The Anatomy Of The Liver Biology Essay

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Identify the right, left, caudate and quadrate lobes of liver and describe Riedel lobe. Riedel lobe is a downward tongue-like projection of the anterior edge of the right liver lobe to the right of the gallbladder. It is seen most frequently in women. It has been considered as either a sessile accessory lobe of the liver or as a normal variant. A Riedel lobe varies in size and shape and may extend into the right iliac fossa. Riedel lobe may sometimes be attached to the liver by a wide sulcus which can undergo torsion.

Label the three parts of the gallbladder and describe the function of the spiral valve of Heister within the cystic duct.

The neck of the gallbladder is continuous with the cystic duct that receives and empties bile duct from the common bile duct. Heister spiral valve is the spiral tracts formed by the rugae of cystic duct mucosa. The Spiral valve of Heister acts like a sphincter to regulate substances entering and leaving the gallbladder.

Describe the location of Hartmann pouch and its significance to gall stone formation.

Hartmann's pouch is an out-pouching of the wall of the gallbladder at the junction of the neck of the gallbladder and cystic duct. Its identification is useful in delineating biliary anatomy when performing a cholecystectomy.

Draw and label the biliary ducts from the liver, pancreas and gallbladder to the duodenum.

List at least 4 functions of the liver, name and discuss four liver function test the technologist routinely records on study records.

Functions of liver:

Storage of glycogen.

Decomposition old red blood cells.

Plasma protein synthesis.

Hormone production.


Production of bile

Liver function test is performed by a medical technologist on a patient's serum or plasma sample obtained by phlebotomy. Some tests are associated with functionality (e.g. albumin); some with cellular integrity (e.g. transaminase) and some with conditions linked to the biliary tract(e.g. alkaline phosphatase). These biochemical tests are useful in the evaluation and management of patients with hepatic dysfunction. These tests can be used to detect the presence of liver disease, distinguish among different types of liver disorders, gauge the extent of known liver damage and follow the response to treatment.

Standard liver function test records the albumin levels in liver. Albumin is a protein made specifically by the liver, and can be measured cheaply and easily. It is the main constituent of total protein; the remaining fraction is called globulin (including the immunoglobulins). Albumin levels are decreased in chronic liver disease, such as cirrhosis. It is also decreased in nephritic syndrome, where it is lost through urine. Poor nutrition of states of protein catabolism may also lead to hypoalbuminaemia. The half-life of albumin is approximately 20days. Albumin is not considered to be an especially useful marker of liver synthetic function; coagulation factors are much more sensitive. The reference range for albumin level is 3.5 to 5.0 g/dL.

It also records the levels of Alanine Transminase (ALT), also called Serum Glutamic Pyruvate Transminase (SGPT) or Alanine Aminotransferase (ALAT) is an enzyme present in hepatocytes (liver cells). When a cell is damaged, it leaks this enzyme into the blood, where it is measured. ALT rises dramatically in acute liver damage such as viral hepatitis. Elevations are often measured in multiples of the upper limit of normal (ULN). The reference range for ALT level is 9 to 60 IU/L.

Aspartate Transminase (AST) also called Serum Glutamic Oxalocetic Transminase (SGOT) is similar to ALT that is another enzyme associated with liver parenchymal cells. It is raised in acute liver damage but is also present in red blood cells and cardiac and skeletal muscles. Therefore it is not specific to the liver. The reference range for AST level is 10 to 40 IU/L.

Alkaline Phophatase (ALP) is an enzyme in the cells lining the biliary ducts of the liver. ALP levels in plasma will rise with large bile duct obstruction, intrahepatic cholestasis or infiltrative disease of the liver. ALP also present in bone and placental tissue, so it is higher in growing children and elderly patients with Paget's disease. The reference range for ALP is 30 to 120 IU/L.

State which fat-soluble vitamins are stored in the liver and which one affects blood coagulation factors.

Vitamin A, Vitamin B12, Vitamin D, Vitamin E and Vitamin K are the fat-soluble vitamins stored in the liver. Vitamin K can affect blood coagulation factors.

Discuss the location of the portal hepatic and list the structures found in this region to the liver.

