Which murmur is classic for aortic stenosis and best heard at the right upper sternal border?

• A. Crescendo-decrescendo systolic murmur best heard at the right upper sternal border
• B. Holosystolic murmur at the apex radiating to the axilla
• C. Early diastolic decrescendo murmur at the left sternal border
• D. Pansystolic murmur best heard at the left lower sternal border

Answer: (A)

The main concept tested is recognizing the classic auscultation features of aortic stenosis: a harsh, crescendo-decrescendo systolic murmur heard best at the right upper sternal border (second intercostal space), often radiating to the carotids. This pattern happens because blood is forced through a narrowed aortic valve during systole, producing a high-velocity jet that accelerates (crescendo) and then decelerates (decrescendo) as the valve obstruction limits flow. The right upper sternal border location reflects the aortic valve’s position, and carotid radiation is a hallmark clue. The other murmurs align with different conditions: a holosystolic murmur at the apex radiating to the axilla suggests mitral regurgitation; an early diastolic decrescendo murmur at the left sternal border points to aortic regurgitation; a pansystolic murmur at the left lower sternal border is typical for tricuspid regurgitation or VSD.