The right coronary artery supplies which myocardial segments?

• A. Inferior and basal septal segments (and sometimes apex)
• B. Anterior and apical segments
• C. Lateral segments
• D. Inferior and lateral segments

Answer: (A)

Understanding how coronary artery territories map to heart muscle helps explain why the right coronary artery is responsible for certain regions. The RCA most commonly supplies the right ventricle and the inferior portion of the left ventricle, through the posterior descending artery in a right-dominant circulation. From this pathway, the basal portion of the interventricular septum can also receive blood flow, and in some individuals the posterior descending artery extends far enough to reach the apex. That combination—inferior wall and basal septum, with possible apex involvement—is the territory associated with the RCA, making that option the best fit. By contrast, the anterior and apical segments are typically supplied by the left anterior descending artery, while the lateral wall is supplied by the left circumflex artery.