Final answer:
A Computerized Tomography (CT) scan is necessary to code a basilar skull fracture when only physical manifestations are present, providing the radiographic confirmation required for accurate diagnosis.
Step-by-step explanation:
To code a basilar skull fracture when only physical manifestations are present, it is often necessary to have imaging confirmation in order to accurately diagnose and document the injury. Radiographic confirmation usually comes in the form of a Computerized Tomography (CT) scan, which is an imaging technique that involves taking a number of x-rays of a particular section of a person's body or brain to construct an image of the area being scanned. The CT scan is preferred because it is excellent for visualizing bone fractures. Magnetic Resonance Imaging (MRI) could also localize the injury, but it is typically used for soft tissue evaluation. A physical examination can suggest the presence of a fracture but cannot confirm it without the use of imaging techniques.