Foramen rotundum

On the ventral surface of the rostral border of the wing of the basisphenoid bone, in most species (Equidae, Carnivorous, Men), we find two superimposed holes: one, ventral, the ventral foramen (foramen rotundum), destined to the crossing of the maxillar nerve and the other, the orbital fissure (Fissura orbitalis)-formerly great sphenoidal fissure.

In Horses, dorsolaterally to the orbital fissure, the small trochlear canal isolates itself for the trochlear nerve.