[Distribution pattern of coronary arteries and their intramyocardial architecture: on the functional anatomy of the coronary arteries (author's transl)].

A study of 100 human hearts demonstrated a diverse normal pattern of coronary arteries. Variations were classifiable into three general groups: 1. balanced coronary circulation (68 specimens), 2. right coronary artery preponderance (22), and 3. left coronary artery preponderance (9). A large intercoronary anastomosis between the left anterior descending and right coronary arteries, measuring about 2 mm in diameter, was seen in one heart. In about 57% of hearts the left anterior descending artery was partially covered by cardiac muscle bridges, up to 6 cm long. In some instances the artery passed through the wall of the right ventricle, running through the inner layer of the myocardium. Such coronary arterial course would not be demonstrable by coronary angiography. Yet it increases the risk of coronary artery surgery at the site of a thin-walled right ventricle. A phylogenetic explanation for the variations in normal arterial pattern and the muscle bridges is given.