The anterior ethmoidal cells of the ethmoidal sinus open into the front part of the infundibulum as well.

The area in front of this furrow forms part of the middle meatus of the nose; that behind it articulates with the ethmoid, and completes some of the anterior ethmoidal cells.

The middle ethmoidal cells open into the central part of this meatus, and a sinuous passage, termed the infundibulum, extends upward and forward through the labyrinth and communicates with the anterior ethmoidal cells, and in about 50 per cent.