Fondamenti di anatomia e istologia › dati › corsi › 95005 › 95960-Lez7d... · Omental bursa...

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Fondamenti di anatomia e istologia

aa. 2019-20

Lesson 7. Digestive system and peritoneum

Peritoneum, abdominal vessel

and spleen

= a thin serous membrane that line walls of abdominal and pelvic cavities and cover organs within these cavities •Parietal peritoneum －lines walls of abdominal and pelvic cavities •Visceral peritoneum －covers organs •Peritoneal cavity － potential space between parietal and visceral layer of peritoneum, in male, is a closed sac, but in female, there is a communication with exterior through uterine tubes, uterus, and vagina

PERITONEUM: General features

Function

• Secretes a lubricating serous fluid that continuously moistens associated organs

• Absorb • Support viscera

Peritoneum Histology

The peritoneum is a serosal membrane that consists of a single layer of mesothelial cells and is supported by a basement membrane.

The layer is attached to the body wall and viscera by a glycosaminoglycan matrix that contains collagen fibers, vessels, nerves, macrophages, and fat cells.

relationship between viscera and peritoneum

• Intraperitoneal viscera －viscera completely surrounded by peritoneum, example, stomach, superior part of duodenum, jejunum, ileum, cecum, vermiform appendix, transverse and sigmoid colons, spleen and ovary

• Interperitoneal viscera －most part of viscera surrounded by peritoneum, example, liver, gallbladder, ascending and descending colon, upper part of rectum, urinary bladder and uterus

• Retroperitoneal viscera －some organs lie on the posterior abdominal wall and are covered by peritoneum on their anterior surfaces only, example, kidney, suprarenal gland, pancreas, descending and horizontal parts of duodenum, middle and lower parts of rectum, and ureter

Intraperitoneal viscera

Interperitoneal viscera

Retroperitoneal viscera

Interperitoneal viscera

Structures which are formed by peritoneum

Omentum = 2-layered fold of peritoneum that extends from stomach to adjacent organs

Structures which are formed by peritoneum

Lessor omentum

2-layered fold of peritoneum which extends from porta hepatis to lesser curvature of stomach and superior part of duodenum

• Hepatogastric ligament －extends from porta hepatis to lesser curvature of stomach

• Hepatoduodenal ligament Extends from porta hepatis to superior part of duodenum

– Contains common bile duct, proper hepatic a. and hepatic portal v.

• Behind the right border of hepatoduodenal ligament

• Superior－caudate lobe of liver

• Inferior－superior part of duodenum

• Anterior－hepatodudenal ligament

• Posterior－peritoneum covering the inferior vena cava

Omental foramen

Greater omentum －four-layered fold of

peritoneum, the anterior two layers descend from the greater curvature of stomach and superior part of duodenum and hangs down like an apron in front of coils of small intestine, and then turns upward and attaches to the transverse colon. If an infection occurs in the intestine, plasma cells formed in the lymph nodes combat the infection and help prevent it from spreading to the peritoneum.

Structures which are formed by peritoneum

Lessor omentum

Greater omentum

Structures which are formed by peritoneum

Omental bursa Position－situated behind the lesser omentum

and stomach Walls • Superior－peritoneum which covers the

caudate lobe of liver and diaphragm • Anterior－formed by lesser omentum,

peritoneum of posterior wall of stomach, and anterior two layers of greater omentum

• Inferior－conjunctive area of anterior and posterior two layers of greater omentum

• Posterior－formed by posterior two layers of greater omentum, transverse colon and transverse mesocolon, peritoneum covering pancreas, left kidney and suprarenal gland

Structures which are formed by peritoneum

• Left－formed by the spleen, gastrosplenic ligament and splenorenal ligament

• Right－formed by omental foramen

The Omental bursa (lesser sac) communicates with the greater sac through the omental foramen.

