Sphenoidal sinus opens into:
(d) Spheno-ethmoidal recess(Ref. Cummings, 6th ed., 659)The Sphenoid sinus opens into the spheno-ethmoidal recess just above the superior turbinate.
Superior meatus
Inferior meatus
Middle meatus
Spheno-ethmoidal recess
Congenital Lesions and Stridor