Welcome back. Imagine you have pain in the right upper abdomen, which structures can be causing this pain? Or imagine someone having had an accident and tumbled on the bicycle handle bars with the left upper abdomen. Which structures could have been hit? In all these cases, you need a clear overview of which structures lie where in the abdomen. That will be the topic of this video. To start with a seemingly strange question. Where in fact, is the abdomen? For instance, Are there abdominal structures at the place indicated with the question mark? To make it more clear, we projected the rib cage over the body. Imagine we could look through the skin. We would see the organs lying as they lie in this drawing. The liver lies behind the right rib cage. The stomach also lies partially behind the rib cage. The spleen lies to the left, hidden behind the stomach. The thick line roofing the organs is the diaphragm. As you see, abdominal organs reach quite some distance upwards behind the ribcage. You can now answer the question are there abdominal structures at the place indicated with the question mark? You see the diaphragm projected on the torso. It is clear that the abdomen reaches quite some distance upwards, behind the ribcage, and that the thorax and the lungs are far smaller than the ribcage. Now we'll imagine you are a surgeon. We will virtually open up the abdomen. You will see which structures you encounter from the front, to the back of the abdomen, and how the organs are positioned in relation to each other. If you would move the front abdominal wall, we would see this. A brim of liver may be seen protruding, inferiorly of the ribcage. Also a part of the stomach can be seen protruding below the rib cage. Hanging down from the stomach is a membrane loaded with a smaller or larger amount of fat that may cover all of the intestines. It's called the greater omentum. Well now zoom in on the upper abdomen on the indicated area. The overlying skin and rib cage have been removed to allow a better view. The liver has been lifted together with the gallbladder that was tucked away behind the liver. When the liver is in its normal place, the gallbladder rests on the duodenum. The stomach, that was first partially covered by the liver has also now become completely visible. Further we see that there is a membrane stretched between the liver and the stomach which is called the lesser omentum. Finally we might get a glimpse of the spleen hidden behind the stomach. Now we'll dig a bit deeper. To that aim we will cut the greater omentum at the indicated line and then flip the stomach upwards and that gives this appearance. One sees the cutting line of the greater omentum and the lifted stomach now seen from its back. It appears that there's a cavity behind the stomach the so-called omental bursa. Also unveiled now is the pancreas which lies in the back wall of the omental bursa. Note that the pancreas stretches obliquely upwards from the duodenum to the spleen. And the duodenum disappears downwards behind the transverse colon. So far, these were the upper abdominal organs and we now return to the view of the open abdomen and will now shift our attention downwards and to that aim, we lifted the greater omentum. As you see the transverse colon is lifted together with the greater omentum as it is adhered to it. Further we notice the small bowels or more precisely, the jejunum and the ileum lying centrally. Bordering it we might see the ascending colon. Next we will virtually remove the jejunum and the ileum. Where the jejunum and the ileum were ,we now see a kind of folded curtain. The small bowel was attached to it. It's a double layer of peritoneum called the mesentery that connects the intestines to the back wall. The small bowel has been removed from here to here. At this place it seems to spring from the depths. You might recall that the duodenum disappeared behind the transverse colon. And the gut reappears here and by definition, the jejunum starts here. This point is an important landmark in abdominal surgery, it's called the point of Treitz. Which you ever talk with abdominal surgeons about their work you will probably hear this word Treitz within a few sentences. The small bowel was removed all the way up to the last part of the ileum where it attaches to the large bowel. Now we can also fully see the large bowel and its parts. The cecum, the ascending colon, the transverse colon, the descending colon, the sigmoid colon, and finally disappearing out of sight into the depths, the rectum. Did you notice that we are still missing important structures? Where are the kidneys, and where are the Aorta and inferior Vena Cava, the largest two blood vessels of the body? To find them, we'll need to dig even deeper, and remove all the structures we see now. In this drawing, all the intestines have been removed. And so have the liver, the stomach, and the spleen. The membrane that formed the floor of what we could see so far, the peritoneum, has now been drawn transparently so we can look through it. We might say we're now looking into the cellar of the abdomen. And there are the kidneys, the aorta, and inferior vena cava. Also, we again see the duodenum, which was at first partially hidden behind the transverse colon, and finally the pancreas that we saw before. Now it's time to get a question to rehearse a little bit. Finally, we'll move down to the pelvis. We use a lateral view now on a female pelvis. Here is the abdominal front wall and here the back with the vertebral column. The sigmoid can be seen coming from above and ending in the rectum lying at the back. At the front side of the pelvis lies the bladder. Wedged between the bladder and rectum lies the uterus. The situation is somewhat simpler in the male. With only the rectum at the back and the bladder at the front. And below the bladder note the prostate. And this brings us to the end of our tour. We saw all the major structures of the abdomen. We saw how they are arranged, from front to back and from top to bottom in the abdominal cavity.
