Two hundred and eighty‐six patients were exposed to puncture and irrigation of 468 maxillary sinsuses after completion of radiological examination. The radiological interpretations were made by the same radiologist and related to the clinical rate of demonstrable antral fluid in fully and not fully developed sinsuses. Radilogically normal sinuses contained fluid in patients over the age of twelve in 15.3% and when under that age in 39%. The radilogical findings should not override one's clinical judgment, and the age of the patient should be considered when conclusions are to be drawn from the radilogical finding