The wrist is a small joint with an outsized amount of soft tissue packed into it - eight carpal bones, a triangular fibrocartilage disc, two rows of intrinsic ligaments, the median and ulnar nerves, and roughly twenty tendons in and out. An X-ray, which is what most patients get first, shows exactly one of those things: the bones. Everything else - the pain generator in the majority of wrist referrals - is invisible on X-ray and only shows on MRI.
This is not a plea to skip the X-ray. It is a plea to know when the X-ray has done its job and when the next step is an MRI. This piece walks through what wrist X-ray shows, what MRI adds, the eight diagnoses wrist MRI is built for, when an MR arthrogram is the right test instead, and how a private wrist MRI is actually booked in the UK in 2026.
The one-line answer
X-ray shows fractures and joint space. MRI shows everything else, and everything else is where most wrist pain lives.
What wrist X-ray shows first
An X-ray is a good first test and it is still the correct first test after a fall on the outstretched hand or any acute injury. Four things it shows well:
- Fractures of the distal radius and ulna. The classic Colles' and Smith's fractures are obvious on a plain film.
- Most carpal bone fractures, with the important exception of subtle scaphoid fractures in the first days after injury.
- Dislocations and joint alignment, including perilunate and lunate dislocations that can be missed clinically.
- Joint space narrowing and osteoarthritis, particularly at the base of the thumb (first carpometacarpal joint) and the radiocarpal joint.
What an X-ray cannot show: cartilage, ligaments, tendons, nerves, the TFCC, bone bruising, ganglia, or the state of the bone marrow. If your wrist X-ray came back "normal" and your wrist still hurts, that report is doing exactly what an X-ray report can do, and it is not the end of the story.
What MRI adds
Wrist MRI is one of the highest-yield musculoskeletal MRIs in radiology because so many important structures are crammed into such a small area. A well-protocolled wrist MRI, ideally on a 3T scanner with a dedicated wrist coil, shows:
- The median nerve through the carpal tunnel - its calibre, flattening ratio and any surrounding tenosynovitis or space-occupying lesion.
- The triangular fibrocartilage complex (TFCC) on the ulnar side of the wrist - tears, degeneration and ulnar impaction.
- The scapholunate and lunotriquetral ligaments, the two intrinsic ligaments that hold the carpal rows together.
- The extensor and flexor tendons, including De Quervain's involvement of the first extensor compartment and extensor carpi ulnaris (ECU) subsheath disruption.
- Articular cartilage across the radiocarpal and midcarpal joints.
- Bone marrow oedema, which is how MRI catches an occult scaphoid fracture that the X-ray missed and diagnoses Kienbock's disease of the lunate.
- Ganglia and soft-tissue masses, and their exact anatomical relationship to nerves and tendons.
The eight diagnoses wrist MRI is built for
If your hand surgeon or MSK physiotherapist is asking for a wrist MRI, it is almost certainly to answer one of these eight questions.
- 1. Carpal tunnel syndrome. MRI is not the first-line test - nerve conduction studies still are - but MRI is invaluable when the picture is atypical, when symptoms are severe and surgery is being considered, or to rule out a mass compressing the nerve.
- 2. TFCC tear. Ulnar-sided wrist pain after a fall or a forced rotation, worst on gripping and rotating. MRI, and particularly MR arthrogram, is the definitive test.
- 3. Scapholunate ligament tear. The most commonly injured intrinsic ligament. Untreated it leads to scapholunate advanced collapse (SLAC wrist). MRI arthrogram is the gold standard.
- 4. Occult scaphoid fracture. Up to 25 per cent of scaphoid fractures are invisible on the initial X-ray. MRI within days confirms or excludes the fracture, avoiding weeks of unnecessary casting and preventing the non-union that a missed scaphoid fracture can cause.
- 5. Kienbock's disease. Avascular necrosis of the lunate, seen as bone marrow oedema in early stages and collapse later. MRI is the only way to diagnose it before X-ray changes appear.
- 6. Ganglion cyst. Common, usually benign, but MRI is used when the lump is deep, painful, or close to a nerve, and to plan surgery.
- 7. ECU tendinopathy or subluxation. A frequent cause of ulnar-sided wrist pain in racquet sports. MRI shows the tendon within its subsheath and any disruption.
- 8. De Quervain's tenosynovitis. Clinically diagnosed most of the time, but MRI is used when injections have failed or when the diagnosis is uncertain, showing thickening and fluid in the first extensor compartment.
Wrist MRI vs MRI arthrogram
The difference between a standard wrist MRI and an MRI arthrogram is worth spelling out because it changes the accuracy of the test for the two most commonly asked questions of the wrist.
A standard wrist MRI images the joint as it lies. It is excellent for bone marrow, tendons, nerves, ganglia and cartilage. It is good, but not perfect, at picking up small tears in the TFCC and the scapholunate ligament.
An MR arthrogram adds a step: a musculoskeletal radiologist injects a small amount of contrast into the wrist joint under X-ray guidance, distending the joint and letting the contrast track into any tear. The MRI is then performed. For suspected TFCC and scapholunate ligament tears, arthrogram is considered the gold-standard non-invasive test - sensitivity climbs from around 75 per cent for standard MRI to over 90 per cent for arthrogram in most published series.
