Wrist Imaging & Orthopedic Articles

Reading a Wrist MRI Report Structure by Structure

A wrist MRI report rarely reads top to bottom the way a novel does. Radiologists move structure by structure, and knowing the order helps you find the sentence that actually matters to you. Most reports open with the triangular fibrocartilage complex, the cushion of cartilage and ligaments on the pinky side of the wrist that absorbs load transmitted through the forearm. Next to it sits a measurement called ulnar variance, which compares the relative length of the two forearm bones at the wrist; a longer ulna concentrates more force on that same cartilage disc and can accelerate wear over years.

The report then usually moves to the intrinsic carpal ligaments, especially the scapholunate ligament between the scaphoid and lunate bones and the lunotriquetral ligament between the lunate and triquetrum. These small bands are graded by how much of their fibers are torn and whether the bones they connect have started to shift out of alignment on the images. The scaphoid itself gets its own paragraph because its blood supply enters mostly from one end, near the thumb side, and travels backward through the bone. A fracture near the far end can cut off that supply entirely, which is why radiologists comment specifically on where along the scaphoid a fracture line sits.

Further down, look for a line about the distal radioulnar joint, the small pivot where the two forearm bones rotate against each other to let you turn a doorknob or a screwdriver. Reports also describe the carpal tunnel and the median nerve running through it, noting whether the nerve looks compressed or swollen, and the six extensor compartments running across the back of the wrist, where tendons can develop their own inflammation independent of any bone or ligament injury.

TFCC Tears, Carpal Instability, and Scaphoid Union: What the Terms Mean

Triangular fibrocartilage complex tears are usually classified with the Palmer system. Class 1 covers traumatic tears from a single fall or twisting injury, and is further split by where the tear sits on the disc, since a tear near the outer rim can often be repaired while a central tear typically cannot. Class 2 covers degenerative tears that develop gradually alongside ulnar-sided wear, and these are staged by how much cartilage thinning and bone change has accumulated rather than by a single traumatic moment.

Carpal instability describes a pattern where torn ligaments let the carpal bones tip out of their normal line, most often labeled dorsal or volar intercalated segment instability depending on which way the lunate rotates on a side-view X-ray. Scaphoid union is the term for a fracture that has finished healing into solid bone; its opposite, nonunion, means the fracture gap never bridged and the two fragments remain separate, which over time can reshape how the whole wrist moves and load-bears.

Healing Timelines, and Why a Missed Scaphoid Fracture Matters

A stable scaphoid fracture near the wide end typically unites within six to eight weeks of cast immobilization, because that segment has a rich local blood supply. Fractures at the narrow waist or the far tip can take three to four months, and some never bridge without surgery because the retrograde blood flow simply cannot reach that fragment. This is exactly why a missed scaphoid fracture is treated so seriously: it is easy to mistake for a simple sprain on first X-ray, but if it goes untreated the bone can die in place, collapse, and drag the surrounding wrist bones into a degenerative pattern that is far harder to fix than the original break.

Scapholunate and lunotriquetral ligament tears heal on a slower, more variable clock than bone. Partial tears treated early with splinting and activity changes can settle over eight to twelve weeks, while complete tears that have already let the bones shift usually need surgical repair or reconstruction, followed by months of protected motion before the repair is trusted to bear full load again.

What Rehabilitation Targets After Wrist Surgery

After a distal radius fracture, early therapy focuses on controlling swelling and coaxing finger and thumb motion back so the hand does not stiffen while the wrist is splinted, then progresses to forearm rotation and grip strengthening once the bone is stable enough to tolerate load. After a scaphoid fixation with a percutaneous screw, therapy is more conservative early on, protecting the fixation while the fracture consolidates before wrist extension and loaded grip work are reintroduced. After a carpal tunnel release, the priority shifts to nerve gliding exercises and scar tissue management, since the goal is restoring normal median nerve movement through the tunnel rather than rebuilding bone strength.

X-ray, MRI, MR Arthrogram, or CT: Which Answers Your Question

A plain X-ray is still the first study for a suspected fracture because it is fast and shows bone alignment clearly, though a hairline scaphoid crack can be invisible on day one and only appear on a repeat film weeks later. MRI is better suited to soft-tissue questions: it can show a TFCC tear, early scaphoid bone bruising before a fracture line is visible on X-ray, or swelling around the median nerve. An MR arthrogram, where contrast is injected directly into the joint before scanning, sharpens the view of small ligament tears like the scapholunate ligament that a standard MRI can miss. CT is the tool of choice when a fracture is already confirmed and a surgeon needs a precise, three-dimensional map of fragment position and any healing gap before planning fixation.