Variant Mesenteric and Pancreatic Vasculature. A Case Report

Variant Mesenteric and Pancreatic Vasculature. A Case Report | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Variant Mesenteric and Pancreatic Vasculature. A Case Report Madison Lather, Brooklyn Brekke-Kumley, Bianca McAravey, Nathan Roberts, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9458593/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Purpose The vasculature of the pancreas and colon is highly variable and clinically relevant in pancreatic and colon surgeries. Although variant arterial branching between colonic and pancreatic arteries has been described, the variant in this study has not previously been reported. This study highlights variant arterial anatomy between the colon and pancreas to enhance anatomic knowledge for surgical planning. Methods During a routine cadaveric dissection in our medical school anatomy laboratory, we identified an unusual branching pattern of the superior mesenteric artery (SMA) on a 72 y/o male donor. Results An unnamed artery originated from the posterior middle colic artery (MCA). This artery descended from its origin and bifurcated into an inferior branch and a transverse branch that crossed the SMA anteriorly. The transverse branch bifurcated into a small intestinal branch and a long ascending branch that supplied the head, uncinate process, body, and tail of the pancreas. Conclusion This case represents a previously undescribed arterial branching pattern of the colon and pancreas. Knowledge of unique arterial variants benefits fields of anatomy and surgery and supports efforts to reduce operative complications in colorectal and pancreatic surgeries. Anatomical variant inferior pancreaticoduodenal artery middle colic artery superior mesenteric artery colorectal surgery pancreatic surgery Figures Figure 1 Introduction The vasculature of the pancreas and colon is highly variable, and identification of variant arterial branches has important clinical applications in both pancreatic and colorectal surgery. In a systematic review of over 6,000 specimens the infrapancreatic anatomy of the superior mesenteric artery (SMA) and its colic branches were highly variable, highlighting the need for careful vascular identification [ 5 ].Valenzuela Fuenzalida et al. noted that variants of this circulation can influence both surgical margins and collateral circulation between the pancreas and adjacent organs and described a shared trunk between the inferior pancreatic artery and middle colic artery (MCA) arising from the SMA. Identification of variant branching of the SMA during SMA nerve plexus dissection has been shown to be critical to ensure colonic blood supply is maintained during pancreatic resection surgeries [ 2 ]. Preservation of variant colonic anastomoses between the MCA and left colic artery (LCA) has been associated with decreased rates of postoperative colonic ischemia in colorectal surgeries [ 8 ]. Recent studies have shown that the caliber of the LCA directly influences perfusion in the distal colonic anastomosis [ 3 ] and that maintaining the marginal arterial arcade particularly the ascending branch of the LCA, can reduce ischemic complications following colectomy [ 4 ]. Embryologically, the pancreas develops from dorsal and ventral buds that are interwoven with a capillary plexus whose endothelial cell pattern determine subsequent vascular organization [ 6 ]. Remodeling of this network, guided by vascular endothelial growth factor (VEGF) signaling, establishes the mature pancreatic arterial supply. Variations in this process can result in the mesenteric and pancreatic vascular variants observed in adults [ 1 , 6 ]. The dorsal pancreatic artery typically arises from the splenic artery and supplies the head, body and tail of the pancreas, making it a critical vessel to consider during surgical procedures such as pancreatectomy or pancreaticoduodenectomy (Whipple procedure) [ 6 ]. The inferior pancreaticoduodenal artery (IPDA) typically arises as the first singular branch from the SMA and splits into anterior and posterior parts that anastomose with the superior pancreaticoduodenal arteries [ 7 ]. The SMA and inferior mesenteric artery (IMA) arise as unpaired ventral branches of the aorta that supply the midgut and hindgut, respectively. Both show considerable anatomic variability due to intestinal rotation and elongation during development [ 6 ]. While previous reports have demonstrated variant anastomoses between the colonic and pancreatic arteries [ 2 , 7 , 9 ], this case highlights a unique arterial variant that to our knowledge has not previously been reported. Recognition of such arterial variants is essential for careful vascular planning in colorectal and pancreatic surgeries to avoid complications and adverse patient outcomes [ 2 , 4 , 5 , 8 , 9 ]. Case Presentation This study was approved by the Institutional Review Board of Rocky Vista University (#2025 − 296). The subject of this case study was a formalin-fixed cadaveric donor donated to the Montana College of Osteopathic Medicine anatomy lab through the Anatomical Gift Program. During routine cadaveric dissection, an unusual branching pattern of the SMA was identified on a 72 y/o male donor with a prior medical history of dementia, Parkinson’s disease and urinary tract infection. Upon examining the SMA, a well-defined superior branch was identified as the MCA. The MCA had three branches that supplied the entirety of the right colic flexure, most of the ascending and transverse colon. A fourth branch was observed arising from the posterior aspect of the MCA. This unnamed artery descended from its origin and split into a branch that descended inferiorly along the SMA (cut in dissection), and a transverse branch that crossed the anterior surface of the SMA (Fig. 1 ). The transverse branch measured 1.8 cm in length and bifurcated into a small vessel that supplied the small intestine and a large ascending branch that measured 6.8 cm in length that traveled cranially toward the pancreas. Prior to the inferior border of the pancreas the unnamed artery split again into three branches, one that ascended to the left to supply the mid to distal end of the body and tail of the pancreas, one that coursed posterior to the superior mesenteric vein (SMV) to supply the head and uncinate process of the pancreas, and one that ascended posterior to the pancreas (Fig. 1 ). Further dissection of the SMA branches revealed no obvious right colic artery (RCA), and a very prominent ileocolic artery (ILCA). The ILCA descended towards the cecum in a normal fashion and bifurcated shortly after its origin into a horizontal branch at the level of the mid ascending colon. This branch anastomosed with the right branch of the MCA and supplied the ascending colon and was identified as the RCA. We concluded from these findings that the RCA and ILCA originated from a common trunk of the SMA. The LCA arose from the IMA in an expected fashion and bifurcated into descending and ascending branches. The ascending LCA anastomosed with the left branch of the MCA in the splenic flexure. No additional vascular anomalies were noted between branches of the SMA and IMA. Discussion Based on its origin and course, this unnamed vessel most closely resembled a variant IPDA. However, this variant did not originate directly from the SMA and instead arose from the MCA posteriorly and traversed the SMA horizontally to form a unique H-shaped configuration (Fig. 1 ). A typical IPDA splits into anterior and posterior branches that supply the head of the pancreas [ 5 ], whereas this variant had branches that supplied the colon, small intestine and a large majority of the pancreas. The MCA in this case had more extensive branching than expected. Typically, the MCA supplies the proximal 2/3rd of the transverse colon and part of the right colic flexure [ 5 ]. In contrast, this donor demonstrated a MCA with three colic branches that supplied the transverse colon, right colic flexure and almost the entirety of the ascending colon before anastomosing with the RCA that came off a common trunk with the ILCA. Interestingly, branches of the IMA did not deviate from the typical presentation. The LCA supplied the descending colon, left colic flexure, and anastomosed with left branches of the MCA in the left colic flexure. The sigmoid arteries and superior rectal artery branched at their typical locations in the left lower quadrant and supplied the sigmoid colon and rectum [ 3 , 5 ]. Previous reports have demonstrated variant vasculature between the colon and the pancreas. Ito et al. described an accessory MCA (AMCA) ~ 28% of patients who presented for pancreatic resection. Eleven of the 31 AMCA identified also had pancreatic branches, which made dissection of the SMA nerve plexus during pancreatic resection more challenging and variable. Venieratos, 2018 described a Middle Mesenteric Artery (MMA) that branched from the abdominal aorta between the SMA and IMA. The MMA described had pancreatic branches that anastomosed with the superior