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1. Anatomy of the stomach
Vishy Mahadevan
Abstract
The stomach is the widest part of the alimentary canal. Continuous
proximally with the abdominal oesophagus and distally with the duo-
denum, the stomach is ensleeved in peritoneum. The principal func-
tions of the stomach are: (i) to act as a receptacle and reservoir for
ingested food and to release the food into the duodenum in small
and physiologically appropriate amounts; (ii) to secrete hydrochloric
acid and proteolytic enzymes that initiate protein digestion and
neutralize harmful bacteria in the ingested food; and (iii) to churn the
ingested food and soften it with the help of gastric juice to produce
a liquefied mixture termed chyme. Embryologically, the stomach is
derived entirely from the foregut and this is reflected in the stomach
deriving its blood supply wholly from the coeliac axis. The past two de-
cades have seen a dramatic decline in the need for surgical interven-
tion in acid-peptic disease in the developed world. This has been due
largely to the advent of proton-pump inhibitors and to the discovery of
a medically treatable microbial cause for most cases of peptic ulcer
disease. In the present day, operations for gastric neoplastic disease
and bariatric surgery collectively account for most of the major gastric
surgical procedures in adults. This article describes in detail the
surgically relevant topographical anatomy of the stomach, including
its blood supply and lymphatic drainage.
Keywords Antrum; fundus; gastric blood supply; lesser sac;
lymphatic drainage; pylorus; stomach bed
External features
The stomach lies largely in the left hypochondrial region under
cover of the lower part of the rib cage. The lower and distal parts
of the stomach, however, lie in the epigastric and upper umbilical
regions of the abdomen. The stomach is a distensible organ. In
the adult, it has an average capacity of 1.5 litres. The stomach is
approximately J-shaped, although in certain individuals it may
lie transversely when it is known as a steer-horn stomach. The
size, shape and position of the stomach can vary considerably,
depending on the posture of the individual and on the state of
fullness of the stomach.
The empty stomach appears flattened. It presents anterior and
posterior surfaces, which are demarcated from each other by the
greater and lesser curvatures (Figure 1). The lesser curvature
forms the upper right border of the stomach while the greater
curvature forms the lower left border. The stomach has two
openings or orifices. The proximal one is termed the cardiac
orifice through which the stomach communicates with the
oesophagus. The distal orifice is the pyloric orifice through which
the stomach communicates with the duodenum. The regions of
the stomach adjacent to the cardiac and pyloric openings are
known as the cardia and pylorus, respectively. The main parts of
the stomach are the fundus, body and pyloric part.
The various parts of the stomach (Figure 1) have significant
physiological and histochemical differences and these are taken
into account by the endoscopist, radiologist and surgeon in the
diagnostic interpretation of gastric pathologies and their
management.
The fundus of the stomach is the part which projects upwards
above the level of the cardiac orifice. Lying to the left of the
abdominal oesophagus, it makes contact with the left dome of
the diaphragm. Two-thirds of the way from the cardiac orifice
along the lesser curvature of the stomach is a distinct notch, the
angular notch (incisura angularis). The body of the stomach
extends from the cardiac orifice to the level of the angular notch.
It is the largest and most distensible part of the stomach and is
the part that contains in its inner lining, the parietal cells which
secrete hydrochloric acid (HCl). The pyloric part of the stomach
extends from the angular notch to the gastro-duodenal junction.
It comprises the pyloric antrum proximally and the pyloric canal
distally. The distal end of the pyloric canal features a very
distinct ring of sphincter muscle, which is situated immediately
proximal to the pyloric orifice, and can be easily felt. This
sphincter is greatly thickened in the condition of infantile hy-
pertrophic pyloric stenosis. The position of the pyloric sphincter
is indicated by the presence of a fairly constant vein, the pre-
pyloric vein (of Mayo) that runs vertically on the anterior surface
of the pylorus.
The pyloric antrum produces the hormone gastrin, which is
responsible for the hormonal phase of gastric acid secretion.