The hepatic portal system begins in the capillaries of the digestive organs and ends in the portal vein. Consequently, portal blood contains substances absorbed by the stomach and intestines. Portal blood is passed through hepatic lobules where nutrients and toxins are absorbed, excreted or converted. Restriction of outflow through the hepatic portal system can lead to portal hypertension. Portal hypertension is most often associated with cirrhosis. The consequences of portal hypertension are due to portal systemic anastomosis formed by the body as an attempt to bypass the obstructed liver circulation. These collateral vessels form along the falciform ligament, diaphragm, spleen, stomach and peritoneum. These collaterals find their way to the renal vein where blood drained from the digestive the digestive organ is let into the systemic circulation.

Name the vessels that form the portal vein and discuss the duel blood supply to the liver.

Hepatic portal vein, often called as portal vein, is a short vein present in the abdominal cavity. It is formed by the confluence of the superior and the splenic veins. The hepatic portal vein is located in the right quadrant of the abdomen and measures about 3 inches in adults. It originates behind the neck of the pancreas, and ascends anterior to the inferior vena cava. At the right end of the porta hepatis, it divides into two branches which ramify within the liver forming several smaller venous branches and ultimately portal venules. 

The hepatic portal vein is responsible for draining blood from the gastrointestinal tract and spleen into the liver. It receives blood from the stomach, small intestine, large intestine, pancreas, spleen and gall bladder through the inferior mesentric, gastric, and cystic veins. It carries the blood received from all these parts of the body to the liver. The blood that is brought to the liver by the hepatic portal vein is cleaned by the liver and flows into the inferior vena cava through the hepatic veins. It is then taken to the heart for systemic circulation. The blood coming from the different parts of the digestive system is fully loaded with nutrients and toxins that have been absorbed along the tract from the ingested food. The liver detoxifies the blood by filtering it and that is the main reason why the blood is brought to the liver by the hepatic portal vein. The blood can enter the systemic circulation of the body after all the toxins have been removed.

Discuss the counter-current system for bile formation within the liver sinusoids.

Bile formation is a vital process. Bile acid secretion serves the intestinal digestion of lipids and assimilation of lipid-soluble nutrients. In addition, superfluous and potentially toxic material is disposed of in bile, including cholesterol, bilirubin, and an abundance of xenobiotics such as drugs and environmental chemicals and their metabolites.

The primary sites of bile production is the network of tiney bile canaliculi, formed by and embedded between adjacent liver cells. At this site, bile constituents may be synthesized within hepatocytes and secreted across their apical (canalicular) cell membranes into the bile canaliculi. Alternatively, liver cells may extract and take up "cholephils" from the sinusoidal blood stream by transport across their basolateral (sinusoidal) membranes and, after intracellular binding, sequestration, biotransformation, or conjugation, they produce metabolites that are amenable for secretion across the canalicular membrane. These primary processes result in canalicular bile formation in which secretory products such as bile acid and glutathione are excreted at concentrations that are high enough to generate osmotic water flow into bile canaliculi. In parallel with the transport of water-soluble bile constituents, lipid vesicles are detached from the apical membrane to form biliary micelles composed of phospholipids, cholesterol and bile salts. In addition, high molecular bile constituents such as plasma proteins are secreted by vesicular transport and by apical exocytosis. Forward movement of bile within the canaliculi is promoted by peristaltic contractions of an actin-myosin web located underneath the apical membrane of hepatocytes. Bile is then drained into the branches of intrahepatic bile ductules that converge to the common hepatic bile duct. At these latter sites, bile composition and bile volume are modified by reabsorption of some bile constituents (eg. reuptake of some bile acids), but the predominant mechanism accomplished by the cholangiocytes is the secretion of HCO3- together with additional fluid, resulting in ductular bile formation.

Discuss the function of the structure and function of the cystic duct in regulating bile flow.

The cystic duct is a small channel between the gall bladder and common bile duct. Its primary function is to transmit bile between the gall bladder and other ducts essential for digestion. It is typically located beside the cystic artery, which delivers oxygenated blood to both the cystic duct and the gall bladder.

The digestive system breaks down food with the help of bile. The cystic duct plays an important role in this process, transferring bile to and from the gall bladder and the hepatic and common bile ducts. This allows for the free flow of the vital fluid, which helps process lipids in the small intestine.

In addition to its slim, vessel-like shape, the cystic duct also has a spiral valve. The spiral valve is a system of intricate folds that rise and fall with the passage of bile. Though there is some mystery surrounding the precise function of the spiral valve, it is commonly believe that he conveyance of bile and the regulation of gall bladder size are the chief responsibilities of these surging folds.

Define enterohepatic circulation and give the correct order of absorption/secretion bile cycle.

