Synonyms: These are also known as Infra orbital recess cells.
These are pneumatized ethmoid air cells that project along the medial roof of the maxillary sinus and the most inferior portion of the lamina papyracea.This air cell lies below the ethmoid bulla and lateral to the uncinate process.
Commonly these cells arise from anterior ethmoid air cells and are closely related to the infundibulum. Rarely these cells can arise from posterior ethmoidal cells in which case it does not compromise the infundibulum. Infections involving these cells can compromise and narrow the infundibulum causing obstruction to the drainage of maxillary sinus ostium. It has been suggested that infections involving these cells could be a factor in recurrent maxillary sinusitis.