FIGURE 109.16 Radiographs depicting perilunate dislocation, best seen on the lateral radiograph (Courtesy of Children’s Orthopaedic Surgery Foundation.) In addition to fractures, suspicion for ligamentous injuries should be high, particularly in late childhood and adolescence An important part of radiologic evaluation is assessment of the distance between the scaphoid and lunate bones In a true scapholunate dissociation, this space is widened, often called the Terry Thompson sign This can be difficult to assess in children in whom this space is naturally widened, as the carpals are not fully ossified The normal plain radiograph scapholunate interval decreases with age in children It is also important to note that dynamic scapholunate instability may not be shown on routine x-ray, and may only be obvious under stressed view Perilunate