RELATION BETWEEN MICROANATOMY AND FUNCTIONAL PROPERTIES OF THE CORONARY ARTERIES.

Abstract

AbstractThe different anatomic properties of the three major coronary arteries of the dog were revealed by reconstruction of serial histologic sections. It was found that while the right and circumflex arteries consist of sequential segments of muscles arising and inserting into the adventitia, the anterior descending has a distinctly different muscle pattern. In the right coronary artery, six muscle bundles occur in short segments (0.6 mm in length), while only four arranged in longer segments (1.6 mm) characterize the circumflex artery. Two of the four muscle bundles in the anterior descending follow a spiral course down the entire length of the artery, while the other two execute a short spiral with a staggered origin from collagen septa 0.6 mm apart. Of the two types of branching from the major arteries one has no muscle connection, while the other has muscle continuity with the major artery. Innervation of the major arteries occurs at the muscle origin and insertion sites. Nerves penetrate to the intima of the right, circumflex and the structurally independent branches, suggesting interesting reflex control for vasomotion. Movements of the coronary arteries as followed by cineangiographic techniques are apparently determined by the gross movements of the heart, the neuromuscular features of the arteries, and the location of the branches.