The Viscera Associatedwith the AlimentaryTract: The Liver, thePancreas, and the Spleen20

Accessory Bile Duct 361

Congenital Choledochal Cyst 361

The Pancreas 362

Diagnosis of Pancreatic Disease 362

Trauma of the Pancreas 362

Cancer of the Head of the Pancreas

and the Bile Duct 362

The Pancreatic Tail and Splenectomy 362

Congenital Anomalies of the Pancreas 362

Anular Pancreas 362

Ectopic Pancreas 363

Congenital Fibrocystic Disease 363

The Spleen 363

Splenic Enlargement 363

Trauma to the Spleen 363

Congenital Anomalies of the Spleen 363

Supernumerary Spleens 363

Clinical Problem Solving Questions 363

Answers and Explanations 364

The Liver 358

Liver Supports and Surgery 358

Liver Trauma 358

Liver Biopsy 358

Subphrenic Spaces 359

Portal–Systemic Anastomoses 359

Portal Hypertension 359

Blood Flow in the Portal Vein and

Malignant Disease 359

Gallstones 359

Biliary Colic 359

Acute Cholecystitis 359

Cholecystectomy and the Arterial Supply to the

Gallbladder 359

Gangrene of the Gallbladder 359

Congenital Anomalies of the Gallbladder 359

Biliary Atresia 359

Absence of the Gallbladder 361

Double Gallbladder 361

Absence of the Cystic Duct 361

Chapter Outline

THE LIVERLiver Supports and SurgeryThe liver is held in position in the upper part of the abdom-inal cavity by the attachment of the hepatic veins to the in-ferior vena cava. The peritoneal ligaments and the tone ofthe abdominal muscles play a minor role in its support. Thisfact is important surgically because even if the peritonealligaments are cut, the liver can be only slightly rotated.

Liver TraumaThe liver is a soft, friable structure enclosed in a fibrous cap-sule. Its close relationship to the lower ribs must be empha-sized. Fractures of the lower ribs or penetrating wounds of

the thorax or upper abdomen are common causes of liverinjury. Blunt traumatic injuries from automobile accidentsare also common, and severe hemorrhage accompaniestears of this organ.

Because anatomic research has shown that the bileducts, hepatic arteries, and portal vein are distributed in asegmental manner, appropriate ligation of these structuresallows the surgeon to remove large portions of the liver inpatients with severe traumatic lacerations of the liver or witha liver tumor. (Even large, localized carcinomatous metasta-tic tumors have been successfully removed.)

Liver BiopsyLiver biopsy is a common diagnostic procedure. With thepatient holding his or her breath in full expiration—to re-duce the size of the costodiaphragmatic recess and the like-lihood of damage to the lung—a needle is inserted through

the right eighth or ninth intercostal space in the midaxillaryline. The needle passes through the diaphragm into theliver, and a small specimen of liver tissue is removed formicroscopic examination.

Subphrenic SpacesThe important subphrenic spaces and their relationship tothe liver are described on text page 713. Under normalconditions these are potential spaces only, and the peri-toneal surfaces are in contact. An abnormal accumulationof gas or fluid is necessary for separation of the peritonealsurfaces. The anterior surface of the liver is normally dullon percussion. Perforation of a gastric ulcer is often ac-companied by a loss of liver dullness caused by the accu-mulation of gas over the anterior surface of the liver and inthe subphrenic spaces.

Portal–Systemic AnastomosesSee CD Chapter 8.

Portal HypertensionSee CD Chapter 8.

Blood Flow in the Portal Vein andMalignant DiseaseSee CD Chapter 8.

GallstonesGallstones are usually asymptomatic; however, they cangive rise to gallstone colic or produce acute cholecystitis.

Biliary ColicBiliary colic is usually caused by spasm of the smoothmuscle of the wall of the gallbladder in an attempt to ex-pel a gallstone. Afferent nerve fibers ascend through theceliac plexus and the greater splanchnic nerves to the tho-racic segments of the spinal cord. Referred pain is felt inthe right upper quadrant or the epigastrium (T7, 8, and 9dermatomes).

Obstruction of the biliary ducts with a gallstone or bycompression by a tumor of the pancreas results in backup ofbile in the ducts and development of jaundice. The im-paction of a stone in the ampulla of Vater may result in thepassage of infected bile into the pancreatic duct, producingpancreatitis. The anatomic arrangement of the terminal partof the bile duct and the main pancreatic duct is subject toconsiderable variation. The type of duct system present

determines whether infected bile is likely to enter the pan-creatic duct.

