Congenital fusion of the 5th middle and distal phalanges is a remarkably common phenomenon. This finding is never much of a diagnostic dilemma or of clinical concern, except in the rare cases where the 5th digit has been traumatized, when one must distinguish between a fracture and a normal unfused articular interface. In this case, the fracture line is somewhat oblique, without the smooth corticated margins which round at the margins, as one would expect with normal synovial joint.