Abdomen

1. The duodenum
(L. the breadth of 12 fingers)
Dr M Idris Siddiqui

3. The duodenum is divisible into four parts
1. Superior (first) part: (approximately 5 cm)
 Short and lies anterolateral to the body of the L1
vertebra.
1. Descending (second) part: (7 to 10 cm)
 Longer and descends along the right sides of the L1 to
L3 vertebrae.
1. Horizontal (third) part: (6 to 8 cm long)
 Crosses the L3 vertebra.
1. Ascending (fourth) part: (5 cm)
 Short and begins at the left of the L3 vertebra and rises
superiorly as far as the superior border of the L2
vertebra.

8. 1st
or superior part of duodenum
• The first 2 cm of the superior part of the
duodenum, immediately distal to the pylorus,
has a mesentery and is mobile.
– This free part, called the ampulla (duodenal cap),
has an appearance distinct from the remainder of
the duodenum when observed radiographically
using contrast medium.
• The distal 3 cm of the superior part and the
other three parts of the duodenum have no
mesentery and are immobile because they are
retroperitoneal.
Parts of the duodenum

11. The superior part of the duodenum
Ascends from the pylorus and is overlapped by
the liver and gallbladder.
Peritoneum covers its anterior aspect, but it is
bare of peritoneum posteriorly, except for the
ampulla.
The proximal part has the hepatoduodenal
ligament (part of the lesser omentum) attached
superiorly and the greater omentum attached
inferiorly .

13. The Superior (1st) Part of the Duodenum
• This part is 2.5 (Ashwell) to 5 (Moore) cm
long.
• The most movable part of the
duodenum.
• It lies anterolateral to the body of L1
vertebra.
• It begins at the pylorus and passes to the
right, posteriorly, and slightly
superiorly toward the neck of the
gallbladder and the right kidney.
• It begins near neck of pancreas posteriorly
& ends close to neck of gall bladder
anteriorly.

14. Relations of 1st
part
Anteriorly: The quadrate lobe of the liver and
the gallbladder
Posteriorly: The lesser sac (first inch only),
The gastroduodenal artery,
The bile duct and portal vein,
The inferior vena cava
Superiorly: The entrance into the lesser sac (the
epiploic foramen)
Inferiorly: The head of the pancreas

18. The Descending (2nd) Part of the
Duodenum
• This has no mesentery (it is retroperitoneal).
• It lies to the right of the bodies of L1 to L3 vertebrae.
• Runs inferiorly, curving around the head of the pancreas .
• It extends from the superior duodenal flexure to the inferior
duodenal flexure.
• During its descent, it passes right of and parallel with the
inferior vena cava.
• The common bile duct and main pancreatic duct (these
ducts usually unite to form the hepatopancreatic ampulla of
Vater) enter the posteromedial wall of this part of the
duodenum, about 2/3 of the way along its length.
• This opens on the summit of the major duodenal papilla,
located 8-10 cm distal to the pylorus.
• The opening of this papilla has a sphincter.
• The lesser duodenal papilla lies about 6-8 cm distal to the
pylorus and has at its summit the opening of the accessory
pancreatic duct.

20. Relataions of the descending part
Anteriorly: The fundus of the gallbladder
and the right lobe of the liver,
The transverse colon, and
The coils of the small intestine
Posteriorly: The hilum of the right kidney
and
The right ureter &
Right renal vessels(which
separates duodenum from right
psoas muscle).
Laterally: The ascending colon,
The right colic flexure, and
The right lobe of the liver
Medially: The head of the pancreas,
The bile duct, and
The main pancreatic duct

21. Entrance of the bile duct and the main and accessory pancreatic ducts into
the second part of the duodenum. Note the smooth lining of the first part of the
duodenum, the plicae circulares of the second part, and the major duodenal papilla.

22. The inferior or horizontal part of the duodenum
• Runs transversely to the left, passing
over the IVC, aorta, and L3 vertebra.
• It is crossed by the superior mesenteric
artery and vein and the root of the
mesentery.
• Superior to it is the head of the pancreas
and its uncinate process.
• The anterior surface of the horizontal part
is covered with eritoneum(retroperitoneal),
except where it is crossed by the superior
mesenteric vessels and the root of the
mesentery.

