TMJ Flashcards

Question 1

Q

Imaging technique

Answer

A

T2 weighted images: disc / inflammation
* Parasagittal closed-mouth

PD weighted images: disc-condyle relation
* Coronal closed-mouth
* Parasagittal pseudo-dynamic exam

Every parasaggital slice is taken in 4 different stages of open mouth.

Question 2

Q

Question 3

Q

Anatomy

Answer

A

TMJ = ginglymoarthrodial joint
* ginglymo-: gliding movement → superior compartment
* -arthrodial: rotatory hinging movement → inferior compartment
Articular disc: most important structure in joint mobility
* Saddle-shaped: convex superior concave inferior surface
* Made of tough, avascular fibrocartilaginous tissue

Open mouth: Anterior inferior tranlation of disc and condyle onto the articular eminence

Articular disc

Consists of three zones with varying thickness:
* Anterior band: 2 mm
* Intermediate zone: 1 mm
* Posterior band: 3 mm
 Extends into the retrodiscal region, consisting of two laminae
 Fixation to PGP and posterior capsule respectively

Question 4

Q

Most frequent indication?

Commonest cause of dysfunction?

Answer

A

Impairment in TMJ movememnt.

Degnerative is most common cause of TMJ pathology.

Due to disc displacement

Changes typically occur in three phases:
 Displacement without morphological alteration
 Changes in shape with development of ‘rounded’ disc
 Chronic degeneration with signal intensity changes

Anterior disc location is most common direction but can occur in all directions.

Question 5

Q

Types of disc dislocation

Answer

A

May occur WITH and WITHOUT reduction upon mouth opening (disc returns to normal position below articular eminence)

With reduction
Usually accompanied by clicking sound
Can be complete or partial

Without reduction on opening
 Typically limited mouth opening
 Changes in shape and signal intensity (T2-weighted images)
 May evolve to ‘stuck disc’ due to adhesions
 Treatment:
* Acute: attempted manual reduction
* Chronic: arthroscopy / arthroplasty when conservative
therapy fails