Orbital spaces

The orbit is divided into three main surgical orbital spaces:

• Extraconal space

• Intraconal space

• Subperiosteal space

Varying from sources, some other orbital spaces are variably described:

• Globe: the space occupied by the eyeball

• Conal space (myofascial cone): the space occupied by the four recti extraocular muscles

• Episcleral space (Subtenon’s space): a virtual space between the fascial sheath of eyeball Tenon’s capsule) and the sclera. It is referred as the “episcleral layer” in the Terminologia Anatomica.

• Optic nerve-sheath complex: the orbital and intracanalicular components of the optic nerve are invested by a nerve sheath continuous with the intracranial meninges that delineates it from the intraconal fat. As such, the unit of the optic nerve and sheath share common pathologic processes, which can be related to intraconal or intracranial pathologies.

• Preseptal space: the space located anteriorly to the orbital septum, and mainly containing the superior and inferior eyelids and tarsi. The postseptal space corresponds to the orbit proper.