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TOPOGRAPHIC ANATOMY OF THE ORGANS OF THE
ABDOMINAL CAVITY
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The boundaries of the abdominal cavity are: the diaphragm - superiorly, the anterior
abdominal wall - anteriorly, the posterior abdominal wall - posteriorly, the pelvic brim (or
linea terminalis) - inferiorly.
The peritoneum is a thin serous membrane lining the walls of the abdominal and
pelvic cavities and clothing the abdominal and pelvic viscera. The parietal peritoneum lines
the walls of the abdominal and pelvic, and the visceral peritoneum covers the organs.
The potential space between the parietal and visceral layers of peritoneum is called
the peritoneal cavity. In the male this is closed cavity, but in the female there is a
communication with the exterior trough the uterine tubes, the uterus, and the vagina.
Relation of the peritoneum to the organs is different. Organs which surrounded
by peritoneum in all its sides are termed intraperitoneal. They have the large mobility.
Organs which surrounded by peritoneum on the three sides are termed
mesoperitoneal.
Organs which surrounded by peritoneum on the one side are termed retroperitoneal,
they lie behind the peritoneal cavity. This means that organ is covered only in the front by
peritoneum. Examples of retroperitoneal organs are the pancreas, the large part of the
duodenum, the kidneys, the ureÂters.
The abdominal cavity is divided into two parts by the transverse colon and its
mesocolon. They are the superior floor or the supracolic compartment and the inferior floor
or the infracolic compartment.
The liver, stomach, spleen, pancreas, superior part of the duodenum, gallblader are
located in the superior floor of the abdominal cavity. The inferior part of the duodenum,
the small intestine, the large intestine are located in the inferior floor of the abdominal
cavity.
The peritoneum forms the bursae, the pouches (or fossae), spaces, gutters and
sinuses.
The omental bursa or lesser sac, pregastric bursa, right and left hepatic bursae,
subhepatic space are located into the superior floor of the abdominal cavity.
The lateral or paracolic gutters, the mesenterial sinuses, the peritoneal pouches
(superior and inferior duodenojejunal fossae, superior and inferior iliocecal fossae,
retrocecal fossa, intersigmoid fossa) are located into the inferior floor of the abdominal
cavity.
The omental bursa or lesser sac is situated behind the lesser omentum and stomach
and lying in front of structures situated on the posterior abdominal wall. It projects upward
as far as the diaphragm and downward between the layers of the greater omentum. The
lower part of the lesser sac is often obliterated by the adherence of the anterior layers of
the greater omentum to the posterior layers. Its left margin is formed by the spleen and its
ligaments. The left part of the transverse mesocolon limits of this bursa from below.
The lesser omentum, posterior wall of the stomach and gastrocolic ligament form
the anterior wall of the omental bursa. The right margin of the sac opens into the greater
sac, that is the main part of the peritoneal cavity, through the opening of the lesser sac, or
epiploic foramen (Winslovi).
The opening into the lesser sac (epiploic foramen) has the following boundaries:
anteriorly - hepatoduodenal ligaments, posteriorly - the inferior vena cava, superiorly - the
caudate lobe of the liÂver, inferiorly - the first part of the duodenum.
The right heÂpatic bursa or right subphrenic space lie between the diaphragm superiorly and the right lobe of the liver - inferiorly. The falciform ligament limits this
space on the left. The right coÂronary ligament and right triangular ligament form the
posterior wall of the right hepatic bursa.
The left hepatic bursa lie between the diaphragm - superiorly and the left lobe of
the liver - inferiorly. The falciform ligament limits this space on the right. The left coronary
ligament and the left triangular ligament form the posterior wall of the left hepatic bursa.
This bursa is communicated with the pregastric bursa.
The pregastric bursa is limited by the left lobe of the liver and diaphragm superiorly, by the lesser omentum and anterior wall of the stomach - posteriorly, by the
parietal peritoneum of the anterior abdominal wall - anteriorly, by the transverse colon  inferiorly. The left hepatic bursa and the pregastric bursa together compose the left
subphrenic space.
The subhepatic space lies between the inferior visceral surface of the liver and the
transverse colon and its mesocolon.
Folds of peritoneum associated with the ascending part of the duodenum and
duodenojejunal junction may form small recesses or fossae. The importance of these lies
only in that very occasionally a piece of small intestine may become trapped in one and
form an internal hernia. The two fossae most commonly found are the superior and inferior
duodenojejunal fossae.
