In disc displacement disorders, what distinguishes disc displacement with reduction from without reduction in exam findings?

In disc displacement disorders, what distinguishes disc displacement with reduction from without reduction in exam findings?

• A. DDwR typically has a click; DDwoR has limited opening without a click
• B. DDwR has no click; DDwoR has a click
• C. DDwR is painless; DDwoR causes fever
• D. DDwR improves with cortisol injection

Answer: (A)

In disc displacement disorders, the key difference lies in whether the displaced disc returns to its normal position during jaw movement. When the disc displacement has reduction, the disc slips back under the condyle as the mouth opens, producing a distinct click or pop. This reduction means opening can occur with a relatively normal range of motion, and the sound is a diagnostic clue that the disc is returning to place. When the displacement occurs without reduction, the disc stays anterior to the condyle throughout opening, so the mouth opening is limited and there is typically no click. The jaw may also deviate toward the affected side on opening. So, the exam finding distinguishing the two is the presence of a click with reduction versus the absence of a click accompanied by limited opening without reduction. Fever or systemic signs aren’t typical features, and treatments like cortisol injections are not exam findings.

In disc displacement disorders, the key difference lies in whether the displaced disc returns to its normal position during jaw movement. When the disc displacement has reduction, the disc slips back under the condyle as the mouth opens, producing a distinct click or pop. This reduction means opening can occur with a relatively normal range of motion, and the sound is a diagnostic clue that the disc is returning to place.

When the displacement occurs without reduction, the disc stays anterior to the condyle throughout opening, so the mouth opening is limited and there is typically no click. The jaw may also deviate toward the affected side on opening.

So, the exam finding distinguishing the two is the presence of a click with reduction versus the absence of a click accompanied by limited opening without reduction. Fever or systemic signs aren’t typical features, and treatments like cortisol injections are not exam findings.