[Anatomical variations of the ethmomaxillary sinus].

The enlarged posterior ethmoidal air cell can occupy the posterior superior portion of the maxillary sinus and even reach the alveolar bone. Such a cell is called the ethmomaxillary sinus and, as a rule, its presence is accompanied by excessive pneumatization of other cranial bones. Inflammation of the mucous membrane of the ethmomaxillary sinus is most often not combined with the radiographic signs of maxillary sinusitis, and a direct communication of the EMS and MS was detected in only one patient.