From a time at least as early as the meeting of Eneas and Dido, caverns—antra—have been the abiding places of mystery and romance. From a perusal of the literature one might even suspect that the same terms would apply to much that has been written about the antrum. The increased attention given diseases of the nares and the accessory cavities has greatly increased the number of cases recognized within the last two decades. Lennox Browne1states that no cases were diagnosed during his association with Sir Morrell Mackenzie, 1866-73. Post-mortem investigation2now brings to light numerous cases not recognized during life. Anatomy. —Let us refer briefly to the anatomy of the antrum, merely noting its vulnerable points and those peculiarities that give to inflammation of this cavity its peculiar characteristics. It is a closed cavity, except for the ostium maxillare, which is located about 2 to 2.5 cm.