Presentation on theme: "Liver, biliary system, pancreas and spleen"— Presentation transcript:
1 Liver, biliary system, pancreas and spleen Long Nguyen
2 Embryology of the digestive glands Liver, gallbladder and pancreas develop from endodermal diverticulae that bud from the duodenum in the 4th to 6th weeksLiver sprouts first and expands in ventral mesenteryCystic diverticulum also in ventral mesenteryPancreas arises from a dorsal and ventral bud.Ventral pancreatic bud migrates posteriorly to fuse with the dorsal bud.Main duct of ventral bud becomes the main pancreatic duct.
3 Liver - exam questionsWrite short notes on the segmental anatomy of the liver. (9/07, 9/05, 4/05, 9/04, 9/02)Write short notes on the arterial supply to the liver and its normal variants. (9/08, 10/01)
4 Liver Lies in right upper quadrant. Underlies the thoracic cage. Conforms to right dome of diaphragmConnected to the diaphragm by the falciform and coronary ligaments
5 Liver - relationsSurfaces separated by inferior border of liver and coronary ligament posteriorlyBare area between the reflections of coronary ligaments in direct contact with diaphragm and not covered by peritoneumDiaphragmatic surfaceSmooth and convexSeparated from diaphragm by subphrenic recess
6 Liver – relations (2) Visceral (posteroinferior) surface Lies in contact with oesophagus, stomach and lesser omentum on the leftDuodenum in midlineRight kidney, adrenal and hepatic flexure of the colon on the rightH-shaped arrangement of structuresCrossbar formed by porta hepatis (portal vein, hepatic artery, hepatic ducts, nerve plexus and lymph vesselsLeft: ligamentum teres (remnant of left umbilical v.) and ligamentum venosum (remnant of ductus venosum)Left umbilical v. carries blood from placenta to foetus.Ductus venosum shunts blood form the left umbilical vein to the IVC in the foetus bypassing the liver.
8 Liver - old lobar anatomy Right and left lobes divided by plane through the IVC and gallbladder fossa on (Moore)Caudate lobeLies posteriorly between lig. venosum and IVC fossaPorta hepatis inferiorlyTail-like caudate process connects to right lobe and separates portal vein from IVCQuadrate lobeAnteroinferior between GB bed and lig. teresPorta hepatis superiorlyCaudate and quadrate lobe considered to be part of left lobeReidel’s lobe (not a true lobe)Lower border of the right lobe lateral to the GB may project downwards for a considerable distance as a broad or bulbous processOccurs in 5-10% of females and rarely in malesEven older anatomyFalciform ligament anteriorly and lig. teres and venosum on visceral surfaceCaudate and quadrate lobe considered to be part of right lobe
9 Liver - vascular anatomy Double blood supply from hepatic artery (30%) and portal vein (70%)Arterial supply by common hepatic artery branch of coeliac artery.Gives off right gastric and gastroduodenal arteries before reaching the liver in the free edge of the lesser omentum.Divides into left and right hepatic arteries before entering the liver at the porta.Variants of right hepatic artery belowPortal vein formed posterior to neck of pancreas by union of SMV and splenic veinHepatic a. carries oxygenated blood and conducted to central v of each liver lobulePortal v carries venous blood containing products of digestion absorbed from the GI tract.
10 Liver - vascular anatomy (2) Right and left lobes functionally independent and defined by arterial distributionEach supplied by left and right portal v., left or right hepatic arteries and drained by left or right hepatic duct (portal triad)Quadrate lobe supplied by left hepatic arteryCaudate lobe supplied by both
11 Liver - hepatic veinsHepatic veins are intersegmental and do not run with the structures of the portal triadRight, middle and left hepatic veins drain corresponding thirds of the liverMiddle hepatic vein lies in the principal plane between right and left lobesLeft hepatic vein lies between medial and lateral segments of the left lobeRight hepatic vein lies between anterior and posterior segments of the right lobeAll drain into the IVC without an extrahepatic courseInferior group of small veins from right lobe also drains into IVC
12 Liver - segmental anatomy (Couinaud system) Knowledge of segments important in the assessment of location and extent of hepatic pathology as surgery is performed in segmental fashion and distribution of disease determines whether lesions are resectable.The hepatic veins divide the liver into 4 divisionsA horizontal plane through the portal vein divides the 4 divisions into superior and inferior segmentsSegments numbered in clockwise direction starting at caudate lobe (segment 1)
13 Liver – Lymph drainage and innervation Superficial and most deep lymph vessels converge at the porta and end in the hepatic lymph nodes (eg. Cystic LN near GB neck or LN of omental foramen)Hepatic LN’s drain into coeliac LN’s around the coeliac trunk, then thoracic ductSome deep lymph vessels follow hepatic veins to IVC foramen in diaphragm and end in middle phrenic LN’sInnervationSympathetic and parasympathetic supply from the hepatic plexus, a derivative of coeliac plexus (formed from fibres of left and right vagus and right phrenic nerves)
