Which statement about DC/TMD axis I categories is true?

• A. Myofascial pain, disc displacement with/without reduction, osteoarthritis/arthralgia
• B. Bruxism as a category
• C. Only imaging findings define axis
• D. Axis I excludes disc displacement

Answer: (A)

DC/TMD Axis I diagnoses are the clinical categories that describe what tissue is affected in the TMJ region: muscle, disc, or the joint itself. The muscle category is myofascial pain, with or without referral. The intra-articular disc disorders are disc displacement with or without reduction, reflecting whether the disc stays in place during movement. The joint disorders include arthralgia and degenerative changes such as osteoarthritis or osteoarthrosis. This is why listing myofascial pain, disc displacement with/without reduction, and osteoarthritis/arthralgia captures the true Axis I categories. Imaging can support a diagnosis but does not alone define Axis I, and bruxism is not itself an Axis I category. Also, Axis I does not exclude disc displacement.