Development of frontal sinus in human fetuses as seen in computerized tomography

Using computerized tomography 7 human fetuses were examined, aging 24 to 39 weeks. Frontal sinus developes in the region of frontal recess of the frontal nasal meatus in a fetus aging 27 weeks. In the latter weeks of the fetal life the frontal recess of the middle nasal meatus transforms upwards into an oval thin-walled space corresponding to the developing frontal sinus. It adheres to the ethmoidal slabyrinth, integrating with it.