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THE PANCREAS
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The Pancreas in situ
Right lobe of liver
Falciform ligament
Gallbladder
Pancreas
Duodenum
L-3
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Pancreas, Introduction, continued
D. Head fills concavity of duodenum
E. Body crosses left kidney
F. Tail reaches hilus of the spleen
G. Related anteriorly to transversecolon
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Pancreas in situ
Duodenum
Head of Pancreas
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Pancreas, Introduction, continued
H. Aorta, IVC lie posterior
I. Uncinate process:
a. Lies posterior to SMA and SMV
b. Lies anterior to aortaJ. Neck lies anterior to SMV, with
pylorus just above
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Venous Drainage of the PancreasIVC
SMV
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Introduction, continued
L. Body relatedposteriorly to left
crus, left adrenal,left renal vein, andsplenic vein
K. Celiac Axis(trunk, artery) liessuperior to body
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II. Detailed Anatomy
A. Landmark structures
1. Splenic Artery:
a. Branch of celiactrunk
b. passes right toleft
c. Course is alongupper margin ofbody and tail
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Detailed Anatomy, cont
2. Hepatic Artery:a. Branch of celiac trunk
b. courses left to rightc. along upper margin of neck and
head
3. Superior Mesenteric Artery: at itsorigin from aorta, points at body of
pancreas
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Arterial Supply to Pancreas
Common HepaticArtery
Proper HepaticArtery
SuperiorMesenteric Artery
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Landmark structures, continued
4. Splenic Vein:a. runs parallel
to arteryb. on posterior
surface ofpancreas
c. Terminates inportal vein
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Landmark structures, continued
5. Superior & InferiorMesenteric Veins:
a. pass (inferior tosuperior) deepto pancreas
b. merge with splenicvein
c. Terminate in portalvein
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Landmark structures, continued
6. Common Bile Duct:a. passes behind first portion of
duodenumb. then through head of pancreas
c. Terminates at ampulla of vater
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Detailed Anatomy continued
B. Head of Pancreas
1. Important clinically because:a. Numerous ducts and vessels traverse it
b. Carcinoma usually located here
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Head of Pancreas, Detailed Anatomy, continued
2. Tumor will compress surrounding
structuresa. First indication may be jaundiceb. Tumor may compress
duodenumc. May involve local vessels
*Metastases may spread through these vessels*
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Head of Pancreas, Detailed Anatomy, continued
3. Lymphatics from head of pancreas
a. Drain to celiac nodesb. metastases may follow lymph
c. Metastases may spread vialesser omentum to liver
d. Some terminate in lumbar nodes
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Head of Pancreas, Detailed Anatomy, continued
4. Vessels supplying head of pancreasa. Superior & inferiorpancreaticoduodenal arteries
b. Both divide into two parallelvessels
c. one anterior and one posterior tohead
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Head of Pancreas, Detailed Anatomy, continued
1. Anterior branch ofpancreaticoduodenal
arterya. superior branch:
anterior superiorpancreaticoduodenalartery
b. inferior branch:anterior inferior
pancreaticoduodenalartery
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Head of Pancreas, Detailed Anatomy, continued
2. Posterior branch ofpancreaticoduodenal
arterya. superior branch:
posterior superiorpancreaticoduodenal artery
b. inferior branch:posterior inferior
pancreaticoduodenal artery
**extensive blood supply**
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Anterior Pancreaticoduodenal Artery
Branches arecontinuous withone another
Superiorbranchesoriginate from theGDA
Inferior branchesoriginate from theSMA
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Detailed Anatomy, continued
C. Body & Tail of Pancreas:
1. Supplied by splenic artery2. Have three surfaces:
a. Anterior surface
1. Concave2. Deep to stomach3. Separated from stomach by
lesser sac of peritoneum
(aka omental bursa)
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Anterior surface of pancreas
Anterior surfaceof pancreas
Epiploicforamen
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Lesser sac, continued
4. Lesser sac bounded by:
a. Liver, superiorlyb. Below, extends to
greater omentumc. Anteriorly: lesser
omentum, stomach,greater omentum
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Lesser sac, continued
d. Posteriorly: greateromentum
transverse colon,transverse mesocolon
e. Laterally:
1. Foramen of Winslow onright
2. Spleen on left
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Detailed Anatomy, continued
f. Foramen of Winslow (AKA: Epiploic
Foramen):
1. Lies between greater & lesser
sacs of peritoneum
2. posterior to free edge oflesser omentum
3. close to porta hepatis
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Three Surfaces, continued
2. Posterior surface: separated from vertebrae by
a. Aorta
b. Splenic veinc. Left kidney and renal vesselsd. Left adrenal glande. Left Crus of diaphragmf. SMA and SMV
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Detailed Anatomy, continued
D. Pancreatic Duct System
1. Pancreatic Duct (of Wirsung)a. Course is left to rightb. Receives numerous small ducts
c. @ neck of pancreas, duct turnsinferior, posterior & to the rightd. AKAmain pancreatic duct
