Video: Veins of abdomen and pelvis

Hello everyone! It's Megan from Kenhub here, and welcome to our tutorial on veins of the abdomen and pelvis. In today's tutorial, we will be looking at the veins that drain the abdominal and pelvic viscera as well as the abdominal walls. First, we'll begin by looking at the veins that drain the abdominal viscera then we'll move on to look at the veins of the pelvic viscera. Please note that this tutorial will not cover any of the superficial veins found in these regions.

The first vein we're going to look at today is the inferior vena cava which we can see here highlighted in green. It is the largest vein in the human body and it transports venous blood from the lower limbs, the back, the abdominal walls, the pelvic viscera and the abdominal viscera to the right atrium of the heart. The inferior vena cava is formed by the union of the left and right common iliac veins and we can see that very clearly here in this image. This union occurs approximately at the level of the fifth lumbar vertebra.

The inferior vena cava receives several tributaries along its course and these tributaries travel alongside the arteries of the same name. An example of direct tributaries of the inferior vena cava include the right and left renal veins which we can see here. The inferior vena cava is situated in the retroperitoneal space posterior to the abdominal cavity. It runs along the right side of the vertebral column with the aorta lying laterally to the left.

The direct tributaries of the inferior vena cava include the inferior phrenic veins, the hepatic veins, the right suprarenal vein, the renal veins, the lumbar veins, the right gonadal veins, the median sacral vein, and, of course, the common iliac veins. It should be noted that all of the veins of the abdomen and pelvis eventually drain into the inferior vena cava either directly or indirectly.

So now let's look at the direct tributaries of the inferior vena cava starting with the inferior phrenic veins. Here in this image on the right we can see the inferior vena cava as it appears in the abdomen. The inferior phrenic veins are paired veins which basically means that there's a left inferior phrenic vein and a right inferior phrenic vein. These veins follow the course of the inferior phrenic arteries which we can see here highlighted in green. These veins drain blood from the diaphragm and drain into the posterolateral aspect of the inferior vena cava at approximately the level of the eighth thoracic vertebra.

The next tributaries of the inferior vena cava we're going to look at are the three main hepatic veins which we can see highlighted in green here and a few minor hepatic veins. These veins drain blood from the liver's tissues before draining into the inferior vena cava. The liver can be divided into eight segments and each of the hepatic veins are responsible for draining one or more of these segments. For instance, the minor hepatic veins drain segment I of the liver and open directly into the inferior vena cava.

The right hepatic vein which runs at the right hepatic fissure is the longest and most variable of the three main hepatic veins. It drain segments VI and VII of the liver as well as parts of segments V and VIII. The middle hepatic vein which runs at the middle hepatic fissure drains segments IV, V and VIII of the liver. Finally we have the left hepatic vein which partially runs at the fissure for ligamentum teres hepatis and the left hepatic fissure. This vein drains segments II and III of the liver. Because of its position, the tributaries of the inferior vena cava are not always symmetrical. It's for this reason that the right suprarenal vein opens directly into the inferior vena cava whereas the left suprarenal vein does not.

We will look at the left suprarenal vein a little later on in this tutorial but first let's focus on the right suprarenal vein. This vein opens into the inferior vena cava at approximately the level of the twelfth thoracic vertebra. In this illustration, we can see the right suprarenal vein here and we can see the structure that it drains which is the suprarenal gland or the adrenal gland. Please note that all the direct tributaries of the inferior vena cava are paired veins with the exception of the right suprarenal vein, the right gonadal vein and the median sacral vein.

The next veins we're going to look at today are the renal veins which are also direct tributaries of the inferior vena cava and are paired veins. These veins lie anterior to the renal arteries and because of the position of the inferior vena cava, the right renal vein is shorter than the left renal vein. So here we can see the right renal vein which is approximately 2.5 centimeters whereas the left renal vein is approximately 7.5 centimeters. These veins, as the name suggests, drain the kidneys.

The left gonadal veins – that is, the left ovarian and testicular veins – open into the left renal vein between the level of the first and second lumbar vertebrae. The left suprarenal vein also terminates in the left renal vein. In other words, the left renal vein receives the left gonadal veins and the left suprarenal vein. The left renal vein courses anterior to the abdominal aorta and posterior to the superior mesenteric artery. Due to its position behind the superior mesenteric artery, there's a risk of it being compressed by this vessel.

