Download File

Stomach & Duodenum
Abdomen, Pelvis & Perineum Unit
Lecture 5
‫ حيدر جليل األعسم‬.‫د‬
Abdominal Esophagus
It is a muscular, collapsible tube about 25
cm long that joins pharynx to stomach. It
enters the abdomen through an opening in
diaphragm to the left of midline. After a
short course 0.5 inch, it enters the stomach
on its right side.
Relations:
Anteriorly: left liver lobe & left vagus.
Posteriorly: left crus of diaph.& right vagus
Arterial supply: from the left gastric artery.
Venous drainage: left gastric vein, a
tributary of the portal vein.
Lymph Drainage: vessels follow arteries
into left gastric nodes.
Nerve Supply: anterior & posterior gastric
nerves (vagi) & sympathetic branches of the
thoracic part of the sympathetic trunk.
Gastroesophageal Sphincter
No anatomic sphincter, but (physiologic
sphincter of lower esophagus)
Stomach
It is J-shaped dilated portion of GIT that is situated in upper part of
abdomen, extending from beneath left costal margin region into
epigastric and umbilical regions.
2 openings: cardiac & pyloric orifices
2 curvatures: greater & lesser curvatures
2 surfaces: anterior & posterior surfaces
2 notches: cardiac notch & incisura angularis.
Functions of the stomach:
stores food, mixes food with gastric secretions
to form chyme, and controls rate of delivery
of chyme to small intestine.
Divisions of Stomach:
Fundus: is dome-shaped and projects
upward and to left of cardiac orifice (full of gas)
Body: extends from level of cardiac orifice
to level of the incisura angularis.
Pyloric antrum: extends from incisura angularis to the pylorus.
Pylorus: is the most tubular part of the stomach. The thick muscular wall
is called pyloric sphincter, and cavity of pylorus is the pyloric canal.
Stomach
Lesser curvature
Greater curvature
Gastrosplenic omentum
Pyloric orifice: is formed
by pyloric canal (1 inch).
It lies on transpyloric plane.
Circular muscle coat of
stomach is much thicker
and forms anatomic and
physiologic pyloric sphincter.
Sphincter receives motor fibers
from sympathetic system and
inhibitory fibers from vagi.
Mucous membrane of stomach
is thick & vascular & is folded
into numerous Rugae.
Stomach muscular layers are
longitudinal, circular & oblique
Relations of the stomach
Anteriorly: anterior
abdominal wall, left costal
margin, left pleura and
lung, diaphragm, and left
lobe of liver
Posteriorly: lesser sac,
diaphragm, spleen, left
suprarenal gland, upper
part of left kidney, splenic
artery, pancreas,
transverse mesocolon, and
transverse colon.
Arterial Supply of Stomach
They are branches from celiac artery.
Left gastric artery: It passes upward and to the left to reach esophagus
and then descends along lesser curvature. It supplies lower third of
esophagus and upper right part of stomach.
Right gastric artery: arises from hepatic artery at upper border of
pylorus and runs to left along lesser curvature. It supplies lower right
part of stomach.
Short gastric arteries arise from splenic
artery at hilum of spleen and pass
forward in gastrosplenic omentum
to supply the fundus.
Left gastroepiploic artery arises from
splenic artery at hilum of spleen and
passes forward in gastrosplenic
omentum to supply stomach
along upper part of greater curvature.
Right gastroepiploic artery arises
from gastroduodenal artery. It passes
to left and supplies stomach along
lower part of greater curvature.
Venous drainage of stomach
Veins drain into portal circulation.
Left and Right gastric veins drain directly into portal vein.
Short gastric veins & Left gastroepiploic veins join splenic
vein.
Right gastroepiploic vein joins the superior mesenteric vein
Nerve Supply
Parasympathetic innervation: motor & secretomotor
A. Anterior vagal trunk: formed from left vagus nerve. It supplies
anterior surface of stomach. A large hepatic branch passes up to liver,
and from this a pyloric branch passes down to pylorus.
B. Posterior vagal trunk: formed from right vagus nerve. It divides into
branches that supply mainly posterior surface of stomach. A large
branch passes to celiac and superior mesenteric plexuses and is
distributed to intestine as far as splenic flexure of colon and to pancreas.
Sympathetic innervation: carries pain-transmitting nerve fibers & motor
to Pyloric sphincter.
Small Intestine - Duodenum
Small Intestine: extends from pylorus to ileocecal junction. It
is divided into three parts: duodenum, jejunum, and ileum.
Duodenum
It is a C-shaped tube(25 cm long), which
joins stomach to jejunum. It receives
openings of bile and pancreatic ducts.
It curves around the head of pancreas.
First inch of duodenum is covered on its
anterior and posterior surfaces with
peritoneum and attached to lesser
and greater omentum. Remainder of
duodenum is retroperitoneal (partially
covered by peritoneum).
Mucous Membrane of duodenum:
It is thick which is smoth in first part
of duodenum and has numerous
circular folds called plicae circulares in the
remainder of the duodenum.
Parts of Duodenum
It is divided into four parts.
1. First Part of the Duodenum
It begins at pylorus and runs upward and backward on
transpyloric plane at level of first lumbar vertebra L1.
The relations of this part are as follows:
Anteriorly: quadrate lobe of liver and gallbladder
Posteriorly: lesser sac, gastroduodenal artery, bile duct and
portal vein, and inferior vena cava
Superiorly: entrance into lesser sac (Epiploic foramen)
Inferiorly: head of the pancreas.
Parts of Duodenum
2. Second Part of the Duodenum
It runs vertically downward in front of hilum of right kidney on right side
of L2 & L3 vertebrae. About halfway down its medial border, bile duct
and main pancreatic duct pierce duodenal wall. They unite to form
ampulla that opens on summit of a rounded elevation major duodenal
papilla. Accessory pancreatic duct, if present, opens into duodenum a
little higher up on minor duodenal papilla.
Anteriorly: fundus of gallbladder & right lobe of liver, transverse colon,
and coils of small intestine
Posteriorly: hilum of right kidney and right ureter
Laterally: ascending colon, right colic flexure, and right lobe of liver
Medially: head of pancreas, bile duct, and main pancreatic duct
Parts of Duodenum
3. Third Part of the Duodenum
runs horizontally toward left on subcostal plane passing
anterior to vertebral column & following lower margin of
head of pancreas.
Relations:
Anteriorly: root of mesentery of small intestine, superior
mesenteric vessels, and coils of jejunum
Posteriorly: right ureter, right psoas muscle, inferior vena
cava, and aorta
Superiorly: head of pancreas
Inferiorly: Coils of jejunum
Parts of Duodenum
4. Fourth Part of the Duodenum
It runs upward and to left to duodenojejunal flexure. This
flexure is surrounded by a fold of peritoneum containing
muscle fibers called suspensory muscle (ligament) of
duodenum (ligament of Treitz) which is attached to right crus
of the diaphragm.
Relations:
Anteriorly: beginning of root of mesentery & coils of jejunum.
Posteriorly: left margin of aorta and medial border of left
psoas muscle.
Blood Supply of the Duodenum
Arterial Supply:
Upper half is supplied by superior pancreaticoduodenal
artery, a branch of gastroduodenal artery. Lower half is
supplied by inferior pancreaticoduodenal artery, a branch of
superior mesenteric artery.
Venous Drainage:
Superior pancreaticoduodenal
vein drains into portal vein;
inferior vein joins superior
mesenteric vein.
Nerve Supply: sympathetic &
parasympathetic (vagus) nerves from
celiac superior mesenteric plexuses.
Thank You