On opening, jaw deviation toward the affected side indicates which condition?

• A. Disc displacement without reduction (DDwoR)
• B. Disc displacement with reduction (DDwR)
• C. Myofascial pain
• D. Osteoarthritis

Answer: (A)

Opening toward the side with the displaced disc is a hallmark of disc displacement without reduction. When the disc sits anteriorly and does not move back into place during opening, that joint side loses forward translation. The other side can continue to glide forward, so the mandible swings toward the affected side. Mouth opening is usually limited because the joint mechanics on that side are obstructed by the displaced disc.

Disc displacement with reduction would typically produce a noticeable click as the disc recaptures during opening, and the deviation pattern isn’t as consistently toward the affected side. Myofascial pain involves muscle tenderness and referred pain rather than a consistent intra-articular mechanical blockage causing deviation. Osteoarthritis can cause limited opening and pain too, but the characteristic finding is joint changes with crepitus and gradual progression rather than a specific opening deviation toward the affected side.