The growth of coronary artery branches in man under physiological conditions. Morphological studies of corrosion casts of the anterior interventricular branch of the coronary artery]

In corrosion casts of the left anterior descending coronary artery and its branches of higher order, the length, diameter, and number of branches were examined in 20 hearts, from 9 adults, 3 children, 4 new-born and 4 fetuses. We counted 5245 branches in total, thereof 147 branches in the corrosion casts of adult hearts were systematically analyzed, as were 46 branches of children's hearts, 55 branches of the new-born and 35 branches of the fetuses, respectively (left anterior descending coronary arteries and branches of 1st to 6th order). The length of the left coronary arteries and of their branches of 1st and 2nd order increases to almost the same degree as the linear measurements of the hearts. The left anterior descending coronary artery is about four times as long as the 1st order branches and these have twice the length of the 2nd order branches. These differences result from the divergent course of the branches. The results indicate that no significant increase in the number of the 1st to 3rd order branches of the coronary arteries occurs from birth to adulthood in human hearts. During the postnatal growth in human hearts there seems to be no remarkable neogenesis of coronary artery branches of greater diameter. Nearly all of them exist at birth and even in the late fetal period. Their length increases harmonically with the linear measurements of the heart and they become progressively separated. These findings parallel those obtained in a previous study in pigs.