Venous collaterals in external and common iliac vein obstruction

Sixty patients with post-thrombotic partial or total obstruction of the common and external iliac veins, either alone or in combination, have been investigated by serial film pelvic phlebography. The collaterals fall into three main groups depending on the site of obstruction. From a study of these collaterals it is usually possible to localise the site of obstruction and to speculate on the completeness of the obstruction.