Two Variants in One: Celiomesenteric Trunk with a Proximal SMA-originated Trunk with a Retrograde Hepatic Artery

Abstract

Purpose

This case report describes an asymptomatic 23-year-old male volunteer in whom an incidental celiomesenteric trunk (CMT) with an associated aberrant retrograde hepatic artery arising from the proximal superior mesenteric artery (SMA) was identified during an educational ultrasound session.

Methods

High-resolution ultrasonography with color Doppler was used to visualise the abdominal aorta and its visceral branches in both sagittal and transverse planes.

Results

Imaging demonstrated a single common trunk originating from the anterior abdominal aorta, which bifurcated into the celiac trunk and SMA. Additionally, a distinct arterial branch arose from the proximal SMA and coursed superiorly toward the porta hepatis, consistent with a replaced right hepatic artery following a retrograde trajectory.

Conclusion

This combination of a CMT and a retrograde replaced right hepatic artery from the proximal SMA represents an uncommon anatomical configuration with direct implications for complex aortic debranching procedures, mesenteric revascularisation, and hepatopancreatobiliary surgery. The case also illustrates the educational value of point-of-care ultrasound in revealing anatomical variations beyond the classic textbook description.

Introduction

The celiac trunk (CT) and superior mesenteric artery (SMA) typically arise as independent anterior branches of the abdominal aorta at the levels of T12 and L1, respectively [1]. However, a celiomesenteric trunk (CMT), a common origin for both vessels, occurs in approximately 1–3% of individuals [2, 3]. When present, this variant alters the arterial branching pattern supplying the foregut and midgut and carries significant implications for both open and endovascular interventions involving the visceral segment of the aorta.

Hepatic arterial anatomy is similarly variable. In the classic Michels classification, a replaced right hepatic artery (RHA) originating from the SMA (Type III) is reported in approximately 10–12% of individuals [4]. Hiatt’s more surgically oriented classification likewise recognises this pattern as a replaced RHA from the SMA (Type 3), occurring in approximately 11% of cases [5]. The coexistence of a CMT and an aberrant RHA arising from the proximal SMA in a retrograde course is, however, infrequently described, and its precise implications for complex aortic and mesenteric reconstructions warrant detailed examination.

We report a case of a CMT associated with a retrograde replaced RHA from the proximal SMA, identified incidentally during an educational ultrasound session. This report aims to classify the variant within existing anatomical schemes, delineate its embryological basis, and address its relevance to surgical disciplines including vascular, hepatopancreatobiliary, and transplant surgery.

Case report

During a practical ultrasound session on abdominal vascular anatomy, a 23-year-old asymptomatic male volunteer underwent scanning using a high-resolution ultrasound system (Resona i9) equipped with a low-frequency curvilinear transducer (2–6 MHz). Written informed consent was obtained, and the participant was placed supine. The abdominal aorta was interrogated in sagittal and transverse planes from the diaphragmatic hiatus to the bifurcation.

Sagittal imaging of the proximal abdominal aorta revealed a single large common trunk arising from the anterior aortic wall (Fig. 1). This trunk measured approximately 1.5 cm in length and bifurcated into a superior branch (celiac trunk) and an inferior branch (SMA). Color Doppler demonstrated normal arterial flow within the trunk and both branches without evidence of turbulence (Fig. 2).

Fig. 1.

Ultrasound image of the long axis of the proximal abdominal aorta demonstrating the celiomesenteric trunk (CMT). The common trunk originates from the aorta and bifurcates into the celiac trunk (CT) and the superior mesenteric artery (SMA)

Fig. 2.

Uultrasound image in the long axis of the aorta showing the aberrant replaced retrograde right hepatic artery (RHA) arising from the proximal superior mesenteric artery (SMA), just distal to its origin from the common trunk. The vessel courses posterior to the portal vein (PV) toward the liver

Transverse imaging of the proximal SMA identified an additional vascular anomaly. Approximately 5 mm distal to its origin from the common trunk, the SMA gave rise to a branch that coursed superiorly toward the porta hepatis (Fig. 2). The vessel passed posterior to the portal vein. Based on its origin and trajectory, this branch was interpreted as a replaced right hepatic artery. Flow within this vessel was physiologically antegrade, but its anatomical course was retrograde, meaning it ascended cranially toward the liver rather than following the typical distal SMA trajectory into the mesentery. No normal right hepatic artery branch from the celiac trunk was identified, consistent with a replaced rather than accessory vessel (Michels Type III; Hiatt Type 3).

