Cavernous sinus syndrome

A cavernous sinus thrombosis is a blood clot within the cavernous sinus, a large channel of venous blood in a cavity bordered by the sphenoid bone and the temporal bone of the skull.</P> The cavernous sinus is an important structure because of its location and its contents which include the third cranial (oculomotor) nerve, the fourth cranial (trochlear) nerve, parts 1 (the ophthalmic nerve) and 2 (the maxillary nerve) of the fifth cranial (trigeminal) nerve, and the sixth cranial (abducens) nerve.</P> A thrombosis (clot) in this key crossroads causes the cavernous sinus syndrome which is characterized by edema (swelling) of the eyelids and the conjunctivae of the eyes and paralysis of the cranial nerves which course through the cavernous sinus.