Question

a. right av valve
b. pulmonary semilunar valve
c. left av valve
d. aortic semilunar valve

in a patient with normal heart sounds which of the following would you hear in the fifth left intercostal space at the mid - clavicular line?
a. a loud and strong \dupp\ sound
b. a faint and weak \lubb\ sound
c. a soft \lubb\ sound that grows louder, then ends softly, followed by a \dupp\ sound
d. a loud and strong \lubb\ sound

Explanation:

The fifth left intercostal space at the mid - clavicular line is the location of the apex of the heart, where the mitral (left AV) valve closure sound (the "Lubb" sound, produced by the closure of the atrioventricular valves during ventricular systole) is best heard. The "Lubb" sound here should be loud and strong as it's the point of maximum intensity for the first heart sound. Option A is incorrect as "Dupp" is the second heart sound (semilunar valve closure) and not prominent here. Option B is wrong as the sound at the apex is not faint/weak. Option C's description doesn't match the normal first heart sound at the apex.

Answer:

D. A loud and strong "Lubb" sound