Gallstones have been known to ulcerate through thegallbladder wall into the transverse colon or the duodenum.In the former case, they are passed naturally per the rectum,but in the latter case, they may be held up at the ileocecaljunction, producing intestinal obstruction.

Acute CholecystitisAcute cholecystitis produces discomfort in the right upperquadrant or epigastrium. Inflammation of the gallbladdermay cause irritation of the subdiaphragmatic parietal peri-toneum, which is supplied in part by the phrenic nerve (C3,4, and 5). This may give rise to referred pain over the shoul-der, because the skin in this area is supplied by the supra-clavicular nerves (C3 and 4).

Cholecystectomy and the ArterialSupply to the GallbladderBefore attempting a cholecystectomy operation, the surgeonmust be aware of the many variations in the arterial supplyto the gallbladder and the relationship of the vessels to thebile ducts (CD Fig. 20-1). Unfortunately, there have beenseveral reported cases in which the common hepatic duct orthe main bile duct has been included in the arterial ligaturewith disastrous consequences.

Gangrene of the GallbladderUnlike the appendix, which has a single arterial supply, thegallbladder rarely becomes gangrenous. In addition to thecystic artery, the gallbladder also receives small vessels fromthe visceral surface of the liver.

CONGENITALANOMALIES OFTHE GALLBLADDER

Biliary AtresiaFailure of the bile ducts to canalize during developmentcauses atresia. The various forms of atresia are shown in CDFig. 20-2. Jaundice appears soon after birth; clay-coloredstools and very dark colored urine are also present. Surgicalcorrection of the atresia should be attempted when possible.If the atresia cannot be corrected, the child will die of liverfailure.

The Viscera Associated with the Alimentary Tract: The Liver, the Pancreas, and the Spleen 359

360 Chapter 20

right hepatic artery

cystic artery

left hepatic artery

hepatic artery

bile duct

CD Figure 20-1 Some commonvariations of blood supply to thegallbladder.

atresia of bile duct atresia of hepatic duct

atresia of entire extrahepatic apparatus atresia of hepatic ductsCD Figure 20-2 Some common congeni-tal anomalies of the biliary ducts.

Absence of the GallbladderOccasionally, the outgrowth of cells from the hepatic budfails to develop. In these cases, there is no gallbladder andno cystic duct (CD Fig. 20-3).

Double GallbladderRarely, the outgrowth of cells from the hepatic bud bifur-cates so that two gallbladders are formed (see CD Fig. 20-3).

Absence of the Cystic DuctIn absence of the cystic duct, the entire outgrowth of cellsfrom the hepatic bud develops into the gallbladder and failsto leave the narrow stem that would normally form the cystic

duct. The gallbladder drains directly into the bile duct. Thecondition may not be recognized when performing a chole-cystectomy, and the bile duct may be seriously damaged bythe surgeon (see CD Fig. 20-3).

Accessory Bile DuctA small accessory bile duct may open directly from the liverinto the gallbladder, which may cause leakage of bile intothe peritoneal cavity after cholecystectomy if it is not recog-nized at the time of surgery (see CD Fig. 20-3).

Congenital Choledochal CystRarely, a choledochal cyst develops because of an area ofweakness in the wall of the bile duct. A cyst can contain 1 to2 L of bile. The anomaly is important in that it may press

The Viscera Associated with the Alimentary Tract: The Liver, the Pancreas, and the Spleen 361

congenital absence of gallbladder double gallbladder

absence of cystic duct abnormally long cystic duct

accessory bile duct choledochal cyst CD Figure 20-3 Some common congeni-tal anomalies of the gallbladder.

Cancer of the Head of the Pancreasand the Bile DuctBecause of the close relation of the head of the pancreas tothe bile duct, cancer of the head of the pancreas oftencauses obstructive jaundice.

The Pancreatic Tail and SplenectomyThe presence of the tail of the pancreas in the splenicorenalligament sometimes results in its damage during splenec-tomy. The damaged pancreas releases enzymes that start todigest surrounding tissues, with serious consequences.

CONGENITALANOMALIES OFTHE PANCREAS

Anular PancreasIn anular pancreas, the ventral pancreatic bud becomesfixed so that, when the stomach and duodenum rotate, theventral bud is pulled around the right side of the duode-num to fuse with the dorsal bud of the pancreas, thus en-circling the duodenum (CD Fig. 20-4). This may causeobstruction of the duodenum, and vomiting may start afew hours after birth. Early surgical relief of the obstructionis necessary.

on the bile duct and cause obstructive jaundice (see CDFig. 20-3).

