A patient has reduced mouth opening with localized muscle tenderness that improves with rest. What is the most likely TMD category?

• A. Disc displacement with reduction
• B. Degenerative joint disease
• C. Arthralgia
• D. Myofascial (muscle) TMD

Answer: (D)

The key idea is that this presentation points to muscle-related pain rather than joint pathology. Myofascial (muscle) TMD involves pain originating in the jaw muscles with tender points in the masticatory muscles (like the masseter or temporalis) and often shows limited mouth opening due to muscle spasm. Importantly, the pain improves with rest, stretching, or relaxation of the jaw muscles, which fits the scenario given.

In contrast, disc displacement with reduction or without reduction centers on intra-articular issues, often with jaw noises (clicking) or mechanical restriction that isn’t simply explained by muscle tenderness. Degenerative joint disease would typically present with crepitus, more persistent joint pain, and possibly signs of OA on imaging. Arthralgia is joint pain itself, but the description here emphasizes muscle tenderness and relief with rest, not primary joint pain.

So the localized muscle tenderness that improves with rest and causes reduced mouth opening is best explained by myofascial TMD.