The structure indicated is the left anterior descending artery (also known as the anterior interventricular artery).

The left anterior descending artery is one of the coronary arteries which supplies the anterior and lateral parts of the myocardium and the interventricular septum. It is responsible for approximately 45-55% of the left ventricles blood supply.

The left coronary artery arises from the left aortic sinus of the ascending aorta. The left coronary artery has two terminal branches:

• Left anterior descending (LAD)/anterior interventricular
• Circumflex branch

The left anterior descending artery itself has two different types of branches

• Septal branches
• Diagonal branches

Septal branches supply the anterior two thirds of the interventricular septum.

Diagonal branches supply the lateral wall of the left ventricle as well as the anterior papillary muscle.

This artery is often referred to morbidly as the “widow maker” – occlusion of the LAD can have catastrophic consequences due to the large proportion of blood it supplies to the left ventricle.

Learn more about the arterial supply to the heart in this anatomy tutorial.