No fracture line is visualized in the scaphoid. This view not uncommonly shows fractures invisible on the standard three view wrist series. This principle of getting a different projection applies not only to plain radiographs, but also to radionuclide, ultrasound, CT and MR studies as well. What is hard to see on an axial image may be a piece of cake to see on a sagittal image. It is hard to overstate the importance of comparing an imaging study to a prior examination.
Life is a movie, and each medical image is only a single frame from that movie.
One of a radiologist's many challenges is to try to deduce the rest of the movie from the few scraps of films that are available. The more scraps that one has, the easier the job. This young patient fell on his outstretched hand, and now complains of wrist pain. Having a prior film is especially important in patients where there is a strong clinical suspicion for something bad, like a malignancy. For example, in a patient with an osteosarcoma, one will be performing many chest films during the rest of the patient's life looking for possible lung metastases.