Posterior ethmoidal cells

Within the complex architecture of the ethmoid bone lie the posterior ethmoidal cells. They are a collection of roughly six air-filled cavities that form a key part of the ethmoidal labyrinth. Together with the anterior and middle ethmoidal air cells, they form a sophisticated network within the ethmoid bone, positioned strategically on either side of the nasal cavity's midline. Such organization underscores the role of the ethmoid bone as a central element of the paranasal air sinuses, with its cells originating from and intricately connected to the nasal cavity.

The anatomical arrangement of the ethmoidal air cells is meticulously designed. Encased laterally by the orbital plate—a slender bone plate—they are shielded from the orbital cavity. Medially, the ethmoidal labyrinth's medial wall demarcates them from the nasal cavity. These cells are systematically categorized into anterior, middle, and posterior groups, each distinguished by its unique location and drainage route. Significantly, the posterior ethmoidal cells are configured to drain into the superior meatus of the nasal cavity.