The participant remained asymptomatic with no history of abdominal pain, weight loss, or previous abdominal surgery. Following the examination, the volunteer was counselled regarding the incidental finding. He was advised to document this anatomical variant in his personal medical records and to inform any future surgical or interventional team should he ever require abdominal, aortic, or hepatic procedures. He was also informed that although the variant is currently asymptomatic, it could theoretically predispose to complications such as mesenteric ischemia if the common trunk were compromised, or increased technical complexity during hepatobiliary interventions. No follow-up imaging was arranged given the absence of symptoms and the non-clinical context of the examination.

Discussion

Classification of the celiomesenteric trunk and hepatic artery variant

Uflacker’s anatomical classification of CMT variants categorises them based on the level of aortic origin and the length of the common trunk [6]. The present case corresponds to a Type VI CMT, characterised by a short common trunk (< 2 cm) originating at the T12–L1 level, then with the celiac trunk and SMA arising as distinct branches.

The hepatic arterial variant in this case is a replaced right hepatic artery arising from the proximal SMA, corresponding to Michels Type III and Hiatt Type 3 [4, 5]. The designation “replaced” rather than “accessory” is based on the sonographic absence of a normal right hepatic artery originating from the proper hepatic artery or celiac trunk, implying that this vessel is the sole arterial supply to the right hepatic lobe. The term “retrograde” refers to the anatomical course of the vessel, which ascends superiorly and posteriorly toward the liver rather than following the typical distal mesenteric trajectory of the SMA. It does not imply reversal of physiological blood flow.

Comparison with prior reports

CMT variants are well documented in angiographic and cadaveric series, with reported incidences ranging from 1.0% to 2.9% [2, 3, 7]. The coexistence of a CMT with a replaced hepatic artery is less common. Ognjanovic et al., in a multidetector CT study of 150 patients, identified CMT in 2% of cases but did not report any instance of an associated retrograde RHA from the SMA [2]. Santos et al., in a systematic review of 36 studies encompassing over 12,000 individuals, documented CMT variants but noted that detailed characterisation of concomitant hepatic artery anomalies was often lacking [3].

Specific case reports describing a CMT with a retrograde RHA from the proximal SMA are limited. Yi et al. described a cadaveric case of CMT with a replaced RHA, though the hepatic branch originated from the common trunk rather than the SMA proper [8]. Huang et al. reported a similar configuration in a preoperative CT angiogram prior to pancreaticoduodenectomy, emphasising the surgical risk during dissection of the pancreatic head [9]. The present case differs from these prior descriptions in two respects: first, the RHA arises distinctly from the SMA approximately 5 mm beyond the CMT bifurcation, and second, its course posterior to the portal vein was clearly demonstrated sonographically, a relationship that carries specific implications for hilar dissection during hepatectomy or transplantation.

Embryological considerations

The CMT results from incomplete regression of the longitudinal ventral anastomosis that connects the primitive 10th and 13th vitelline arteries during the fourth to sixth weeks of gestation [10]. Normally, this anastomotic channel regresses, leaving the 10th root as the celiac trunk and the 13th as the SMA. Persistence of the connecting segment produces a common trunk of variable length.

The retrograde replaced RHA represents persistence of a portion of the primitive hepatic arterial plexus that maintains a connection to the SMA root rather than migrating entirely to the celiac axis. The retrograde course reflects the vessel’s embryological origin from the more caudal SMA segment, necessitating a cranial trajectory to reach the developing liver bud.

Clinical complications associated with CMT

Although most CMT variants remain asymptomatic, several complications have been documented. Aneurysmal degeneration of the common trunk has been reported, potentially leading to rupture or thromboembolism [11]. Compression of the CMT by the median arcuate ligament can produce symptoms of chronic mesenteric ischemia, analogous to median arcuate ligament syndrome affecting an isolated celiac trunk. Acute thrombosis of a CMT, whether spontaneous or iatrogenic, carries a more extensive ischemic burden than occlusion of either vessel alone, jeopardising both the foregut and midgut simultaneously.

