Application of computed tomography in studies on development of human paranasal sinuses in the early postnatal period.

Seven skulls of newborns and of infants aged 3 weeks to 12 months were studied using computed tomography. Size of the maxillary sinuses was measured. Between 3rd and 12th week of life the ethmoidal sinus formed small spaces in ethmoidal labyrinth. Maxillary sinus could be noted at the level of lower orbital margin. In newborns, it formed a shallow indentation in the lateral wall of the nasal cavity. The anteroposterior dimension of the sinus was greater than the two remaining dimensions. Beginning from the 3rd month of life, number of ethmoidal cells increased, maxillary sinuses enlarged and entered the body of the maxilla. Between 6th and 12th month, the mediolateral and the superoinferior dimensions of the sinuses increased. Small air spaces were also seen in the part of sphenoid bone, corresponding to sphenoidal sinuses.