2. Learning Objectives:
At the end of this lecture student
should be able to:
Explain anatomy of lower end of esophagus
Explain clinical aspect of esophagus like esophageal
constrictions and Porto-systemic anastomosis at lower
end of esophagus.
Explain anatomy of stomach with focus on shape,
divisions, relations, interior, structure, blood supply,
nerve supply and lymphatic drainage.
Explain applied aspect of stomach like gastric ulcer,
gastric carcinoma, gastric pain and gastroscopy.
3. Abdominal Part of Esophagus
Esophagus enters in the
abdomen through
esophageal opening of
diaphragm at T10
vertebral level.
It is related to:
Anteriorly : Left lobe of
liver.
Posteriorly: Left crus of
diaphragm.
4. Blood supply and Nerve supply of Abdominal
Part of Esophagus
Blood supply:
Arterial supply: Left
gastric artery from
Coeliac trunk.
Venous drainage: Left
gastric vein tributary of
Portal vein
Lymphatic drainage: Left
gastric and coeliac lymph
nodes
Nerve Supply:
Parasympathetic: Vagus
nerves
Sympathetic: Thoracic
sympathetic chain
6. Esophageal Constrictions
Esophagus has three constrictions:
1. At its upper end, where it joins the Pharynx.
2.Near its middle, where it is crossed by the arch of
aorta and left main bronchus.
3.Near its lower end, where it pierces the diaphragm.
The approximate distances:
From the incisor teeth to these constrictions are 6,10 and 16
inches ( 15, 25 and 41 cms) respectively.
From the external nares to these constrictions are 7.2, 11.2
and 17.2 inches ( 18, 28 and 44 cms) respectively.
7.
8. Porto-systemic Venous Anastomosis
The lower end of the esophagus is an important site
of Porto-systemic anastomosis between the
esophageal tributaries of the Azygos vein (Systemic)
and the left gastric vein (Portal).
Importance:
In case of postal obstruction in cirrhosis of liver,
Portal hypertension occurs. It results in dilatation of
this anastomosis and forms esophageal varices.
These varicose veins (varices) may rupture and cause
severe bleeding in the stomach and vomiting of
blood known as Hematemesis.
10. Achalasia of the cardia
It is failure of the function
of gastroesophageal
junction.
Cause unknown but
associated with
degeneration of
parasympathetic plexus in
the wall of esophagus.
It leas to dysphagia
(difficulty in swallowing
and regurgitation.
Later on it leads to distal
narrowing and proximal
dilatation of esophagus.
12. Position and Shape
Stomach is dilated part of GIT responsible for
storage and mixing of food.
Position: Occupy Left hypochondrium, epigastrium
and umbilical regions.
Shape:
In tall and thin persons: J-Shaped (Elongated
vertically.
In short obese persons: Steer-horn shape (High and
transversely placed)
15. Features of stomach
Ends (Openings):
Cardiac End (Opening): Upper end at the junction with the
esophagus.
Pyloric End (Opening): Lower end at the junction with the
first part of Duodenum.
Borders (Curvatures):
Lesser Curvature (Right Border): Extends from right side of
cardiac end to pyloric end. It is concave. Its maximum concavity
is known as Angular notch (Incisura angularis). It is attached to
liver by lesser omentum.
Greater Curvature (Left Border): Extends from Left side of
cardiac end, follow fundus of stomach to pyloric end. It is convex.
It is attached to spleen by gastrosplenic ligament in upper part
and to transverse colon by greater omentum in the rest of the
part.
16.
17.
18. Features of stomach
Surfaces:
Anterior surface: Between lesser and greater curvature facing
anteriorly.
Posterior surface: Between lesser and greater curvature facing
posteriorly.
19. Relations of Stomach
Anterior Surface: covered by peritoneum of
greater sac.
Related to:
Liver ( left lobe and quadrate lobe)
Spleen
Anterior abdominal wall
Diaphragm which separates stomach from left
pleura, left lung an lower ribs.
21. Relations of Stomach
Posterior Surface: covered by peritoneum of lesser sac except near
cardiac end.
Structures related to posterior surface also known as Stomach bed and
separated by cavity of lesser sac)
Structures forming stomach bed (Posterior relations):
Left crus of diaphragm
Abdominal aorta
Left inferior phrenic artery
Coeliac trunk and splenic artery
Body of pancreas
Left kidney and left suprarenal gland
Transverse colon and transverse mesocolon
Spleen (separated by cavity of greater sac)
23. Divisions of stomach
Stomach is divided into two portions by line extending from angular notch of
lesser curvature to the bulge on the greater curvature.
