Functional anatomy of esophagus and
stomach
Practical 4
Objectives
By the end of the session the students should be able to:
a. Describe the functional anatomy of the esophagus and stomach,
sphincters and their key relations to other abdominal organs
b. Identify blood supply, lymphatic drainage and nerve supply of
esophagus and stomach
c. Identify clinical application
Esophagus
 It is muscular, collapsable tube
about 25cm long joining the
pharynx to the stomach.
 Commences at the lower border of
the cricoid cartilage.(C6)
 Descends along the front of the
spine, through the posterior
mediastinum,
 Enters the abdomen through an
opening in the right crus of the
diaphragm at the level of T10 at 7th
left costal cartilage, terminates at
the cardiac orifice of the stomach,
opposite the (T11)
Relations of the esophagus
In the Neck( cervical part of
esophagus)
Anteriorly- trachea, and in the
lower part of the neck it is
related to the thyroid gland
and thoracic duct
Posteiorly- the vertebral
column and longus colli
muscle
Laterally- lobes of the thyroid
gland
Relations of the esophagus
In Thorax
 Anteriorly- Trachea, Left recurrent
laryngeal nerve, Left principal bronchus,
Pericardium , Left atrium,Left atrium.
 Posteriorly-Bodies of the thoracic
vertebrae,Thoracic duct,Azygos vein,
Right posterior intercostal arteries,
Descending thoracic aorta (at the lower
end)
 On the Right side:
Right mediastinal pleura,
Terminal part of the azygos
vein.
 On the Left side:
Left mediastinal pleura
Left subclavian artery
Aortic arch
Thoracic duct
Relations of esophagus
In the Abdomen
 Anteriorly - Posterior
surface of the left lobe of
the Liver
 Posteriorly - Left crus of
the Diaphragm
 The left and the right Vagus
nerve lie on the anterior
and posterior surfaces
respectively.
ESOPHAGEAL
CONSTRICTIONS
 The esophagus has 3 anatomic
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constrictions.
The first is at the junction with the
pharynx(pharyngeoesophageal
junction). 15 cm from incisor teeth.
The second is at the crossing with
the aortic arch (22.5 cm) and the
left main bronchus (27.5 cm)
The third is at the junction with the
stomach (40 cm).
They have a considerable clinical
importance.
Why?
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They may cause difficulties in
passing an esophagoscope.
In case of swallowing of caustic
liquids (mostly in children), this
is where the burning is the worst
and strictures develop.
The esophageal strictures are a
common sites of the
development of esophageal
carcinoma.
In this picture what is the
importance of the scale?
Blood supply of esophagus
 Arterial supply- arterial supply to
the esophagus in the upper third is
by Inferior thyroid artery, middle
third is by thoracic aorta and lower
third is by the branches of the left
gastric artery.
 Venous drainage- venous blood
from the upper third of esophagus
drains into inferior thyroid vein,
from middle third into azygous
vein and lower third into the left
gastric vein which is the tributary
of portal vein.
Lymph Drainage
 The upper third is drained
into the deep cervical
nodes.
 The middle third is
drained into the superior
and inferior mediastinal
nodes.
 The lower third is drained
in the celiac lymph nodes
in the abdomen.
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Nerve Supply
 It is supplied by
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sympathetic fibers
from the sympathetic
trunks.
The parasympathetic
supply comes form the
vagus nerves.
Inferior to the roots of
the lungs, the vagus
nerves join the
sympathetic nerves to
form the esophageal
plexus.
The left vagus lies
anterior to the
esophagus.
The right vagus lies
posterior to it.
Gastroesophageal sphincter
 No anatomical sphincter exist
in the junction of the
esophagus with the stomach.
 Physiologically sphincter
action is produced by the
circular muscles of the region
 The closure of the sphincter
is under vagal control, and
this can be augmented by the
hormone gastrin and reduced
in response to secretin,
cholecystokinin, and
glucagon.
 GERD, Achalasia of the cardia
Location
STOMACH
 The stomach is a
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dilated part of the
alimentary canal.
It is located in the
upper part of the
abdomen.
It extends from
beneath the left costal
margin into the
epigastric and
umbilical regions.
Most of the stomach is
protected by the lower
ribs.
It is roughly J-shaped.
PARTS
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2 Orifices:
 Cardiac orifice
 Pyloric orifice
2 Borders:
 Greater curvature
 Lesser curvature
2 Surfaces:
 Anterior surface
 Posterior surface
3 Parts:
 Fundus
 Body
 Pylorus:
The pylorus is formed of 3
parts
 Pyloric antrum
 Pyloric canal
 Pyloric sphincter
Cardiac Orifice
 It is the site of the gastro
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esophageal sphincter.
It is a physiological rather
than an anatomical,
sphincter.
Consists of a circular layer of
smooth muscle (under vagal
and hormonal control).
Function:
Prevents (GER)
regurgitation (reflux)
NB. Notice the abrupt
mucosal transition from
esophagus to stomach (Zline)
Fundus
 Dome-shaped
 Located to the left of the
cardiac orifice
 Usually full of gas.