The presens of folds of peritoneum in the vicinity of the cecum creates three
peritoneal fossae: the superior iliocecal, the inferior iliocecal, and the retrocecal fossae.
The intersigmoid fossa is situated at the apex of the inÂverted, V-shaped root of the
sigmoid mesocolon. Its mouth opens downward and lies in front of the left ureter.
PARACOLIC GUTTERS
The arrangement of the ascending and descending colon, the attachments of the
transverse mesocolon and the mesentery of the small intestine to the posterior abdominal
wall, result in formation of four important paracolic gutters. These gutters lie on the lateral
and medial sides of the ascending and descending colons, respectively. The gutters, which
lie on the lateral sides are called lateral canals. The gutters, which lie on the medial sides
are called mesenterial sinuses.
The right lateral canal is limited by the ascending colon - medially and by the
peritoneum covering lateral abdominal wall - laterally. This canal is communicated with
the right hepatic bursa, subhepatic space.
The left lateral canal is limited by the descending colon - medially and by the
peritoneum covering lateral abdominal wall - laterally. This canal is separated from the
area around the spleen by the phrenicocolic ligament, a fold of peritoneum that passes from
the left colic flexure to the diaphragm. But this canal freely is communicated with the pelvic
cavity (pouch of Douglas).
The mesenterial sinuses are triangular-shaped spaces. The right mesenterial sinus
is limited by the ascending colon - on the right, the colon transverse and mesocolon superiorly and by the mesentery of the small intestine - on the left.
The left mesenterial sinus is limited by the descending coÂlon - on the left, the
colon transverse and mesocolon - superiÂorly and by the mesentery of the small intestine
- on the right. It is interesting to note that the right mesenterial sinus is closed off from the
pelvic cavity inferiorly by the mesentery of the small intestine, while the others are in free
communication with the pelvic cavity.
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ABDOMINAL PART OF THE ESOPHAGUS
The esophagus passe through the muscular part of the diaphragm in company with
the anterior and posterior vagal trunks at the level of the tenth thoracic vertebra. After a
course of about 1,25 cm, it enters the stomach on its right side (cardiac region). It is covered
on its anteriorly to the posterior surface of the left lobe of the liver and posteriorly to the
left crus of the diaphragm. The left and right vagi lie on its anterior and posterior surfaces,
respectively. The right margin of the esophagus passe in the lesser curvature. The left
margin of the esophagus forms cardiac notch or Giss angle with the fundus of the stomach.
The esophagus forms a functional sphincter controlling the entry of food to the
stomach and preventing reflex of stomach contens with the diaphragm. Dysfunction of this
sphincter may lead to the accumulation of food in the thoracic esophagus and its subsequent
dilatation.
Also, parts of the stomach or other mobile abdominal organs may pass into the
thoracic cavity through defects in the esophageal diaphragmatic opening or hiatus. These
hiatal defects may be congenital or acquired. The abdominal esophagus is supplied by a
branch of the left gastric artery and drained by the left gastric vein. Its autonomic nerve
supply is received from the two vagi (parasimpathetic) and the splanchnic nerves
(sympathetic).
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THE STOMACH
The stomach is a mobile muscular and distensible organ lying between the
esophagus proximally and the duoudenum distally. The stomach is situated in the upper
part of the abdomen, extending from beneath the left costal margin region into the
epigastric and umbilical regions. Its long axis passes downward and forward to the right
and then backward and slightly upward. Much of the stomach lies under cover of the lower
rib. It is roughly V-shaped and has two opening, the cardiac and pyloric orifices, two
curvatures known as the greater and lesser curvatures, and two surfaces, an anterior and a
posterior surface. Its anterior and posterior surfaces are covered by peritoneum and its
greater and lesser curvatures this is reflected onto the greater and lesser omenta,
respectively.
The stomach is divided into the followings parts: The founds is dome-shaped and
projects upward and to the left of the cardiac orifice. It is usually full of gas. The body
extends from the level of the cardiac orifice to the level of the incisura angularis, a constant
notch in the lower part of the lesser curvature. The funnel-shaped pyloric part which begins
at the incisura and may be divided into the pyloric antrum and the pyloric canal.
