Posterior ethmoidal sinus drains into:

Ref: Diseases of Ear. Nose & Throat, by Dhingra chapter on Anatomy of NoseExplanation:Lateral wall of Nose* Lateral wall of nose - has 3 turbinates - superior, middle and inferior.Inferior turbinate is a separate bone.Superior and middle turbinates are parts of ethmoidal bone.Inferior meatusNasolacrimal duct opens into itSite for maxillary antral puncture and wash outSite for intranasal antrostomy Middle meatusStructures opening into it from anterior to posterior are:o Frontal sinus through frontonasal ducto Anterior ethmoidal cellso Middle ethmoidal cellso Maxillary sinusHas bulla ethmoidalis formed by middle ethmoidal cellsHiatus seminularis is a curved depression below the bullaeSuperior meatusPosterior ethmoidal cells open into itSphenoethmoidal recessLies above superior turbinateSphenoidal sinus opens into it