Maxillary hiatus

The maxillary hiatus is the opening of a maxillary sinus into the middle nasal meatus of the nasal cavity. It is situated superoposteriorly upon the lateral nasal wall, opening into the nasal cavity at the posterior portion of the ethmoidal infundibulum. Its opening in the maxillary sinus is present upon the superior part of the medial wall of the sinus near the roof of the sinus; because of the position, gravity cannot drain the maxillary sinus contents when the head is erect.

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