Final answer:
A single fracture involving both the skull vault and base should be coded as a combined fracture.
Step-by-step explanation:
If a single fracture involves both the skull vault and base, it should be coded as a combined fracture. This means that there is a fracture that affects both the top of the skull (vault) and the base. It is important to note that a combined fracture can result from a strong blow to the brain-case portion of the skull, which can produce different types of fractures such as linear, comminuted, depressed, or contrecoup fractures.