<P> Through the hiatus semilunaris the meatus communicates with a curved passage termed the infundibulum, which communicates in front with the anterior ethmoidal cells and in rather more than fifty percent of skulls is continued upward as the frontonasal duct into the frontal air - sinus; when this continuity fails, the frontonasal duct opens directly into the anterior part of the meatus . </P> <P> Below the bulla ethmoidalis and hidden by the uncinate process of the ethmoid is the opening of the maxillary sinus (ostium maxillare); an accessory opening is frequently present above the posterior part of the inferior nasal concha . </P> <P> The inferior meatus is the largest of the three . It lies below the inferior concha and above the nasal cavity . It extends most of the length of the nasal cavity's lateral wall . It is broader in the front than at the back, and presents anteriorly the lower orifice of the nasolacrimal canal . </P> <Ul> <Li> <P> Left maxilla . Nasal surface . </P> </Li> <Li> <P> Left palatine bone . Nasal aspect . Enlarged . </P> </Li> <Li> <P> Left orbicularis oculi, seen from behind . </P> </Li> <Li> <P> Coronal section of nasal cavities . </P> </Li> <Li> <P> Sagittal section of nose mouth, pharynx, and larynx . </P> </Li> </Ul>

What are the differences between nasal conchae and nasal meatuses