23. The 3rd
part, relations
Anteriorly: The root of the mesentery of the small
intestine,
The superior mesenteric vessels
contained within it,
Coils of jejunum
Posteriorly:
(right to left)
The right ureter,
The right psoas muscle,
The inferior vena cava, and
The aorta
Superiorly: The head of the pancreas
Inferiorly: Coils of jejunum

25. The Ascending (4th) Part of the Duodenum
This ascends on the left side of the aorta anterior to the left
renal vessels to the level of L2 vertebra.
• Here it meets the jejunum at the duodenojejunal flexure.
• For the most part of this section of the duodenum, it is
retroperitoneal and fixed to the posterior abdominal wall.
• The duodenojejunal flexure is supported by a fibromuscular
band called the suspensory muscle (ligament) of the
duodenum (ligament of Treitz).
• This suspensory ligament passes from the 4th part of the
duodenum and the duodenojejunal flexure, ascends upwards
and then divides into two parts.
– One part is attached to the right crus of the diaphragm.
– The other part is attached to the connective tissue around
the coeliac trunk.

26. The suspensory muscle (ligament) of
the duodenum (ligament of Treitz).
• This suspensory ligament may act as a
valve, sharpening and augmenting the
duodenojejunal flexure.
• Contraction of this muscle widens the
angle of the duodenojejunal flexure,
facilitating movement of the intestinal
contents.
• The suspensory muscle passes posterior
to the pancreas and splenic vein and
anterior to the left renal vein.

27. Variations of the attachment of the suspensory
muscle (ligament) of Treitz.
A. Attachments to the flexure and the third
and fourth portions of the duodenum. This
is the most common type.
B. Attachment to the duodenojejunal flexure.
C. Attachments to the third and fourth portions
only.
D. Multiple separated attachments of the
suspensory ligament

28. Relations of the 4th
part
Anteriorly: The beginning of the root of the mesentery and
Coils of jejunum
Transverse colon & t. mesocolon
Posteriorly: The left margin of the aorta and
The medial border of the left psoas muscle
Left sympathetic trunk
Testicular/ovarian artery & vein
To the right: Head of pancreas
Abdominal aorta
Vertebral column(left side of bodies of L2&L3)
To the left: First coils of jejunum

29. Part Anterior Posterior Superior Inferior Medial Lateral
First Liver
Gall bladder
Portal vein
Gastro-
duodenal
artery
Bile duct
Lesser sac
IVC
Liver
(quadrate)
Hepatic artery
Neck of gall
bladder
Pancreatic
head
Bifurcation of
gastro-
duodenal
artery
Second Liver
Gall bladder
Transverse
colon
Small intestine
Right renal
vessels
Right kidney
IVC
R.Psoas major
Right ureter
Pancreatic
head
Branches of
pancreatico-
duodenal
artery
Ascending
colon
Right colic
flexure
Right kidney
Third Superior
mesenteric
vessels
Root of
mesentery
jejunum
Right and left
psoas major
Right ureter
IVC
Aorta
Inferior
mesenteric
artery
Pancreatic
head
Inferior
pancreatico-
duodenal
artery
Fourth Root of
mesentery
Left psoas major
Left sympathetic
trunk
Testicular/ovaria
n artery& vein
head of
pancreas
Aorta
Vertebral
column
coils of
jejunum

30. Duodenal Papillae
• At the site where the bile duct and the
main pancreatic duct pierce the medial
wall of the second part is a small, rounded
elevation called the major duodenal
papilla.
• The accessory pancreatic duct, if present,
opens into the duodenum on a smaller
papilla about 0.75 in. (1.9 cm) above the
major duodenal papilla.

32. Blood supply
• The arteries of the duodenum arise from
– The celiac trunk and
– The superior mesenteric artery.
• The celiac trunk, via
– The gastroduodenal artery and its branch, the superior
pancreaticoduodenal artery, supplies the duodenum proximal to
the entry of the bile duct into the descending part of the duodenum.
• The superior mesenteric artery,
– Through its branch, the inferior pancreaticoduodenal artery,
supplies the duodenum distal to the entry of the bile duct.
• The pancreaticoduodenal arteries lie in the curve between the
duodenum and the head of the pancreas and supply both
structures.
• The anastomosis of the superior and inferior
pancreaticoduodenal arteries, which occurs approximately at
the level of entry of the bile duct (or, according to some authors,
at the junction of the descending and horizontal parts of the
duodenum) is formed between the celiac and the superior
mesenteric arteries.