In the present configuration, the additional presence of a replaced RHA from the proximal SMA introduces further considerations. Should SMA flow be compromised whether by embolism, surgical clamp application, or dissection, the hepatic arterial supply would also be threatened, potentially resulting in combined mesenteric and hepatic ischemia. Conversely, during selective hepatic arterial interventions, the proximity of the RHA origin to the CMT bifurcation increases the risk of non-target embolisation to the SMA territory.

Clinical and surgical implications

Vascular surgery: aortic and mesenteric reconstructions

This variant configuration alters operative strategy in several vascular scenarios. During open repair of thoracoabdominal aortic aneurysms (TAAA) involving the visceral segment, identification of a CMT mandates that both the celiac and SMA territories be revascularised through a single aortic patch or a branched graft limb. Failure to recognise a common trunk preoperatively may result in inadequate debranching, leaving one visceral territory without inflow.

In endovascular repair of complex aortic aneurysms using fenestrated or branched stent grafts, a CMT requires customised device planning. The common origin may be accommodated by a single large fenestration or a dedicated branch, but this depends on accurate preoperative characterisation of the trunk length, diameter, and angulation. An unrecognised CMT risks incomplete exclusion of the aneurysm or unintentional coverage of the common trunk.

The retrograde RHA from the proximal SMA further complicates visceral debranching. During open SMA reimplantation or bypass, the proximity of the RHA origin to the SMA ostium means that a proximal SMA anastomosis could inadvertently exclude or compromise the hepatic branch. In hybrid TAAA repairs involving retrograde visceral bypass from the infrarenal aorta or iliac arteries, the surgeon must ensure that the bypass graft to the SMA is placed distal to the RHA origin, or alternatively, that the RHA is separately revascularised.

During isolated mesenteric revascularisation for chronic mesenteric ischemia, the presence of a CMT with an SMA-origin RHA means that restoring flow to the SMA also restores hepatic arterial perfusion, a potentially favourable arrangement. However, if the RHA is stenotic at its origin, a standard SMA bypass may not adequately perfuse the liver, and intraoperative assessment of hepatic inflow becomes essential.

Relevance in bowel surgery

A celiomesenteric trunk (CMT) eliminates the usual physiological redundancy between the celiac trunk and SMA, making foregut and midgut territories dependent on a single arterial inflow. The added presence of a replaced right hepatic artery (RHA) from the proximal SMA means that surgical manipulation near the SMA origin, during right hemicolectomy, mesenteric resection, or central vascular ligation, risks compromising both intestinal and hepatic perfusion. Clamping, thrombosis, or iatrogenic injury to the proximal SMA may produce combined mesenteric and hepatic ischemia, a complication with high morbidity. The close proximity of the RHA origin to the SMA ostium also increases the risk of inadvertent hepatic artery injury during lymphadenectomy. Surgeons should identify the SMA origin early, avoid blind clamping, and consider intraoperative hepatic perfusion assessment. In emergency settings without preoperative imaging, failure to recognize this variant can lead to extensive ischemic burden. Thus, this configuration transforms bowel surgery into a procedure with systemic perfusion implications, where preserving a single arterial axis is critical for both intestinal and liver viability.

Hepatopancreatobiliary surgery

In pancreaticoduodenectomy, the replaced RHA from the SMA is a well-recognised anatomical risk factor. The vessel typically courses posterior to the pancreatic head and may be encountered during dissection of the uncinate process or mobilisation of the portal vein. In the present case, the RHA arises from the very proximal SMA, even closer to the midline than typical replaced RHA variants, potentially placing it at greater risk during division of the gastroduodenal artery or dissection along the superior border of the pancreatic neck. Inadvertent ligation or injury can lead to right hepatic lobe ischemia, biliary anastomotic leakage, or hepatic abscess formation [9, 12].

The CMT adds a further layer of complexity. During lymphadenectomy along the common hepatic artery or proximal SMA, the surgeon must recognise that the celiac trunk and SMA share a common aortic origin. Aggressive dissection around the CMT could compromise flow to both vessels, resulting in catastrophic foregut and midgut ischemia.