The next veins we're going to look at are the lumbar veins which are also direct tributaries of the inferior vena cava. These veins drain blood from the lumbar back and skin, the anterior, posterior and lateral abdominal walls as well as from the parietal peritoneum. There are four lumbar veins in total which we can see here highlighted in green. The lumbar veins also collect blood from the vertebral plexuses near the vertebral column and are connected with the ascending lumbar vein at this point. Please note that occasionally the first lumbar vein may open into the second lumbar vein and the second lumbar vein may also occasionally open into the third lumbar vein or the ascending lumbar vein.

As we saw earlier, the left gonadal vein opens into the left renal vein. In contrast, the gonadal veins on the right side open directly into the inferior vena cava. The right gonadal veins – to be more specific the right ovarian vein and the right testicular vein – open into the inferior vena cava at an acute angle on its right anterolateral aspect. These veins drain blood from the gonads or the ovaries in women and the testicles in men.

The next vein we're going to look at is the median sacral vein. It is one of the unpaired direct tributaries of the inferior vena cava which we can see in this illustration on the right. The median sacral vein is a small vein that accompanies the corresponding median sacral artery which we can see in this image here. It receives blood from the sacral venous plexus and may sometimes open into the left common iliac vein.

The final direct tributaries of the inferior vena cava are the left common iliac vein and the right common iliac vein. As we've seen previously, these veins unite to form the inferior vena cava at approximately the level of the fifth lumbar vertebra, and because of this, they're considered to be tributaries of origin. Some veins of the abdomen and pelvis do not drain directly into the inferior vena cava but first drain into the hepatic portal vein which we can see here highlighted in green. The function of the portal vein is to transport nutrient-rich blood from the GI tract and blood from the spleen, pancreas and gallbladder to the liver. Once this blood enters the liver, it undergoes metabolic processing before it drains into the inferior vena cava.

There are several tributary veins that drain directly into the hepatic portal vein. The first tributaries we'll look at are the right and left gastric veins which we can see here highlighted in green. Here, we can see the right gastric vein which is sometimes known as the pyloric vein and drains part of the lesser curvature of the stomach. We can also see the left gastric vein which courses along the lesser curvature to anastomose with the right gastric vein. This vein drains the left part of the lesser curvature of the stomach and also receives some esophageal veins. The cystic vein is another tributary of the hepatic portal vein. Although not present in this image, the cystic vein branches from the portal vein and travels alongside the cystic duct to drain the gallbladder.

Next we have the posterior superior pancreaticoduodenal vein which is one of four pancreaticoduodenal veins that drain the head of the pancreas and the duodenum. In this image, we can see the anterior superior and inferior pancreaticoduodenal veins. The posterior superior pancreaticoduodenal vein is not visible as it's obscured by the head of the pancreas.

Another tributary of the portal vein is the prepyloric vein which is also known as the prepyloric vein of Mayo. Although not present in this image, the prepyloric vein branches from the right gastric vein to supply the pylorus of the stomach. This vein crosses the anterior surface of the pylorus and is therefore a surgical significance as it's a helpful indicator in the location of the pylorus of the stomach.

Finally, we have the paraumbilical veins which are subcutaneous veins of the umbilical region. These veins are of clinical significance as they may become distended and engorged in patients with severe portal hypertension and portal systemic shunting through the umbilical veins. These distended veins may become visible on the abdomen of patients and their appearance is known as caput medusae. Please keep in mind that the hepatic portal vein is formed by the union of the superior mesenteric vein and the splenic vein.

The next vein we're going to look at is the superior mesenteric vein which we can see here highlighted in green. This vein as I just mentioned joins with the splenic vein to form the hepatic portal vein and drains blood from the jejunum and the ileum of the small intestines. Like the portal vein, the superior mesenteric vein has many tributaries. The first of which are the pancreaticoduodenal veins which we can see here highlighted in green. These veins drain the head of the pancreas and the duodenum. Next, we have the right gastro-omental vein which drains the right part of the greater curvature of the stomach. In this illustration, we can see both the right and left gastro-omental veins highlighted in green. Here we can see the right gastro-omental vein coursing along the greater curvature of the stomach until about this point here where it anastomoses with the left gastro-omental vein.

The pancreatic veins are also branches of the superior mesenteric vein which we can see here highlighted in green. These veins are not visible in this image but they function to drain the body and tail of the pancreas.

