Which region of the heart does the LAD primarily supply?

• A. Anterior wall
• B. Inferior wall
• C. Lateral wall
• D. Posterior wall

Answer: (B)

The left anterior descending artery runs in the anterior interventricular groove and supplies the front part of the left ventricle and the anterior portion of the interventricular septum. Its branches—the septal perforators and diagonal branches—give blood to the anterior wall and the apex. Because of this, the region it most strongly supports is the anterior wall (and the anterior septum). The inferior wall, on the other hand, is typically supplied by the right coronary artery via the posterior descending artery in most people (and by the circumflex in some left-dominant patterns). The lateral wall is mainly fed by the circumflex system. So the LAD is best associated with the anterior wall.