pancreaticoduodenal artery (SPDA), and a separate branch that entered the head of the pancreas. The MMA was also noted to take over the role of the MCA and provided blood flow to the transverse colon [ 10 ]. Silva Júnior et al. reported a common trunk off the SMA that gave rise to both the IPDA and MCA; however, this variant did not demonstrate the course or distribution observed in our case. The IPDA identified coursed superiorly to the body of the pancreas and gave off an anterior and posterior branch to the neck of the pancreas before diving into the inferior pancreatic body [ 7 ]. Thus, this case describes a previously unreported variant arterial branching pattern between the colon and pancreas. Recognition of variant pancreatic and colonic arterial branching has direct surgical implications. In colonic surgeries that involve resection of the ascending colon and transverse colon, accidental ligation of variant pancreatic branches arising from the SMA or abdominal aorta can disrupt perfusion to a large majority of the pancreas [ 5 , 7 ]. Similarly, dissection of the pancreas and its arterial supply during pancreatic surgeries can disrupt critical anastomoses that perfuse the colon, especially if the IPDA and MCA arise from a common trunk [ 3 , 4 , 8 ]. Conclusions This case demonstrated to our knowledge, a previously undescribed arterial branching pattern of the SMA. The unnamed artery originated from a common trunk with the MCA and gave off branches that supplied the colon, small intestine, and large majority of the pancreas. These findings highlight an example of the variable arterial anatomy between the pancreas and colon. Awareness of such variants is essential for safe surgical planning to avoid unnecessary complications and improve patient outcomes during pancreatic and colorectal surgeries. Declarations Statements and Declarations The authors of this case report have no competing interest to disclose. No funding was received for this project. Author Contribution M Lather: Project development, Data collection/management, Manuscript writing/editing B Brekke-Kumley: Manuscript writing/editing B McAravey: Manuscript writing/editing N Roberts: Manuscript writing/editing C Funk: Project supervision, Manuscript editing Acknowledgement The authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. Results from such research can potentially increase mankind's overall knowledge that can then improve patient care. Therefore, these donors and their families deserve our highest gratitude. References Azizoglu DB, Chong DC, Villasenor A, Magenheim J, Barry DM, Lee S, Marty-Santos L, Fu S, Dor Y, Cleaver O (2016) Vascular development in the vertebrate pancreas. Dev Biol 420:67–78. 10.1016/j.ydbio.2016.10.009 Ito K, Takemura N, Inagaki F, Mihara F, Kurokawa T, Kokudo N (2019) Arterial blood supply to the pancreas from accessary middle colic artery. Pancreatology 19:781–785. 10.1016/j.pan.2019.05.458 Li B, Wang J, Yang S, Shen J, Li Q, Zhu Q, Cui W (2022) Left colic artery diameter is an important factor affecting anastomotic blood supply in sigmoid colon cancer or rectal cancer surgery: a pilot study. World J Surg Oncol 20:313. 10.1186/s12957-022-02774-0 Mann MR, Kawzowicz M, Komosa AJ, Sherer YM, Lazarz DP et al (2021) The marginal artery of Drummond revisited: A systematic review. Transl Res Anat 24. https://doi.org/10.1016/j.tria.2021.100118 Negoi I, Beuran M, Hostiuc S, Negoi RI, Inoue Y (2018) Surgical anatomy of the superior mesenteric vessels related to colon and pancreatic surgery: A systematic review and meta-analysis. Sci Rep 8:4184. 10.1038/s41598-018-22641-x Pratt IJ, Ryan AL, Gresner EJ, Loczi-Storm AR, Sperling E (2025) Rare pancreatic arterial variations: A cadaveric case report. Cureus 17:e82446. 10.7759/cureus.82446 Silva Júnior LM, Alexandre M, Gonçalves L, Silva FS, Caetano AG (2014) Variations in The Vascular Supply of Pancreas and Transverse Colon: A Case Report. Int J Morphol 32:190–193. https://www.scielo.cl/pdf/ijmorphol/v32n1/art32.pdf Tatt Toh JW, Matthews R, Kim SH (2018) Arc of Riolan-Preserving Splenic Flexure Takedown During Anterior Resection: Potentially Critical to Prevent Acute Anastomotic Ischemia. Dis Colon Rectum 61:411–414. https://doi.org/10.1097/dcr.0000000000000995 Valenzuela-Fuenzalida JJ, Urzúa-Somarriva MC, González-Bello F, Tapia-Carmona C, Pérez-Rojas F, Naranjo CA (2024) Anatomical Variants in Pancreatic Irrigation and Their Clinical Implications: A Review. Cureus 61:666. 