CVS Practice Test

Which papillary muscle is the most susceptible to rupture?

1. Anterior (lateral) papillary muscle

2. Posterior (medial) papillary muscle

3. Inferior papillary muscle

4. Superior papillary muscle

The correct answer is: Posterior (medial) papillary muscle

The posterior (medial) papillary muscle is considered the most susceptible to rupture, particularly in the context of myocardial infarction (heart attack) or ischemia. This susceptibility is primarily due to its vascular supply, which generally comes from the right coronary artery or the left circumflex artery, depending on the individual’s coronary circulation pattern. In cases of coronary artery disease, if there is an occlusion in these vessels, the blood flow to the posterior wall of the heart, where this muscle is located, can be significantly impaired. As a result, in instances of heart attacks that affect the inferior wall of the left ventricle, or if the underlying vessels supplying this area are compromised, the posterior papillary muscle is at a high risk of ischemic damage, leading to rupture. The rupture of this muscle can result in acute mitral valve insufficiency, which can be a life-threatening condition requiring immediate medical intervention. The other papillary muscles, while they can also be affected, do not carry the same level of risk in this specific context, making the posterior (medial) muscle particularly noteworthy in discussions of potential rupture due to ischemia.