Enterohepatic circulation refers to the circulation of biliary acids from the liver, where they are produced and secreted in the bile, to the small intestie, where it aids in digestion of fats and other substances, back to the liver.

Hepatocytes metabolize cholesterol to cholic acid chenodeoxycholic acid. These lipid-soluble bile acids are conjugated mainly to glycine or taurine molecules to form water soluble primary conjugated bile acids, sometimes called "bile salts". These bile acids travel to the gall bladder during the inter digestive phase for storage and to the descending part of the duodenum via the common bile duct through the major duodenal papilla during digestion. 95% of the bile acids which are delivered to the duodenum will be recycled by the enterohepatic circulation.

Due to the pH of the small intestine, most of the bile acids are ionized and mostly occur as their sodium salts which are then called "primary conjugated bile salts". In the lower small intestine and colon, bacteria dehydroxylate some of the primary bile salts to form secondary conjugated bile salts (which are still water soluble). Along the proximal and distal ileum, these conjugated primary bile salts are reabsorbed actively into hepatic portal circulation. Bacteria deconjugate some of the primary and secondary conjugated bile salts back to lipid soluble acids, which are passively absorbed into hepatic portal circulation. Finally, the conjugated bile acids which remained un-ionized conjugated bile acids are passively absorbed.

Venous blood from the ileum goes straight into the portal vein and then into the liver sinusoids. There, hepatocytes extract bile acids very efficiently and very little escapes the healthy liver into systemic circulation. If bile does escape, jaundice may be observed.

The net effect of enterohepatic recirculation is that each bile salt molecule is reused about 20 times, often multiple times during a single digestive phase.

Enterohepatic Circulation

State the two main functions (endocrine and exocrine) of the pancreas.

Pancreas is a dual functioning gland as it exhibits the properties of the endocrine as well as the exocrine gland.

Endocrine: This part of pancreas which performs endocrine function is formed out of millions of cell clusters. These cell clusters are known as the Islets of Langerhans. These islets consist of four types of cells, which are classifies on the basis of the hormones they secrete. Cells secreting glucagon are called alpha cells. The cells secreting insulin are known as the beta cells while somatostatin is secreted by delta cells. Pancreatic polypeptide is secreted by the PP cells.

Exocrine: Exocrine pancreas generate digestive enzymes along with an alkaline fluid. Both of these are secreted into the small intestine thrugh exocrine ducts. This function of secretion is performed in respone to the small intestinal hormones called cholecystokinin and secretin. Digestive enzymes produced by the exocrine glands consist of chymotrypsin, trypsin, pancreatic lipase and pancreatic amylase. Digestive enzymes are actually produce by the acinar cells present in the exocrine pancreas. Cells lininh the pancreatic ducts are called as the centrocinar cells. The centrocinar cells secrete a solution rich in salt and bicarbonate contents into the intestine.

Discuss the role of the duct of Wirsung in the exocrine function of the pancreas.

The pancreatic duct or duct of Wirsung is a duct joining the pancreas to the common bile duct to supply pancreatic juices which aid in digestion provided by the "exocrine pancreas". The pancreatic duct jins the common bile duct just prior to the ampulla of Vater, after which both ducts perforate the medial side if the second portion of the duodenum at the major duodenal papilla.

Label a diagram of the biliary tree and discuss the flow of bile in the biliary tree.

Bile flows out of the liver through the left and right hepatic ducts, which come together to form the common hepatic duct. This duct then joins with a duct connected to the gall bladder, called the cystic duct to form the common bile duct. The common bile duct enters the small intestine at the sphincter of Oddi (a ring-shaped muscle) located a few inches below the stomach.

About half the bile secreted between meals flows directly through the common bile duct into the small intestine. The rest of the bile is diverted through the cystic duct into the gall bladder to be stored. In the gall bladder, up to 90% of the water in bile is absorbed into the bloodstream, making the remaining bile very concentrated. When food enters the small intestine, a series of hormonal and nerve signals triggers the gall bladder to contract and the sphincter of Oddi to relax and open. Bile then flow from the gall bladder into the small intestine to mix with food contents and perform its digestive functions.

After bile enters and passes down the small intestine, about 90% of bile salts are reabsorbed into the bloodstream through the wall of the lower small intestine. The liver extracts these bile salts from the blood and resecretes them back into the bile. Bile salts go through this cycle about 10 to 12 times a day. Each time, small amounts of bile salts escape absorption and reach the large intestine, where they are broken down by bacteria. Some bile salts are reabsorbed in the large intestine. The rest are excreted in stool.

