Learn how to say Sphenoidal correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word sphenoid:
(also sphenoid bone) a compound bone which forms the base of the cranium, behind the eye and below the front part of the brain. It has two pairs of broad lateral ‘wings’ and a number of other projections, and contains two air-filled sinuses.
relating to the sphenoid bone.
mid 18th century: from modern Latin sphenoides, from Greek sphēnoeidēs, from sphēn ‘wedge’