[Postnatal development and anatomical relationship of the maxillary sinus].

In children, the maxillary sinus is pyramidal in shape. The apex of the pyramid looks forward, and the base looks backwards. The maxillary sinus has three walls--the superior, the medial and the inferior. The superior wall establishes a relationship with the infraorbital groove and the infraorbital canal during the 4th year. During the first months of life, the maxillary sinus has no relationships with the inferior nasal meatus. At about 6th year, the maxillary sinus is at the height of the floor of the nasal cavity and thus a close relationship is established with the inferior nasal meatus.