Anatomy of the Heart

Question 1

Coronary Arteries?

Answer 1

Left and right coronary arteries, and arise from the left and right aortic sinuses within the aorta.

• The aortic sinuses are small openings found within the aorta behind the left and right flaps of the aortic valve.
• When the heart is relaxed, the back-flow of blood fills these valve pockets, therefore allowing blood to enter the coronary arteries.
• The left coronary artery (LCA) initially branches to yield the left anterior descending (LAD) or anterior interventricular artery. The LCA then progresses to become the left marginal artery (LMA) and the left circumflex artery (Cx).
• The right coronary artery (RCA) branches to form the right marginal artery (RMA) anteriorly and the posterior interventricular artery (PIv) posteriorly.

Question 2

Distribution of the Coronary Arteries?

Answer 2

The area of the heart which an artery passes over will be the area that it perfuses. The following describes the anatomical course of the coronary arteries:

• The RCA passes to the right of the pulmonary trunk and runs along the coronary sulcus before branching.
• The right marginal artery arises from the RCA and moves along the right and inferior border of the heart towards the apex.
• The RCA continues to the posterior surface of the heart, still running along the coronary sulcus.
• The posterior interventricular artery then arises from the RCA and follows the posterior interventricular groove towards the apex of the heart.
• The LCA passes between the left side of the pulmonary trunk and the left auricle.
• The LCA divides into the anterior interventricular branch and the circumflex branch.
• The anterior interventricular branch (LAD) follows the anterior interventricular groove towards the apex of the heart where it continues on the posterior surface to anastamose with the posterior interventricular branch.
• The circumflex branch follows the coronary sulcus to the left border and onto the posterior surface of the heart. This gives rise to the left marginal branch which follows the left border of the heart.

Question 3

Answer 3

Question 4