Coronary arteries of the European bison (Bison bonasus)

Background: The European bison (Bison bonasus) is an endangered species. More information on its anatomy is needed as only few studies have been published. This study is the first report on the morphology of the coronary ves‑ sels. Given the anatomical similarity between the European bison and other ruminants, the results of this study can be applied to other species, including endangered ones. Results: The study was conducted on 70 hearts of European bisons of both sexes, aged 5–20 years, with an aver‑ age body weight of 449 kg. A distinct view of subepicardial arterial vessels was obtained by filling them with dyed synthetic latex (LBS 3060) and Plastogen G. There was a division of the common trunk of the left coronary artery into the interventricular paraconal branch and the left circumflex branch in 63 individuals (90 %). In five individuals (7.1 %), the presence of a third vessel, which was a branch of the interventricular septum, was observed. There was a lack of a common trunk in two individuals (2.9 %). Ramifications of the interventricular paraconal branch to the wall of the left ventricle were significantly larger than those to the wall of the right ventricle. In 17 individuals (24.3 %), the right coronary artery extended into the subsinuosal interventricular branch. Conclusion: The blood supply to the heart in bisons is provided by the left and right coronary arteries. In all the stud‑ ied specimens, the left coronary artery was better developed than the right coronary artery