Lecture 18 Flashcards
Pancreas Gross Mrophology
Glandular organ - Endocrine and Exocrine
Head= in Concavity of duodenum
-Uncinate process wraps behind SM vessels
Neck= narrow area from head to body. L1 transpyloric plane
-Lies anterior to SM vessel origins
Body= passes across laterally and superiorly. Main part. Mostly contained in epigastic
Tail= Passes into lienorenal ligament and into contact with hilus of spleen. slightly Left hypochondrium region.
Relations of the Pancreas
important to know for trauma, how it will effect other surrounding structures
Anterior = Transverse Colon (movable, sometimes sitting above pancreas) + Stomach
Posterior = Bile duct, Portal vein (comes out anteriorly to uncinate process), splenic vein, IVC, aorta, Superior Mesenteric artery (exits ontop of uncinate process) (little IM), L psoas, L suprarenal gland (association with L kidney), L kidney, spleen
-Main duct from tail to Ampulla of Vater
-Accessory duct may be present, drains into Upper part of head and into Duodenum (not ampulla of Vater)
Pancreatic Ducts
Main duct = from Tail –> Ampulla of Vater - length of pancreas
-joined by Bile duct
-enters descending duodenum via the Sphincter of Oddi (major duodenal papilla)
(main bulk of pancreas forms from dorsal bud, but main pancreatic duct but isnt termination of dorsal bud. Ventral bud already connected to bile duct of ventral diverticulum, rotates, and dorsal duct splits and joins ventral part/descending central part of Duodenum)
Accessory Duct - may be present/variable (continuation of dorsal bud into duodenum)
-typically found a little higher up
-drains into upper part of head –> and then into duodenum (minor duodenal papilla)
Papilla = sphincter of Oddi
Ampulla (hepato-pancreatic)= swelling (joining of two ducts- each has own sphincters)
Arterial supply of Pancreas
Highly vascular
-as is sending alot of things all over the body
-division between Foregut and Mid gut occurs 1/2 (coeliac axis –> superior mesenteric supply)
Quite complicated
Halfway between foregut and midgut (Dual Supply!)
1. Common hepatic - Gastroduodenal - superior Pancreatoduodenal (Anterior and Posterior Pancreatoduodenal)-wraps around head and lil neck of pancreas (off Ceoliac trunk-more)
2. Splenic -Dorsal and Greater Pancreatic (spreading up body and tail, anastomosing with other arteries) (off Coeliac trunk -more)
-Majority of supply is from coelac axis, therefore pancreas is mainly classified as Foregut. Is also join ventral bud rom ventral mesogastrium, hepaticdiverticulum - entwined with foregut structures
2. Superior Mesenteric L1 (midgut) - Inferior Pancreatoduodenal (Anterior and Posterior Inferior Pancreatoduodenal) anastomose around and supplying head and uncinate process,coming from inferiorly, directly with respective pairings.
-arterial supply has high amount of variation
Bile duct blood supply
branches from pancreato duodenal
-supplied all the way down dorsally as it pierces into pancreatic head dorsally to join pancreatic duct
Venous Lymphatic Drainage and ANS of Pancreas
Portal system: Will flow back to portal vein, regardless of artery origin
-back through splenic or SMV –> into liver –> into IVC
Lymphatics:
Dual arterial supply = Dual lymphatic drainage
-Pre Aortic Coeliac Nodes T12
-Pre Aortic Superior Mesenteric Nodes L1
ANS:
Coeliac (& Superior Mesenteric) Plexi
-Greater T5-9 (and Lesser Splanchnic T10-11)
-Vagus (X)
Pain: referred to Epigastric region
(superior mesenteric umbilical region?)
Spleen
Not part of foregut as isnt part of digestive system
Largest single mass of lymphoid tissue in the body
Lies inferior to ribs 9-11 in the Left hypochondrium (posterior to stomach) -left and infront of kidneys and posterior abdominal wall
-develops in dorsal mesogastrium
Gastrosplenic ligament carrying short gastric and gastro-epiploic vessels
Lienorenal ligament (doesnt attach to kidney itself. Kindeys are in Posterior abdominal wall Retroperitoneally, surrounded by fat) More attached to parietal peritoneum on the wall. to left kidney carrying splenic vessels and tail of pancreas
Relationships of the Spleen
Anterior -Tail of Pancreas -Left Colic Flexure -Stomach Posterior -Left Kidney -Ribs 9-11 (protecting spleen, lymphoid tissue, huge blood supply (splenic artery biggest branch off coeliac axis)) Risk: Trauma to this region/LEft hypochondrium of rib cage- ribs fracture at most lateral point- spleen is located at most lateral point. Will pierce inwards and rupture spleen =huge heamoraging in abdomen
Spleen Morphology
2x surfaces=
Diaphragmatic (tilted) and Visceral
2x Poles = Upper and Lower poles (points)
3x Areas = Related to neighbouring organs =Gastric, Renal (posterior) and Colic (Flexure)
Hilum - splenic artery and vein (in and out)
Medial end= Posterior extremity
Splenorenal ligament containing splenic vessels and tail of pancreas
Gastrosplenic ligament contains Short Gastric vessels + Left gastro-omental vessles
Splenic Ligaments
Dual layers of peritoneum (folded back on itself)
-provide structural support and passageway
1. Splenorenal/Lienorenal:
spleen - L kidney
- Splenic vessels (from ceoliac axis)
-Tail of pancreas
2. Gastrosplenic/Gastrolienal:
stomach - spleen
-potential space in middle:
-short gastric vessels (up greater curvature and round to top)
-gastroepiploic vessels
Supply to spleen
Arterial: Splenic artery (from Coeliac Axis) Venous: Splenic vein (into Portal Vein) Lymph: Coeliac nodes T12 ANS: Coeliac plexus T12 -Vagus X -Greater Splanchnic T5-9
Trans-pyloric Plane
Midway between Suprasternal notch and pubic symphosis L1
- Pyloric region of stomach (hence transpyloric plane)
- 1st part of duodenum
- Fundus of Gallbladder (midclavicular 9th costal cartilage)
- Hila of kidneys
- Hilum of Spleen (run along back side of pancreas)
- Neck of Pancreas
- Transverse Mesocolon origin + Colic Flexures (left and right)
- SMA origin (L1, originating from aorta)
- Portal Vein origin/formation - tip of 9th costal cartialge - re gallbladder
- Tip of 9th Costal Cartilage
- End of spinal cord (cauda equina/horses tail beginning)
Transverse CT at Transpyloric plane
L1 Gall bladder Liver (Right lobe) Stomach Duodenum 1st and 2nd parts right and Left kidney Left colic flexure Spleen Aorta (SMA coming out) Inferior Vena Cava
