Imaging Case of the Week 138

The following wrist x-ray is from a 27 year old with a right wrist deformity following a fall on his outstretched hand. What can be seen?


Right wrist AP viewRight wrist lateral view

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The AP and lateral wrist x-rays show injury to the greater arc of the wrist; this area is also called the zone of vulnerability.

On the AP view, there is an intra-articular fracture of the radial styloid, a scaphoid fracture and an ulnar styloid fracture.

greater arc injury


The lateral view shows a perilunate dislocation. A normal lateral view of the wrist should have the distal radial articular surface, the lunate and the capitate aligned with each other. In the above x-ray, the distal radius and the lunate are in a straight line but the capitate has been displaced posteriorly.

perilunate dislocation


Here are the post-reduction films following a procedural sedation in the ED. The patient was referred to an orthopaedician from the ED and underwent internal fixation.

Post reduction APPost reduction lateral


The greater arc of the wrist represents an arc from the radial styloid to the ulnar styloid, traversing the scaphoid, capitate and triquetrum.

If an injury is seen involving any of the above bones, the entire zone should be carefully scrutinised for the associated injuries.

Thanks to Dr. Ignatius Munjodzi for the case and images.