Fig. (2) Relationship between the Cavernous Sinus (CS) and other dural sinuses and veins of the head region. The extensive input and output venous channels of the CS are non-valvular in nature. Therefore, the direction of blood flow within the CS venous system is highly susceptible to changes in pressure gradients precipitated by infective thrombi, potentially allowing for extensive spread of infections from and into the CS. Trabeculated structure within the CS also facilitates trapping of septic emboli.