Arterial branching pattern of the cranial mesenteric artery in the degu (Octodon degus)

BACKGROUND

The cranial mesenteric artery exhibits a species-specific ramification pattern that adapts to the morphology of the intestinal tract. The degu is a strictly herbivorous rodent with a well-developed large intestine with a spiral loop in the ascending colon; therefore, the cranial mesenteric artery likely demonstrates a degu-specific ramification pattern. Thus, we traced the cranial mesenteric artery to establish the detailed ramification pattern of the branches.

METHODS

Eighteen male degus were injected with 0.3-0.8 ml of a latex mixture and water at a 1:1 ratio in conjunction with red acrylic paint coloring using a catheter inserted into the thoracic aorta. The cranial mesenteric artery was traced using a surgical microscope and photographed using a digital camera.

RESULTS

The arteries emerging from the cranial mesenteric artery exhibited frequent variations in number, distribution area, anastomosis pattern, and branching order. In the most frequent cases (22%), the cranial mesenteric artery sequentially gave rise to caudal pancreaticoduodenal, middle colic, right colic, jejunal, and ileocolic arteries. The right and middle colic arteries exhibited four different ramification patterns. In the most common cases (67%), the middle and right colic arteries emerged independently from the cranial mesenteric artery. The former was distributed to the transverse and descending colon, whereas the latter sent branches to the spiral loop of the ascending colon.

CONCLUSIONS

The complex ramification pattern of the right colic artery in the degu may be an adaptation to the characteristic running pattern of the ascending colon. Thus, we present the first comprehensive report of the arterial branching pattern of the cranial mesenteric artery in the degu.

A case report of a rare ramification pattern and distribution area of the mesenteric arteries in a Japanese White rabbit (Oryctolagus cuniculus)

The rabbit intestinal tract is supplied by the cranial and caudal mesenteric arteries. Generally, the cranial mesenteric artery supplies the duodenum, jejunum, ileum, cecum, proximal colon and ascending and transverse distal colon, whereas the caudal mesenteric artery supplies the descending distal colon and rectum. The present study describes an abnormal branching pattern of the cranial and caudal mesenteric arteries in a Japanese White rabbit, where the caudal mesenteric artery but not the cranial mesenteric artery supplied the distal ileum, cecum, proximal colon and ascending and transverse distal colon. Such a rare mesenteric arterial ramification pattern may be explained by anomalies of the remaining anastomotic branches between the primitive mesenteric arteries and regressed their parent arteries during the developmental process.

Macroscopic Study of Celiac, Cranial Mesenteric and Caudal Mesenteric Arteries in the European Hare

The aim of this paper was to describe the branching schema of the ventral branches of the abdominal aorta: the a. celiaca, the a. mesenterica cranialis and the a. mesenterica caudalis. The study was carried out on nine adult European hares using the corrosion cast technique. After the euthanasia, the vascular network was perfused with saline. Batson’s corrosion casting kit No. 17 was used as a casting medium. After polymerisation of the medium, the maceration was carried out in KOH solution. In all specimens, the first branch originating from the a. celiaca was the a. lienalis. The a. hepatica was present as the second branch in four cases and as the third branch also in four cases. The first branch of the a. mesenterica cranialis was the a. colica media in seven cases. The second branch was represented by the a. pancreaticoduodenalis caudalis also in seven cases. Two aa. jejunales originated as the third branch. In seven cases, the fourth branch formed the truncus jejunalis and the fifth branch the a. ileocecalis. The a. mesenterica caudalis had a uniform arrangement in all of the specimens. The results enabled us to conclude that there was higher variability of the branching pattern of the a. celiaca in comparison with the a. mesenterica cranialis and the a. mesenterica caudalis in the European hare.

Macroscopic anatomical study of the distribution of the cranial mesenteric artery to the intestine in the rabbit

Intestinal surgery is commonly performed to cure bowel obstruction in rabbits, but detailed descriptions of the arterial supply to the intestine are incomplete. We investigated anatomical variations of the distribution of the cranial mesenteric artery to the intestine in 33 New Zealand White rabbits by injecting colored latex into the arteries. The cranial mesenteric artery arose independently from the abdominal aorta at about 2.0 cm caudal to the celiac artery and branched off the pancreaticoduodenal, middle colic, ileocecocolic, jejunal and ileal arteries. One or occasionally two caudal pancreaticoduodenal arteries supplied the distal duodenum, and one to three middle colic arteries supplied the transverse colon and the initial portion of the descending colon. The ileocecocolic artery arose distal to the middle colic arteries and provided the right colic, ileocecal and appendicular arteries, and branches to the proximal colon, with various branching patterns, which were grouped into four major types. These arteries and branches supplied the ileum, cecum, appendix and proximal colon. The cranial mesenteric artery also provided the jejunal arteries (predominantly 17; range 11-21) and one ileal artery supplying the jejunum and proximal ileum, respectively. The results show that the distribution patterns of the cranial mesenteric artery to the intestine in the rabbit are highly specialized to this species. Such specialization should always be considered when performing intestinal surgery in rabbits.