 In X-Ray film it appears black
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Body
 Extends from:
 The level of the fundus
to
 The level of Incisura
Angularis:
 A constant notch on
the lesser curvature
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Lesser
Curvature
 Forms the right
border of the
stomach.
 Extends from the
cardiac orifice to
the pylorus.
 Attached to the
liver by the lesser
omentum.
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Greater Curvature
 Forms the left
border of the
stomach.
 Extends from the
cardiac orifice to the
pylorus.
 Its upper part is
attached to the
spleen by
gastrosplenic
ligament
 Its lower part is
attached to the
transverse colon by
the greater
omentum.
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PYLORIC ANTRUM AND
PYLORUS
 The pyloric antrum
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extends from Incisura
angularis to the pylorus
The pylorus is a tubular
part of the stomach
It lies in the transpyloric
plane
It has a thick muscular
end called pyloric
sphincter.
The cavity of the pylorus
is the pyloric canal.
Anterior Relations
 Anterior abdominal
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wall
Left costal margin
Left pleura & lung
Diaphragm
Left lobe of the liver
Posterior Relations
mach Bed:
 Peritoneum (Lesser sac)
 Left crus of diaphragm
 Left suprarenal gland
 Part of left kidney
 Spleen
 Splenic artery
 Pancreas
 Transverse mesocolon
 They are separated from
the stomach by
Peritoneum (Lesser sac
except the spleen)
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 The bed of the stomach, on which the stomach rests in the
supine position, is formed by the structures forming the
posterior wall of the omental bursa. From superior to
inferior, the bed of the stomach is formed by the left dome of
the diaphragm, spleen, left kidney and suprarenal gland,
splenic artery, pancreas, and transverse mesocolon
Arteries
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 5 arteries:
 As it is derived from
the foregut all are
branches of the celiac
trunk
 1- Left gastric artery:
 It is a branch of celiac
artery.
 Runs along the
lesser curvature.
 2- Right gastric artery:
From the hepatic of
celiac.
 Runs to the left
along the lesser
curvature.
Arteries
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 3-Short gastric arteries –
arise from the splenic
artery.
 Pass in the gastrosplenic
ligament.
 4- Left gastroepiploic
artery:
from splenic artery
 Pass in the gastrosplenic
ligament, along the
greater curvature
 5- Right gastroepiploic
artery:
 from the gastroduodenal
artery of hepatic .
 Passes to the left along
the greater curvature.
Veins
 All of them drain into the portal circulation.
 The right and left gastric veins drain directly into the portal vein.
 The short gastric veins and the left gastroepiploic vein join the splenic vein
which joins superior mesenteric vein to form portal vein.
 The right gastroepiploic vein drain in the superior mesenteric vein.
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Lymph Drainage
 The lymph vessels follow
the arteries.
 They first drain to the:
 Left and right
gastric nodes
 Left and right
gastroepiploic
nodes and the
 Short gastric
nodes
 Ultimately, all the lymph
from the stomach is
collected at the celiac
nodes.
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Nerve
Supply
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NERVE SUPPLY OF STOMACH
 There are two types of nerve supply of the stomach;
sympathetic and parasympathetic.
 The sympathetic constricts the sphincters, however the
parasympathetic is a secreto-motor and stimulate smooth
muscles for peristaltic movement and induce evacuation.
 Therefore, to empty the pylorus, the sympathetic stimulation
must be inhibited and the parasympathetic excited.
 Distribution of the vagus innervation to the stomach; the
right vagus nerve innervates the posterior portion of the
stomach while the left vagus supplies the anterior part of the
stomach.
Parasymathetic innervation of the
stomach
I-The anterior gastric nerve(left vagus):
 1. mainly supplies the anterior portion of the body,
 2. it also innervates the liver(hepatic branch),
 3. nerve to the pylorus
 4. duodenal branch
 5. anterior gastric branch
 II-The posterior gastric nerve(right vagus):
 1. innervates a small portion of the anterior body,
 2. a main fiber innervates the posterior body with posterior gastric
branch,
 3. and another celiac branch which innervates all the small intestines, up
until the lateral third of the transverse colon(innervates the medial two
thirds), along with the pancreas.
Sympathetic innervation of the
stomach
 Those fibers are mainly derived from T5-T9 spinal cords, and
supply their targets by the splanchnic chain, which is a branch
from the thorax ganglia that penetrates the diaphragm to the
abdomen. They synapse in the celiac ganglia, or the superior
mesenteric ganglia, which incapsulates the blood vessels(the
post ganglionic fibers pass the myenteric plexus without
synapsing with it).
•Gastric ulcer
•Gastric pain
•Cancers of stomach
•Gastroscopy
•Nasogastric intubation
References
 Clinical Anatomy by Region 9th Edition, PAGE 168 –172
 Gray’s anatomy- the anatomical basis of clinical practice,
14th edition, chapter 65, Abdominal esophagus and
stomach
 https://www.youtube.com/watch?v=KR8yCSB-RXc
 https://www.youtube.com/watch?v=HJXmyr4r21M