Base of skull, nasopharynx, and parapharyngeal space.

The base of skull, the nasopharynx, and the parapharyngeal space are among the most anatomically complex regions of the body. When pathologic changes arise in these areas, the close topographic relationship of soft-tissue structures and central nervous system structures, often separated only by an osseous or a thin soft tissue layer, generally necessitates sensitive diagnostic and complex therapeutic procedures.