Surgical anatomy of Pancreas with blood supply

1. SURGICAL ANATOMY OF
PANCREAS
Moderator – Dr. B.R.Das, MS
Asstt. Professor
Presenter – Dr. Smaranika Baishya

2. Introduction
• The word pancreas comes
from the Greek πᾶν (pân,
"all") & κρέας (kréas,
"flesh").
• The pancreas is a
posteriorly situated
retroperitoneal organ that
lies transversely.
• The organ is composed of a
head, neck, body, and tail.

3. Location
• Related anteriorly to the
omental bursa above,
the greater sac below,
and the transverse
mesocolon
• Fixed organ

4. Location
• Lies transversely in the
retroperitoneal space,
between the duodenum
on the right and the
spleen on the left
• The head is
encompassed by the
duodenum, whereas
the tail rests in the
splenic hilum.

5. Location
• A portion of the head
inferiorly is termed the
uncinate process and is
intimately related to the
SMV and SMA.
• Posteriorly, the
pancreas is related to
the IVC, aorta, left renal
vein and kidney, and
spleen.

6. RELATIONS OF THE PANCREAS
• Neck of the pancreas lies
anterior to the SMV and
SMA
• SMV joins with the splenic
vein behind the neck to
form Portal vein
• The neck of the pancreas is
anterior to the vertebral
body of L2,so if there is a
blunt anteroposterior
trauma, then it can
compress the neck of the
pancreas against the spine

7. RELATIONS OF THE PANCREAS
• Venous branches
draining the pancreatic
head and uncinate
process enter along the
right lateral and
posterior sides of the
SMV and portal vein
• This is helpful during
tunneling in Whipple’s
procedure

8. RELATIONS OF THE PANCREAS
• The body and tail of the
pancreas lie just
anterior to the splenic
vein and splenic artery

9. Embryology
• Carnegie stages are a standardized system of 23 stages
used to provide a unified developmental chronology .
• The pancreas is induced within the endoderm at
Carnegie Stage (CS) 12.
• The pancreatic precursors arise within three locations:
1. the ventral endodermal domain,
2. the VMEL[ventral midline of endoderm lip] (both the
ventral endodermal domain and the VMEL are
common progenitors with the liver), and
3. a dorsal domain to give rise to the dorsal and ventral
pancreatic buds.

10. Steps in the development of pancreas

11. Development from Ventral and Dorsal
Anlagen
• The pancreas is derived from ventral and dorsal
anlagen, which arise from the foregut
diametrically opposite each other and are distinct
from about day 26 to 32
• The ventral duct is an off-shoot of the bile duct
and maintains this bile duct connection
throughout
• The dorsal anlage will give rise to the head, body,
and tail of the pancreas, whereas the ventral bud
gives rise to the uncinate (Latin – “shaped like a
hook”) process

12. Development from Ventral and Dorsal
Anlagen
• Actual fusion of pancreatic parenchyma occurs
after a rotation of the ventral duct around the
axis of the foregut at about 50 to 55 days
• This differential heritage can still be evident
histologically by staining for pancreatic
polypeptide (PP)
• PP cells localize to the area derived from the
ventral anlage, while the dorsal pancreas has
larger lobules with PP-poor islets

14. Pancreatic Ducts
Main pancreatic duct (duct of Wirsung), joins
the CBD to empty into the duodenum at the
ampulla of Vater
Diameter -- 2 to 4 mm
Pressure --15 to 30 mm Hg

15. • The duct of Wirsung, beginning in
the distal tail as a confluence of
small ductules, runs through the
body to the head, where it usually
passes downward and backward in
close juxtaposition to the CBD
• The sphincter of Oddi consists of a
unique cluster of smooth muscle
fibers distinguishable from the
adjacent smooth muscle of the
duodenal wall
• The papilla of Vater at the
termination of the CBD is a small,
nipple-like structure that protrudes
into the duodenal lumen and is
marked by a longitudinal fold of
duodenal mucosa

16. • Several sphincters composed of smooth-
muscle fibres surround the intramural portion
of CBD, the main pancreatic duct, and the
ampulla.
• The complex may be as short as 6 mm or as
long as 30 mm

17. VARIATIONS IN PANCREATIC
DUCT OPENING
• Type 1 – Pancreatic duct
opens into CBD
• Type 2 – pancreatic and
bile ducts open close to
one another but
seperately without an
ampulla
• Type 3 – Pancreatic and
bile ducts open into the
duodenum seperately
without an ampulla

18. • The ‘T’ arrangement of
the duodenal mucosal
fold
• Blood supply of Hepato-
pancreatic ampulla

19. Surgico-anatomic segments of
pancreas

20. Relation of CBD to the posterior
surface of pancreas

21. Relation of tail of pancreas to the
spleen is variable

22. • The duct of Wirsung runs downward and parallel to the
CBD for approximately 2 cm and joins it within the
sphincter segment in 70% to 85% of patients; it enters
the duodenum independently in 10% to 13% of
patients and is replaced by the duct of Santorini in 2%
of patients
• Rarely, the duct of Santorini and the duct of Wirsung
are separate, which is known as pancreas divisum
• The islets of Langerhans, which provide the endocrine
component of the gland, are scattered throughout the
pancreas.

