In case of IVC obstruction the collaterals which open up are all except ?
Superficial epigastric pain drains into great saphenous vein. Iliolumbar vein drains into internal iliac vein,so these two do not form collateral between SVC & IVC as both of them will be ultimately drained into IVC.All other choices form collaterals between SVC & IVC.
Superior epigastric & inferior epigastric vein
Azygos & ascending lumbar vein
Superficial epigastric & iliolumbar vein
Lateral thoracic veins & preveebral vein