Introduction of present-day sinonasal endoscopy and progress in endonasal surgery under endoscopic guidance of endoscopy provide for anatomical exploration of the anterior part of the ethmoid bone, which is the crosspoint of the facial sinus draining paths. We propose to present here a simple and logical scheme of the topographical anatomy of the ethmoid bone. Classification of the ethmoidal cells allows to define the structures, whereby appropriate nomenclature may be adopted and certain confusions avoided. Thus, each cell within particular cell groups acquires a specific designation based on its draining paths and location in relation to basal lamellae. Endoscopic analysis also deserves being described in some length, since the panoramic view afforded by currently used optics modifies the image ans requires that the observer develop an "endoscopic eye". We draw attention to the endoscopic anatomical fine points in the crucial area of the bullar "circus". These landmarks come in as necessary guides in surgical practice.