When portal hypertension is caused by portal vein obstruction and collateral circulation is formed, varicose veins extend around umbilical cord, which is called jellyfish head, also known as jellyfish head. Blood flow direction: upward above navel, downward below navel, the same as normal blood flow direction. When the inferior vena cava is blocked, most varicose veins are distributed on both sides and behind the abdominal wall. When the superior vena cava is blocked, the blood flow direction of superior epigastric vein and inferior epigastric vein is from top to bottom. Under normal circumstances, the abdominal vein above the umbilical level passes through the superficial vein and axillary vein of the chest wall from bottom to top, enters the superior vena cava and returns to the heart; The epigastric vein below umbilical level flows into the inferior vena cava from top to bottom through the great saphenous vein, and then returns to the heart. Judging the direction of blood flow: put the index finger and middle finger together, press a varicose vein without bifurcation, push the umbilical cord blood to both ends to empty the blood vessels, and then lift one finger alternately to observe where the blood flows in and fill the blood vessels, so as to judge the direction of blood flow.