ABSTRACT
Transnasal sinus surgery began in 1886, when Miculicz reported on the endonasal fenestration of the maxillary sinus (1). A transnasal approach to performing an ethmoidectomy was not described until 1915, when Halle reported his experience (2). Even then, it was immediately apparent that a transnasal ethmoidectomy posed significant inherent risks for the patient. Indeed, these risks were best paraphrased by Mosher, in 1929, when he described intranasal ethmoidectomy as being "one of the easiest operations with which to kill a patient" (3). In the three decades that followed Mosher's work, a number of significant anatomical studies helped further define the threedimensional anatomy and variations of the ethmoid labyrinth, turbinates, and surrounding ostia and recesses that drain the dependent sinuses (maxillary, frontal, and sphenoid) (4-10). Initially designed to evaluate the feasibility of irrigating the antrum via direct transnasal cannulation of the natural ostium, these studies contributed significantly to our current understanding of paranasal sinus endoscopic anatomy. They describe the wide variability in distances and dimensions among virtually all the intranasal anatomical structures currently used as landmarks in endoscopic sinus surgery (ESS).