Attached along the lesser curve is the lesser omentum, a
double-layered peritoneal sheet that extends from the lesser
curvature of the stomach to the visceral surface of the liver. At
the lesser curvature the two leaves of the lesser omentum
diverge; the anterior leaf covering the anterior wall of the
stomach and the posterior leaf adhering to the posterior wall. At
the greater curvature the two leaves meet to form the greater
omentum. The greater omentum hangs down like an apron from
Fundus
Body
Greater
curvature
Pyloric antrum
Sulcus intermedius
Pyloric canal
Duodenum
Pylorus
Lesser curvature
Cardiac region
Abdominal part
of oesophagus
Cardiac incisura
Incisura angularis
Figure 1 The borders and regions of the stomach (viewed from the
front)
Vishy Mahadevan MBBS PhD FRCS (Ed & Eng) is the Barbers’ Company
Professor of Anatomy at the Royal College of Surgeons of England,
London, UK. Conflicts of interest: none.
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2. Decussating fibres
of the right crus
Left diaphragm
Left suprarenal gland
Left inferior phrenic artery
Splenic artery
Transverse colon mesentery origin
Left kidney
Duodenojejunal flexure
Spleen
Anterior pancreas
Figure 2 Posterior topographical relations of the stomach
Oesophageal branch
Left
gastroepiploic
artery
Splenic artery
Short gastric
arteries
Right gastroepiploic
artery
Superior
pancreaticoduodenal
artery
Gastroduodenal artery
Right gastric artery
Hepatic artery
Coeliac trunk
Left gastric artery
Figure 3 Arterial supply of the stomach
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3. the greater curvature. The lesser and greater omenta contain the
blood vessels, lymphatics and nerve supply of the stomach.
Topographical relations
In addition to the lesser and greater omenta which are attached to
the lesser and greater curvatures of the stomach, respectively,
other important topographical relations of the stomach are as
follows.
Posterior relations: Situated immediately behind the stomach
and lesser omentum is the lesser sac (also known as the omental
bursa). The lesser sac is, in effect, a diverticulum or recess of the
general peritoneal cavity (also known as the greater sac). The
window of communication between the lesser sac and general
peritoneal cavity is termed the epiploic foramen or foramen of
Winslow. Behind the peritoneum that forms the posterior wall of
the lesser sac are a number of structures which collectively make
up the ‘stomach bed’ (Figure 2). These structures include the
diaphragmatic crura, left dome of the diaphragm, the proximal
part of the abdominal aorta with the coeliac axis originating from
it, the upper part of the left kidney, the left suprarenal gland, the
pancreas, the medial surface of the spleen and the upper surface
of the transverse mesocolon.
Anterior relations: The stomach is related anteriorly to a num-
ber of structures but is separated from these structures by the
greater sac. The portion of the stomach lying under cover of the
left rib cage is related anteriorly to the left hemidiaphragm.
Further to the left the anterior wall of the stomach is related to
the medial surface of the spleen. In the epigastric region the
stomach and lesser omentum are overlapped by the left lobe of
the liver. Lower still the anterior wall of the stomach is related to
the posterior surface of the anterior abdominal wall.
Arterial supply and venous drainage of the stomach
The stomach has a rich blood supply which it derives entirely
from the coeliac axis (coeliac artery) reflecting its embryological
derivation from the foregut. The coeliac axis typically gives rise
to three branches: the left gastric artery, the common hepatic
artery and the splenic artery. These are termed the primary
branches of the coeliac artery, and all three contribute to the
blood supply of the stomach (Figure 3). Two arterial arcades, one
situated alongside the lesser curvature and the other along the
greater curvature of the stomach, provide most of the blood
supply to the stomach. The arcade along the lesser curvature lies
between the two leaves of the lesser omentum and is formed by
the anastomosis of the right and left gastric arteries. This arcade
supplies the anterior and posterior walls of the stomach along-
side the lesser curvature. The left gastric artery is a direct branch
of the coeliac axis. Initially it runs upwards and to the left behind
the lesser sac and on reaching the right side of the gastro-
oesophageal junction it gives off the oesophageal arteries
Right gastroepiploic nodes
Right gastroepiploic artery
Right gastroepiploic nodes
Left gastroepiploic artery
Left gastroepiploic nodes
Short gastric
nodes
Short gastric arteries
Inferior
pancreaticoduodenal
artery
A
Infrapyloric nodes
Superior mesenteric artery
Gastroduodenal
artery
Splenic artery
Suprapyloric
nodes
Hepatic artery
Right gastric artery
Common hepatic artery
Common hepatic nodes
Coeliac nodes
Coeliac artery
Left gastric artery
Left gastric nodes
Lesser curvature nodes
Right paracardiac nodes Left paracardiac nodes
Figure 4 Lymphatic drainage of the stomach
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4. before running downwards along the lesser curvature to enter
the lesser omentum. The right gastric artery arises within the free
edge (right edge) of the lesser omentum as a branch of the he-
patic artery (a terminal branch of the common hepatic artery). It
runs to the left along the lesser curvature to meet the left gastric
artery.