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Duct of Wirsung (Main pancreatic duct)
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Pancreatic Duct System, continued
d. joins CBD at Ampulla of Vater
3 - 4 below pyloruse. results from fusion of ducts during
fetal development
1. One from ventral pancreas2. One from dorsal pancreas
(see Netters Embryology, p. 142, for Pancreasdevelopment)
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Duct of Wirsung
Duct ofWirsung
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Pancreatic Duct System, continued
2. Duct of Santorini:a. accessory pancreatic duct
b. Not universally identified
c. joins duodenum @ minor papilla
d. part of duct from dorsal pancreas
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Duct of Santorini
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III. Scanning AnatomyA. Depends on recognition of pancreatic
margins
B. Sonography best used as screeningprocedure
1. May be interference from bowelgas (especially in tail region)
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Scanning Anatomy, continued
2. Extremely accurate in detectionof pseudocysts
3. U/S can show texture of organ
4. By ID-ing vessels, can delineate
head, portions of body
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Scanning Anatomy, continued
C. Head:1. SMV outlines medial head to neck
region2. Duodenum & GB outline lateral
head
3. Superiorly, delineated bygastroduodenal artery (GDA)
4. Inferiorly, bounded by CBD
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Scanning Anatomy, continued
D. Further delineation by vascularlandmarks:
1. SMA:
a. Lies immediately posterior to
body, points to it!b. Recognized by echogenic fat
collar surrounding vessel
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Vascular Landmarks of the Pancreas
Pancreaticsonography
depends largelyon identifyingsurroundinglandmark vessels
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Scanning Anatomy, continued
2. SMV:a. Delineates medial headb. Larger diameter than SMAc. Lies to right of SMAd. Uncinate process wraps it (and
SMA), lies posterior & medial
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Vascular Landmarks of the Pancreas
Venouslandmarks of the
pancreasinclude the SMVand renal veins
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Scanning Anatomy, continued
E. Tail of Pancreas
1. May be visualized through fluid-filledstomach
2. Tail seen as 2-3 cm roundedmass anterior to hilus of left kidney
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Pancreatitis, Pancreatic Disorders, continued
5. Important factor is release of proteinkinins
a. Increase permeability of vessels& cells
b. Releases tissue fluidc. Edema may compress vesselsd. Tissue damage occurs
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Pancreatic Disorders, continued
B. Pseudocysts:
1. False cysts that may arisea. due to tissue necrosis
b. From enzymatic destruction
2. May persist after inflammation subsides
3. Usually near or in pancreas
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Pancreatic Diseases, continued
D. Chronic Pancreatitis
1. organ usually appears as small,atrophic
2. Contains scattered echoes fromcalcifications
3. Primary cause is alcoholism
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Pancreatic Diseases, continued
E. Dilation of Pancreatic Duct
1. Seen in acute or chronicpancreatitis
2. Frequently associated withneoplasm of pancreas
3. Biliary tract problems
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Pancreatic Diseases, continued
F. Abscess or Hemorrhagic Pancreatitis
1. Similar in sonographic appearance2. Hemorrhagic:a. Mass with inhomogeneous texture
b. Acute hemorrhage: sonolucent to
echogenicc. CT scan used for differentiation
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Pancreatic Disorders, continued
G. Pancreatic Tumors
1. Malignant tumors usually ariseas adenocarcinomas
2. In head of Pancreas: Sx
a. Painless jaundiceb. Anorexia
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Pancreatic Tumors, In head, continued
c. Nausea
d. Weight losse. Increased plasma amylase
f. Increased alkaline phosphatase
g. May involve compression ofpancreatic duct, CBD
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Pancreatic Tumors in the Head
Tumors in the headmay compressbiliary ducts orpancreatic ducts
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Pancreatic tumors, continued
3. In Body of Pancreas: Sxa. Gnawing pain radiating to back
b. Pain increases after eating orlying down
c. Weight loss, anorexia
d. Large tumor may compress IVC,portal vein
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Pancreatic tumors, continued
4. In Tail ofPancreas: Sx
a. Often silent until localmetastasis occurs
b. May metastasize to:1. para-aortic lymph
nodes2. spleen
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Pancreatic tumors, continued
5. Identified by organ enlargement,
subtle echo changes, irregular outline
6. Metastases to stomach, liver & lungsare common
7. Often causes dilation of ducts
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Pancreatic Disorders, continued
H. Fibrocystic Disease1. Result of cystic fibrosis
2. Diagnosed by methods other than
ultrasound
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Pancreatic Disorders, continued
I. Pancreaticolithiasis
1. Characteristic stone echoes in pancreatic duct
2. May see atrophied pancreatic parenchyma
3. Associated with chronic alcoholic pancreatitis
4. Contours of body, tail show irregularities
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Pancreatolithiasis, continued
5. Incidence slightly higher in head
6. Associated with occult pancreaticcarcinoma
a. Mass < 2mm diameter
b. Seen with dilation of pancreaticduct or CBD