Peritoneal development, step 2, model, Rotation of the bowels

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From the course by Universiteit Leiden

Anatomy of the Abdomen and Pelvis; a journey from basis to clinic.

321 ratings

Universiteit Leiden

Anatomy of the Abdomen and Pelvis; a journey from basis to clinic.

321 ratings

In this anatomy course you will explore the organs involved in our food digestion and discover the common causes of abdominal and pelvic pain. The latest graphics and animations will help you to find new insights and understanding of this part of the body, that has been the focus of anatomical research for centuries and presently arouses renewed scientific interest. You will explore the 3D anatomy of the organs from a basic level, providing thorough anatomical understanding, to its advanced application in surgical procedures. This course will challenge you to discover and help you to understand the anatomy of the abdomen and pelvis in all its aspects, ranging from its embryological underpinnings, via digital microscopy to gross topography and its clinical applications. The course is unique in that it continuously connects basic anatomical knowledge from the lab with its medical applications and current diagnostic techniques. You’ll get the chance to discuss anatomical and clinical problems with peers and experts in forum discussions and you will receive guidance in exploring the wealth of anatomical information that has been gathered over the centuries. Follow us on an exciting journey through the abdomen and pelvis where you digest your food but also where new life starts!

From the lesson

Knowing your peritoneal relationships

You have already learned that the bowels are not arranged symmetrically left and right. The rotation processes of the gut and its suppliers have important consequences for the peritoneal coverings of the gut and the abdominal wall. It determines why some structures lie easily accessible in the abdomen and others are more hidden away. In this week you will get a grip on difficult concepts as 'intraperitoneal' and 'retroperitoneal'. It is also a starter week about abdominal surgery. You will also learn a secret: The best way to mobilize the abdominal and pelvic organs is to separate what got adhered when the patient was just an embryo! Please feel free to dive into these embryonic matters and enjoy all the twists and turns!

Peritoneal development1:04

Peritoneal development, step 0, model, Introduction8:09

Peritoneal development, step 1, model, Rotation of stomach, duodenum, pancreas3:57

Peritoneal development, step 2, model, Rotation of the bowels8:18

Peritoneal development, step 3, model. Development of the greater omentum4:06

Anatomy on the table - Peritoneal structures and relations – an overview6:51

Meet the Instructors

Marco De Ruiter, PhD
Professor of Clinical and Experimental Anatomy
Leiden University Medical Centre
Paul Gobée, MD
Assistent professor of Anatomy
Leiden University Medical Centre
Beerend P. Hierck, PHD.
Associate professor of developmental biology
Leiden University Medical Center
Daniël Jansma, MSc
E-Learning developer
Leiden University Medical Centre
Bas Boekestijn, MD
Trainee Radiology
Leiden University Medical Centre
Friso Jansen
Drs.
Leiden University Medical Centre

Okay, this is the short video in the series about the Rotation of

the Peritoneum or the Development of the Peritoneum during the embryological phase.

This is going to depict you the rotation of the intestines.

During the sixth to the eighth week of the embryological development,

the intestines grew so fast that they grew out of the body of the embryo,

into the umbilical cord that protruded outside the embryo.

And that's depicted here.

And you see at topside coming from the duodenum

is the small intestine and at the bottom side is the large intestine.

Then as the embryo grows at it's 10th or 11th week,

there's enough space again for the guts to go back into the embryo,

and it returns into the embryo, and at the same time, it rotates.

In fact, a part of rotation has already accrued during the phase,

that's the gut goes out of the embryo but I'll skip that for the purpose of ease.

So I'm going to demonstrate to you the rotation that happens of the intestine and

you must imagine that the large intestine rotates over the small intestine.

In fact more precise, it rotates around the superior

mesenteric artery and it rotates in this direction.

In this direction.

Now I'm going to demonstrate it to you.

So the large intestine rotates over the small intestine and

it draws with it its mesentery.

And at the same time it retracts in the body.

And now you see that this gives rise to the well

known configuration of the ascending colon,

transverse colon and descending colon

with the small intestine below it.

And actually if you look well you can see that large intestine,

the colon has crossed over the small intestine over the small bowel.

Then after it has rotated back into the body the ascending and

the descending colon adhere to the back wall like

this and

this, and therefore they became secondary retroperitoneal.

It seems now that they're behind the peritoneum, but

after they were infraperitoneal, first they're called secondary retroperitoneal.

And again, the surgeon makes very practical use of this fact.

If a surgeon wants to remove a part of the colon, in fact what the surgeon

does is detach this adherence that's arose during the embryological phase.

So I think it's very fascinating that a surgeon,

if a patient is let's 40, 50, 60 years old, it uses the,

fact what happens during the embryological phase of that person,

so 50, 60 years ago the colon attached and the surgeon simply detaches the colon.

And the great thing of that manuever is that

as the mesentery also get detached at that moment.

The surgeon automatically, in a safe way,

detaches the blood vessels from the back wall.

So, there is no, or little risk of cutting the blood vessels.

So, so far, about the ascending, and the descending colon,

the transverse colon, in contrary to that, does not attach to the back wall, and

the transverse colon If hanging on the transfers mesocolon.

And you see that the transverse colon can be easily moved, it remains loose, so

it remains infraperitoneal and now I mentioned the word mesocolon.

In fact the mesentery is called after the part of the intestines that it attaches.

So this is the transverse colon and the mesentery that attaches to it is

the transverse miso colon and you must imagine that this part of the mesentery

that attaches the ascending colon is called the ascending mesocolon.

And here we have the descending mesocolon.

And the ascending and the descending mesocolons are,

just as the colons themselves, they're attached to the back wall.

Finally, we have the intestines that are here,

the smaller intestines and as you see and I'll move over a little bit.

As you see I have to put away all this peritoneum

as you see the small intestines seems to

arise from the depths because it has crossed over behind the colon.

So it arises from the depth.

And then here we have the small intestine.

And that's connected to the back wall

via this double layer of peritoneal this mesentery.

And we simple call that the mesentery.

And this point where it arises from the depth as a kind of fountain is a surgical,

very important landmark because you can imagine that

the surgeon can follow the intestine all the way to there and

can't go further because then the intestine goes into the depth.

And that point is called the point of plates.

And it's also by definition the transition

point of the duodenum to the jejunum.

Now, then finally one can imagine that

here's the ascending major colon.

Here's the mesentery.

The ascending major colon is fixed to the back.

The mesentery which is the small intestine is mobile.

And in fact there's a,

Line where the mesentery detaches from the back wall.

That's this line, an oblique line,

running from the point of traits to the ileocecal junction.

This line is called the root of the mesentery.

And that's because it's also the line where

the mesentery here more or less bulges out or

it radiates from the back wall to the intestine.

And you must imagine that this line is more or less 20 centimeters long.

But the intestine is maybe a couple of meters long.

So therefore it's called the root.

Okay, so at the end we have the configuration with descending colon,

ascending colon being secondary retroperitoneal,

a transverse colon being intraperitoneal, and

the small intestine also being intraperitoneal.

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