Sphenoidal sinus

The sphenoidal sinus is a usually small sinus carved inside the body of the presphenoid bone and sometimes extended in the palatine bone (Horses), where it communicates not only with the nasal cavity but also with the maxillary sinus.

In Bulls, its cavity is often obstructed by fat-like formations .

In Dogs, it is so completely invaded by the last endoturbinal that it seems to have disappeared and is not described among the sinuses.

In Cats, it is proportionally vast.

In elder Suidae, it may excavate also the occipital bone.