Anatomical Science International

, Volume 88, Issue 2, pp 93–96

Right hepatic artery traveling anteriorly to the common bile duct

Authors

    • Division of Morphological Neuroscience, Department of AnatomyShiga University of Medical Science
  • Wakoto Matsuda
    • Division of Anatomy and Cell Biology, Department of AnatomyShiga University of Medical Science
  • Motoi Kudo
    • Division of Morphological Neuroscience, Department of AnatomyShiga University of Medical Science
    • Neurosensing and Bionavigation Research CenterDoshisha University
Case report

DOI: 10.1007/s12565-012-0134-1

Cite this article as:
Honma, S., Matsuda, W. & Kudo, M. Anat Sci Int (2013) 88: 93. doi:10.1007/s12565-012-0134-1

Abstract

The topographic relationship between arteries and hepatobiliary ducts can be crucial during cholecystectomy. We observed the right hepatic artery traveling a rare route in a 91-year-old male. The common hepatic artery gave off the left hepatic, the right gastric, the gastroduodenal, and the right hepatic arteries consecutively without forming the proper hepatic artery. The right hepatic artery crossed the common bile duct anteriorly, ascended on the right side of the duct, passed the cystic duct posteriorly, and entered the right lobe of the liver. The so-called 9 o’clock artery running on the right side of the common hepatic and common biliary is reasonably speculated to be the aberrant right hepatic artery as presently shown. Developmental and clinical issues are discussed.

Keywords

Common bile ductCystic arteryCystic ductPosterior superior pancreaticoduodenal arteryRight hepatic artery

Abbreviation

ALGA

Accessory left gastric artery

CA

Cystic artery

CBD

Common bile duct

CD

Cystic duct

CHA

Common hepatic artery

CT

Celiac trunk

DPA

Dorsal pancreatic artery

FL

Falciform ligament

GdA

Gastroduodenal artery

GbF

Gallbladder fossa

HN

Hepatic nerve

IPA

Inferior phrenic artery

LGA

Left gastric artery

LHA

Left hepatic artery

PSPdA

Posterior superior pancreaticoduodenal artery

PV

Portal vein

RGA

Right gastric artery

RHA

Right hepatic artery

RPV

Right portal vein

SA

Splenic artery

SMA

Superior mesenteric artery

SV

Splenic vein

Introduction

The right (RHA) and left (LHA) hepatic arteries usually divide from the proper hepatic artery, which ascends on the left side of the common bile duct (CBD). The RHA usually crosses posterior to the common hepatic duct (CHD) to enter the cystic triangle of Calot (Michels 1955; Skandalakis 2004). According to Michels (1955), who classified the hepatic arteries into ten types based on the origin, the course and the supplying lobes, such a pattern is found only 55 % of 200 cases. Although Michels’ classification has been used widely in describing the branching of the hepatic artery (Covey et al. 2002; Saba and Mallarini 2011), the topographic relationship with the arteries and the ducts, the CBD and the CHD, has not been a matter of concern.

According to Skandalakis (2004), the most obvious danger in biliary tract surgery is hemorrhage from the large arteries lying anterior to the biliary tract such as the posterior superior pancreaticoduodenal artery (PSPdA) and the gastroduodenal artery (GdA). The present paper reports a case in which the RHA arose directly from the common hepatic artery (CHA) and crossed the CBD anteriorly. While anatomical variation has been well reported in hepatic vasculature, the present study focuses on the position of the RHA with the CBD.

In the gross anatomy of arterial variations, some branches, which can be found even in the normal cases, are considered to participate partly in forming the variant artery. Such arterial branches are similar in origin and course to the variant artery (Aizawa et al. 1996; Honma et al. 2008; Kawai et al. 2008). In the present case, we paid attention to the PSPdA because it travels anteriorly to the CBD as well as the present RHA.

Case report

An atypical RHA was found during our student dissection practice in a 91-year-old male Japanese cadaver, who died of acute cardiac failure. The celiac trunk (CT) trifurcated into the splenic (SA), and left gastric (LGA) arteries, and the CHA. Thereafter, the CHA divided RHA and LHA without forming the proper hepatic artery; RGA, GdA, and PSPdA were branched from RHA (Fig. 1a, b). Covey et al. (2002) called this branching pattern the distal (or late) origin of the GdA. The RHA then crossed anteriorly to the CBD and traveled on the right side of the CBD, branching out the PSPdA (Fig. 1a, b). The PSPdA passed right to the CBD and the portal vein (PV) to supply the posterior aspect of the first and second portion of the duodenum and the pancreatic head (Fig. 1a–c). The RHA ascended parallel to the CBD and crossed posterior to the cystic duct to enter the porta hepatis. The RHA passed behind the gallbladder (Gb) without appearing in Calot’s triangle, and branched the cystic artery (CA) before the porta hepatis (Fig. 1a, d). The RHA and the LHA were the sole hepatic blood source, whereas no other artery entered the liver. Incidentally, the accessory left gastric artery (ALGA) branched from the LHA to supply the cardiac region of the stomach.
https://static-content.springer.com/image/art%3A10.1007%2Fs12565-012-0134-1/MediaObjects/12565_2012_134_Fig1_HTML.gif
Fig. 1

