Ramification of the a. mesenterica cranialis and its variability in the guinea pig (Cavia aperea f. porcellus).

The authors studied ramification of the a. mesenterica cranialis and its variability in 30 guinea pigs (Cavia aperea f. porcellus) after injecting red-dyed latex into their arterial bed. In every case, this artery arose from the truncus hepato-mesentericus, which in turn was a branch of a thick arterial truncus coeliaco-mesentericus. After leaving its site of origin, the a. mesenterica cranialis formed a long arc whose convexity was directed leftwards and caudally. Its first branch was most frequently (18 cases-60%) the a. colica media. In seven cases (23.3%) this artery arose together with the a. pancreaticoduodenalis caudalis from the same site. The a. pancreaticoduodenalis caudalis was the first branch of the a. mesenterica cranialis in two cases only (6.7%). In 18 cases (69%) the a. pancreaticoduodenalis caudalis was the second branch of the a. mesenterica cranialis and in seven cases (23.3%) it arose from the same site as the a. colica media. It supplied the caudal part of the pancreas and the duodenum as far as the flexura duodenojejunalis, where it formed an anastomosis with the first a. jejunalis. In every case, the ileum, caecum and colon were supplied by a thick a. ileocaecocolica, which after giving off the last a. jejunalis, formed a continuation of the trunk of the a. mesenterica cranialis. Near the ileocaecal junction it divided into a r. ileacus, rr. caecales, a r. prae--and retrocaecalis and a r. colicus. The caecum was further fed by thick r1. caecales which usually branched from the middle segment of the a. mesenterica cranialis.(ABSTRACT TRUNCATED AT 250 WORDS)