The very name "ethmoid labyrinth" implies structural intricacy. Like the other nasal accessory sinuses the ethmoid cells are extremely variable in anatomic characteristics. This variability seems more pronounced in them than in the others, no doubt because the cellular mass is complex. The honeycomb-like appearance of the cells gives the impression of a mélange, a hopeless entanglement, a jumble of cells thrown together with little design or reason, and considered en masse, as they usually are, they may well be regarded as a labyrinth. Studied individually, however, they are found to be no more variable than the frontal, maxillary or sphenoid sinuses and may readily be identified and segregated into groups, each group having its own area of drainage in the nose and having no communication with cells of another group.
These characteristics were noted in the early 1890's by Seydel,1 Zuckerkandl2 and others, and a plan was then devised