[The ethmoido-maxillary plate and paranasal sinuses--a study by HRCT].

The ethmoido-maxillary plate is a thin layer of bone separating the maxillary sinus from the ethmoidal cells or sphenoidal sinus. The plate was studied using axial HRCT images obtained from various otological lesions. One hundred forty-one adults were included in this study. The ethmoido-maxillary plate was first classified into four groups of configurations, namely, straight or near-straight, anterior-concave, posterior-concave and ant. and post. concave forms. The incidences of these forms were 55%, 23%, 13%, and 9%, respectively. A symmetrical configuration between the two sides was seen in 50%. The numbers of ethmoidal cells and/or sphenoidal sinus in contact with the plate and their incidences were 2 cells (47%), 3 cells (30%), 1 cell (15%), 4 cells (5%), and 5 cells (1%). The straight form showed lower numbers of cells than the other forms. The sphenoidal sinus and the maxillary sinus were in direct contact with each other at the ethmoido-maxillary plate in 19% of cases.