Structures which are formed by peritoneum

Mesenteries or mesocolons－two-layered fold of peritoneum that attach part of the intestines to the posterior abdominal wall

Structures which are formed by peritoneum

Mesentery －suspends small intestine

from posterior abdominal wall

• Broad and a fan-shaped

• Consists of two peritoneal layers

• Intestinal border－folded, 7 m long

• Radix of mesentery – 15 cm long

– Directed obliquely from left side of L2 to in front of right sacroiliac joint

Structures which are formed by peritoneum

Structures which are formed by peritoneum

Mesoappendix • Triangular mesentery－extends from terminal part of ileum to appendix

• Appendicular artery runs in free margin of the mesoappendix

Structures which are formed by peritoneum

Transverse mesocolon －a double fold of peritoneum which connects the transverse colon to the posterior abdominal wall

Sigmoid mesocolon －inverted V-shaped, with apex located in front of left ureter and division of common iliac artery

Structures which are formed by peritoneum

Ligaments －two-layered folds of

peritoneum that attached the lesser mobile solid viscera to the abdominal wall

Ligaments of liver

• Falciform ligament of liver – Consists of double peritoneal

layer – Extends from anterior

abdominal wall (umbilicus) to live

– Free border of ligament site of ligamentum teres

Structures which are formed by peritoneum

• Coronary ligament －the area between upper and lower parts of the coronary ligament is the bare area of live, this area is devoid of peritoneum and lies in contract with the diaphragm

• Left and right triangular ligaments

－formed by right extremity of coronary ligament and left leaf of falciform ligament, respectively

Structures which are formed by peritoneum

• Hepatogastric ligament

• Hepatoduodenal ligament

• Ligamentum teres hepatis

Structures which are formed by peritoneum

Ligaments of spleen • Gastrosplenic ligament -

a double layer of peritoneum that connects the fundus of stomach to hilum of spleen. In this double layer of peritoneum are the short gastric and left gastroepiploic vessels

• Splenorenal ligament -extends between the hilum of spleen and anterior aspect of left kidney. The splenic vessels lies within this ligament, as well as the tail of pancreas

• Phrenicosplenic ligament • Splenocolic ligament

Structures which are formed by peritoneum

Ligaments of stomach

• Hepatogastric ligament • Gastrosplenic ligament • Gastrophrenic ligament • Gastrocolic ligament • Gastropancrestic ligament

Structures which are formed by peritoneum

Folds and recesses of posterior abdominal wall

• Superior duodenal fold and recess

• Inferior duodenal fold and recess

• Intersigmoid recess －formed by the inverted V attachment of sigmoid mesocolon

Structures which are formed by peritoneum

• Retrocecal recess - in which the appendix frequenty lies

• Hepatorenal recess - lies between the right lobe of liver, right kidney, and right colic flexure, and is the lowest parts of the peritoneal cavity when the subject is supine

Structures which are formed by peritoneum

Folds and fossas of anterior abdominal wall • Median umbilical fold －

contain the remnant of urachus (median umbilical ligaments)

• Medial umbilical fold －contains remnants of the umbilical arteries (medial umbilical ligaments)

• Lateral umbilical fold －contains the inferior epigastric vessels

• Supravesical fossa • Medial inguinal fossa • Lateral inguinal fossa

Structures which are formed by peritoneum

Pouches

• In male－rectovesical pouch

• In female – Rectouterine pouch －between rectum and uterus

– Vesicouterine pouch －between bladder and uterus

Structures which are formed by peritoneum

Peritoneal subdivisions The transverse colon and

transverse mesocolon divides the greater sac into supracolic and infracolic compartments.

Supracolic compartments

(subphrenic space)－lies between diaphragm and transverse colon and transverse mesocolon

Suprahepatic recess lies between the diaphragm and live－the falciform ligament divides it into right and left suprahepatic recesses

Structures which are formed by peritoneum

• Left suprahepatic recesses – left anterior suprahepatic

spaces

– left posterior suprahepatic spaces

• Right suprahepatic recesses – right anterior suprahepatic

spaces

– right posterior suprahepatic spaces

– bare area of live (extraperitoneal space)

Structures which are formed by peritoneum

Infrahepatic recess

lies between the liver and transverse colon and transverse mesocolon－the ligamentum teres hepatic divides it into right and left infrahepatic recesses

• Right infrahepatic recesses (hepatorenal recess)

• Left infrahepatic recesses

– left anterior infrahepatic space

– left posterior infrahepatic space

Structures which are formed by peritoneum

Infracolic compartments －lies below the transverse colon and transverse mesocolon

• Right paracolic sulcus (gutter) • －lies lateral to the ascending colon.

It communicates with the hepatorenal recess and the pelvic cavity. It provides a route for the spread of infection between the pelvic and the upper abdominal region.

• Left paracolic sulcus (gutter) • －lies lateral to the descending colon.

It is separated from the area around the spleen by the phrenicocolic ligament, a fold of peritoneum that passes from the colic flexure to the diaphragm.

