First paranasal sinus to develop at bih is:
Maxillary
Ethmoidal
Frontal
Sphenoidal
Development of SinusesSinusGestational Month WhenDevelopment StasPresent in ClinicallySignificant SizeFully DevelopedMaxillary2degBihdeg12 yearsdegEthmoid30Bihdeg12 yearsdegFrontal4deg3 yearsdeg18-20 yearsdegSphenoid3deg8 yearsdeg12-15 yearsdeg