ABSTRACT
The roof of the orbit constitutes the floor of the frontal sinus and is formed anteriorly by the frontal bone and posteriorly by the lesser wing of the sphenoid bone. The medial wall divides the orbit from the ethmoid cells, and is formed by parts of the maxilla, frontal, ethmoid, lacrimal and sphenoid bones. The lateral wall is the thickest, separating the orbit from the temporal fossa anteriorly and from the middle cranial fossa posteriorly. The floor of the orbit is also thin and prone to blow-out fracture. It contains a passage for the infraorbital nerve and is made up of the zygomatic, maxillary, and palatine bones. The extraocular muscles — the four recti, two obliques, and the levator palpebrae superioris — divide the retro-orbital space into intra- and extraconal spaces. An autoimmune inflammatory process, that affects the extraocular muscles and orbital fat, is particularly frequent in females, and is associated with thyroid dysfunction.
