Dorsal avulsion fractures of the scaphoid: diagnostic implications and applied anatomy.

Three cases of acute dorsal avulsion fracture of the scaphoid are presented. Anatomical and radiological studies indicate that these fractures arise from a ridge on the dorsum of the scaphoid at the distal end of the radial facet. This is not the site suggested by other authors. The clinical significance of these fractures is that they are only visible on the 45 degrees anteroposterior oblique X-ray view of the scaphoid. Without this view they are indistinguishable from X-ray negative scaphoid fractures, since both have similar clinical signs and isotope bone scans.