10.3390/medicina61040666 Venieratos D, Tsoucalas G, Panagouli E (2018) A Rare Branching Pattern of a Middle Mesenteric Artery Supplying the Head of the Pancreas and the Transverse Colon. Acta Med Acad 47:199–203. https://doi.org/10.5644/ama2006-124.232 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 15 May, 2026 Reviews received at journal 30 Apr, 2026 Reviewers agreed at journal 29 Apr, 2026 Reviewers invited by journal 27 Apr, 2026 Editor assigned by journal 27 Apr, 2026 Submission checks completed at journal 25 Apr, 2026 First submitted to journal 18 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9458593","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":634142193,"identity":"3be862c4-f1cb-4732-a102-6fd8e3a1d463","order_by":0,"name":"Madison Lather","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAElEQVRIie3PMUvDQBTA8RcCl+XVrJFQv4FwEshU6gfpVA4yNeCY0alZgrNCP0TF1eGVB52KWQUdlMBNXbpFEDQ3VB281NHh/sPdcdyPuwNwuf5nksx4BCC6afS17V0eIgJ8QzLAvxD4QfgwOS35dtUWzyCCev2yu68n5zDQMcJouKTfSbrJLhg3GgSq4OxaP+UVBGlHssRKaCbZm3P3MCViJEOEnyDw1ErqrVy9GRI2In6nhz35sJPHmaSBIVF3CxAZ4jUI1EO0+QujiJr0uCKVVyy814VUyY31Yepu1xZ8EoZTHbU0zstyDrQtxsMrC9mH30vfDLL/uMvlcrn6+wTBiVqg2SqfVAAAAABJRU5ErkJggg==","orcid":"","institution":"Rocky Vista University-Montana College of Osteopathic Medicine","correspondingAuthor":true,"prefix":"","firstName":"Madison","middleName":"","lastName":"Lather","suffix":""},{"id":634142225,"identity":"76aeca13-931d-4451-8782-cdf0c4a94b29","order_by":1,"name":"Brooklyn Brekke-Kumley","email":"","orcid":"","institution":"Rocky Vista University-Montana College of Osteopathic Medicine","correspondingAuthor":false,"prefix":"","firstName":"Brooklyn","middleName":"","lastName":"Brekke-Kumley","suffix":""},{"id":634142228,"identity":"7b0e2461-dcf9-48a1-b257-bbfd98e92504","order_by":2,"name":"Bianca McAravey","email":"","orcid":"","institution":"Rocky Vista University-Montana College of Osteopathic Medicine","correspondingAuthor":false,"prefix":"","firstName":"Bianca","middleName":"","lastName":"McAravey","suffix":""},{"id":634142249,"identity":"c005509b-ebc1-4ec3-83e2-b6bd7b573f6d","order_by":3,"name":"Nathan Roberts","email":"","orcid":"","institution":"Rocky Vista University-Montana College of Osteopathic Medicine","correspondingAuthor":false,"prefix":"","firstName":"Nathan","middleName":"","lastName":"Roberts","suffix":""},{"id":634142257,"identity":"53d40826-259a-402c-b3b0-a9a7f1c7c16b","order_by":4,"name":"Cindy Funk","email":"","orcid":"","institution":"Rocky Vista University-Montana College of Osteopathic Medicine","correspondingAuthor":false,"prefix":"","firstName":"Cindy","middleName":"","lastName":"Funk","suffix":""}],"badges":[],"createdAt":"2026-04-19 01:38:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9458593/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9458593/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108629972,"identity":"d78a8d40-4c83-49c2-898e-ffd30fa20d5b","added_by":"auto","created_at":"2026-05-06 16:32:08","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1712734,"visible":true,"origin":"","legend":"\u003cp\u003eVariant branching of the superior mesenteric artery (SMA) identified on cadaveric dissection. The middle colic artery (MCA) with three colic branches was found to share a common trunk with an unnamed artery (white star). This artery bifurcated into a descending artery (cut in dissection) (black star) and a transverse branch that crossed the SMA anteriorly (green star). The unnamed artery then split again into a branch supplying the small intestine (blue star) and a long ascending branch that coursed along the SMA towards pancreas (orange star). The pancreatic branch trifurcated into a branch that coursed posterior to the superior mesenteric vein (SMV) to supply the head and uncinate process of the pancreas (purple star), a branch that coursed posterior to the pancreas (yellow star) and a branch that coursed to the left supplying the inferior body and tail of the pancreas (pink star)\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-9458593/v1/38e34a76fa4a3e7ffd236bc3.png"},{"id":108805397,"identity":"ea204314-3e47-424b-9ed4-bf6b5800f015","added_by":"auto","created_at":"2026-05-08 15:25:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1833339,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9458593/v1/a42af7f9-4968-4013-b577-857ff2cb1c08.