Define the term cholesecretagogue and discuss the role of cholecystokinin (CCK) in bile flow.

Cholesecretagogue are the hormone CCK, gastrin and secretin. A secretagogues is a substance that stimulates secretion. Cholesecretagogue stimulates secretion of bile by the gall bladder. Bile is released when fat and some proteins are present in the diet. The mechanism for bile concentration, storage and release is controlled primarily by the hormone cholecystokinin (CCK); other hormones, gastrin and secretin along with vagal stimulation play minor roles. When the sphincter of Oddi is closed, hydrostatic pressure forces bile through the cystic duct into the gall bladder (retrograde filling). When the chime-containing fat reaches the duodenum, cells in the duodenum secrete CCK into the blood. Cholecystokinin is a hormone that when it reaches the gall bladder it causes it to contrast. The action of CCK on the duodenal sphincter is to relax allowing muscular contractions of the gall bladder moves bile without resistance. The time from ingestion of lipids to stimulation of the gall bladder to contract is roughly 30minutes. Complete emptying of the gall bladder takes about 1 hour.

Define the terms cholangitis, cholecystitis, cholelith, cholelithiasis, choledocholithiasis and jaundice.

Cholangitis - Inflammation of bile duct.

Cholecystitis - Inflammation of gall bladder.

Cholelith - Gall stone.

Cholelithiasis - The presence of one or more calculi (gallstones) in the gall bladder. 

Choledocholithiasis - the presence of a gall stone in the common bile duct.

Jaundice - the yellowish staining of the skin and sclera (the white of the eyes) that is caused by high levels in blood of the chemical bilirubin. 

Discuss the use of the operative and T-tube cholangiogram in detecting biliary stone.

The operative cholangiogram os performed during cholecystectomy. When the surgeon suspects residual cholelith may be in the biliary ducts the operative cholangiogram id performed. It can be performed either before or after removal of the gall bladder. The cystic duct is tied off just proximal to the neck of the gall bladder and a catheter is inserted into the cystic duct near its joining the common hepatic duct. Approximately 6 to 10 ml of water soluble iodinated radiocontrast is injected. The surgeon is careful not to inject air since even a small quantity of air can mimic a radiolucent biliary stone. The entire biliary tree should be demonstrated with contrast spilling into the duodenum.

The operative cholangiogram can also demonstrate patency of the biliary tract and hepatopancreatic ampulla. Strictures, mass lesions and dilatations of the biliary ducts can also be assessed. Unlike the ERCP this is not a therapeutic study for removing stones from the biliary tree. Radiographs are then taken using fluoroscopic C-arm so that they can be evaluated.

Discuss the role of ERCP in diagnosing and treating biliary and pancreatic duct disorders.

Endoscopy refers to the illumination of the lumen of an organ using an endoscope. Cholangiopancretography refers to imaging the biliary ducts and pancreatic duct. The term endoscopic retrograde cholangiopancretography (ERCP) refers to imaging the biliary ducts using a retrograde approach through endoscope. ERCP is both a diagnostic tool and a therapeutic procedure for certain conditions. It is usually performed following other radiologic studies that are inconclusive (i.e. ultrasound or MRCP). It is used as a preoperative study to plan a cholecystectomy or postoperative to remove stones that have become lodges in the biliary ducts. Examples of therapeutic treatments with ERCP include but are not limited to dilating stenosed biliary or pancreatic ducts, removal of biliary or pancreatic duct stones, opening the sphincter of Vater by cutting to increase narrowing (sphincterotomy), taking tissue sample by brushing or biopsy, or placement of a stent to facilitate bile flow.

There is a special type of endoscope called a duodenoscope is used to perform cholangiopancretoscopy. It allows for detection of indeterminate ductal strictures, pancreatitis, treat large intraductal stones and can identify and take tissue samples to diagnose ductal diseases like intraductal papillary mucinous tumors and hemobilia.

State why ultrasound imaging is used to diagnose liver and pancreas disorders.