14 Gallbladder and biliary tree – exam questions Write short notes on the anatomy of the gall bladder (9/04)Write short notes on the anatomy of the biliary tree (excluding the gallbladder) and normal variations (4/08, 9/07, 4/05)
15 Gallbladder and cystic duct Pear shaped sac lies to the right of the quadrate lobe in GB fossa on the visceral surface of liverConcentrates and stores bile secreted by the liverCholecystokinin produced by intestinal mucosa during digestion, passes to GB and causes it to contract and release bileFundus, body and neckMucosal membrane arranged into spiral folds (valves of Heister) at GB neck and cystic duct
16 Gallbladder - relations AnterosuperiorlyGB fossa of liverFundus projects from inferior border of liver, located at tip of 9th costal cartilage in MCL where lateral edge of rectus abdominis meets costal marginPosteroinferiorlyNeck: lesser omentum. Omental (epiploic) foramen lies immediately to the left.Body: D1Fundus: transverse colon
17 Gallbladder – blood supply Arterial supplycystic arteryVenous drainagedirectly into liver or via a cystic vein
18 Biliary TreeBile is secreted by hepatocytes into bile canuliculi which drain into interlobular bile ducts. Progressively larger ducts formed.Left and right hepatic ducts emerge from porta and merge to form common hepatic duct (4cm)Joined on the right by the cystic duct from the GB to form the common bile duct (8-10cm long, 5-6mm diameter)Runs in free edge of lesser omentum, passes posterior to D1 and head of pancreasComes in contact with pancreatic duct on the left side of D2Usually unite in the duodenal wall to form hepatopancreatic ampulla (of Vater)Ampulla opens into descending part of duodenum at summit of major duodenal papilla, 8-10cam from pylorusAreas drained by hepatic ducts are the same as those supplied by the accompanying portal v. and hepatic a.Choledochal sphincter surrounds the bile duct as it penetrates the duodenal wallHepatopancreatic sphincter (sphincter of Oddi) at distal end of hepatopancreatic ampulla controls release of both bile and pancreatic fluid
19 Biliary Duct – blood supply Arterial supplyProximally: cystic arteryMiddle: right hepatic arteryDistally: posterior superior pancreaticduodenal a.Venous drainageProximally: drainage directly into liverDistally: posterior superior pancreaticduodenal v.Lymph drainageCystic LN, node of omental foramen, hepatic LN’s
20 Biliary Tree - variants Accessory hepatic ducts may arise in the liver and join the right hepatic duct, common hepatic duct, common bile duct, cystic duct or GBRight and left hepatic ducts may fail to unite giving a double ductCystic ductAbsentJoins common hepatic duct on the left rather than the rightJoins the right hepatic duct or an accessory ductJoins the common hepatic duct anywhere between the porta and the duodenum (low and high union)
22 Pancreas – exam questions Write short notes on the anatomy of the pancreatic ducts and variations. (9/08)Make brief notes on the embryology of the pancreas. (10/00)What sonographic landmarks are useful in identifying the pancreas? (10/00) Describe the sonographic appearance of a normal pancreas.
23 PancreasRetroperitoneal organ lies transversely and slightly obliquely at L1-L2 levelTransverse mesocolon attached to anterior marginExocrine (pancreatic enzymes) and endocrine functions (glucagon and insulin)Head, neck, body and tail
24 Pancreas - Relations Head Neck Body Tail Lies in curvature of duodenum Anterior to IVC, aorta, right renal vessels and left renal veinUncinate process projects posteriorly and to the left and lies posterior to superior mesenteric vesselsCBD passes posteriorly in a groove or embedded withinNeckAnterior to the union of splenic vein and SMV to form the portal veinBodyCurves over vertebrae and great vesselsAnterior to the aorta and lies between the coeliac trunk and the SMASplenic vein passes posteriorTaillies in the splenorenal ligamentUsually contacts the hilum of the spleen
26 Pancreas - EmbryologyArises from the junction of the primitive foregut and midgut as a larger dorsal division and a smaller ventral budVentral bud swings posteriorly to unite with the inferior aspect of the dorsal bud trapping the superior mesenteric between divisionsVentral bud forms the uncinate processDuct of the ventral bud forms the proximal end of the main pancreatic duct; the distal end of the dorsal pancreatic duct forms the remainder.
28 Pancreas – blood supply Arterial supplyHead: superior pancreaticoduodenal a. (from gastroduodenal artery) and inferior pancreaticoduodenal a. (from SMA)Body and tail: branches from splenic arteryVenous drainageMostly splenic v., but also portal v. and SMV
29 Spleen Large soft vascular lymphatic organ in the left upper quadrant Up to 12cm with long axis in line with 10th ribArises from mass of mesenchymal cells located between layers of dorsal mesogastrium.
30 Spleen - relationsPosterior to stomach. Connected to greater curvature by gastrosplenic ligamentAnterior to superior part of left kidney. Connected by splenorenal ligamentLaterally: diaphragm, 9th-11th left ribsTail of pancreas lies at splenic hilum
31 Spleen – blood supply Arterial supply Venous drainage Lymph drainage Splenic artery divides into end arteries as it enters the spleenNo anastamoses, hence obstruction of one end artery results in area of splenic infarctionVenous drainageSplenic veinLymph drainagePancreaticopsplenic LN’s