During dorsiflexion, the scaphoid bears the compressive stresses passing through the capitate as well as those from the thumb axis on its dorsal side. Since the scaphoid crosses the two carpal rows, it also acts as the principal bony block to excessive dorsiflexion at which point the scaphoid is under high tension loading palmarly. When the distal carpal row translates on the distal pole of the scaphoid, this makes the scaphoid particularly susceptible to fracture, especially at the waist. The palmar aspect fails in tension and the dorsal aspect fails in compression. Rockwood and Greene found that a classic waist fracture could be incurred in a position of greater than 97 degrees dorsiflexion and 7- 10 degrees radial deviation.
Patients usually present with a history of wrist dorsiflexion injury.
On physical exam, tenderness is elicited on palpation of the dorsal scaphoid in the anatomic snuffbox. Swelling may be minimal. There may be palpable abnormalities just distal to the radial styloid. Pain is elicited with dorsiflexion and radial deviation of the wrist, as well as with longitudinal compression or tension applied to the thumb metacarpal. The latter view places distraction across the fracture site, making it more readily visible.