Ventral wall
Paries ventralis
Definition
The ventral wall or floor(Paries ventralis) of the orbit has a very different constitution according to the species. It is formed on a more or less broad extend by the zygomatic bone, that the lacrymal bone completes medially and rostrally + caudally in Bulls, Cats, Rabbits, the caudal extremity of the maxilla.
In Bulls and to a lower degree in small Ruminants, it is formed partially by a lacrymal bulla (Bulla lacrimalis), that reaches in Bulls an enormous development.
On the medial side, this surface is virtual on the dry skeleton and its limit is only marked under the medial wall by the ventral orbital crest (Crista orbitalis ventralis) of the frontal bone.
Between this crest and the mentioned bony elements, there is a narrow space in Men (Inferior orbital fissure or Sphenomaxillary fissure) and still not much extended in Bulls but vast in most domestic animals; this space, closed on the living animal by a fibrous sheet (ossified in Men), creates a communication between the orbit and the temporal and pterygopalatine fossae.
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