|Year : 2017 | Volume
| Issue : 1 | Page : 54-56
A unique variation in axial gut vasculature
V Dinesh Kumar, R Rajprasath, Virender Kumar Nim
Department of Anatomy, Pondicherry Institute of Medical Sciences, Puducherry, India
|Date of Submission||19-Apr-2017|
|Date of Acceptance||06-May-2017|
|Date of Web Publication||12-Jul-2017|
V Dinesh Kumar
Department of Anatomy, Pondicherry Institute of Medical Sciences, Puducherry
Source of Support: None, Conflict of Interest: None
Variations in gut axial vasculature warrant attention owing to its catastrophes which arise during surgeries of the upper abdomen. Here, we report a case of anomalous origin of the middle colic artery from the celiac trunk in an approximately 70-year-old male cadaver. Celiac trunk forms the axial vasculature of the foregut. The middle colic artery is a branch of the superior mesenteric artery, the axial vasculature of mid-gut. Among the anatomical variations in the branching pattern of gut vasculature, the knowledge regarding this anomaly would, therefore, be helpful for the gastroenterologists, radiologists, and interventionists.
Keywords: Celiac trunk, embryology, gastroenterology, middle colic artery
|How to cite this article:|
Kumar V D, Rajprasath R, Nim VK. A unique variation in axial gut vasculature. J Curr Res Sci Med 2017;3:54-6
| Introduction|| |
The gut gets specified into foregut, midgut, and hindgut as early as 5th week of intrauterine life (IUL). In addition, their blood supply also gets specified. In rare instances, the blood supply of a particular part of a midgut can be derived from a blood vessel supplying foregut, i.e., celiac trunk. The middle colic artery which supplies the transverse colon has been noted for its variations. Even though the conventional teaching emphasizes the origin of the middle colic artery from superior mesenteric artery (SMA), the supplier of midgut, variations tend to occur.
These data regarding variations form a valuable input for gastroenterologists who perform diagnostic, minimal access, and conventional surgeries and also for radiologists who interpret the sectional anatomy.
| Case Report|| |
During routine educational dissection of an approximately 70-year-old male cadaver, an ectopic origin of middle colic artery was noted. The vessel was traced above to its origin and below till its termination. The vessel had originated from the celiac trunk after it had given the splenic and left gastric vessels and before the origin of common hepatic artery [Figure 1].
|Figure 1: The course of the entire ectopic vessel originating from celiac trunk and related to anterior surface of head of pancreas|
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The vessel occupied the typical location of gastroduodenal artery. It passed behind the first part of duodenum and occupied the location at the junction between head and neck of the pancreas [Figure 2]. It gave branches which supplied duodenum and pancreas, resembling superior pancreaticoduodenal artery. It then continued in a vertical course in front of third part of the duodenum, entered the transverse mesocolon, and terminated by supplying the middle part of the transverse colon. The vessel measured 24 cm in length and 3.5 mm in diameter.
|Figure 2: Entire ectopic vessel (yellow arrows) arching over the head of pancreas to transverse colon|
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The usual middle colic artery, sprouting from the right side of the SMA, near the inferior border of the head of pancreas, was found to be absent in this case [Figure 3]. Thus, the variant middle colic artery from the celiac trunk had substituted the usual branch from SMA. This might have supplemented the territories of the usual middle colic artery and would have prevented any vascular compromise.
|Figure 3: Separate right colic artery and ileocolic artery from superior mesenteric artery with the absence of middle colic artery from it|
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| Discussion|| |
The middle colic artery usually originates as a branch from the anterolateral aspect of SMA just inferior to the uncinate process of pancreas. At its point of entry into the transverse colon, it is closely related to the neck of pancreas. This is a potential site of danger in adhesions and malignancies. After its course in the transverse mesocolon, it usually divides into the right and left branches, 3–11 cm from the colonic wall, and supplies the transverse colon.
