Sphenoidal sinus opens into:: (A) Superior meatus, (B) Inferior meatus, (C) Middle meatus, (D) Spheno-ethmoidal recess
Answer is D. (d) Spheno-ethmoidal recess(Ref. Cummings, 6th ed., 659)The Sphenoid sinus opens into the spheno-ethmoidal recess just above the superior turbinate.