All open into hiatus semilunaris except
Posterior ethmoid sinus
Anterior ethmoid sinus
Frontal sinus
Maxillary sinus
Hiatus semilunaris. The hiatus semilunaris is a semicircular shaped openinglocated on the lateral wall of the nasal cavity. It is a component of the ostiomeatal complex and serves as the opening for the frontal and maxillary sinuses and the anterior ethmoid air cells.