In disc displacement with reduction, what does imaging typically reveal?

• A. Anterior disc displacement relative to the condyle in closed-mouth position with reduction during opening.
• B. Posterior disc displacement in both positions.
• C. The disc remains anterior regardless of mouth position.
• D. No displacement observed.

Answer: (A)

In disc displacement with reduction, the disc sits anterior to the condyle when the jaw is closed, and then moves back into a normal position between the condyle and the articular eminence as the mouth opens. Imaging typically shows the disc anterior to the condyle in the closed-mouth position, with reduction occurring during opening as the disc returns to its proper place. This is why patients often have a noticeable click when starting to open or close the mouth. If imaging showed the disc posterior to the condyle in both positions, or the disc staying anterior regardless of mouth position, it would indicate a non-reducing displacement or a different condition, while no displacement would look like a normal joint.