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Variant Mesenteric and Pancreatic Vasculature. A Case Report","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe vasculature of the pancreas and colon is highly variable, and identification of variant arterial branches has important clinical applications in both pancreatic and colorectal surgery. In a systematic review of over 6,000 specimens the infrapancreatic anatomy of the superior mesenteric artery (SMA) and its colic branches were highly variable, highlighting the need for careful vascular identification [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].Valenzuela Fuenzalida et al. noted that variants of this circulation can influence both surgical margins and collateral circulation between the pancreas and adjacent organs and described a shared trunk between the inferior pancreatic artery and middle colic artery (MCA) arising from the SMA. Identification of variant branching of the SMA during SMA nerve plexus dissection has been shown to be critical to ensure colonic blood supply is maintained during pancreatic resection surgeries [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Preservation of variant colonic anastomoses between the MCA and left colic artery (LCA) has been associated with decreased rates of postoperative colonic ischemia in colorectal surgeries [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Recent studies have shown that the caliber of the LCA directly influences perfusion in the distal colonic anastomosis [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] and that maintaining the marginal arterial arcade particularly the ascending branch of the LCA, can reduce ischemic complications following colectomy [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eEmbryologically, the pancreas develops from dorsal and ventral buds that are interwoven with a capillary plexus whose endothelial cell pattern determine subsequent vascular organization [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Remodeling of this network, guided by vascular endothelial growth factor (VEGF) signaling, establishes the mature pancreatic arterial supply. Variations in this process can result in the mesenteric and pancreatic vascular variants observed in adults [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The dorsal pancreatic artery typically arises from the splenic artery and supplies the head, body and tail of the pancreas, making it a critical vessel to consider during surgical procedures such as pancreatectomy or pancreaticoduodenectomy (Whipple procedure) [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The inferior pancreaticoduodenal artery (IPDA) typically arises as the first singular branch from the SMA and splits into anterior and posterior parts that anastomose with the superior pancreaticoduodenal arteries [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The SMA and inferior mesenteric artery (IMA) arise as unpaired ventral branches of the aorta that supply the midgut and hindgut, respectively. Both show considerable anatomic variability due to intestinal rotation and elongation during development [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile previous reports have demonstrated variant anastomoses between the colonic and pancreatic arteries [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], this case highlights a unique arterial variant that to our knowledge has not previously been reported. Recognition of such arterial variants is essential for careful vascular planning in colorectal and pancreatic surgeries to avoid complications and adverse patient outcomes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eThis study was approved by the Institutional Review Board of Rocky Vista University (#2025\u0026thinsp;\u0026minus;\u0026thinsp;296). The subject of this case study was a formalin-fixed cadaveric donor donated to the Montana College of Osteopathic Medicine anatomy lab through the Anatomical Gift Program.\u003c/p\u003e \u003cp\u003eDuring routine cadaveric dissection, an unusual branching pattern of the SMA was identified on a 72 y/o male donor with a prior medical history of dementia, Parkinson\u0026rsquo;s disease and urinary tract infection. Upon examining the SMA, a well-defined superior branch was identified as the MCA. The MCA had three branches that supplied the entirety of the right colic flexure, most of the ascending and transverse colon. A fourth branch was observed arising from the posterior aspect of the MCA. This unnamed artery descended from its origin and split into a branch that descended inferiorly along the SMA (cut in dissection), and a transverse branch that crossed the anterior surface of the SMA (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The