Orbital fissure

The orbital fissure is found in the lower part of the wing of the basisphenoid, next to other important foramens:

In most species (Equidae, Carnivorous, Men) there are two superposed holes: one, ventral, is the foramen rotundum, through which passes the maxillar nerve; the other, dorsal, is the orbital fissure (Fissura orbitalis)-formerly great sphenoidal fissure. In Equidae, the trochlear canal (Canalis trochlearis)  isolates itself for the trochlear nerve. In Ruminants and Pigs, all these orifices are fused in a vast foramen orbitorotundum. They could be called 'suprasphenoidal' by opposition to the pterygoid and alar canals , that are 'infrasphenoidal'.