Structures which are formed by peritoneum

• Right mesenteric sinus －triangular space, lies between root of mesentery, ascending colon, right 2/3 of transverse colon and transverse mesocolon

• Left mesenteric sinus －lies between root of mesentery, descending colon, right 1/3 of transverse colon and transverse mesocolon, its widens below where it is continuous with the cavity of the pelvis

Structures which are formed by peritoneum

Supracolic region

Structures which are formed by peritoneum

abdominal part of esophagus

stomach

duodenum

liver

extrahepatic biliary apparatus

spleen

pancreas

ABDOMINAL VESSELS

Abdominal aorta • Continuation of

thoracic aorta at aortic hiatus of diaphragm in front of T12

ABDOMINAL VESSELS

• Terminates at lower border of L4 vertebra by dividing into right and left common iliac arteries

Parietal branches • Inferior phrenic a.

(one pair)

• Lumbar a. (four

pairs of arteries that

supply the posterior

abdominal wall)

• Median sacral a.

ABDOMINAL VESSELS

Visceral branches

• Paired branches – Middle suprarenal

artery

– Renal artery

– Testicular (ovarian) artery

ABDOMINAL VESSELS

• Unpaired branches – Celiac trunk

– －a short thick vessel that arises from the front of aorta, at the level of T12

– Superior mesenteric a. －arises from the front of aorta, at the level of L2

– Inferior mesenteric a. －arises from the front of aorta, at level of L3

ABDOMINAL VESSELS

Left gastric a.

Common

hepatic a. Splenic a.

Gastroduodenal a.

Proper hepatic a.

Right gastric a.

Left branch

Right branch

Cystic a.

Short gastric a.

Left gastrioeploic a.

Right gastroepiploic a.

Superior pancreaticoduodenal a.

Splemic branches

Celiac trunk

ABDOMINAL VESSELS

Celiac trunk

ABDOMINAL VESSELS

Superior

mesenteric a.

Inf. pancresticodudenal a.

Jejunal and ileal a. Ileocolic a.

Appendicular a.

Right colic a.

Middle colic a. Superior

Mesenteric v.

ABDOMINAL VESSELS

Inferior mesenteric a.

Left colic a.

Sigmoid a.

Superior rectal a.

Inferior mesenteric v. ABDOMINAL VESSELS

Colic marginal artery

ABDOMINAL VESSELS

Relations of abdominal aorta

• Anteriorly (from above

downward)

– Pancreas

– Ascending part of duodenum

– Radix of mesentery

• Posteriorly

– Upper four lumber vertebrae

• On its right

– Inferior vena cava

• On its left

– Left sympathetic trunk

ABDOMINAL VESSELS

Veins of abdomen and pelvis

Internal iliac vein • Parietal tributaries: accompany with arteries

• Visceral tributaries

→superior rectal vein→inferior mesenteric v.

①Rectal venous plexus →inferior rectal vein→internal iliac v.

→anal vein→internal pudendal v.

②Vesical venous plexus →vesical v.

③Uterine venous plexus →uterine v.

ABDOMINAL VESSELS

• External iliac vein– accompany the artery

• Common iliac vein– formed by union of internal and external iliac veins in front of sacroiliac joint, end upon L4~L5 by uniting each other to form inferior vena cava

ABDOMINAL VESSELS

Inferior vena cava • Formed by union of two

common iliac veins anterior to and just to the right of L4~L5

• Ascends on the right side of aorta, pierces vena cava foramen of diaphragm opposite the T8 and drains into the right atrium

• Conveys blood from the whole body below the diaphragm to the right atrium

ABDOMINAL VESSELS

Chief tributaries • Parietal

– Paired inferior phrenic v.

– paired lumbar v. (four)

• Visceral

– Right and left renal veins

– Right suprarenal vein (left drain into left renal vein)

– Right testicular or ovarian v. (left drain into left renal vein)

– Hepatic veins : right, left and intermediate

ABDOMINAL VESSELS

Relations of inferior vena cava • Anteriorly (cranially to caudally)

– Liver

– Head of pancreas

– Horizontal part of duodenum

– Right testicular (or ovarian) a.