transverse branch measured 1.8 cm in length and bifurcated into a small vessel that supplied the small intestine and a large ascending branch that measured 6.8 cm in length that traveled cranially toward the pancreas. Prior to the inferior border of the pancreas the unnamed artery split again into three branches, one that ascended to the left to supply the mid to distal end of the body and tail of the pancreas, one that coursed posterior to the superior mesenteric vein (SMV) to supply the head and uncinate process of the pancreas, and one that ascended posterior to the pancreas (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFurther dissection of the SMA branches revealed no obvious right colic artery (RCA), and a very prominent ileocolic artery (ILCA). The ILCA descended towards the cecum in a normal fashion and bifurcated shortly after its origin into a horizontal branch at the level of the mid ascending colon. This branch anastomosed with the right branch of the MCA and supplied the ascending colon and was identified as the RCA. We concluded from these findings that the RCA and ILCA originated from a common trunk of the SMA.\u003c/p\u003e \u003cp\u003eThe LCA arose from the IMA in an expected fashion and bifurcated into descending and ascending branches. The ascending LCA anastomosed with the left branch of the MCA in the splenic flexure. No additional vascular anomalies were noted between branches of the SMA and IMA.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eBased on its origin and course, this unnamed vessel most closely resembled a variant IPDA. However, this variant did not originate directly from the SMA and instead arose from the MCA posteriorly and traversed the SMA horizontally to form a unique H-shaped configuration (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). A typical IPDA splits into anterior and posterior branches that supply the head of the pancreas [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], whereas this variant had branches that supplied the colon, small intestine and a large majority of the pancreas.\u003c/p\u003e \u003cp\u003eThe MCA in this case had more extensive branching than expected. Typically, the MCA supplies the proximal 2/3rd of the transverse colon and part of the right colic flexure [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In contrast, this donor demonstrated a MCA with three colic branches that supplied the transverse colon, right colic flexure and almost the entirety of the ascending colon before anastomosing with the RCA that came off a common trunk with the ILCA. Interestingly, branches of the IMA did not deviate from the typical presentation. The LCA supplied the descending colon, left colic flexure, and anastomosed with left branches of the MCA in the left colic flexure. The sigmoid arteries and superior rectal artery branched at their typical locations in the left lower quadrant and supplied the sigmoid colon and rectum [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrevious reports have demonstrated variant vasculature between the colon and the pancreas. Ito et al. described an accessory MCA (AMCA)\u0026thinsp;~\u0026thinsp;28% of patients who presented for pancreatic resection. Eleven of the 31 AMCA identified also had pancreatic branches, which made dissection of the SMA nerve plexus during pancreatic resection more challenging and variable. Venieratos, 2018 described a Middle Mesenteric Artery (MMA) that branched from the abdominal aorta between the SMA and IMA. The MMA described had pancreatic branches that anastomosed with the superior pancreaticoduodenal artery (SPDA), and a separate branch that entered the head of the pancreas. The MMA was also noted to take over the role of the MCA and provided blood flow to the transverse colon [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Silva J\u0026uacute;nior et al. reported a common trunk off the SMA that gave rise to both the IPDA and MCA; however, this variant did not demonstrate the course or distribution observed in our case. The IPDA identified coursed superiorly to the body of the pancreas and gave off an anterior and posterior branch to the neck of the pancreas before diving into the inferior pancreatic body [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Thus, this case describes a previously unreported variant arterial branching pattern between the colon and pancreas.