Final answer:
Angling the x-ray tube 15 degrees caudally allows the petrous pyramids to be filled with contrast and visualized clearly, aiding in the examination of the skull's inner ear structures.
Step-by-step explanation:
When the x-ray tube is angled 15 degrees caudally during an imaging procedure, the resulting effect is that it 'opens up' or fills with contrast the petrous pyramids of the temporal bones. This caudal angle positions the beam in such a way that the dense bone of the petrous ridges is projected inferiorly and anteriorly, which allows for a clearer view of the structures that are otherwise overshadowed by the petrous portion of the temporal bones.
It is a technique commonly used in radiographic examinations of the skull to visualize certain areas of the inner ear and the bony labyrinth that contains the cochlea and the semicircular canals, which are key structures involved in hearing and balance.