The Frontal Sinus Drainage Pathway and Related Structures

The purpose of this pictorial essay is to provide a visual guide to the frontal sinus drainage pathway (FSDP), associated anatomic structures, and normal variations in sinus anatomy (Figs 1–9). Suggested readings provide more detailed descriptions of para-nasal sinus anatomy and terminology for further study (1–9). Sinus nomenclature may be both redundant and confusing (10, 11). Originally, the terms sinus, antrum, and recess all referred to a cavity, then a cavity within a bone. Now an osseous recess is an air space with more than one drainage ostium (as distinct from an osseous air cell, which has only one drainage ostium), whereas the terms maxillary sinus and maxillary an-trum may be used interchangeably. Both cribrifor