\u003c/p\u003e \u003cp\u003eRecognition of variant pancreatic and colonic arterial branching has direct surgical implications. In colonic surgeries that involve resection of the ascending colon and transverse colon, accidental ligation of variant pancreatic branches arising from the SMA or abdominal aorta can disrupt perfusion to a large majority of the pancreas [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Similarly, dissection of the pancreas and its arterial supply during pancreatic surgeries can disrupt critical anastomoses that perfuse the colon, especially if the IPDA and MCA arise from a common trunk [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis case demonstrated to our knowledge, a previously undescribed arterial branching pattern of the SMA. The unnamed artery originated from a common trunk with the MCA and gave off branches that supplied the colon, small intestine, and large majority of the pancreas. These findings highlight an example of the variable arterial anatomy between the pancreas and colon. Awareness of such variants is essential for safe surgical planning to avoid unnecessary complications and improve patient outcomes during pancreatic and colorectal surgeries.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eStatements and Declarations\u003c/h2\u003e \u003cp\u003eThe authors of this case report have no competing interest to disclose. No funding was received for this project.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM Lather: Project development, Data collection/management, Manuscript writing/editing\u003c/p\u003e\n\u003cp\u003eB Brekke-Kumley: Manuscript writing/editing\u003c/p\u003e\n\u003cp\u003eB McAravey: Manuscript writing/editing\u003c/p\u003e\n\u003cp\u003eN Roberts: Manuscript writing/editing\u003c/p\u003e\n\u003cp\u003eC Funk: Project supervision, Manuscript editing\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. Results from such research can potentially increase mankind's overall knowledge that can then improve patient care. Therefore, these donors and their families deserve our highest gratitude.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAzizoglu DB, Chong DC, Villasenor A, Magenheim J, Barry DM, Lee S, Marty-Santos L, Fu S, Dor Y, Cleaver O (2016) Vascular development in the vertebrate pancreas. Dev Biol 420:67\u0026ndash;78. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ydbio.2016.10.009\u003c/span\u003e\u003cspan address=\"10.1016/j.ydbio.2016.10.009\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIto K, Takemura N, Inagaki F, Mihara F, Kurokawa T, Kokudo N (2019) Arterial blood supply to the pancreas from accessary middle colic artery. Pancreatology 19:781\u0026ndash;785. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.pan.2019.05.458\u003c/span\u003e\u003cspan address=\"10.1016/j.pan.2019.05.458\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi B, Wang J, Yang S, Shen J, Li Q, Zhu Q, Cui W (2022) Left colic artery diameter is an important factor affecting anastomotic blood supply in sigmoid colon cancer or rectal cancer surgery: a pilot study. World J Surg Oncol 20:313. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12957-022-02774-0\u003c/span\u003e\u003cspan address=\"10.1186/s12957-022-02774-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMann MR, Kawzowicz M, Komosa AJ, Sherer YM, Lazarz DP et al (2021) The marginal artery of Drummond revisited: A systematic review. Transl Res Anat 24. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.tria.2021.100118\u003c/span\u003e\u003cspan address=\"10.1016/j.tria.2021.100118\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNegoi I, Beuran M, Hostiuc S, Negoi RI, Inoue Y (2018) Surgical anatomy of the superior mesenteric vessels related to colon and pancreatic surgery: A systematic review and meta-analysis. Sci Rep 8:4184. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/s41598-018-22641-x\u003c/span\u003e\u003cspan address=\"10.1038/s41598-018-22641-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePratt IJ, Ryan AL, Gresner EJ, Loczi-Storm AR, Sperling E (2025) Rare pancreatic arterial variations: A cadaveric case report. Cureus 17:e82446. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.7759/cureus.82446\u003c/span\u003e\u003cspan address=\"10.7759/cureus.82446\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva J\u0026uacute;nior LM, Alexandre M, Gon\u0026ccedil;alves L, Silva FS, Caetano AG (2014) Variations in The Vascular Supply of Pancreas and Transverse Colon: A Case Report. Int J Morphol 32:190\u0026ndash;193. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.scielo.cl/pdf/ijmorphol/v32n1/art32.pdf\u003c/span\u003e\u003cspan address=\"https://www.scielo.cl/pdf/ijmorphol/v32n1/art32.