Ultrasound is a reliable investigation of soft tissue organs and lack of ionizing radiation dose at low cost. It can scan the liver from a number of position using transducer with a small foot print and with a configuration that allowa sound to enter through small areas at the surface and to obtain information at depth in the body even though surrounded by ribs and sternum. Ultrasound can be used to evaluate liver texture and of high or low reflexitivity. Ultrasound can demonstrate metastates with varying ultrasonic appearance. Small haemogiomas in the liver can also be can also confirm surgical jaundice by the presence of dilated intra and exra hepatic duct. In pancreas, the ultrasound can measure the pancreatic duct and dilatation excluded dilatation implying, distal obstruction. Inflammatory conditions, calcification, can pseudocyst formation can be seen as tumors in the head and body of pancreas.

Discuss the normal value for gall bladder wall thickness, and common bile duct diameter measured during ultrasound imaging following cholecysectomy.

Longitudinally, the gall bladder appears as a pear-shaped structure with thin white walls surrounding a black fluid. The normal gall bladder wall is thin, echogenic and anechoic lumen, and mild posterior enhancement. Bile is near the consistency of water so it's acoustic impedance in low, as bile does not attenuate the sound waves. Generally there is no acoustic shadowing posterior to the gall bladder so when imaging near the neck an acoustic shadow may represent a stone in the cystic duct. The gall bladder and bile ducts are evaluated for size and shape, wall thickness, contents, course and caliper.

State why CT is useful in diagnosing liver and pancreas disorders.

CT is useful in diagnosing liver and pancreas disorders as it can produce soft tissue image while x-ray cannot. It can also produce cross-sectional image of liver and pancreas, providing more accuracy and better view of the organ. 3D images can also be obtained to reconstruct as well as reformat the organ. CT scanner enables images to be obtained in several projections and thus producing high quality images for more accurate diagnosis purposes.

Name two nuclear medicine studies of the gall bladder and tell the difference between them.

ERCP or Endoscopic Retrograde cholangiopancretography is radiography following injection of a radio opaque material into the papilla of Vater. This is done through a fiber optic endoscope guide by use of fluoroscopy. This procedur is helpful in determining the causes of jaundice. It is an invasive procedure to diagnose chronic pancreatitis.

ERCP reveal in detail the changes in the main pancreatic duct (MPD) and pancreatic branches. However, ERCP is an invasive procedure method that potentially causes severe complication such as pancreatitis.

MRCP or magnetic resonance cholangiopancretography is a recently developed technique that allows non-invasive identification of the biliary tree and pancreatic duct, as clearly as ERCP and MRCP as well as several advantages over ERCP. It is save and operator dependent. MRCP enable viewing of the full length of MPD, regardless even in the presence of duct obstruction.

MRCP can show the entire pancreatic cystic lesion. However, MRCP cannot accurately reveal pancreatic branches irregularities in all cases of chronic pancreatitis, particularly in mild cases. Thus, MRCP can be used as a non-invasive screening tool and follow up method to determine cases of chronic pancreatitis. The efficiency of MRCP is dependent on the apparatus and technique.

Define the following: cirrhosis, ascites, jaundice, gall stones, cholecystitis, cholelithiasis, acute pancreatitis, hepatitis, hepatoma and cholangitis.

Cirrhosis - A consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules (lumps that occur as a result of a process in which damaged tissue is regenerated), leading to loss of liver function.

Ascites - Accumulation of fluid in the peritoneal cavity.

Jaundice - The yellowish staining of the skin and sclera (the white of the eyes) that is caused by high levels in blood of the chemical bilirubin. 

Gall stones - A crystalline concretion formed within the gall bladder by the accretion of bile components.

Cholecystitis - Inflammation of gall bladder.

Cholelithiasis - The presence of one or more calculi (gallstones) in the gall bladder. 

Acute pancreatitis - Sudden inflammation of the pancreas.

Hepatitis - Inflammation of the liver characterized by the presence of inflammatory cells in the tissue of the organ.

Hepatoma - Primary cancer of the liver.

Cholangitis - Inflammation of bile duct.

Define the term cholecystagogue and tell why these are used in the diagnostic imaging.

Cholecystagogue is an agent (as cholecystokinin) which stimulates the secretion of bile by the gall bladder.

Discuss the role of MR imaging of biliary tract. e.g. MRCP.

MRCP is a non-invasive magnetic resonance imaging exam that visualizes the entire gall bladder, biliary tree and pancreatic duct. It is often performed before an endoscopic retrograde choliangiopancretogram (ERCP) to determine if therapeutic ERCP is needed. By contrast, ERCP is both a diagnostic and therapeutic imaging tool for identifying and removing biliary tract stones. MRCP is a good alternative for those patients who need biliary imaging but have renal complications or allergy to iodinated contrast media.