The middle colic artery is not a single artery, but a complex system of different vessels. The “composed system of the middle colic artery” is described as follows:
“The middle colic artery is not a single vessel. Five different vessels can be discerned behaving as arteries or as branches: (1) The middle colic artery (46%), dividing into a branch for the right angle and one for the transverse colon; (2) the artery for the right angle of the colon (32%); (3) the artery for the transverse colon (12%); (4) the accessory artery for the transverse colon (3%); and (5) the accessory left colic artery (7%).”
The middle colic artery is noted in more than 95% of the subjects. As the middle colic artery supplies the junction area between SMA and inferior mesenteric artery (IMA), their absence should only be compensated by the adjacent vasa recta. The left branch of the middle colic artery may supply the territory which is also supplied by the left colic artery. This collateral circulation in the area of the splenic flexure is the most inconsistent of the entire colon and has been referred to as a watershed area, vulnerable to ischemia in the presence of hypotension. In practice, surgeons avoid making anastomoses in the region of the splenic flexure for fear that the blood supply will not be sufficient to permit healing of the anastomosis, a situation that could lead to anastomotic leak and sepsis.
The gastroduodenal artery arises as one of the two terminal branches of the common hepatic artery. It may also arise as a trifurcation with the right and left hepatic arteries or from the SMA. After its origin, it runs behind the first part of duodenum and lodges in the groove at the junction of the anterior surface of the head and neck of pancreas. The possible branches of gastroduodenal artery are:
- Supraduoden al artery
- Retroduodenal artery
- Posterior superior pancreaticoduodenal arteries
- Right gastroepiploic and anterior superior pancreaticoduodenal arteries.
In this case, the middle colic artery is not found arising from its typical origin. However, a variant vessel, probably appearing as a continuation of gastroduodenal artery supplies the transverse colon compensating the vascular compromise. This is an infrequent variation reported in two female cadavers. In an interesting case of a 40-year-old male, presenting with postprandial pain, ultrasound examination had revealed total occlusion of SMA with patent celiac trunk and IMA. In that case, middle colic artery was atypically from celiac trunk which following failure of collateral circulation had resulted in symptomatic angina.
This anomaly draws attention from the surgical perspective, as surgeries involving the head of pancreas or duodenum could potentially injure this vessel, thereby leading to a clinical catastrophe. The vascular pattern in this case would have been suitably supplemented by anastomosis of adjacent vessels, forming marginal artery of Drummond in the colonic wall.
The variations in mesenteric vasculature, which can lead to pathological complications, can be understood by revisiting the embryological origin of mesenteric vessels. The gut wall develops mostly from endoderm and its vasculature from mesoderm. The gut tube then gets specified into foregut, midgut, and hindgut. Each segment has its own blood supply.
Branches from dorsal aortae are named as dorsal, ventral, and lateral intersegmental arteries. The paired ventral segmental arteries course over the dorsal and lateral walls of the gut and yolk sac. With the fusion of the dorsal aortae during 4th week of IUL, the ventral branches fuse and form a series of several unpaired segmental vessels. They fuse in the midline with gut closure and narrowing of the dorsal mesentery to form the celiac artery, SMA, and IMA, respectively.
During formation of these vessels, collaterals get established either within individual arterial systems such as within celiac arterial system or superior mesenteric system or between arterial systems. Rarely, collaterals get established between celiac and superior mesenteric system.
Some of collaterals such as the arch of Bühler may connect the trunk of celiac artery and SMA. In such cases, the vessel is considered as a patent embryological remnant. In some cases, pancreaticoduodenal vessels may establish collaterals between celiac and superior mesenteric circulations.
In very rare cases, like this, the aberrant middle colic artery may establish communication between celiac and superior mesenteric circulation.
| Conclusion|| |
Knowledge regarding the vascular variations not only enlightens the anatomists but also might be handy for the surgeons and image-guided interventionists in avoiding vascular complications.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]