The largest venous trunk in the inferior vena cava is the trunk of the inferior vena cava system, which is synthesized by the left and right common iliac vein on the plane of the fifth lumbar vertebra, sends out along the right side of the abdominal aorta, passes behind the liver, passes through the vena cava hole of the diaphragm, enters the thoracic cavity and enters the right atrium. Collect venous blood of lower limbs, pelvic cavity and abdominal cavity. When the inferior vena cava is blocked, varicose veins can be seen on both sides of the abdominal wall and below the umbilical plane.
Inferior vena cava:
The inferior vena cava (IVC) is the largest venous trunk in human body, which collects venous blood from the lower body and returns to the right atrium. It is formed by the convergence of the left and right common iliac vein at the level of the 4th to 5th lumbar vertebrae. It rises on the right side of the abdominal aorta, passes through the vena cava fossa of the liver and then goes up through the vena cava hole of the diaphragm to the chest cavity, and is injected into the posterior lower part of the right atrium. There is an obscure inferior vena cava valve in the left front of its entrance.
The inferior vena cava is adjacent to the right common iliac artery, mesenteric root, right internal spermatic artery, the third segment of duodenum, pancreas, portal vein and liver from bottom to top. The back is adjacent to the lumbar spine, right renal artery, right lumbar artery, right adrenal artery and right inferior phrenic artery; The lower left is adjacent to the abdominal aorta, and the upper left is adjacent to the caudate lobe of the liver and the right diaphragm foot.
The inferior vena cava and its branches constitute the inferior vena cava system. All veins from the lower limbs, pelvis and abdomen belong to the inferior vena cava system, and finally flow into the right atrium through the inferior vena cava.