Oral Radiology-2: TMJ Anatomy and Imaging

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Questions and Answers

What movement does the condylar head of the mandible perform during maximum mouth opening?

Moves sideways and upward

Moves downward and forward (correct)

Moves upward and backward

Remains stationary

To what location does the condylar head move during maximum mouth opening?

To the base of the articular fossa

To the superior border of the mandible

To the midpoint of the mandibular ramus

To the apex of the articular eminence (correct)

What is the primary direction of movement for the condylar head during mouth opening?

Anteriorly and inferiorly (correct)

Inferiorly and medially

Posteriorly and superiorly

Laterally and posteriorly

What are the three components of the interarticular disk?

Anterior band, posterior band, and intermediate part Signup and view all the answers

Which anatomical feature does the condylar head reach during mouth opening?

Articular eminence Signup and view all the answers

In which position of the mandible is the posterior band of the interarticular disk located on top of the condyle?

In the normal closed mouth position Signup and view all the answers

How is the movement of the condylar head described during normal radiographic imaging of the mandible?

Straight-line movement downward and forward Signup and view all the answers

What is the role of the intermediate part of the interarticular disk?

It connects the anterior and posterior bands Signup and view all the answers

Which statement is true regarding the anterior band of the interarticular disk?

It plays a role in controlling the movement of the mandible Signup and view all the answers

Which part of the interarticular disk is located at the middle section?

Intermediate part Signup and view all the answers

What must occur simultaneously during the opening of the jaw?

Both the condyle and the disc move to the eminence. Signup and view all the answers

In cases of anterior displacement when the mouth is closed, where does the posterior band of the disc position relative to the condylar head?

Anterior to the condylar head. Signup and view all the answers

What happens to the intermediate zone of the disc during anterior displacement?

It is not articulating with the condyle. Signup and view all the answers

Which components are critical for normal jaw opening according to the description?

Simultaneous movement of the condyle and disc. Signup and view all the answers

What is the consequence of improper positioning of the disc relative to the condyle?

Pain in the temporomandibular joint. Signup and view all the answers

What measurement anterior to the articular eminence indicates hypermobility?

More than 8 mm Signup and view all the answers

Hypermobility is characterized by which of the following conditions?

Movement beyond normal limits Signup and view all the answers

What type of crystals are deposited in the joint space in chondrocalcinosis?

Calcium pyrophosphate dihydrate crystals Signup and view all the answers

Which of the following statements about hypermobility is true?

Hypermobility can also occur posteriorly Signup and view all the answers

How are the calcifications typically observed in radiographic imaging of chondrocalcinosis?

Randomly distributed pinpoint calcifications Signup and view all the answers

Which characteristic measurement would indicate a healthy condition regarding anterior movement?

3 mm to 7 mm Signup and view all the answers

Which of the following best describes the underlying problem in chondrocalcinosis?

Deposition of calcium pyrophosphate crystals Signup and view all the answers

What is a common radiographic characteristic of chondrocalcinosis?

Pinpoint calcifications scattered in the joint space Signup and view all the answers

What is the abnormal range associated with hypermobility in relation to the articular eminence?

More than 8 mm Signup and view all the answers

Chondrocalcinosis can be confused with which of the following conditions due to similar joint symptoms?

Gout Signup and view all the answers

What type of fracture requires investigation for symphyseal fractures?

Bilateral fracture Signup and view all the answers

Which of the following is a benign tumor that commonly manifests as a bony growth?

Osteoma Signup and view all the answers

What are the notable changes associated with benign tumors like osteoma and osteochondroma?

trabeculation and cortication changes Signup and view all the answers

Which of the following is not characteristic of benign tumors like osteoma and osteochondroma?

Malignant transformation potential Signup and view all the answers

What is one characteristic feature of osteochondroma?

Manifestation as bony growths Signup and view all the answers

Study Notes

Oral Radiology-2 Study Notes

Temporomandibular Joint (TMJ):
- Composed of bony and soft tissue components
- Soft tissue pathologies can affect joint function and integrity
- Bony component: Condylar head, neck, articular eminence, glenoid fossa, external auditory canal
- Soft tissue component: Lateral pterygoid muscle, interarticular disc, retrodiscal tissue
Normal TMJ Anatomy:
- Interarticular disc: Anterior, posterior, and intermediate bands
  - Posterior band sits atop the condyle in closed mouth position
  - Middle zone articulates with condyle and glenoid fossa
  - Retrodiscal tissue is common site of perforation
- Arthrography is the best method for visualizing perforation
- Cone Beam Computed Tomography (CBCT) is for bony structures
- Magnetic Resonance Imaging (MRI) is used for articular disc visualisation, showing posterior band on condylar head and possible medial/lateral displacement
Normal Radiographic Imaging of the Mandible in Closed Position:
- Condylar head typically centrally located in glenoid fossa
- Variations are normal
- Four distinct abnormal condyle positions are observed
  - Posteriorly positioned: Anterior disc displacement
  - Anteriorly positioned: Rheumatoid arthritis
  - Inferiorly positioned: Fluid/blood accumulation
  - Superiorly positioned: Perforation
Normal Radiographic Imaging of the Mandible During Opening:
- Condylar head moves downward and forward to articular eminence
- Greater than 8mm anterior to articular eminence is abnormal (hypermobility)
Diseases and Anomalies Affecting TMJ:
- Condylar Hyperplasia: Enlargement of condylar head and ipsilateral mandibular ramus, often with midline shift
- Coronoid Hyperplasia: Enlargement of coronoid process, impinging on medial zygomatic arch; causes limited mouth opening
- TMJ Arthritis: Various causes, including rheumatoid arthritis (bilateral), affecting 50% of cases, causing bilateral ankylosis
Juvenile Arthrosis: Bone destruction without inflamatory process, absent condylar head, or absent condylar fracture might occur
Bifid Condyle: True condylar duplication; may appear as vertical depression (possibly confused for fracture)
Internal Derangement/Disc Displacement:
- Normal positioning between condyle and articular eminence, simultaneous condylar and disc movement during opening
- Anterior displacement with or without reduction (depending on ability to return to normal position during opening)
Synovial Osteochondromatosis: Metaplastic condition with capsule fragmentation, resulting in cartilaginous and calcified bodies in joint space
Chondrocalcinosis (Pseudogout): Deposition of calcium pyrophosphate dihydrate crystals in the joint space; radiographically visible as pinpoint calcifications
Fracture: Common site is condylar neck; fracture might shift condylar positions downward, forward, medially from original position, possible increased radiopacity in imaging
Benign Tumours: Common ones are osteoma and osteochondroma, which have bone growth traits
Malignancy and Metastasis: Can affect TMJ (osteosarcoma and chondrosarcoma are examples)
Deep Antegonial Notch: Possible indication of condylar head destruction; compensatory mechanism, caused by hyperactive masticatory muscles
Degenerative Joint Disease (DJD): Bone destruction (osteophytes, flattening of surfaces). Often associated with osteoarthritis or osteoarthrosis
Osteomyelitis in TMJ: An infection in bone; can spread from elsewhere, appearing as moth-eaten bone or onion-skin periosteal reaction

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Description

This quiz focuses on the anatomy and imaging techniques associated with the Temporomandibular Joint (TMJ). It covers both bony and soft tissue components, as well as methods like MRI and CBCT used for diagnosis. Test your knowledge on normal TMJ anatomy and related pathologies through this insightful quiz.