Anatomical variations in the origins of the celiac axis and the superior mesenteric artery: MDCT angiographic findings and their probable embryological mechanisms.

OBJECTIVES: To identify the spectrum and prevalence of anatomical variations in the origin of the celiac axis (CA), the superior mesenteric artery (SMA) and their major branches by using multidetector computed tomographic (MDCT) angiography. METHODS: A retrospective evaluation was carried out on 1,500 abdominal MDCT angiography images. The aortic origins of the CA, the SMA and their major branch patterns were investigated. RESULTS: Normal aortic origins of CA and SMA were noted in 1,347 (89.8%) patients. Seven types of CA and SMA origin variants were identified in 153 (10.2%) patients. The three most common variations were hepatomesenteric trunk (67 patients, 4.47%), celiomesenteric trunk (CMT) (51 patients, 3.4%) and splenomesenteric trunk (18 patients, 1.2%). An evaluation of CMT was classified as long (34 patients, 66.7%) or short (17 patients, 33.3%) subtypes, compared with the length of the common trunk. Further CMT classification was based on the origin of the left gastric artery: subtype I, 26 patients (53.1%); subtype II, 5 patients (10.2%); subtype III, 15 patients (30.6%); subtype IV, 3 patients (6.1%). CONCLUSIONS: Dislocation interruption, incomplete interruption and persistence of the longitudinal anastomosis could be the embryological mechanisms of the variant origins of the CA, the SMA and their major branches. KEY POINTS: • Aortic origins of CA, SMA and their major branches were investigated. • Celiomesenteric trunk includes several different subtypes and configurations. • Probable embryological mechanisms of origin variants in these observed arteries were discussed. • Origin variants in these observed arteries have wide-ranging health implications.

Fetal celiac and splenic artery flow velocity and pulsatility index: longitudinal reference ranges and evidence for vasodilation at a low portocaval pressure gradient.

OBJECTIVES: To establish longitudinal reference ranges for the fetal celiac and splenic arteries flow velocity and pulsatility index (PI), and to determine their hemodynamic relationship to venous liver perfusion and distribution and to other essential arteries. METHODS: This was a prospective longitudinal study of 161 low-risk pregnancies. Doppler recordings of the celiac and splenic arteries were made on three to five occasions at 3-5-week intervals to establish reference ranges for blood velocity and PI measurements. Peak systolic velocity in the ductus venosus, a shunt between the umbilical and inferior caval veins, was used to represent the umbilicocaval (i.e. portocaval) pressure gradient, and the left portal vein blood velocity represented the umbilical distribution to the right liver lobe. The correlations between the celiac, splenic and hepatic arteries were determined, and their association with the middle cerebral and umbilical artery PIs (MCA-PI and UA-PI) was assessed. RESULTS: Longitudinal reference ranges for the fetal celiac and splenic arteries were established based on 510 and 521 observations, respectively, during gestational weeks 21-39. Terms for calculating conditional reference ranges to be used for repeat observations are provided. Celiac and splenic artery PIs were low when portocaval pressure and umbilical supply to the right lobe were low (P < 0.0001). Their peak systolic velocity and PI were correlated (r = 0.7 (95% CI, 0.6-0.8) and r = 0.5 (95% CI, 0.3-0.6), respectively), while the PI of the hepatic artery correlated weakly with those of the celiac and splenic arteries. They were positively associated with the MCA-PI and UA-PI (P < 0.0001). CONCLUSION: We provide longitudinal reference ranges for the fetal celiac and splenic arteries Doppler measurements and show that they are involved in maintaining portal liver perfusion independently from the hepatic artery.

Spatial growth and pattern formation in the small intestine microvascular bed from larval to adult Xenopus laevis: a scanning electron microscope study of microvascular corrosion casts.

The microvascular anatomy of the small intestine of metamorphosing tadpoles of the South African Clawed Toad, Xenopus laevis (Daudin) is studied from developmental stages 55 to 65 and in adults by scanning electron microscopy (SEM) of vascular corrosion casts (VCCs) and light microscopy. Up to stage 62, VCCs reveal a dense two-dimensional vascular network ensheating the intestinal tube, whose proximal portion forms a clockwise spiralling outer and its distal portion an anti-clockwise spiralling inner coil. Vessels of the intestinal network impose flat and run circularly to slightly obliquely. Locally, dense capillary plexus with small "holes" indicating ongoing intussusceptive microvascular growth (IMG) and vessel maturation, are present. The typhlosole, an invagination along the proximal portion of the small intestine, reveals a dense capillary bed with locally ongoing IMG. VCCs of stages 62/63 for the first time reveal a three-dimensional vascular bed with longitudinal intestinal folds of varying size and heights greatly enlarging the luminal exchange area of the intestinal tube. From stage 65 onwards, longitudinal intestinal folds undulate and, though smaller in size and less mature as indicated in VCCs by the presence of wider, sinus-like vessels with small "holes" interposed between, closely resemble the intestinal folds present in the small intestine of adult Xenopus. Our data suggest that maturation of the vascular pattern in the small intestine of X. laevis tadpoles takes place successively after stages 62-63, and growth during this period is preferentially by intussusception.

[Variations of the celiac trunk branches in the fetus]. / Variantes de ramification du tronc coeliaque chez le foetus.