23. • The pancreatic capsule is loosely attached to
the surface of the pancreas and is contiguous
with the anterior layer of the mesocolon such
that it can be dissected in continuity if
necessary.
• The mesenteric attachments to the pancreas
tend to be contiguous

24. Neck of Pancreas
• The neck of pancreas is defined by the
location of the superior mesenteric vessels
running behind the gland, and by the
beginning of the portal vein dorsal to the
pancreas. Length 1.5 to 2.0 cm
• The vascular relations of the neck are
important because if these vessels are
involved in pancreatic cancer, pancreatectomy
is impossible

25. • Both foregut and
midgut arteries supply
pancreas
• From the celiac axis
arise common hepatic
artery which in turn
gives rise to GDA
• GDA in turn gives rise to
anterior and posterior
superior pancreatico-
duodenal artery
ARTERIAL SUPPLY

26. ARTERIAL SUPPLY
• From the SMA arise Inferior
pancreatico-duodenal
artery which in turn divides
into anterior and posterior
inferior pancreatico-
duodenal artery
• The body and the tail of
pancreas is supplied by
Splenic artery
• Splenic artery gives 3
branches , one of them is
Great Pancreatic artery, it
gives rise to Inferior
pancreatic artery

28. • Arterial variations are
common
• RHA arising from
SMA/GDA
• RHA usually lies posterior
to bile duct
• Sometimes it goes
anterior to bile duct
which is important during
Whipple’s procedure

29. • In the CT abdomen, if the
RHA is seen anterior to
the portal vein and
posterior to the bile duct
then it is standard course
RHA and if it is seen
posterior to the the portal
vein then it is replaced/
accessory RHA
• If an artery arise from the
left gastric artery and
goes to the falciform,
then it is replaced LHA

30. Venous Drainage
Suprapancreatic portal vein
Retropancreatic portal vein
Splenic veins
Infrapancreatic SMV

31. Venous Drainage
• Gastrocolic trunk is
important in Whipple’s
procedure
• It is also known as Henle’s
loop or Resident’s vein
• It is formed by Right
gastro epiploic vein,
accessory colic vein or
middle colic vein and
anterior pancreatico-
duodenal vein

32. Lymphatic Drainage
Drain into five main nodal groups
• Superior nodes drain the upper half of the head of the pancreas
• Anterior lymphatic drain to the prepyloric and infrapyloric nodes
• Inferior group of nodes drain to the superior mesenteric and periaortic
nodes
• Posterior pancreaticoduodenal lymph nodes drain into right periaortic
nodes
• Splenic group of nodes drain into the interceliomesenteric lymph nodes

33. The absence of a peritoneal barrier on the posterior
surface of the pancreas results in direct communication
of the intrapancreatic lymphatics with retroperitoneal
tissues, and this contributes to the high incidence of
recurrence after presumably curative resections of
pancreatic cancer

35. Histology
Exocrine Structure
Acinar cells secrete the enzymes responsible for
digestion
Ductular network carry the exocrine secretions into
the duodenum
Constitute 80% to 90% of the pancreatic mass

36. Endocrine Structure
Islets of Langerhans responsible for the secretion of
hormones that control glucose homeostasis
Contains
alpha ()-- glucagon
beta ()-- insulin
delta ()-- somatostatin
pancreatic polypeptide (PP) or F cells– PP
Accounts for 2% of the pancreatic mass

37. Pancreatic Exocrine Enzymes

38. Pancreatic Endocrine Enzymes

39. PANCREAS DIVISUM
• In this condition, there
is failure of fusion of the
dorsal and ventral ducts
and the dorsal duct
becomes the major
ductal system of the
pancreas

40. ANNULAR PANCREAS
• Due to maldevelopment of the
primitive pancreatic ducts, a ring
of pancreatic tissue may surround
the descing portion of the
duodenum
• It usually produces no symptoms
but it may occur in association
with duodenal stenosis in which
case duodenal obstruction occurs
• In the presence of duodenal
obstruction, a
duodenojejunostomy is
performed and no attempt is
made to resect the pancreatic
tissue which would result in a
pancreatic fistula

41. Thank you