Periorbita

The periorbit is a cone-shaped fibrous membrane enveloping the eyeball, its muscles, nerves and vessels. Rostrally, it is attached to the periosteum of the orbital margin. At the apex of the orbit, it is thick, firmly attached to the edge of the optic canal and continuous with the intracranial dura mater.

In humans, as the orbit is entirely bony, the periorbit is entirely attached to the periosteum.

In domestic animals, however, the periosteum of the orbit and the periorbit are two clearly distinct structures. The periorbit is highly developed on the caudolateral side.

Among the fibers of the periorbit there are also fibers of the orbitalis muscle.