The Tempromandibular Joint (TMJ)

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The Tempromandibular Joint(TMJ)

• By
• Nour-Eldin A. Nour-Eldin Mohammed

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Normal Anatomy
Mandibular condyle (head)
Glenoid fossa
Articular tubercle (eminence)
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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
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Mandibular condyle (head)
Articular disc
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MRI and autopsy sections upper row oblique
sagittal MRI, asymptomatic volunteer left
lateral, middle medial, right opened mouth
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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

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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)

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Partial anterior disc displacement at baseline
lateral sections
central sections
open-mouth
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Complete anterior disc displacement
Open-mouth MRI
medial section
Autopsy
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Lateral disc displacement and normal bone
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Medial disc displacement
Oblique coronal MRI
coronal MRI
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Posterior disc displacement
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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

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anteriorly displaced and deformed, degenerated
disc and irregular cortical outline with
osteophytosis and sclerosis of condyle .
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Advanced osteoarthritis and anterior disc
displacement, with joint effusion
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Bone Marrow Abnormalities

• Definition
• Bone marrow edema serum proteins within marrow
  interstitium surrounded by normal hematopoietic
  marrow.
• Osteonecrosis complete loss of hematopoietic
  marrow.

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• 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

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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 doesnt fit
• Crepitation due to secondary osteoarthritis

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Rheumatoid arthritis.
After 1 year
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Rheumatoid arthritis. A MRI shows completely
destroyed disc, replaced by fibrous or vascular
pannus and cortical punched-out erosion (arrow)
with sclerosis in condyle.
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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)
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Inflammatory arthritis
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Ankyloses
Definition Fibrous or bony union between joint
components.
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Growth Disturbances (Anomalies)
Definition Abnormal growth of mandibular condyle
overgrowth, undergrowth, or bifid appearance.
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Condylar hypoplasia and facial asymmetry
Condylar Hypoplasia
Normal TMJ
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Bifid condyle.
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Inflammatory or Tumor-like Conditions
Calcium Pyrophosphate Dehydrate
Crystal Deposition Disease (Pseudogout)
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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.

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Synovial Chondromatosis
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Osteochondroma
Definition Benign tumor characterized by normal
bone and cartilage, near growth zones.
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Osteoma
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Malignant Tumors
Osteosarcoma mandible 18-yearold female
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Malignant tumor, mandible 70- year-old male with
metastasis from lung cancer
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Thank you