Two portions are:
1. Cardiac portion
2. Pyloric portion
Cardiac portion is subdivided in to two parts by transverse line passing
through cardiac end.
The two parts are:
The fundus: lies above the transverse line and dome shaped.
The body: between transverse line and line from angular notch.
Pyloric portion is subdivided in to two parts by constriction.
The two parts are:
The pyloric antrum: between line from angular notch to constriction.
The pyloric canal (pylorus): Terminal part. 1 inch long. In the wall
contains circular muscle fibers which form pyloric sphincter.
24.
25. Structure of Stomach
Mucous membrane: thick, vascular ad thrown in to
folds known as Rugae. Space at the lesser curvature
between prominent longitudinal fold is known as
gastric canal.
Muscular wall: Formed by three layers:
Longitudinal: superficial layer
Circular layer: Middle layer. At pylorus forms pyloric
sphincter.
Oblique: Innermost layer.
26.
27. Arterial Supply of Stomach
The stomach is a part of foregut. Hence it is supplied
by branches of Coeliac artery.
It is supplied by five arteries:
1. Left gastric artery: branch of coeliac trunk. Runs
along upper part of lesser curvature and supplies
lower part of esophagus and upper right part of
stomach.
2. Right gastric artery: branch of hepatic artery (which
is branch of Coeliac artery ) near upper border of
pylorus. Runs near the lower part of lesser curvature
and supplies lower right part of stomach.
29. Arterial Supply of Stomach
3. Short gastric arteries: branches of splenic artery (which
is branch of Coeliac artery) at the hilum of spleen . Runs
in gastrosplenic ligament and supplies fundus of
stomach.
4. Left gastroepiploic artery: branch of splenic artery
(which is branch of Coeliac artery ) near hilum of spleen.
Runs in gastrospleninc ligament and supplies stomach
along greater curvature.
5. Right gastroepiploic artery: branch fomr the
gastroduodenal beanch of hepatic artery (Which is
branch from coeliac artery). Passes along greater
curvature and supplies lower part of stomach along the
greater curvature.
31. Venous drainage of stomach
There are 5 veins corresponding to arteries.
All drain into portal system as follows:
Left and right gastric veins into portal vein.
Short gastric and left gastroepiploic vein into splenic
vein.
Right gastroepiploic vein into superior mesenteric
vein.
33. Lymphatic drainage of stomach
Lymph vessels follow the arteries.
They terminate into right and left gastric and right
and left gastroepiploic lymph nodes.
Efferents from these nodes drain into coeliac lymph
nodes around the root if coeliac artery on posterior
abdominal wall.
34. Nerve supply of stomach
Sympathetic nerve supply:
From coeliac plexus (Formed by greater splanchnic
nerve of thoracic sympathetic chain).
Afferent carry pain sensation.
Efferent are motor to blood vessels and pyloric
sphincter.
37. Nerve supply of stomach
Parasympathetic nerve supply from vagus nerves:
Anterior vagal (gastric)trunk (formed by left vagus):
enter abdomen in front of esophagus. Supply
anterior surface of stomach and liver and pylorus.
Posterior vagal (gastric) trunk (formed by right
vagus) enter abdomen behind esophagus. Supply
posterior surface of stomach, pancreas, intestine
upto right 2/3 rd of transverse colon.
Afferent related to gastric reflex.
Efferent is secretomotor to glands, motor to muscles
wall and inhibitory to pyloric sphincter..
38. Clinical Aspect of stomach
Gastric ulcer: Most common site at Antrum close to
lesser curvature.
Ulcer on posterior wall may perforate into the lesser
sac and becomes adherent to the pancreas. Erosion
of pancreas cause referred pain on back.
Erosion of splenic artery leads to hemorrahge.
Perforation of ulcer from anterior wall leads to
leakage of contents of stomach in greater sac and
cause peritonitis. It may adhere to liver.
39. Gastric Ulcer: Erosion of
mucosa
Gastric Carcinoma: Abnormal
growth of the mucosa
Clinical Aspect of stomach
40. Clinical Aspect of stomach
Gastric carcinoma: Common at the greater curvature
of stomach.
Gastric pain: Caused by stretching of wall
(distension) or spasmodic contraction. Carried by
sympathetic nerves via greater splanchnic nerves to
T6-T9 spinal segments. It is referred to epigastrium.
Gastroscopy: direct visualization of stomach by
flexible fibroptic instrument (Endoscope). It also
used to take mucosal biopsy.
Nasogastric intubation in patients with severe
debilitating illnesses..