MRCP can demonstrate areas of the hepatic and biliary duct that may not be seen when there is onstruction. MRCP has risen to the level of clinical relevance as a preoperative and pre-ERCP diagnostic tool for evaluation of choledodholithiasis. MRCP is also an excellent way to image the pancreatic duct to access its size, detect normal or obstructed Wirsung duct and determine etiology of ductal obstruction or disease.

MRCP images are taken in axial, coronal and 3D formats providing imaging referencing in multiple planes. It is important that the entire gall bladder, biliary ducts and pancreas are included in the axial, coronal and 3D images. Two techniques are combined for imaging the biliary tract: multisection thin-slice and single-slice thick-slab MRCP. Studies show that these techniques should be combined in the imaging protocol to get the most out of the unenhanced and enhanced MR scan. Intravenously administered fentanyl before MRCP has been shown to improve the qualitative and quantitative visualization of the biliary tree. The reason for both techniques is that single-shot-thin-slice imaging is superior to multisection thin slice for bile duct imaging.

State why MRCP is used to determine if an ERCP is needed.

The ERCP is both diagnostic and therapeutic. Some therapeutic uses of ERCP are to dilating stenosed biliary or pancreatic ducts, removal of biliary or pancreatic duct stones, opening the sphincter of Vater by cutting to increase narrowing (sphincterotomy), taking tissue sample by brushing or biopsy, or placement of a stent to facilitate bile flow.

The MRCP is a non-invasive magnetic resonance imaging exam that visualizes the entire gall bladder, biliary tree and the pancreatic duct. MRCP is a good alternative for patients who need biliary imaging but have renal complications or allergy to iodinated radiocontrast.

MRCP has a positive predictive value of 0.95 and a negative predictive value of 0.97 for bile duct stones. Research has shown that about 74% of clinically suspected bile duct stones are proven negative using MRCP, a finding that significantly reduces the risk of unnecessary ERCP. The specificity and sensitivity of MRCP in evaluating the normal pancreatic duct is 98% and 94% respectively.

List the structures demonstrated by the MRCP study.

Gall bladder

Biliary ducts



Pancreatic duct

Wirsung duct

Pancreatic neoplasm

Discuss why MRCP is used as a pre-screening for ERCP.

The ERCP is both diagnostic and therapeutic. Some therapeutic uses of ERCP are to dilating stenosed biliary or pancreatic ducts, removal of biliary or pancreatic duct stones, opening the sphincter of Vater by cutting to increase narrowing (sphincterotomy), taking tissue sample by brushing or biopsy, or placement of a stent to facilitate bile flow.

The MRCP is a non-invasive magnetic resonance imaging exam that visualizes the entire gall bladder, biliary tree and the pancreatic duct. MRCP is a good alternative for patients who need biliary imaging but have renal complications or allergy to iodinated radiocontrast.

MRCP has a positive predictive value of 0.95 and a negative predictive value of 0.97 for bile duct stones. Research has shown that about 74% of clinically suspected bile duct stones are proven negative using MRCP, a finding that significantly reduces the risk of unnecessary ERCP. The specificity and sensitivity of MRCP in evaluating the normal pancreatic duct is 98% and 94% respectively.

Discuss why ultrasound imaging of the gall bladder is used and what can be visualized on the scan.

Ultrasound is used to evaluate patients for biliary stones and cholecystitis. It can detect cystic duct and neck of the gall bladder obstruction as well as distention and inflammation of the gall bladder. It can identify carcinoma of the gall bladder, which is highly malignant and metastasizes quickly. Ultrasound is important because gall bladder cancer has a very low prognosis; therefore, any early diagnosis of this condition is potentially lifesaving. The gall bladder on ultrasound can usually be found between the quadrate and right lobe of the liver on the underside. The fundus may be folded giving a Phrygian cap appearance, which makes the gall bladder look septaed on the ultrasound. When seen, this should be differentiated frm a septate or double gall bladder that it could mimic. The cystic duct that joins the neck of the gall bladder to the common bile duct is only 2-4cm. The common hepatic duct (CHD) is only about 2.5cm in length and runs to the right of the portal vein and hepatic artery. The common bile duct (CBD) is generally long, 7.5 to 10 cm. it runs posterior to the head of the pancreas and can be enclosed in the pancreas distally. Conventionally the union of the CHD and CBD is called the common duct (CD).