On right carotid injections, multiple small branches opacify the ipsilateral cavernous sinus with filling of the contralateral cavernous sinus via the intercavernous sinuses. The left cavernous ICA can be seen as a filling defect within the left cavernous sinus. Drainage from the cavernous sinuses is primarily inferiorly through the inferior petrosal sinuses to the internal jugular veins. Reflux is also seen in the superior ophthalmic veins.