– Radix of mesentery

• Posteriorly – Right crus of diaphragm

– Upper four lumber vertebrae

– Left sympathetic trunk

– Parietal branches of abdominal aorta

• On its right – Psoas major

– Right kidney

– Right suprarenal gland

• On its left – Abdominal aorta

ABDOMINAL VESSELS

Hepatic portal vein

General features

• Formed behind the neck of pancreas by the union of superior mesenteric vein and splenic vein

• Ascends upwards and to the right, posterior to the first part of duodenum and then enters the lesser omentum to the porta hepatis, where it divides into right and left branches

• There are no functioning valves in hepatic portal system

• Drains blood from gastrointestinal tract from the lower end of oesophagus to the upper end of anal canal, pancreas, gall bladder, bile ducts and spleen

ABDOMINAL VESSELS

Variation and anomalies

of hepatic portal vein

ABDOMINAL VESSELS

Tributaries of

hepatic portal

vein

1. Superior mesenteric

v.

2. Inferior mesenteric v.

3. Splenic v.

4. Left gastric v.

5. Right gastric v.

6. Cystic v.

7. Paraumbilical v.

ABDOMINAL VESSELS

Portal-systemic anastomoses

1. At the lower end of the oesophagus Hepatic portal vein → left gastric vein → esophageal

venous plexus → esophageal vein → azygos vein

→ superiorvena cava

2. At rectal venous plexus Hepatic portal vein → splenic vein → inferior mesenteric

vein → superior rectal vein → rectal venous plexus →

inferior rectal and anal veins → internal iliac vein →

inferior vena cava

3. At periumbilical venous plexus Hepatic portal vein→paraumbilical vein→periumbilical

venous plexus→

– thoracoepigastric and superior epigastric vein → superiorvena cava

– superficial epigastric and inferior epigastric veins → inferior vena cava

ABDOMINAL VESSELS

4. Portal-retroperitoneal anastomosis

Between the retroperitoneal branches of the colic veins and the lumbar veins, pancreaticoduodenal veins with the renal veins and the subcapsular veins of the liver with the phrenic veins twigs of colic veins (portal) anastomosing with systemic retroperitoneal veins

ABDOMINAL VESSELS

Lymphatic drainage of

abdominal wall

• To axillary lymph node from

region above umbilicus

• To superficial inguinal lymph

node from region below

umbilicus

• To lumbar lymph node from

post wall of abdomen

Lymphatic drainage of abdomen

Lymphatic drainage of abdominal viscera

• Lumbar lymph nodes

– Lie on posterior abdominal wall, along the abdominal aorta and inferior vena cava

– Receive lymph from kidneys, suprarenal glands, testes, ovaris, fundus of uterus, ovary, and common iliac nodes

– Right and left lumbar trunks formed by efferent vessel

– Paired viscera－drain to the lumbar lymph nodes

Lymphatic drainage of abdomen

• Celiac lymph nodes －situated around the celiac trunk

• Superior mesenteric lymph node －situated around superior mesenteric a.

• Inferior mesenteric lymph node －situated around inferior mesenteric a.

• Intestinal trunk －formed by efferent vessel of celiac, superior and inferior lymph nodes

Lymphatic drainage of abdomen

Thoracic duct • Begins in front of L1 as a dilated sac, the cisterna

chyli, which formed by joining of left and right lumbar trunks and intestinal trunk

• Enter thoracic cavity by passing through aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein

• Travels upward, veering to left at the level of T5

• At the roof of the neck, it turns laterally and arches forwards and descends to enter the left venous angle

• Just before termination, it receives the left jugular, subclavian and bronchomediastinal trunks

• Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb

Lymphatic drainage of abdomen

Location: lies in the left

hypochondriac region

(between stomach

and diaphragm) deep

to the 9th to 11th rib,

its long axis

corresponds roughly

to the 10th rib

Shape－reddish in

colour

Spleen

Two surfaces

• Diaphragmatic: smooth, convex

• Visceral: concave, hilum of spleen

Two extremities

• Anterior－wider

• Posterior－rounder

Two border

• Superior－has 2-3 splenic notch, which serve as a landmark on palpation when it is enlarge; normally it is not palpable

• Inferior－rounder

Functions: considered to be important in:

• Formation of lymphocytes and monocyte

• Phagocytosis of bacteria, inert particles and white blood cells and platelets

• Destroying effete or abnormal red blood cells

• Making antibodies

Spleen

Erythrocyte storage

Phagocytosis Cytopoiesis Immune

responses

Spleen function

Relationships of spleen

Diaphragmatic surface

－diaphragm

Visceral surface

• Anteriorly－fundus of

stomach

• Posteriorly－left

suprarenal gland and

kidney

• Inferiorly－tail of

pancreas and left colic

flexure

Spleen

Spleen: Histology

Spleen: Histology

Spleen: Histology

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