The arcade along the greater curvature lies between the two
leaves of the greater omentum, and is formed by the confluence
of the right and left gastro-epiploic arteries. The latter is
derived from the splenic artery while the right gastro-epiploic
artery is a branch of the gastroduodenal artery (Figure 3).
Branches from the gastro-epiploic arterial arcade supply
the anterior and posterior walls of the stomach alongside the
greater curvature.
The right gastroepiploic artery arises at the bifurcation of the
gastro-duodenal artery (the other terminal branch of the gastro-
duodenal being the superior pancreatico-duodenal artery).
The gastro-duodenal artery is a branch of the common hepatic
artery.
The left gastroepiploic artery originates from the splenic artery
in the vicinity of the splenic hilum and reaches the greater cur-
vature of the stomach in the gastro-splenic ligament. Running to
the right it meets and anastomoses with the right gastro-epiploic
artery.
The short gastric arteries are branches of the splenic artery
which arise near the splenic hilum. They run in the uppermost
part of the gastro-splenic ligament to reach and supply the gastric
fundus.
Venous drainage of the stomach is by veins which correspond
to the arteries which supply the stomach. Some of these veins
drain directly into the portal vein while the majority drain either
into the splenic vein or into the superior mesenteric vein, and
thereby into the portal vein.
Lymphatic drainage of the stomach (Figure 4)
The submucosa of the stomach features a rich network of anas-
tomosing vessels. From this plexus lymphatic channels leave the
stomach wall to drain into the extramural gastric lymph nodes
which are widely distributed along the major arteries which
supply the stomach. Practically all gastric lymph will eventually
drain into the coeliac lymph nodes. The lymphatic vessels from
the stomach generally follow the usual rule of accompanying the
blood vessels of the stomach.
Innervation
Afferent sympathetic fibres from the stomach accompany the
branches of the coeliac artery to reach the coeliac ganglia and
thence to spinal segments T5e12. They account for the ill-
defined referral of gastric pain to the epigastrium and lower
chest. The parasympathetic fibres are branches of the anterior
and posterior vagal trunks. The vagal trunks accompany the
oesophagus into the abdomen and run along the lesser curvature.
The parasympathetic fibres control gastric motility and gastric
secretion. A
FURTHER READING
Ellis H, Mahadevan V, eds. Clinical anatomy. 13th edn. WILEY
Blackwell, 2013; 77e82.
Moore KL, Dalley AF, Agur AMR, eds. Clinically oriented anatomy. 7th
edn. Wolters Kluwer/Lippincott Williams & Wilkins, 2014. 166e169;
230 e 238.
Sadler TW, ed. Langman’s medical embryology. 13th ednvols. 225
e228. Wolters Kluwer, 2015; 230e4.
Williams NS, Bulstrode CJK, O’Connell PR, eds. Bailey and love’s
short practice of surgery. 26th edn. CRC Press, 2013; 1023e30.
BASIC SCIENCE
SURGERY 35:11 611 Ó 2017 Elsevier Ltd. All rights reserved.
Downloaded for Anonymous User (n/a) at Univ Guadalajara from ClinicalKey.com by Elsevier on March 07, 2018.
For personal use only. No other uses without permission. Copyright ©2018. Elsevier Inc. All rights reserved.