In the next illustration, we can see the jejunal veins. Just to orientate ourselves, here we can see the portal vein which is formed by the splenic vein and the superior mesenteric vein. As the superior mesenteric vein courses downwards, it gives off the jejunal veins which course alongside the jejunal arteries. These veins drain the jejunum of the small intestine. Inferior to the jejunal veins, we have the ileal veins which we can see here highlighted in green. These veins, as the name suggest, drain the ileum.

Next we have the ileocolic vein which we can see here highlighted in green. This vein receives tributaries from the ileum, the colon and the cecum. Then we can see the right colic vein which functions to drain the ascending colon. Finally, we have the middle colic vein. Again, the illustration has changed so let's orientate ourselves. Here we can see the hepatic portal vein, the splenic vein and the superior mesenteric vein and highlighted in green, we have the middle colic vein which drains the transverse colon.

The next vein we're going to look at is the inferior mesenteric vein which we can see here highlighted in green. This vein courses along the left side of the inferior mesenteric artery and drains the descending colon, the sigmoid colon and the rectum via its tributaries. These tributaries include the left colic vein which drains the descending colon, the sigmoid veins which drain the sigmoid colon, and the superior rectal vein which is also known as the superior hemorrhoidal vein. This vein drains the rectal mucous membrane and the mucous membrane of the upper half of the anal canal.

In the next illustration, we can see two of the tributaries more clearly. So here we can see the sigmoid veins and here we can see the superior rectal vein. The inferior mesenteric vein terminates when it joins the splenic vein which we can see here highlighted in green. This vein is the final tributary of the hepatic portal vein and drains the spleen as well as part of the stomach and part of the pancreas. The splenic vein runs in the splenorenal ligament alongside the splenic artery and it joins with the superior mesenteric vein to form the hepatic portal vein.

The splenic vein has three tributaries. The first are the pancreatic veins which drain the body and the tail of the pancreas. Next we have the left gastro-omental vein which courses along the greater curvature of the stomach and drains the left part of the greater curvature. And finally, we have the short gastric veins. Although not present in this image, these veins drain the fundus and the left part of the greater curvature of the stomach.

So now that we've seen some of the veins of the abdomen, let's move on and look at some of the veins of the pelvis. We will be looking at the internal iliac vein in particular as it's the main vein that drains the pelvic region. In this illustration, we can see the left internal iliac vein and the right internal iliac vein. As we saw earlier on in this tutorial, there are two common iliac veins which unite to form the inferior vena cava. Similarly, the common iliac veins are formed by the union of the internal iliac vein and the external iliac vein.

The external iliac vein mainly drains the lower limb while the internal iliac vein is responsible for the drainage of blood from the pelvic region via its tributaries. The internal iliac veins receive tributaries from the veins that drain the organs of the pelvis and from some venous plexuses.

The first tributaries we're going to look at are the superior and inferior gluteal veins. Here we can see the superior gluteal veins and in the next illustration we can see one of the inferior gluteal veins. These veins function to drain the gluteal region. Next we have the internal pudendal veins and we can see the left one here highlighted in green. These veins drain the perineum which is basically the area between the anus and the scrotum in males or the vulva in females. Then we have the obturator veins which receive tributaries from the veins that drain the muscles of the upper and posterior part of the thigh as well as veins that drain the hip joint. Here we can see the left obturator vein highlighted in green.

Next we have the lateral sacral veins which we can see in this illustration on the right. Just to orientate ourselves, here we can see the pelvic region in the sagittal plane as it appears in males. We can see structures such as the bladder, the seminal vesicles and the prostate, and superior to this, we can see the external iliac vein and the internal iliac vein. Branching from the internal iliac vein, we can see the left lateral sacral vein highlighted in green. These veins receive the sacral venous plexus.

In the same illustration, we can see the vesical veins which function to drain the bladder. Then we have the uterine and vaginal veins in the female pelvis. In this illustration on the right, we can see the female pelvis in the sagittal plane. We can see structures such as the bladder and the uterus and we can also see the left uterine vein highlighted in green. Finally, we have the middle rectal veins which receive tributaries from the urinary bladder and from the prostate and seminal vesicles in the male pelvis. In this illustration, we can see the left middle rectal vein.

Now that we've covered the veins of the pelvis, that brings us to the end of this tutorial on veins of the abdomen and pelvis. I hope you enjoyed it and thank you for listening.

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