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Lymph nodes and vessels of the pancreas, spleen and duodenum.
Hello everyone! This is Joao from Kenhub, and welcome to our tutorial on the lymphatics of the pancreas, duodenum and spleen. Now before we get into the nitty-gritty of our tutorial today, I first want to familiarize you with this image right here which will be our primary point of reference for most of the lymphatic structures which we are shortly going to meet.
What we are seeing in the image here is an anterior view of the upper abdomen with the liver retracted – meaning it has been pulled upwards and back to then expose the underlying structures. The stomach has been removed from this image, however, if it was present, it would be located around here. Now removing the stomach allows us to get a better view of what lymph nodes are located around the abdominal aorta and anterior to this organ here which is the pancreas.
Our plan today is to then explore the lymph nodes associated with the pancreas, duodenum as well as the spleen which is an often overlooked organ of the upper abdomen. We’d like to note here that the lymphatic drainage of these organs is closely related to their arterial supply, so it’s helpful to have a basic knowledge of these arteries before learning this. However, if you’re not a hundred percent up to scratch on the arterial supply of the pancreas, duodenum or spleen, don’t worry at all. Head on over to kenhub.com and you’ll be able to find all the information you need.
Now let’s continue, and I would like to add here that with each group of nodes, I will talk about the structures that these nodes receive or drain lymph from which are then called the afferent structures. And then I will also talk about the structures that these nodes drain lymph into which are then known as the efferent structures.
Now before we dive into the specifics of each organ, I first would like to speak to you about the preaortic lymph nodes which are the final or terminal nodes that lymph from our mentioned abdominal structures eventually drain into. The preaortic lymph nodes consist of three groups of nodes which are called then the celiac lymph nodes, the superior mesenteric lymph nodes, and the inferior mesenteric lymph nodes – all of which are named according to the major artery located nearest to them.
In today’s tutorial, I will give you a brief introduction to the celiac and superior mesenteric nodes only as they are most relevant to our topic of study. The celiac nodes seen here highlighted in green on the screen form the most superior part of the preaortic lymph nodes, and that is, that they are the highest lymph nodes found directly anterior to the abdominal aorta which is the structure that you see here on the image.
More specifically, we can describe the celiac lymph nodes as surrounding this artery here in green which is the celiac trunk – a branch of the aorta at the level of T12. The celiac nodes receive most of the lymph drained from the nodes of the pancreas, duodenum and spleen.
Now if you’re wondering where the lymph from the celiac nodes drains into, we’ll find out in just a moment, but first I want us to look at the next set of preaortic nodes which are the superior mesenteric lymph nodes.
The superior mesenteric lymph nodes are located around the superior mesenteric artery which we know is also a branch of the abdominal aorta. As you can see in our image, the superior mesenteric artery is located posterior and inferior to the body of the pancreas and anterior to the third part of the duodenum, which is the portion of the duodenum located posterior to both the superior mesenteric artery and vein. The superior mesenteric lymph nodes in general receive lymph from the midgut which comprises the structures spanning from the distal half of the duodenum to the proximal two-thirds of the transverse colon, however, we’ll discuss this in more detail later on on this tutorial.
Switching to another image for just a moment, I quickly want to introduce you to this structure which is the cisterna chyli. The cisterna chyli lies anterolateral to the L1 to L2 vertebrae. To its left, we can see the abdominal aorta with the celiac and superior mesenteric lymph nodes adjacent to their respective arteries. The celiac lymph nodes drain to the cisterna chyli via a structure known as the intestinal lymph trunk. Lymph drain from the superior mesenteric lymph nodes also ends up in the cisterna chyli either directly or via the celiac nodes.
And that’s all I’m going to say about the cisterna chyli for today, however, be sure to check it out on our website if you’re curious to know more about this structure.
Aside from the preaortic nodes, we also need to familiar ourselves with another group of nodes which are the hepatic lymph nodes, which you can see now highlighted in green. These nodes extend in the lesser omentum and are associated with the hepatic artery proper and the biliary ducts. They vary in number and size but can usually be found at the junction of the cystic and common hepatic ducts.
The hepatic lymph nodes drain lymph from the gallbladder, liver, and bile ducts. However, they also partially drain to the duodenum, pancreas, and some parts of the stomach. From here, the lymph collected drains into the celiac nodes. As with the previous lymph nodes, we will learn more about these nodes later on in this tutorial.
But now that we’ve learned about the core lymph nodes of the upper abdomen, let’s turn our attention to the lymphatic drainage of each specific organ on our plan for today beginning with the pancreas.
As you can see in the image here, there are several groups of lymph nodes that surround and drain the pancreas that can be found both anterior and inferior to the pancreas and travel along the head, the body, and tail of the pancreas. And remember this, as in the case of the arterial supply of the pancreas, the lymphatic drainage of the head of the pancreas is different than of the body and tail. And also if I may, I’d like to first have a look at the nodes related to the drainage of the body and tail of the pancreas which are collectively known as the pancreatic nodes.
In this image, we are specifically looking at the superior pancreatic lymph nodes which extend along the superior aspect of the body and tail of the pancreas, receiving lymph from these parts of this organ. These lymph nodes are located along the splenic artery as well as the dorsal pancreatic artery which runs posterior to the pancreas. Not visible in our image here are the inferior pancreatic lymph nodes which are located on the posterior aspect of the pancreas. And unsurprisingly, the inferior pancreatic lymph nodes are found along the length of the inferior pancreatic artery which also runs posterior to the pancreas.
