What it is (overview)

An XR Temporomandibular Joints (TMJ) Open and Closed Bilateral exam is a diagnostic imaging test that uses X-rays to take pictures of both temporomandibular joints—the small joints in front of each ear that connect your lower jaw (mandible) to your skull. “Bilateral” means both the left and right joints are imaged. “Open and closed” means images are taken with your mouth closed and then open, which helps evaluate how the jaw joint moves.

This test looks mainly at the bony structures of the TMJ, such as the mandibular condyle (the rounded end of the jawbone) and the joint surfaces of the skull. It can help identify changes like arthritis-related wear, irregular bone shape, joint alignment problems, or evidence of injury. While TMJ X-rays do not show soft tissues well (such as the cartilage disc inside the joint), they provide useful information about the joint’s overall structure and can be an important first step in the evaluation of jaw pain and facial pain.

In plain language, the results typically fall into a few categories:

• Normal findings: The jaw joints look symmetrical and well-aligned, with no obvious bone damage; opening and closing views show expected motion.

• Degenerative/arthritic changes: Signs of osteoarthritis (such as flattening, spurs/osteophytes, erosion, or narrowing of joint space) may correlate with chronic TMJ pain, stiffness, or grinding/clicking.

• Alignment or motion concerns: Differences between open and closed images can suggest abnormal movement patterns or joint positioning that may contribute to TMJ dysfunction. (Your clinician may recommend additional imaging if needed.)

• Injury or other bony abnormalities: Findings may include old or new trauma-related changes, unusual bone shape, or less common conditions affecting the jaw joint.

When & why it's usually done

Clinicians order bilateral TMJ X-rays (open and closed) when symptoms suggest a problem with the jaw joint or surrounding structures. It is commonly used in dental, oral surgery, and medical settings to help evaluate TMJ disorders and to rule out bony causes of pain or limited jaw motion.

This test is often recommended if you have:

• Jaw pain or tenderness near the ear, especially when chewing, yawning, or speaking

• Facial pain that seems related to jaw movement

• Clicking, popping, or grinding sounds in the TMJ (particularly if accompanied by pain or locking)

• Limited mouth opening, stiffness, or a feeling that the jaw “catches” or “locks”

• Changes in your bite or the feeling that your teeth don’t fit together normally

• Swelling around the jaw joint area

• History of trauma to the face or jaw (sports injury, fall, accident)

• Suspected arthritis affecting the jaw joint (including inflammatory arthritis), especially with other joint symptoms

The open-and-closed views help compare the joint’s position in different states and can provide clues about joint mechanics. Because X-ray is best for evaluating bone, it’s particularly useful when your provider is concerned about arthritis, bony degeneration, or structural changes. If symptoms suggest a soft-tissue issue (such as disc displacement) and the X-ray is normal or doesn’t fully explain symptoms, your clinician may consider other tests (commonly MRI for the disc/soft tissues or CT for detailed bone evaluation).

Common diseases related to it

• Temporomandibular joint disorder (TMD/TMJ dysfunction)
• Osteoarthritis of the temporomandibular joint (degenerative joint disease)
• Inflammatory arthritis affecting the TMJ (e.g., rheumatoid arthritis, psoriatic arthritis)
• TMJ inflammation (synovitis/capsulitis)
• Jaw trauma (fracture, post-traumatic joint changes)
• Condylar abnormalities (flattening, erosions, osteophytes/bone spurs)
• TMJ ankylosis (abnormal fusion/stiffening of the joint, less common)
• Myofascial pain related to clenching or bruxism (teeth grinding) with secondary TMJ strain

Health goals where it may help

• Identifying the cause of chronic or recurrent jaw pain and facial pain
• Assessing suspected TMJ dysfunction to guide treatment planning (splints, physical therapy, dental care)
• Evaluating for arthritis or degenerative changes in the jaw joint to support long-term joint health
• Monitoring jaw joint structure over time when symptoms persist or worsen
• Supporting overall oral health by clarifying whether jaw joint problems may be contributing to bite changes or chewing difficulty
• Checking for bony injury after facial or jaw trauma