THE PANCREASDiagnosis of Pancreatic DiseaseThe deep location of the pancreas sometimes gives rise toproblems of diagnosis for the following reasons:

� Pain from the pancreas is commonly referred to the back.� Because the pancreas lies behind the stomach and trans-

verse colon, disease of the gland can be confused withthat of the stomach or transverse colon.

� Inflammation of the pancreas can spread to the peri-toneum, forming the posterior wall of the lesser sac. Thisin turn can lead to adhesions and the closing off of thelesser sac to form a pseudocyst.

Trauma of the PancreasThe pancreas is deeply placed within the abdomen and iswell protected by the costal margin and the anterior ab-dominal wall. However, blunt trauma, such as in a sports in-jury when a sudden blow to the abdomen occurs, can com-press and tear the pancreas against the vertebral column.The pancreas is most commonly damaged by gunshot orstab wounds.

Damaged pancreatic tissue releases activated pancre-atic enzymes that produce the signs and symptoms of acuteperitonitis.

362 Chapter 20

narrowed lumen of duodenum

fixed ventral pancreatic bud

dorsal bud

dorsal pancreatic bud

duodenum

ventral pancreatic bud

CD Figure 20-4 Formation of the anularpancreas, producing duodenal obstruction.Note the narrowing of the duodenum.

Ectopic PancreasEctopic pancreatic tissue may be found in the submucosa ofthe stomach, duodenum, small intestine (includingMeckel’s diverticulum), and gallbladder and in the spleen.It is important in that it may protrude into the lumen of thegut and be responsible for causing intussusception.

Congenital Fibrocystic DiseaseBasically, congenital fibrocystic disease in the pancreas iscaused by an abnormality in the secretion of mucus. The mu-cus produced is excessively viscid and obstructs the pancre-atic duct, which leads to pancreatitis with subsequent fibrosis.The condition also involves the lungs, kidneys, and liver.

THE SPLEENSplenic EnlargementA pathologically enlarged spleen extends downward andmedially. The left colic flexure and the phrenicocolic liga-ment prevent a direct downward enlargement of the organ.As the enlarged spleen projects below the left costal margin,its notched anterior border can be recognized by palpationthrough the anterior abdominal wall.

The spleen is situated at the beginning of the splenicvein, and in cases of portal hypertension it often enlargesfrom venous congestion.

Trauma to the SpleenAlthough anatomically the spleen gives the appearance ofbeing well protected, automobile accidents of the crushingor run-over type commonly produce laceration of thespleen. Penetrating wounds of the lower left thorax can alsodamage the spleen.

CONGENITALANOMALIES OFTHE SPLEEN

Supernumerary SpleensIn 10% of people, one or more supernumerary spleens maybe present, either in the gastrosplenic omentum or in thesplenicorenal ligament. Their clinical importance is thatthey may hypertrophy after removal of the major spleen andbe responsible for a recurrence of symptoms of the diseasefor which splenectomy was initially performed.

The Viscera Associated with the Alimentary Tract: The Liver, the Pancreas, and the Spleen 363

Clinical Problem Solving QuestionsRead the following case histories/questions and give

the best answer for each.

A 55-year-old woman with a history of flatulent dyspepsiasuddenly experienced an excruciating colicky pain acrossthe upper part of the abdomen. On examination in theemergency department, she was found to have some rigidityand tenderness in the right upper quadrant. A diagnosis ofbiliary colic was made.

1. The following statements would explain this patient’ssymptoms except which?A. The pain of gallstone colic is caused by spasm of the

smooth muscle in the wall of the gallbladder anddistension of the bile ducts by the stones.

B. The pain fibers from the gallbladder and bile ductsascend through the superior mesenteric plexus andthe greater splanchnic nerves to enter the thoracicsegments of the spinal cord.

C. Referred pain is felt in the right upper quadrant orthe epigastrium.

D. T7 through T9 dermatomes are involved.E. The violent contractions of the gallbladder wall are

attempts to expel the gallstones.

On examination of the abdomen of a 31-year-old woman, alarge swelling was found to extend downward and mediallybelow the left costal margin. On percussion, a continuousband of dullness was noted to extend upward from the left ofthe umbilicus to the left axillary region. On palpation, anotch was felt along the anterior border of the swelling. A di-agnosis of splenic enlargement was made.

2. The signs displayed by this patient can be explained bythe following statements except which?A. The spleen has a notched anterior border caused by

incomplete fusion of its parts during development.

across the upper part of the abdomen. On examinationafter the attack, some rigidity and tenderness was notedin the right hypochondrium. Two days later the patientbecame jaundiced, and it was noticed that the degree ofjaundice varied from day to day. The diagnosis of biliarycolic was made. Why should a person passing a gall-stone experience pain? Why is the pain experienced inthe area described above? Why does the jaundice varyin intensity?

