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Coronary Circulation - Arteries

The Left Coronary Artery

• (a. coronaria cordis sinistra), larger than the right, arises from the left anterior aortic sinus
• divides into an anterior descending and a circumflex branch
• there is a free anastomosis between the minute branches of the two coronary arteries in the substance of the heart
• anterior descending branch
  • passes at first behind the pulmonary artery
  • then comes forward between that vessel and the left auricula
  • to reach the anterior longitudinal sulcus
  • descends along to the incisura apicis cordis
  • gives branches to both ventricles
• circumflex branch
  • follows the left part of the coronary sulcus
  • running first to the left and then to the right
  • reaching nearly as far as the posterior longitudinal sulcus
  • gives branches to the left atrium and ventricle

The Right Coronary Artery

• (a. coronaria cordis dextra) arises from the right anterior aortic sinus
• passes at first between the conus arteriosus and the right auricula
• then runs in the right portion of the coronary sulcus, coursing at first from the left to right and then on the diaphragmatic surface of the heart from right to left as far as the posterior longitudinal sulcus, down which it is continued to the apex of the heart as the posterior descending branch
• gives off a large marginal branch which follows the acute margin of the heart and supplies branches to both surfaces of the right ventricle
• gives small branches to the right atrium and to the part of the left ventricle which adjoins the posterior longitudinal sulcus

(text modified from Gray's 1918 Anatomy)