of the Common Bile Duct Into the Duodenum
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A Clinical and Anatomical Study of Anomalous Terminationsof the Common Bile Duct Into the Duodenum
HAROLD H. LINDNER, M.D.,* VAN A. PENA, PH.D., ROBERT A. RUGGERI, M.S.
Termination of the common bile duct into the duodenum wasstudied in 1000 patients by operative cholangiograms obtainedfrom 5 different San Francisco Bay Area hospitals. The resultsindicate the strong probability that the duodenal biliarypapilia is anomalously placed in at least 13% of the 1000patients studied. Comments relative to the importance of thisfact to surgeons and radiologists are made, and suggestion of apossible causative factor for the anomalies is proposed.
A LTHOUGH it is commonly appreciated that there isan inordinately large number of anomalies asso-
ciated with the excretory ducts of the liver, com-paratively little attention has been paid to the positionof entrance of the common bile duct into the duodenum.Our interest in this subject was stimulated by a paperof Keddie, Taylor and Sykes."1 These authors investi-gated the site of termination of the common bile duct in120 patients, and surprisingly reported anomalies in 23%of these individuals. A thorough search of the literaturehas revealed that several other authors have also beeninterested in anomalies of common bile duct termina-tion, namely Lurje,'2 Dowdy,2 and Schulenberg.14 SeeTable 1 for a synopsis of their data. Single casereports of rare anomalous terminations of the commonbile duct have been reported by other authors.1 3'13'15
In our estimation, none of the series reported in Table1 was of sufficient size or reported in sufficient detailto warrant more than cursory interest. True, Schulen-berg14 reported 1093 cases, but only mentioned anomaliesof the site of entrance of the common bile duct into theduodenum in a short paragraph. We felt that the high
* Clinical Professor of Surgery and Topographical Anatomy; Uni-versity of California, San Francisco.
Reprint requests: Harold H. Lindner, Department of Anatomy,School of Medicine, University of California, San Francisco,California.
From the Departments of Surgery andTopographical Anatomy, University ofCalifornia, San Francisco, California
incidence of anomalies in Keddie's 120 patients war-ranted further study, both numerically, and in more de-tail. As a consequence, we decided to study 1000operative cholangiograms and to report completely ourresults relative to common bile duct terminationanomalies.
Descriptions of anomalies of the termination of thecommon bile duct are nonexistent in the standard ana-tomical texts. Of interest is the fact that a minuteperusal of the sections on common bile duct anatomyin the British and American Gray's Anatomy,4'5 Hollins-head's exhaustive Anatomy for Surgeons,8 and Hol-linshead's Textbook of Anatomy9 fail to mentionanomalies of the terminal course and site of termina-tion of the common bile duct.The most outstanding feature of the so-called normal
anatomy of the extrahepatic biliary system is its highdegree of variability. Our brief discussion of thenormal anatomy of the distal biliary tree will focus onthe pancreatic and intraduodenal portions of the com-mon bile duct and most particularly on the site oftermination of the common duct.The pancreatic portion of the common duct extends
from the cephalic border of the pancreatic head to thesite of entrance of the duct into the duodenal wall, adistance which varies from a short 2.5 cm to one aslong as 6 cm. The length of the duct will of necessitydepend on its site of entrance into the duodenum. Thepancreatic portion of the common duct may be retro-pancreatic, lying between the dorsal surface of the
Vol. 184 . No. 5 ANOMALOUS TERMINATI(
TABLE 1. Summary of Selective Literature
Numberof % Type of
Author, Institution Patients Anomalies Study
Lurje, 194 8.25 CadaverMoscow, U.S.S.R., dissection1937
Dowdy et al. 100 92 (Normal) AutopsyHermann Hospital, dissectionHouston, Texas1962
Schulenberg, 1093 5.6 OperativePretoria, South cholangio-Africa grams1970
Keddie et al. 120 23 OperativeRoyal Infirmary, cholangio-Manchester, Eng. grams1974
pancreas and the retroperitoneal tissues of the pos-terior abdominal wall. However, the duct may liewithin the substance of the dorsal portion of thepancreatic head, close to the medial border of thedescending duodenum. The retroduodenal and superiorpancreatic portions of the duct normally curve gentlyto the left. The inferior arc of this curvature isformed by the distal portion of the pancreatic courseof the common bile duct as it turns relatively sharplyto the right to terminate in the mid-portion of thedescending duodenum. Occasionally, the common ductwill abruptly turn laterally toward the descending por-tion of the duodenum and enter it at a right angle.The common bile duct passes through the duodenum
in an oblique manner, similar in some respects to thepassage of the ureters through the bladder wall. Theclassical anatomical description of the site of termina-tion of the common duct places the entrance of the ductinto the posteromedial wall of the descending duodenumat a site superior to the crossing of the duodenum bythe transverse colon. This site is about 7 cm distalfrom the pylorus.The major pancreatic duct also empties into the duo-
denum through the duodenal papilla. Prior to the timethe common bile duct and the major pancreatic ductpenetrate the duodenal wall, the two ducts becomeclosely related and run parallel to one another for adistance of from 2 mm tQ 10 mm. During this closeextra-duodenal association, junction of the two ductsmay occur just external to the duodenal wall. Theducts may also join during their tangential coursethrough the duodenal wall, or the common and majorpancreatic ducts may enter separately and individuallydischarge upon the eminence of the major duodenalpapilla.
