Blockage Maxillary Maxillary Sinus Ostium Blockage Ostium Sinus Maxillary Sinus Ostium Blockage JulieannhtyuiAtwell Wednesday, July 19, 2017 Pneumocele of the maxillary sinus. A second case report.. Pneumocele of the maxillary sinus. A presumably due to obstruction of the major si...