Thrombophlebitis of the facial vein, (inflammation of the facial vein with secondary clot formation) can result in pieces of an infected clot extending into the cavernous sinus, forming thrombophlebitis of the cavernous sinus.
A condition where inflammation of the facial vein is complicated by blood clotting, can result in clots breaking loose and traveling into the cavernous sinus, leading to a secondary inflammatory response.