)NS OF THE BILE DUCT 627
The intraduodenal portion of the common bile ductpasses through the bowel wall, and if joined by themajor pancreatic duct just proximal to the duodenalpapilla, forms the ampulla of Vater. In about 70%o ofcases there is an ampulla of Vater formed in suchfashion by the confluence of the major pancreatic ductand the common bile duct.10 The ampulla reaches fromthe point of confluence to the exit of the joined ductson the duodenal papilla. It averages only 2 mm to 3 mmin length. In those cases in which there is no con-fluence of the two ducts, there is no ampulla of Vater.The ampulla terminates at the ostium of the majorduodenal papilla on the posteromedial surface of theduodenal lumen.The ampulla as well as the entire intraduodenal
portion of the common duct and the intraduodenalsegment of the major pancreatic duct are surroundedby a sheath of circular smooth muscle fibers. Thisencircling musculature is known as the sphincter ofOddi.
r. hepatic duct
FIG. 1. Termination of the common bile duct into the duodenumas determlined by operative cholangiography. Duodenal divisions:duodenal bulb; descending duodenum: normal, that part extending fromthe duodenal bulb to approximately 3 cm distal to the midpoint;low, below the center portion, but above the angle between thedescending and transverse duodenum; angle, the junction betweenthe descending and transverse duodenum; transverse duodenum;ascending duodenum.
LINDNER, PENA AND RUGGERI
FIGS. 2a and b. Normal operative cholangiograms. The common bileduct terminates into the posteromedial wall of the descendingduodenum.
The portion of the sphincter of Oddi which sur-rounds the common bile duct is the thickest and mostextensive of the duodenal smooth muscle prolonga-tions. It stretches from the point of entrance of thecommon duct into the duodenal wall all the way to theampulla, if present, and is called the sphincter chole-dochus. It increases in thickness as it runs proximallyin the direction of the duodenal lumen. The muscle of
the sphincter choledochus also extends distally to even-tually completely encircle the ampulla and thus formthe sphincter ampullae. Some circular mnuscle fibersextend a short distance proximally from the ampulla tosurround the lower end of the pancreatic duct. Thesefibers form the pancreatic sphincter. It becomes obvioustherefore, that the sphincter of Oddi is made up of thecondensation of three separate sphincteric groupings,those about the common bile duct alone, those about theterminal part of the pancreatic duct and those fiberssurrounding the discharging of the duodenal eminence.Longitudinal smooth muscle fibers are present betweenthe surfaces of the common bile duct and the pancreaticduct. They facilitate the flow of bile through the commonduct, shortening the duct as they contract. However,these longitudinal smooth muscle fibers are not part ofthe sphincteric muscle complex.
This short anatomical description of the terminalportion of the common bile duct relates only to thosecases in which the common bile duct empties into thecentral portion of the descending duodenum. As far aswe know there is no information available at presentrelative to the mode of entrance of the common bileduct into the duodenal lumen in those cases where itsentrance is into the lower descending or the trans-verse portion of the structure. In those few cases inwhich visualization of the common bile duct resultedin a concomitant visualization of the major pancreaticduct (common channel), it appears that the mode andmethod of junction is similar to that described for theentrance of the two ducts into the midportion of thedescending duodenum. However, the number of cases sonoted is far too small for us to do more than speculateon the ductal and sphincteric arrangements when ananomalous site of common duct entrance is present.Our contribution in this paper is to emphasize thefact that a high percentage o