About a TMJ MRI scan
The temporomandibular joints (TMJs) connect the lower jaw to the skull, just in front of each ear. They let the jaw open, close and move from side to side when you talk and chew. Inside each joint is a small disc of cartilage that cushions the joint and slides forwards as the mouth opens. A TMJ MRI uses a strong magnetic field and radio waves, not X-rays, to show the joint, the disc and the surrounding muscles. It is the only scan that shows the disc clearly.
Problems with the jaw joint and the muscles that move it are known as temporomandibular disorder (TMD). Symptoms include pain around the jaw, ear or temple, clicking or popping, headaches, and the jaw getting stuck or not opening fully. TMD is common, is usually diagnosed from an examination, and often gets better with simple measures such as soft food, painkillers, jaw exercises or a mouth guard, without a scan.
A TMJ MRI may be suggested when symptoms do not settle, when the jaw locks or cannot open fully, or when treatment such as surgery is being considered. It can show whether the disc has slipped out of place (disc displacement) and whether it moves back into position when you open your mouth, as well as fluid in the joint, arthritis and other problems. Some disc displacement is seen in people with no symptoms, so the results are always read alongside your symptoms and examination. For the bones of the face, see face and facial bones MRI. When you book, choose the left or right side; both joints are often scanned together for comparison.
What happens during the scan
You lie on your back on the scanner bed with your head in a coil, or with small coils placed over each joint just in front of your ears. Pictures are taken with your mouth closed and then open, and you may be given a small plastic block to bite on to hold your mouth open at different positions. The scanner is loud, so you will wear ear plugs or headphones, and the radiographer can talk to you throughout. You need to keep your head and jaw still while each set of pictures is taken. Contrast dye is not usually needed; where contrast is needed, it is charged separately.
What the scan can show
A TMJ MRI can help to look at:
- the position of the disc and whether it slips forward (disc displacement)
- whether the disc moves back into place when the mouth opens
- fluid and inflammation in the joint
- osteoarthritis and inflammatory arthritis
- how the jaw moves when opening and closing
- other causes of jaw pain and locking
Preparing for your scan
No special preparation is needed, and you can eat and drink normally. Remove any removable dentures, braces or retainers if you can, and tell the radiographer about any fixed metal dental work. Upload any previous scan reports and letters from your dentist or specialist when you book.
You can usually eat, drink and take your normal medicines unless the scanning centre tells you otherwise. Wear loose, comfortable clothing without metal zips or buttons, and leave jewellery at home. You will be asked to remove metal items such as hair clips, hearing aids, coins and keys, and you may be asked to change into a gown.
Before the scan you will complete a safety questionnaire. Tell the team if you have a pacemaker, any metal implant, surgical clips or other device, if you have kidney problems or allergies, or if you are, or might be, pregnant or breastfeeding. If you feel anxious in enclosed spaces, let us know when you book. Some centres can offer a relaxant, and if you take one you will need someone to take you home and must not drive for 24 hours.
Frequently asked questions
Do I need a scan for jaw clicking?
Usually not. Clicking without pain or locking is common and often needs no treatment. A scan may be suggested if you have pain that does not settle, your jaw locks or you cannot open your mouth fully.
Why do I need to open my mouth during the scan?
The disc in the jaw joint moves as you open your mouth. Taking pictures with the mouth closed and open shows whether the disc is in the right place and how it moves.
Will both sides be scanned?
Choose the side with symptoms when you book. Many centres scan both jaw joints together, as they work as a pair. If you have symptoms on both sides, contact us so the centre can plan the appointment.
Do I need a referral?
You can tell us if you have a referral from your GP, physiotherapist, dentist or consultant and upload it when you book. If you do not have one, select “no referral” when you book and the scanning centre will confirm the next steps with you.
Sources
- NHS – Temporomandibular disorder (TMD)
- Applied Radiology – MRI of temporomandibular joint disorders
- Relationship between anterior disc displacement with/without reduction and effusion in temporomandibular disorder patients using MRI (PMC)
- NHS – MRI scan
The information on this page has been gathered from various sources and is provided for general information only. It is not medical advice. TOP MRI is not liable for the accuracy or completeness of this information. Please speak to your doctor or the scanning centre about your own situation.