Which of the following is not supplied by the right coronary aery?
**Core Concept**
The right coronary artery (RCA) is a vital branch of the coronary circulation, supplying blood to the right atrium, right ventricle, and parts of the left ventricle. Its distribution is crucial for understanding coronary anatomy and potential areas of ischemia.
**Why the Correct Answer is Right**
The RCA primarily supplies the right atrium, right ventricle, and the posterior third of the left ventricle. It also gives off the posterior descending artery (PDA) in approximately 85% of the population, which supplies the inferior wall of the left ventricle. **Option C**, however, is not supplied by the RCA. Instead, the left circumflex artery (LCx) supplies the lateral and posterior walls of the left ventricle.
**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because the RCA does supply the right atrium, which is a critical structure for maintaining cardiac function.
* **Option B:** Incorrect because the right ventricle is indeed supplied by the RCA, which is essential for its contraction and relaxation.
* **Option D:** Incorrect because the posterior descending artery (PDA), a branch of the RCA, supplies the inferior wall of the left ventricle, thereby indirectly supplying the left ventricle.
**Clinical Pearl / High-Yield Fact**
Remember that the RCA typically gives off the PDA in approximately 85% of the population, which is a crucial detail for understanding coronary artery anatomy and potential areas of ischemia.
**Correct Answer: D. The left circumflex artery supplies the lateral and posterior walls of the left ventricle.**