The study was performed on 60 human foetuses, aged between 4 to 9 months, using as methods dissection and plastic and contrast substances injection. We studied the celiac trunk in what concerns the division into its terminal branches, insisting on the possible morphological variations, some rare collateral branches starting from the common arterial trunk, the dimensional relations between the branches at their origin and the level of the celiac trunk origin from the aorta, in relation with the vertebral column, the diaphragmatic passage of the aorta and with the superior mesenteric artery. We also assessed the dimensional relations (calibers at origin) between the branches of the celiac trunk. Ass possible variations of the division of the celiac trunk, we assessed: gastro-hepatic trunk, with the splenic artery directly from the aorta or from the hepatic artery; gastro-splenic trunk, with the hepatic artery originating from the aorta; hepato-splenic trunk, with origin of the left gastric artery either directly from the aorta or from the hepatic artery. Rare variations: celiaco-mesenteric trunk; two arterial trunks, hepato-splenic and hepato-gastric; separate aortic origin for all three "classic" branches of the celiac trunk; two hepatic arteries, one from the celiac trunk and the other from the aorta or superior mesenteric artery; celiac trunk that divides into several terminal branches; one or two suprarenal arteries originating from the celiac trunk.

Embryology, anatomy, and surgical exposure of the great abdominal vessels.

This article describes the embryology of the abdominal aorta and the anatomic features of its major visceral branches, including the celiac, superior mesenteric, and inferior mesenteric arteries. The common anatomic variants of these visceral vessels also are reviewed. Various operative techniques to gain surgical exposure to these vessels are described.

Hepatic artery anatomy in relation to reconstruction in liver transplantation: some unusual variations.

The anatomy of the hepatic artery and its variations were studied in 70 donor livers harvested for liver transplantation in the Austin Hospital. Forty three (61.5%) had a 'normal' vascular anatomy and 27 (38.5% had anomalous anatomy. The anomalies were single in 13 instances and multiple in 14 and involved the origin of the right or left hepatic arteries or the coeliac axis. The hepatic artery was reconstructed most frequently by end-to-end anastomosis of the donor to the recipient common hepatic artery (79%). A Carrel patch, an interposition aortic graft and the donor superior mesenteric artery were other techniques used for reconstruction. Two patients (3%) had a postoperative hepatic artery thrombosis, with one of those patients having a further reconstruction. When one vascular anomaly is found, there is a high probability of others being present. The authors' experience confirms that safe hepatic arterial anastomosis can be performed even in the presence of abnormalities of the vascular arterial system.

[Various cases of direct connections between the celiac artery and the superior mesenteric]. / Alcuni casi di connessione diretta fra le arterie celiaca e mesenterica superiore.

The authors produce three cases in which an anastomotic arterial trunk between the coeliac artery and the superior mesenteric artery was present. Although this finding is rather rare (0.4% in vivo) it is important for the surgeons who operate upon the pancreas.

[The arterial distribution to the abdominal digestive organs in human fetuses].

The arterial supply of the abdominal digestive organs and the developmental process were studied in 25 Japanese fetuses from 3 months to 9 months old into whose arteries latex rubber was injected. The results were as follows: 1) The branching patterns of the celiac trunk were classified into 5 types. The most common type or the complete celiac trunk was found in 18 cases (72%). Four variation types or incomplete celiac trunks were found in 7 cases (28%). 2) The rates at which the following arteries were observed in the stomach were as follows: 100% for the left gastric artery, 100% for the left and right gastroepiploic artery, 100% for the short gastric artery, 100% for the gastroduodenal artery, 92% for the right gastric artery, 24% for the branch of the left inferior phrenic artery, and 16% for the posterior gastric artery arising from the splenic artery. The left gastric artery was better developed than the other arteries in 3-month-old fetuses. 3) The rates at which the following arteries were observed in the liver were as follows: 100% for the proper hepatic artery, 28% for the accessory left hepatic artery and 8% for the accessory right hepatic arteries. The accessory left hepatic artery in 3-month-old fetuses was better developed than in older fetuses. 4) The rates at which the following arteries were observed in the pancreas were follows: 100% for the branches of the splenic artery, 100% for the branches of the gastroduodenal artery and 100% for the branches of the superior mesenteric artery. Further, dorsal pancreatic arteries not arising from the splenic artery were found in 20% of cases. The dorsal and great pancreatic arteries branching from the splenic artery could not be distinguished from one another in younger fetuses. 5) The rates at which the following arteries were observed in the duodenum were as follows: 100% for the branches of the superior and the inferior pancreaticoduodenal arteries. This arterial supply was the same in all the fetuses. 6) The arterial supply of the jejunum and the ileum were as follows: the jejunum and the ileum were supplied only by the branches of the superior mesenteric artery. The minimum number of the branches was 7 and the maximum 12. 7) The arterial supply of the large intestine was as follows: the caecum was supplied only by the ileocolic artery.(ABSTRACT TRUNCATED AT 400 WORDS)

Accessory blood supply to the liver from the dorsal pancreatic artery: an unusual anatomic variant.

A case of an accessory hepatic artery from the dorsal pancreatic artery is illustrated. A discussion of anatomic variations and embryology of the arterial blood supply to the liver from the celiac axis and aberrant blood supply from other vessels is presented with a consideration of the surgical and diagnostic significance of anatomic variance.