Transcript The Tempromandibular Joint (TMJ) - eLearning

THE TEMPROMANDIBULAR JOINT
(TMJ)
By:
Nour-Eldin A. Nour-Eldin Mohammed
Normal Anatomy
Mandibular condyle (head)
Glenoid fossa
Articular tubercle
(eminence)
Posterior band of articular disc
Anterior band of articular disc
Mandibular condyle (head)
Lateral pterygoid muscle raphe
Lower head of lateral pterygoid muscle
Posterior disc attachment
Mandibular condyle (head)
Articular disc
MRI and autopsy
sections: upper row
oblique sagittal MRI,
asymptomatic
volunteer: left lateral,
middle medial, right
opened mouth
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
Internal Derangements
Imaging Features
 Anterior disc displacement: posterior band of the
disc located anterior to the superior portion of
the condyle at closed mouth on oblique sagittal
images
 Disc may have normal (biconcave) or deformed
morphology
 In opened mouth position disc may be in a
normal position (“with reduction”) or continue to
be displaced (“without reduction”)
Partial anterior disc displacement at baseline
lateral sections
central sections
open-mouth
Complete anterior disc displacement
medial section
Autopsy
Open-mouth MRI
Lateral disc displacement and normal bone
Medial disc displacement
coronal MRI
Oblique coronal MRI
Posterior disc displacement
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
anteriorly displaced and deformed, degenerated disc and irregular
cortical outline with osteophytosis and sclerosis of condyle .
Advanced osteoarthritis and anterior disc
displacement, with joint effusion
Bone Marrow Abnormalities
Definition
 Bone marrow edema: serum proteins within
marrow interstitium surrounded by normal
hematopoietic marrow.
 Osteonecrosis: complete loss of
hematopoietic marrow.
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
Arthritides
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
Rheumatoid arthritis.
After 1 year
Rheumatoid arthritis. A MRI shows completely destroyed disc, replaced
by fibrous or vascular pannus and cortical punched-out erosion (arrow)
with sclerosis in condyle.
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)
Inflammatory arthritis
Ankyloses
Definition
Fibrous or bony union between joint
components.
Growth Disturbances (Anomalies)
Definition
Abnormal growth of mandibular condyle; overgrowth,
undergrowth, or bifid appearance.
Condylar hypoplasia and
facial asymmetry
Condylar Hypoplasia
Normal TMJ
Bifid condyle.
Inflammatory or Tumor-like Conditions
Calcium Pyrophosphate Dehydrate Crystal
Deposition Disease (Pseudogout)
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.
Synovial Chondromatosis
Osteochondroma
Definition
Benign tumor characterized by normal bone and
cartilage, near growth zones.
Osteoma
Malignant Tumors
Osteosarcoma mandible; 18-yearold female
Malignant tumor, mandible; 70- year-old male
with metastasis from lung cancer
Thank you