Low flow dural based AVMS of the orbit

These non-traumatic fistulas are indirect and involve communication between small meningeal branches of the ICA or ECA and the cavernous sinus or tributaries. Symptoms are mild and subacute, compared to CCF. They include conjunctival injection, mild motility disturbance, and elevated intraocular pressure. MRI may be normal or show mild abnormality of the cavernous sinus, but often enlarged extaocular muscles or superior opthalmic veins are seen.