Which diagnosis corresponds to a TMJ that can open normally but is accompanied by a click?

Which diagnosis corresponds to a TMJ that can open normally but is accompanied by a click?

• A. Anterior disc with reduction
• B. Anterior disc without reduction
• C. Muscle problems
• D. Dislocation

Answer: (A)

The key idea is that a normal mouth opening with a joint click points to anterior disc displacement with reduction. In this condition, the disc sits anterior to the condyle when the mouth is closed. As you begin to open, the condyle glides forward and the disc returns to its proper position (reduces) in front of the condyle, producing a snapping or clicking sound. Because the disc reduces during opening, there isn’t a persistent restriction of motion, so opening can be normal in range. If the disc remains anterior and does not reduce, you typically see limited or blocked opening—displacement without reduction. Muscle problems tend to cause pain, tenderness, and variable movement rather than a distinct, consistent click with normal opening. Dislocation usually leads to an inability to open or to return to a normal position, often with a sudden lock or severe deviation, not a normal opening accompanied by a click. So the presentation described is classic for anterior disc displacement with reduction.

The key idea is that a normal mouth opening with a joint click points to anterior disc displacement with reduction. In this condition, the disc sits anterior to the condyle when the mouth is closed. As you begin to open, the condyle glides forward and the disc returns to its proper position (reduces) in front of the condyle, producing a snapping or clicking sound. Because the disc reduces during opening, there isn’t a persistent restriction of motion, so opening can be normal in range.

If the disc remains anterior and does not reduce, you typically see limited or blocked opening—displacement without reduction. Muscle problems tend to cause pain, tenderness, and variable movement rather than a distinct, consistent click with normal opening. Dislocation usually leads to an inability to open or to return to a normal position, often with a sudden lock or severe deviation, not a normal opening accompanied by a click.

So the presentation described is classic for anterior disc displacement with reduction.