Sphenethmoid \Sphe*neth"moid\, a. [Sphenoid + ethmoid.] (Anat.)
Of or pertaining to both the sphenoidal and the ethmoidal
regions of the skull, or the sphenethmoid bone;
sphenethmoidal.
{Sphenethmoid bone} (Anat.), a bone of the skull which
surrounds the anterior end of the brain in many amphibia;
the girdle bone.