[Functional anatomy of the pelvic veins in women].

Pelvic veins and lower extremities veins form a functional unit resulting in the interaction of their pathology. The intrapelvic venous system consists of two independent networks, under physiological conditions: the parietal and the visceral networks. The main collectors are the internal iliac veins, the ovarian superior rectal veins. The original venous plexi, located in the sub-peritoneal pelvic connective tissue, remain open because of the adhesion of their wall to the parietal pelvic fascia. The parietal venous network, abundant and supplied with valves, includes the retro-public and sacral plexi. The usual venous drainage is encouraged by abundant anastomoses, the decrease or even the absence of valves and the abdominal pressure. When this pressure increases, especially during walking, this encourages pelvic drainage. Occasional venous drainage is observed in case of obstruction of the usual collectors. Anatomical obstacles to the drainage, besides thrombosis and tumors, are essentially: compression of the left common iliac vein by the right common iliac artery, and direct compression of the inferior vena cava by the uterus during pregnancy which compresses it against the spine. It is responsible for gravidic postural shock, and an increased abdominal pressure, exceeding 20 mmHg. The main supply pathways are the ovarian veins and the vertebral plexi. This large, low-pressure avalvular plexus may function easily in both directions caudo-cranial and cranio-caudal. The relationship of this plexus with the roots of the sciatic nerve explain certain sciaticas during pregnancy. Dilatation of the ovarian veins during pregnancy cause a so called syndrome of the ovarian vein. Various venous compressions during pregnancy are responsible for some hematurias, increased collateral abdominal circulation, and turgescent haemorrhoids and vulvar varicose veins.