<prompt> All open into middle meatus except ?Frontal sinusSphenoid sinusMaxillary sinusEthmoidal sinus  <response>: Ans. is b i.e., Sphenoid sinus Pa of lateral nasal wallOpeningsInferiorNasolacrimal ductMiddleFrontal sinus, Maxillary sinus, Anterior ethmoidal sinusSuperiorPosterior ethmoidal sinusSphenoethmoidal recessSphenoid sinus 