Septum of sphenoidal sinuses

The middle of the rostral border of the sphenoid bone is made of the body of the sphenoid bone.

It is carved in most species by two deep cavities, of which each can be continued in the palatine bone on the same side and forms the sphenoidal sinus (Sinus sphenoidalis).

The two sinuses are separated by a median wall: the septum of sphenoidal sinuses (Septum sinuum sphenoidalium) dorsally of which the body of the presphenoid forms some kind of spike, the rosrum sphenoidal, that is continued by the perpendicular plate of the ethmoid bone.