The Omentum, Summaries of Anatomy

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The Omentum

Gastrointestinal block-Anatomy-Lecture 5

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Color guide : Only in boys slides in Green Only in girls slides in Purple important in Red

At the end of the lecture, students should be able to: Notes in Grey

Objectives

● Brief knowledge about peritoneum as a thin

serous membrane and its main parts; parietal

and visceral.

● The peritonial cavity and its parts the greater sac

and the lesser sac (Omental bursa).

● The omentum, as one of the peritonial folds

● The greater omentum ,its extends, and contents.

● The lesser omentum, its boundaries, and contents

● The Omental bursa, its boundaries.

● The Epiploic foramen, its boundaries.

Intraperitoneal and retroperitoneal structure:

describe the relationship between various organs and their peritoneal covering.

Intraperitoneal Retroperitoneal

Is entirely surrounded by the visceral peritoneum and has a supporting mesentery :

● Stomach ● 1st Part Of Duodenum ● Liver ● Gallbladder ● Spleen ● Jejunum ● Ileum ● Transverse Colon ● Sigmoid Colon ● Uterus ● Ovaries

Structure that lies behind the parietal peritoneum or partially covered by the peritoneum and has no supporting mesentery.

● Primary retroperitoneal organs: ○ Aorta ○ Inferior Vena Cava ○ Kidneys ○ Suprarenal Glands ○ Urinary Bladder ○ Vagina ○ Rectum.

● Secondary retroperitoneal organs: develop in mesenteries, but get pushed against the body wall (parietal peritoneum) during growth so that only half of their surface is covered by peritoneum : ○ Pancreas ○ Duodenum ○ Ascending Colon ○ Descending Colon.

Omenta

Two layered fold of peritoneum connecting the stomach to another viscus.

The lesser omentum The greater omentum

The largest peritoneal fold, with cribriform appearance,

Attaches the lesser curvature of the stomach to theliver.^ the greater curvature of the stomach to the transverse colon.

Course

(1) It is continuous with the two layers of peritoneum which cover the anterior & posterior surfaces of stomach and 1st part of the duodenum. (2) Ascend as a double fold to the porta hepatis of liver, and (3) fissure for ligamentum venosum

It consists of a double sheet of peritoneum, folded on itself so that it is made up of four layers (2 anterior ,2 posterior). (1) The two layers which descend from the greater curve of the stomach and commencement of the duodenum, pass downward in front of the small intestines, then (2)turn upon themselves, and (3) ascend to the transverse colon, where they separate and enclose it.

Left Border

To the left of porta hepatis it is carried to the diaphragm.

continuous with the gastrosplenic ligament.

Right Border

is a free margin; constitutes the anterior boundary of the epiploic foramen

extends as far as the commencement of the duodenum.

Content

★ Close to the right free margin, are the hepatic artery, common bile duct, portal vein, lymphatics, and hepatic plexus ★ At the attachment to the stomach, run the right and left gastric vessels.

● Adipose tissue. ● Right & left gastroepiploic vessels and The anastomosis between them ● Lymph nodes

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2

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2

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The lesser omentum right border left border

The greater omentum right border left border L L

R R

❖ Two-layered folds of peritoneum that attach solid viscera to the abdominal wall and diaphragm ❖ its doubling up of visceral peritoneum and connecting viscera to the viscera or the abdominal wall ❖ Ligaments of liver:

❖ Two-layered fold of peritoneum suspends the small intestine from the posterior abdominal wall ❖ its doubling up of visceral peritoneum and wrapping around an organ, then attaches it to posterior abdominal ❖ Broad and a fan-shaped ❖ Intestinal border: folded, 7cm long ❖ Root of mesentery: ➔ 15 cm long ➔ Directed obliquely from duodenojejunal flexure at the level of left side of L2 to the ileocecal junction in the right iliac fossa at the level of right sacroiliac joint.

(^2) Coronary ligament

(^3) Left and right triangular ligaments

(^4) Ligamentum teres

(^1) Falciform of liver

Mesentery and Ligaments

Mesentery Ligaments

Nerve supply of peritoneum

Visceral

peritoneum

parietal

peritoneum

● The parietal peritoneum lining the anterior abdominal wall is supplied by: ○ Thoracic nerves T7-12 (Lower 6 intercostal nerves) and L 1 (iliohypogastric nerve) ● The central part of the diaphragmatic peritoneum is supplied by ○ phrenic nerves, C3,4,and 5 ● Peripheral part of the diaphragmatic peritoneum supplied by ○ intercostal nerves T7- ● pelvic wall by ○ obturator nerve L2,3,and 4

Clinical point : ● it sensitive to: pain.temperature,touch and pressure. ● Abdominal pain originating from the parietal peritoneum is therefore of the somatic type, it is usually severe, and can be accurately localized

● Supplied by autonomic afferent nerves that supply the viscera or traveling in the mesenteries.

Clinical point : ● its sensitive only to stretch and tearing. ● The visceral peritoneum, including the mesenteries, It is due to Stretch caused by over distension of a viscus and pulling on a mesentery that gives rise to the sensation of pain. ● leading to poorly localized, poorly characterized pain. (dull, cramping, aching)

● Peritoneal Dialysis: Because the peritoneum is a semi permeable membrane : It allows transfer of substances across itself. It has been made use of in patients with acute renal insufficiency.

Members board

● Abdulrahman Shadid ● Ateen Almutairi

Girls team :

● Ajeed Al Rashoud ● Taif Alotaibi ● Noura Al Turki ● Amirah Al-Zahrani ● Alhanouf Al-haluli ● Sara Al-Abdulkarem ● Renad Al Haqbani ● Nouf Al Humaidhi ● Jude Al Khalifah ● Nouf Al Hussaini ● Danah Al Halees ● Rema Al Mutawa ● Maha Al Nahdi ● Razan Al zohaifi ● Ghalia Alnufaei

Team leaders

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Boys team:

● Mohammed Al-huqbani ● Salman Alagla ● Ziyad Al-jofan ● Ali Aldawood ● Khalid Nagshabandi ● Sameh nuser ● Abdullah Basamh ● Alwaleed Alsaleh ● Mohaned Makkawi ● Abdullah Alghamdi