6. A 65-year-old woman was admitted to the hospital withprogressive jaundice of three months’ duration andweight loss. She had not experienced any colicky pain.On examination, a soft swelling could be felt in the ab-domen in the region of the tip of the right ninth costalcartilage. A diagnosis of cancer of the head of the pan-creas was made. What anatomic structure is responsiblefor the swelling?

7. A patient with thrombocytopenic purpura was advisedto have a splenectomy to stop the episodes of bleedingfrom the gums and gastrointestinal tract. The operationwas successful. Eighteen months later the clinical fea-tures returned. Can you explain in anatomic terms therecurrence of the bleeding after the condition had ap-parently been cured by splenectomy?

8. Following a splenectomy, it was noticed that pancreaticjuice was exuding through the patient’s abdominalwound. Is the pancreas likely to be damaged duringsplenectomy? Which part of the pancreas?

9. The anatomic arrangement of the terminal part of thebile duct and the main pancreatic duct is subject toconsiderable variation. Which variations are likely to beassociated with a pancreatitis should a gallstone be-come impacted at the lower end of the bile duct?

B. Because of the presence of the left colic flexure andthe phrenicocolic ligament, the spleen is unable toexpand vertically downward.

C. A pathologically enlarged spleen extends downwardand forward, toward the umbilicus.

D. The spleen is situated in the upper left quadrant ofthe abdomen beneath the diaphragm.

E. The long axis of the spleen lies along the twelfth rib.

3. A 19-year-old football player was accidently kicked onthe left side of his chest. On returning to the lockerroom he said he felt faint and collapsed to the floor. Onexamination in the emergency department, he wasfound to be in hypovolemic shock. He had tendernessand guarding in the left upper quadrant of his ab-domen. He also had extreme local tenderness over hisleft tenth rib in the midaxillary line. A diagnosis of aruptured spleen and the possibility of a fractured tenthrib was made. Explain the tenderness and guarding inthe abdomen in this patient.

A 40 year-old obese woman complaining of indigestion wasadmitted to the hospital for investigation. She had a pasthistory of gallstones and transient attacks of jaundice.Large gallstones have been known to erode through theposterior wall of the gallbladder and enter the intestinaltract.

4. Which part of the intestinal tract is likely to initiallycontain the stone?A. The sigmoid colonB. The descending colonC. The transverse colonD. The ascending colonE. The jejunum

5. A 50-year-old woman with a history of flatulent dyspep-sia suddenly experienced an excruciating colicky pain

364 Chapter 20

Answers and Explanations1. B is the correct answer. The pain fibers from the gall-

bladder and bile ducts ascend through the celiac plexus.

2. E is the correct answer. The long axis of the spleen liesalong the tenth rib (see text Fig. 20-27).

3. Initially in this patient, the spleen underwent asubcapsular hemorrhage, and later, in the lockerroom, the capsule gave way, allowing the blood toescape into the peritoneal cavity. The presence ofblood in the peritoneal cavity irritated the parietalperitoneum, causing tenderness in the left upper

quadrant and reflex guarding of the muscles in thesame area.

4. C is the correct answer. The transverse colon is in closeposterior relation to the gallbladder.

5. The pain is due to the spastic contraction of the muscleof the gallbladder attempting to flush the stone downthe bile ducts and to the distension of the ducts by thestone. The afferent pain fibers from the gallbladder andbile ducts enter the spinal cord between segments T5and T9. Pain is referred to the epigastrium via the sev-

enth to the ninth intercostal nerves. A variable amountof bile gets past the stone.

6. A small carcinoma of the head of the pancreas wasfound at operation to be compressing the bile duct.Back pressure along the bile ducts produced dilatationof the gallbladder, which could be felt in the region ofthe tip of the right ninth costal cartilage.

7. About 10% of persons have accessory spleens. Theseshould always be looked for when performing asplenectomy for such conditions as thrombocytopenicpurpura. If an accessory spleen is missed, it will enlargeand take over the functions of the main spleen.

8. The tail of the pancreas lies within the splenicorenalligament, and its tip is related to the hilus of the spleen.The surgeon has to take extreme care not to damage thetail of the pancreas during a splenectomy.

9. Any variation in which the bile duct and the pancreaticduct open by a common orifice into the duodenum islikely to cause this problem (see text Fig. 20-26). Gall-stones are usually associated with infected bile. A stoneimpacted at the orifice into the duodenum will allowreflux of infected bile along the main pancreatic duct,and pancreatitis will occur.

The Viscera Associated with the Alimentary Tract: The Liver, the Pancreas, and the Spleen 365