a Frontal view of celiac trunk and visceral aspect of the liver. Left hepatic artery (LHA) and right hepatic artery (RHA) arise separately from the common hepatic artery (CHA). LHA gives rise to the accessory left gastric artery (ALGA). After branching to give the LHA, the CHA divides to form the gastroduodenal artery (GdA) and RHA in crossing anteriorly to common bile duct (CBD). RHA runs parallel to CBD on the right side. The posterior superior pancreaticoduodenal artery (PSPdA) arises from RHA thereafter. b Schematic drawing of the branching of the celiac trunk (CT). c Posterior view. PSPdA supplies the first and the second portion of duodenum and pancreatic head. d Parenchyma of the right lobe is removed and Glissonian sheaths opened. RHA is the sole supply to the right lobe of liver. CA Cystic artery, CD cystic duct, DPA dorsal pancreatic artery, FL falciform ligament, GbF gallbladder fossa, HN hepatic nerve, LGA left gastric artery, IPA inferior phrenic artery, PV portal vein, RGA right gastric artery, RPV right portal vein, SA splenic artery, SMA superior mesenteric artery, SV splenic vein

To examine the intrahepatic distribution of the RHA, the parenchyma of the right lobe was removed and the Glissonian sheaths were opened (Fig. 1d). After entering the porta hepatis, the RHA passed over the right PV, divided into the anterior and the posterior branches, and supplied the right and caudate lobes of the liver. The anterior branch supplied segments 5 and 8 of Couinaud (Skandalakis 2004); the posterior branch supplied segments 6 and 7. Three small branches deriving from the posterior branch were found to enter the caudate lobe, i.e., segment 1 of Couinaud (not depicted).

Discussion

The incidence of the RHA and the LHA arising separately from the CHA without forming the proper hepatic artery has been stated as below 4 % in previous reports: none of 96 cases (Suzuki 1982), <2 % (Lippert and Pabst 1985), 4 of 148 cases (2.7 %) (Weiglein 1996), 9 of 250 cases (3.6 %) (Song et al. 2006), and 22 of 600 cases (3.7 %) (Covey et al. 2002). Weiglein (1996) depicted the topographic relationship between the separately originated RHA and the CBD, and all four RHA passed anteriorly to the CBD, as we presently observed.

Weiglein (1996) also reported the RHA from the proper hepatic artery traveling anteriorly to the CBD in 2 of 148 cases (1.4 %); Suzuki (1982) reported it in 9 of 96 cases (9.4 %). Hence, traveling of the RHA from the proper hepatic artery anteriorly to the CBD may not be so rare.

The present results demonstrate that the RHA arose from the GDA to give the PSPdA, ascended on the right side of the CBD, gave off the CA and terminated in the right lobe of the liver. The hepatic artery running the right side of the CBD in adult reminds us of the accessory right hepatic artery of Adachi (1928), although the accessory right hepatic artery travels posterior to the PV rather than anterior. Parke et al. (1963) described large anastomotic channels from the PSPdA to the RHA in 2 fetuses of 58 specimens. After crossing the CBD anteriorly, an anastomotic channel from the PSPdA passes under the cystic duct to connect the RHA. The channel supplies the branches to the ducts and gives the CA in Calot’s triangle. What allows this aberrant formation in adult is a matter of discussion.

Northover and Terblanche (1979) studied arteries supplying the CHD and the upper CBD in adults. The rates of origin are 26.9 % from the PSPdA, 9.9 % from the GdA, 25.5 % from RHA and 7.5 % from the CA. Besides these direct supplies, a pair of axially ascending arteries existed in all 21 bodies. They run bilaterally to the CBD and the CHD supplying the walls. The right axial artery coursed posterior to the cystic duct. The authors called the right and the left axial artery the 9 o’clock artery and the 3 o’clock artery, respectively.

According to Northover and Terblanche (1979), the 9 o’clock artery is said to be identical with the anastomotic channels of Parke et al. (1963). It is postulated that the 9 o’clock artery might have changed the normal arterial routes via the proper hepatic artery during development. Given the fact that the 9 o’clock artery gives off the PSPdA proximally and the CA distally, the topographic relationship is very similar to that observed in the present case.

Strasberg and Helton (2011) have stated that, if the extrahepatic biliary ducts are intact, the right lobe of the liver can escape from ischemia in surgeries with occlusion of the RHA. The authors explain this by two arterial shunts: the hilar shunt from the LHA and/or the 9 o’clock artery supply enough blood flow. In patients with a large RHA running on the right side of the CBD, there may be more chance of hepatic ischemia than in those with normal RHA.

In studying hepatic angiography, Song et al. (2006) stated that PSPdA divided from the proper hepatic or the RHA runs the risk of pancreatitis or duodenal mucosal injury caused by unintentional embolization during transcatheter therapy. Of 250 cases, PSPdAs were divided from the proper hepatic artery in 10 cases; PSPdAs were originated in the RHA separating from the GdA in 7. Such anatomical variation of the hepatic artery should be noted in order to avoid possible complications.

Conflict of interest

None.

Copyright information

© Japanese Association of Anatomists 2012