Cavities of the Skull

3. Paranasal Sinuses

There are lateral, medial and rostral frontal sinuses. The medial and the rostral frontal sinuses are small and communicate with the nasal cavity. The medial frontal sinus may be absent. The lateral frontal sinus is the largest of the three. It is bounded laterally by the temporal line and medially by the median septum.

The maxillary recess is bounded laterally and ventrally by the maxilla, and medially by the ethmoid. It opens into the nasal cavity through a transverse plane in front of the roots of the upper shearing tooth. The lateral nasal gland lies within the maxillary recess.