Cavoatrial junction - Wikipedia
Cardiac catheterization revealed a superior vena cava which drained into the left atrium. No other Gardner, D.L. and Cole, L. Long survival with inferior vena cava draining into left atrium. Brit. Heart J. Staff Meet., Mayo Clin.. ; The inferior vena cava (IVC) is a large retroperitoneal vessel formed by the right atrium inferior to the entrance of the superior vena cava (SVC). The auricle moved once after two or three pulsations of the vena cava, but not in the edge where the superior branches of the vena cava meet the inferior one.
Anatomically this usually occurs at the L5 vertebral level. Many veins contain one-way valves to ensure the forward flow of blood back toward the heart. As the diaphragm contracts and creates negative pressure in the chest for the lungs to fill with air, this pressure gradient pulls the venous blood from the abdominal IVC into the thoracic IVC and subsequently into the right heart.
The IVC enters the right atrium of the heart after coursing through the diaphragm, entering the posterior inferior aspect of the atrium. Other left-sided veins, like the left adrenal and left gonadal vein, first join the left renal vein before joining the IVC and continuing as venous flow returning to the heart. This differs from the right side of the body where the right adrenal and right gonadal vein directly join the IVC without first joining the right renal vein.
There have been described anatomic variants to this venous anatomy on both the left and right side. Venous blood from the abdominal wall reaches the IVC through lumbar veins. This potential for collateral flow could be critical if either of the larger veins becomes obstructed.
Below is a list of most common vertebral levels at which different veins enter the IVC. Hepatic veins, inferior phrenic veins L1: Right suprarenal vein, renal veins L2: Left gonadal vein L5: Right and left common iliac veins Structure and Function The inferior vena cava is ultimately responsible for the transport of almost all venous blood deoxygenated from the abdomen and lower extremities back to the right side of the heart for oxygenation.
The cardinal veins, which are primarily responsible for venous drainage of the early embryo, are paired veins divided into anterior and posterior segments. These derivatives of the cardinal veins play an important role in the formation of the inferior vena cava.
The supracardinal veins assume the role of the posterior cardinal veins and drain the body wall by becoming intercostal veins. Supracardinal veins do not directly contribute to the formation of the inferior vena cava. Blood Supply and Lymphatics Blood supply to the inferior vena cava is derived partially from the deoxygenated blood it carries towards the heart and partially supplied by the vasa vasorum that penetrate the tunica adventitia of the vessel.
The superior vena cava is thin-walled, and the blood is under low pressure. It lies near lymph nodes in the chest. Therefore, when the lymph nodes or the aorta of the heart get bigger, the superior vena cava is squeezed, blood flow slows, and complete blockage may occur.
The speed of the blockage and its location determine the seriousness of the syndrome. The more rapidly the obstruction occurs, the more severe the symptoms, since the other veins do not have time to widen to adjust to the increased blood flow. If the blockage occurs above where the superior vena cava and inferior vena cava meet, the syndrome is less obvious, since the veins can swell more easily and handle the increased blood flow.
If the blockage occurs below this point, more symptoms are seen, since the blood must be returned to the heart by the veins in the upper abdomen and the inferior vena cava, which requires higher pressure. Sometimes, the other veins can take over for the superior vena cava if it is obstructed, but this takes time. Diagnosis Once superior vena cava syndrome is recognized, prompt attention is important.
As long as the trachea windpipe is not blocked, superior vena cava syndrome is not usually a life-threatening emergency; therefore, a definite diagnosis should be made before treatment is started. If lung cancer is suspected, a sputum specimen should be collected. If the sputum specimen is negative, a biopsy may be taken. The results of the biopsy will help the healthcare provider decide on the best treatment.
Treatment Treatment of superior vena cava syndrome depends on the cause of the obstruction, the seriousness of the symptoms, the prognosis of the patient, and the patient's preferences. Radiation therapy and chemotherapy should not be started until the cause of the blockage is determined.
The treatments discussed in this summary will focus on superior vena cava blockage caused by cancer. Since the treatment of the blockage may depend on the type of cancer, this diagnosis should be made before treatment is started.
Unless the airway is blocked or the brain is swelling, waiting to start treatment usually presents no problem. The following treatments can be used for superior vena cava syndrome. Watchful waiting A patient with good blood flow through other veins, and few symptoms may not need treatment, but will be closely monitored for new symptoms or changes.
In many cases, SVCS is managed by treating the cancer that is causing the blockage. If the blockage is above the area where the superior and inferior vena cava veins join, and other veins are able to take over for the superior vena cava, the symptoms may stabilize and the patient may be comfortable enough to forego more therapy.
Diuretics may help symptoms of swelling, but can cause problems such as dehydration. Radiation therapy If the blockage of the superior vena cava is caused by a tumor that is not sensitive to chemotherapy, radiation therapy may be given. So to think about exactly what the heart does, I think one, kind of neat way to do it is to actually imagine that you're a cell.
So put yourself in the perspective of a cell, and let's say you're a cell hanging out over here.
Anatomy, Abdomen and Pelvis, Inferior Vena Cava - StatPearls - NCBI Bookshelf
And you can think about any part of the body that you could be. Let's say a little toe cell.
So let's say you're a toe cell and your job, of course, is to live and be happy,and you've got near by, a little blood vessel. And in fact, every cell in our body has a little blood vessel that's near by.
And this toe cell is just trying to make a living. And toe cells need certain things, right? They need, for example, let's say oxygen. I'll write it in white so it's very clear. They need oxygen and they need nutrients, right?
Inferior vena cava
So cells need certain things to live and be happy. And on the flip-side, they also make waste. They're in a sense just like us, they make waste. And that waste could be all sorts of things, and one that kind of jumps to mind is carbon dioxide CO2. So carbon dioxide is waste for this cell.
Vena cava | anatomy | mikan-toumorokoshi.info
So it's making some waste and for the moment let's imagine that there's no blood flow. So, even though there's a blood vessel near by, really, no flow is happening, so I'll just write "no flow".
So as the little cell makes waste. That waste, let's draw a little ball right here, it's going to start accumulating, you're going to start collecting more and more of it since the blood is not really flowing. And it might kind of end up getting all the way around our toe cell.
So our toe cell is getting swamped, literally getting kind of covered by its own waste. And on the flip-side, is it getting oxygen or nutrients? It's not getting either of these things. So, before very long, I would say within minutes, our toe cell is thinking, "Well this is not a very happy way to live! And if this continues the toe cell would die.
So, what a toe cell needs, and what every cell needs, and that could be a finger cell or a skin cell, or really any cell that's living, needs flow. It needs this blood to be flowing nicely and smoothly.
And if there is flow then you get a very different picture, right? If there's flow then all the sudden all the waste product is actually now lifted and taken away. It's flowing away, and it's a little bit like having someone come by and pick up the trash, then you don't have trash all over the house. So then you have nice flow, and in return, oxygen and nutrients are delivered.
So this stuff gets delivered as well. So, all of the sudden the cell is going to be very, very happy, and is going to be living just fine. So, really if you want all of the cells in your body to be living just fine like this cell here, you really want good flow throughout the body.
- The azygos vein pathway: an overview from anatomical variations to pathological changes
- Cavoatrial junction
- Superior vena cava
And so this is really point number one.