Diagonal branches of the left anterior descending artery

Diagonal branches of the left anterior descending coronary artery supply blood flow to the anterior and anterolateral walls of the left ventricle. There are usually denoted as D1, D2, D3, etc.

There are termed "diagonal" due to them branching from their parent vessel at acute angles. They extend over the left ventricle in a diagonal fashion toward the acute margin and the apex. They often run parallel to one another and are variable in number (often 2 to 9). If a ramus intermedius artery is present, the diagonal arteries are less prominent and arise more distally. The first diagonal (D1) branch tends to be the most prominent. When the first diagonal is large, the other diagonal vessels tend to be small and run a shorter course.