36. Major arterial supply to the duodenum

37. Anterior view of arterial supply of the duodenum and pancreas

38. Posterior view of arterial supply of duodenum and pancreas

39. The veins of the duodenum
• The veins of the duodenum
follow the arteries and drain
into the portal vein, some
directly and others indirectly,
through the superior
mesenteric and splenic veins

40. Diagrammatic presentation of duodenal lymphatics

41. The lymphatic vessels of the
duodenum
• The lymphatic vessels of the duodenum follow
the arteries. The anterior lymphatic vessels of
the duodenum drain into the
pancreaticoduodenal lymph nodes, located
along the superior and inferior
pancreaticoduodenal arteries, and into the
pyloric lymph nodes, which lie along the
gastroduodenal artery. The posterior lymphatic
vessels pass posterior to the head of the
pancreas and drain into the superior
mesenteric lymph nodes.
• Efferent lymphatic vessels from the duodenal
lymph nodes drain into the celiac lymph nodes.

42. The nerves of the duodenum
• The nerves of the duodenum derive from the
vagus and greater and lesser
(abdominopelvic) splanchnic nerves by way of
the celiac and superior mesenteric plexuses,
from which they are conveyed to the
duodenum via periarterial plexuses extending
to the pancreaticoduodenal arteries
• REFERRED PAIN:In common with other
structures derived from the foregut, the
visceral sensation of pain arising from the
duodenum is poorly localized and referred to
the central epigastrium

43. Duodenal Ulcers
• Most (65%) duodenal ulcers occur in the
posterior wall of the superior part of the
duodenum within 3 cm of the pylorus.
• Occasionally, an ulcer perforates the duodenal
wall, permitting the contents to enter the
peritoneal cavity and causing peritonitis.
• Because the superior part of the duodenum
closely relates to the liver, gallbladder, and
pancreas, any of these structures may become
adherent to the inflamed duodenum and also
become ulcerated as the lesion continues to
the tissue that surrounds it.
• A duodenal ulcer results in severe hemorrhage
into the peritoneal cavity and subsequent
peritonitis.

44. Trauma to the Duodenum
• Apart from the first inch, the duodenum is
rigidly fixed to the posterior abdominal wall by
peritoneum and therefore cannot move away
from crush injuries.
• In severe crush injuries to the anterior
abdominal wall, the third part of the duodenum
may be severely crushed or torn against the
third lumbar vertebra

45. Duodenal fossae

47. Paraduodenal Hernias
• There are two or three inconstant folds
and fossae (recesses) around the
duodenojejunal junction. The
paraduodenal fold and fossa are large and
lie to the left of the ascending part of the
duodenum. If a loop of intestine enters this
fossa, it may strangulate. During repair of
a paraduodenal hernia, care must be
taken not to injure the branches of the
inferior mesenteric artery and vein or the
ascending branches of the left colic artery,
which are related to the paraduodenal fold
and fossa

48. Duodenal fossae
(1) Superior duodenal recess - Present in 50% subjects
- At level of L2 vertebra
- 3cm deep - orifice looks downwards
(2) Inferior duodenal recess - present in 75% subjects
- L3 vertebra level
- 3 cm deep
- Orifice looks upwards
(3) Paraduodenal recess : - Present in 20% subjects
-Inferior mesenteric vein lies in the free
edge of the peritoneal fold
- Orifice looks to the right
(4) Retroduodenal recess - Occasionally present
- Largest of duodenal recesses
- 8 to 10 cm deep
- Orifice looks to the left
(5) Duodenojejunal / mesocolic recess - Present in 20% of subjects
- 3cm deep
- Orifice looks downwards & to the right
(6) Mesentricoparietal fossa of waldeyer
- In 1% subjects
-Lies behind upper part of the
mesentery
- The superior mesenteric vessels lie in
the fold of the peritoneum covering this
fossa

49. The "Kocher maneuver"
• Mobilization of the second and proximal third
portions of the duodenum is obtained by incising
the parietal peritoneum along the descending
duodenum (second portion), and by retracting
the duodenum medially with the head of the
pancreas (the "Kocher maneuver").
• This maneuver permits examination of the
posterior wall of the duodenum, as well as
exploration of the retroduodenal and pancreatic
portions of the common bile duct.