1. Coronary Arteries

Branches of the Thoracic Aorta

The two coronary arteries, right and left, are distributed almost entirely to the heart, but send some small twigs to the origins of the great vessels.

The right coronary artery (A. coronaria dextra) arises from the anterior sinus of the aorta. It passes forward between the conus arteriosus and the right auricle (appendix) to the coronary groove, in which it curves around to the right and backward. It then descends in the right ventricular groove almost to the apex of the heart.

The left coronary artery (A. coronaria sinistra) arises from the left posterior sinus of the aorta, passes to the left behind the origin of the pulmonary artery, and divides into two branches. The descending branch (Ramus descendens) passes down the left ventricular groove toward the apex. The circumflex branch (Ramus circumflexus) runs backward in the coronary groove, in which it winds around to the right side.