A<unk>  results from an abnormal communication between the arterial and venous systems within the cavernous sinus in the skull. It is a type of arteriovenous<unk> . As arterial blood under high pressure enters the cavernous sinus, the normal venous return to the cavernous sinus is impeded and this causes engorgement of the draining veins, manifesting most dramatically as a sudden engorgement and redness of the eye of the same side.
Carotid-cavernous fistula
Carotid artery dissection
Cirsoid aneurysm
Cavernous sinus thrombosis
Vertebral artery dissection
Vitreous hemorrhage
Carotid artery stenosis
Charcot–Bouchard aneurysm