The lesser curvature forms the right border of the stomach and extends from the
cardiac orifice to the pylorus. The lesser omentum extends from the lesser curvatur to the
liver, and consists of three ligaments: phrenicogastricum, hepatogastricum and
hepatoduodenal. The greater curvatur is much longer than the lesser curvature and extends
from the left of the cardiac orifice over the dome of the fundus, and then sweeps around
and to the right to the inferior part of the pylorus. The gastrosplenic ligament extends from
the upper part of the greater curvature to the spleen, and the greater omentum extends from
the lower part of the greater to the transverse colon.
The stomach is related anteriorly – to anterior abdominal wall, the left costal
margin, the diaphragm, the left pleura and lung, and the left lobe of the liver. To the left,
contact is made with the spleen. Posteriorly – the stomach is again related to the
diaphragm and also to the suprarenal gland, the upper pole of the left kidney, the pancreas
and the left colic flexure. These structures together with the spleen are said to form the bed
of the stomach, but it should be remembered that all are reparated from the stomach by the
peritoneum forming the lesser sac. Inferiorly the stomach is related to the transverse colon.
The stomach has an extremely rich blood supply. The vessels contributing to this
supply are the left and right gastric arteÂries, the short gastric arteries, and the left and
right gastroÂepiploic arteries. Each of these vessels is directly or indiÂrectly a branch of
the celiac trunk, the first midline branch of the abdominal aorta.
The veins which accompany these arteries drain into the portal vein or its tributaries.
The left gastric artery passes upward and to the left to reach the esophagus and
descends along the lesser curvature of the stomach. It supplies the lower third of the
esophagus and the upper right part of the stomach. The right gastric artery arises from the
hepatic artery at the upper border of the pyloÂrus and runs to the left along the lesser
curvature. It supplies the lower right part of the stomach. The short gastric arteries arise
from the splenic artery at the hilus of the spleen and pass forward in the gastrosplenic
ligament to supply the fundus. The left gastroepiploic artery arise from the splenic artery
at the hilus of the spleen and passes forward in the gastrosplenic ligament to supply the
stomach along the upper part of the greaÂter curvature. The right gastroepiploic artery
arises from the gastroduodenal branch of the hepatic artery. It passes to the left and supplies
the stomach along the lower part of the greaÂter curvature.
THE INNERVATION OF THE STOMACH
The stomach is supplied by both sympathetic and parasympathetic nerves.
Sympathetic nerves reaching the stomach are derived from autonomic plexuses on nearly
arteries, the largest of which is the celiac plexus. These nerves are vasomotor to the gastric
blood vessels and carry pain fibers from the stomach. The parasympathetic supply is
provided be the vagus. The anterior vagal trunk, which is formed in the thorax mainly from
the left vagus nerve, enters the abdomen on the anterior surface of the esophagus. The
trunk, which may be single or multiple then divides into branches that supply the anterior
surface of the stomach. A large hepatic branch passes up to the liver, and from this a pyloric
branch passes down to the pylorus.
The posterior vagal trunk, which is formed in the thorax mainly from the right vagus
nerve, enters the abdomen on the posterior surface of the esophagus. The trunk then divides
into branches that supply mainly the posterior surface of the stomach. A large branch passes
to the celiac and superior mesenteric plexuses and is distributed to the intestine as far as
the splenic flexure and to the pancreas. The gastric branches themselves form plexuses in
the muscular and submucosus coats of the stomach and postganglionic fibers control
muscular activity and secretion.
The fundus and proximal part of the body of the stomach are compliant to permit
storage of ingested food. This adaptive reÂlaxation is mediated through the vagus and loss
of this adaptaÂtion following highly selective vagotomy gives rise to the very common
feeling of bloating following this operation. The lower body and antrum of the other hand
has greater motor activity, acting as a mechanical mill to mix ingested food and deliver it
in liquid form (chyme) through the pylorus. The nerve fibers which control this motor
activity pass along the nerve of LaterÂjet.
The pyloric sphincter is a well defined ring of circular muscle dividing stomach
from duodenum. This sphincter regulates the rate of delivery of chyme into the duodenum
and prevents duÂodenogastric reflux although the mechanisms controlling this are not well
understood.
The stomach has both sympathetic and parasympathetic innerÂvation, the latter
provided by the vagus...
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