Twenty-six patients with painful ophthalmoplegia were classified as having the Tolosa-Hunt syndrome on the basis of their clinical findings and response to steroid therapy. All patients underwent orbital venography, a review of which forms the contents of this investigation. Orbital venography, a review of which forms the contents of this investigation. Orbital venograms were normal in 16 patients and abnormal in 10. The major abnormalities were (1) obstruction of the superior ophthalmic vein in its third segment without displacement; (2) collateral venous flow through small venous channels or collateral veins; and (3) poor opacification of the ipsilateral cavernous sinus.