Branches of the internal thoracic artery of rats supplying the heart, the sinus regions and the brachiocephalic veins.

Abstract

Branches of the internal thoracic artery (ITA) of rats which supply the heart, the sinus regions (see Terminology 1) and the brachiocephalic veins, were macroscopically studied. Two major branches of the ITA, the pericardiacophrenic artery and the descending ramus of the bronchoesophageal artery, were found supplying branches to these central portions of the cardiovascular system (see Table 1). They constituted, together with the ordinal coronary arteries, a system of dual blood supply to the heart as reported by Grant & Regnier (1926), Halpern et al. (1953, 1954) and Hebel & Stromberg (1986). This finding also supports a proposal of Grant & Regnier (1926) that the rat ITA emits cardiac branches which should be classified on the vertebrate scale to the caudal or extracoronary artery. Branches of the ITA to the heart, the sinus regions and to the brachicephalic veins were found to be classified into 2 major groups depending on their choice of entrance--arterial portal and venous porta; the latter was further divided into 3 subgroups depending on their selection of the (lateral or pulmonary or esophageal) mesocardium for traveling to the venous porta (see Table 2).