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTatt Toh JW, Matthews R, Kim SH (2018) Arc of Riolan-Preserving Splenic Flexure Takedown During Anterior Resection: Potentially Critical to Prevent Acute Anastomotic Ischemia. Dis Colon Rectum 61:411\u0026ndash;414. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/dcr.0000000000000995\u003c/span\u003e\u003cspan address=\"10.1097/dcr.0000000000000995\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValenzuela-Fuenzalida JJ, Urz\u0026uacute;a-Somarriva MC, Gonz\u0026aacute;lez-Bello F, Tapia-Carmona C, P\u0026eacute;rez-Rojas F, Naranjo CA (2024) Anatomical Variants in Pancreatic Irrigation and Their Clinical Implications: A Review. Cureus 61:666. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/medicina61040666\u003c/span\u003e\u003cspan address=\"10.3390/medicina61040666\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVenieratos D, Tsoucalas G, Panagouli E (2018) A Rare Branching Pattern of a Middle Mesenteric Artery Supplying the Head of the Pancreas and the Transverse Colon. Acta Med Acad 47:199\u0026ndash;203. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5644/ama2006-124.232\u003c/span\u003e\u003cspan address=\"10.5644/ama2006-124.232\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anatomical variant, inferior pancreaticoduodenal artery, middle colic artery, superior mesenteric artery, colorectal surgery, pancreatic surgery","lastPublishedDoi":"10.21203/rs.3.rs-9458593/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9458593/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eThe vasculature of the pancreas and colon is highly variable and clinically relevant in pancreatic and colon surgeries. Although variant arterial branching between colonic and pancreatic arteries has been described, the variant in this study has not previously been reported. This study highlights variant arterial anatomy between the colon and pancreas to enhance anatomic knowledge for surgical planning.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eDuring a routine cadaveric dissection in our medical school anatomy laboratory, we identified an unusual branching pattern of the superior mesenteric artery (SMA) on a 72 y/o male donor.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAn unnamed artery originated from the posterior middle colic artery (MCA). This artery descended from its origin and bifurcated into an inferior branch and a transverse branch that crossed the SMA anteriorly. The transverse branch bifurcated into a small intestinal branch and a long ascending branch that supplied the head, uncinate process, body, and tail of the pancreas.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis case represents a previously undescribed arterial branching pattern of the colon and pancreas. Knowledge of unique arterial variants benefits fields of anatomy and surgery and supports efforts to reduce operative complications in colorectal and pancreatic surgeries.\u003c/p\u003e","manuscriptTitle":"Variant Mesenteric and Pancreatic Vasculature. A Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-06 16:32:05","doi":"10.21203/rs.3.rs-9458593/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-05-15T15:26:36+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-30T08:48:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"249967990834879997733712534398486369132","date":"2026-04-29T14:40:31+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-27T13:05:29+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-27T06:27:46+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-25T04:44:41+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surgical and Radiologic Anatomy","date":"2026-04-19T01:26:07+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bd530be8-2512-412a-96ec-d0766762a28a","owner":[],"postedDate":"May 6th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-05-15T15:26:36+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-30T08:48:12+00:00","index":10,"fulltext":""},{"type":"reviewerAgreed","content":"249967990834879997733712534398486369132","date":"2026-04-29T14:40:31+00:00","index":9,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-19T01:38:20+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-06 16:32:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9458593","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9458593","identity":"rs-9458593","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}