Now if we were to look at behind the pancreas, we could expect to see the inferior pancreatic nodes to be arranged in a similar fashion to what you see now on the screen. Efferent lymph nodes from both the superior and inferior pancreatic nodes follow along their related arteries eventually draining into the celiac nodes.
Moving onto the lymphatic drainage of the head of the pancreas, we are now going to take a look at the pancreaticoduodenal lymph nodes. Now, just like we saw with the pancreatic lymph nodes, the pancreaticoduodenal lymph nodes are located close to the vessels which provide arterial supply to this region which are the pancreaticoduodenal arteries. These are branches of the gastroduodenal and superior mesenteric arteries and run both anterior and posterior to the pancreas.
Found adjacent to these arteries, both anteriorly and posteriorly to the head of the pancreas, we can see the pancreaticoduodenal lymph nodes here in green. And similar to their arterial counterparts, the pancreaticoduodenal lymph nodes can be subdivided into superior and inferior pancreaticoduodenal lymph nodes.
As I mentioned these particular nodes receive lymph drain from the head of the pancreas, however, they also received lymph from another structure. Perhaps you’ve already spotted what the structure is judging by the name of these nodes. That’s right, you’ve guessed it. We’re moving on to the duodenum.
So as I hinted to in our last slide, in addition to receiving lymph from the pancreas, the pancreaticoduodenal nodes are also responsible for receiving lymph drained from much of the duodenum now outlined in blue. Now, lymph received by the superior pancreaticoduodenal nodes usually drains to the celiac lymph nodes via the hepatic lymph nodes while then the inferior pancreaticoduodenal nodes also drain to the celiac nodes, however, via the superior mesenteric nodes. And even though the pancreaticoduodenal lymph nodes drain the bulk of the duodenum, we should be aware that the first and the last part of the duodenum have a slightly different pattern of drainage.
The first or superior part of the duodenum is the continuation of the gastrointestinal tract from the pylorus of the stomach. This part of the duodenum is drained by the pyloric nodes which are associated with the right gastric and right gastroomental arteries. And similarly drain to the celiac lymph nodes via the hepatic lymph nodes.
At the other end, we have the ascending part of the duodenum which you can see right here and this part of the duodenum is drained by the inferior pancreatic nodes as well as the superior mesenteric nodes both of which we already are familiar with by now. And here, my friends, we are concluding the lymphatic drainage of the duodenum which means we have just one organ to go, and that is the spleen.
Concerning the lymphatic drainage of the spleen, we have just one group of nodes to discuss which are the appropriately named then the splenic lymph nodes, also sometimes known as the pancreaticosplenic lymph nodes. The splenic lymph nodes can be found localized at the hilum of the spleen which is the entry and exit point for the splenic artery and vein respectively. And in addition to receiving lymph drained from the spleen, the splenic lymph nodes also receive lymph drained from the tail of the pancreas.
Now similar to the majority of the structures that we’ve discussed, the efferent vessels of the splenic lymph nodes follow along the course of their related artery which in this case is the splenic artery, of course, eventually then draining into the celiac lymph nodes.
Before we finish this tutorial, I would like to go over a few of the main clinical notes connected to the lymphatics of the pancreas, duodenum and spleen.
The celiac lymph nodes also receive lymph from the most distal portions of the esophagus. For those that are diagnosed with distal esophageal cancer, the celiac lymph nodes can be used for diagnostic and prognostic purposes. Since metastases of tumor cells through the lymphatic system is not so uncommon, examining the celiac lymph nodes for tumor cells is a tool that can be used to determine the stage and progress of esophageal cancer.
Now some studies have evaluated the prognosis of several patients who have been diagnosed with distal esophageal cancer and found that those with tumor metastases to celiac nodes appear to have an increased risk of disease-related mortality following treatment compared with those who did not display this.
And this brings us to the end of our tutorial. Before we wrap up, let’s recap what we have learned about the lymphatic drainage of the pancreas, duodenum, and spleen.
Beginning with the pancreas, we first looked at the lymph nodes associated with the drainage of the body and tail of the pancreas which were namely the superior pancreatic lymph nodes and the inferior pancreatic lymph nodes which we said were located posterior to the pancreas. After that, we moved our attention to the head of the pancreas where we found the pancreaticoduodenal lymph nodes which are located both anterior and posterior to the pancreas. We also subdivided these nodes into the superior and inferior pancreaticoduodenal lymph nodes.
Moving onto the lymphatic drainage of the duodenum, we found out that the pancreaticoduodenal lymph nodes also drain most of this organ in addition to the pancreas. We noted that the first part of the duodenum was drained by the pyloric nodes, while the last or ascending part of the duodenum was drained by both the inferior pancreatic nodes and the superior mesenteric nodes.
That brought us to our final organ of the day which was the spleen. Here we learned about the very appropriately named then the splenic nodes. And finally we learned about some other structures which received the lymph drained from our mentioned nodes. These were the hepatic lymph nodes, the celiac lymph nodes, and finally the cisterna chyli.
And that concludes our tutorial for today. I hope you found it interesting and thank you for joining us. I will see you on the next one.