In liver transplantation, preoperative recognition of a replaced RHA from the SMA is essential for both donor and recipient operations. In the donor hepatectomy, the replaced RHA must be preserved to its SMA origin, requiring a Carrel patch or segmental SMA resection. In the recipient, the presence of a CMT in the native circulation or a replaced RHA in the graft necessitates tailored arterial reconstruction to ensure adequate hepatic inflow [13].

Gallbladder surgery

Unlike the conventional RHA (arising from the proper hepatic artery and coursing posterior to the common hepatic duct), the replaced RHA follows an aberrant trajectory. It may pass through Calot’s triangle behind the common hepatic duct [8], rarely encircle the gallbladder body, or run anterior to the cystic duct before entering the liver [14]. Such anomalous courses risk morbidity and mortality from ischemic liver injury [15].

Altered anatomy within calot’s triangle

In this variant, the replaced RHA may traverse Calot’s triangle, lie atypically relative to the common bile duct, or give rise to a short cystic artery with early branching. These features increase the risk of misidentifying the RHA as the cystic artery and inadvertently clipping, ligating, or thermally injuring it [15]. RHA injury is present in many bile duct injuries, and late referral to a specialized center leads to serious infection.

Interventional radiology

For interventional radiologists performing transarterial chemoembolisation (TACE) or selective internal radiation therapy (SIRT) for hepatic malignancies, the CMT with proximal RHA origin alters catheterisation strategy. The RHA may be accessed via the CMT and SMA rather than the celiac trunk, requiring awareness of this pathway to avoid prolonged procedure time or failed selective catheterisation. The retrograde course and posterior relationship to the portal vein must be appreciated to anticipate catheter trajectory and vessel tortuosity [16].

During mesenteric angiography for gastrointestinal bleeding, the CMT means that a single selective injection into the common trunk may opacify both celiac and SMA territories, potentially obscuring the source of haemorrhage unless subselective catheterisation is performed. The proximal RHA origin also creates a risk of non-target embolisation to the liver during SMA-based interventions.

Educational impact of point-of-care ultrasound

This case was identified during a routine educational session, highlighting the capacity of point-of-care ultrasound to reveal anatomical variations that cadaveric dissection may not demonstrate. Ultrasound allows visualisation of vessels in their physiological state, with real-time assessment of flow dynamics and spatial relationships to surrounding structures. Incorporating ultrasound into anatomy curricula exposes students to the spectrum of human variation and reinforces the clinical relevance of anatomical knowledge [17].

Limitations

This report is limited by the absence of confirmatory imaging such as CT angiography or digital subtraction angiography, which could provide higher spatial resolution and three-dimensional characterisation of the variant. In addition, this was not ethically feasible to subject an asymptomatic volunteer to radiation just for education purposes. Follow-up evaluation was not performed given the asymptomatic nature of the finding and the non-clinical context. Consequently, the long-term clinical significance of this specific configuration in this individual remains unknown.

Conclusion

This report describes a CMT with an associated retrograde replaced right hepatic artery from the proximal SMA in an asymptomatic individual. The variant corresponds to Uflacker Type VI CMT and Michels Type III/Hiatt Type 3 hepatic arterial anatomy. The configuration carries direct implications for visceral debranching during thoracoabdominal aortic repair, mesenteric revascularisation, and complex hepatopancreatobiliary resections. Preoperative recognition of such variants is essential to avoid iatrogenic injury and to guide appropriate operative planning. The incidental sonographic discovery further highlights the educational value of point-of-care ultrasound in anatomical training.

Author contributions

A.N spearheaded the writing of the whole manuscript, acquring images and cordination of the authors. C.N provided the surgical expertise and opinions. J.S participated in draftning of the manuscript. J.K supervised the whole process and give an expert opinion on the general anatomy.

Funding

The authors report no funding.

Data availability

The data that supports the findings of this case report are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

Informed consent was obtained from the participant for this publication. The ethics declaration in the manuscript is in accordance with the Declaration of Helsinki. The consent to publish was approved by the Mengo Research and Ethics Committee, approval number MH/134/07-2025.

Consent for publication

Written informed consent was obtained from the participant for publication of this case report and accompanying images.

Competing interests

The authors declare no competing interests.