The sphenoethmoidal recess is a small space in the nasal cavity into which the sphenoidal sinus and posterior ethmoid sinus open. It lies posterior and superior to the superior concha. The sphenoethmoidal recess drains the posterior ethmoid air cells and sphenoid sinuses into the superior meatus of the nasal cavity. The sphenoethmoidal recess is a small space in the nasal cavity into which the sphenoidal sinus and posterior ethmoid sinus open. It lies posterior and superior to the superior concha. The sphenoethmoidal recess drains the posterior ethmoid air cells and sphenoid sinuses into the superior meatus of the nasal cavity. This article incorporates text in the public domain from page 994 of the 20th edition of Gray's Anatomy (1918)