On a physical examination, if you hear a moderately loud murmur with no thrill, what grade is it likely to be?

A moderately loud murmur without a thrill is classified as a grade 3 murmur. The grading system for heart murmurs ranges from 1 to 6 based on the loudness and characteristics of the sound.

Grade 1 murmurs are very faint and can only be heard in a quiet room under ideal conditions. Grade 2 murmurs are soft but can be heard immediately. Grade 3 murmurs are considered moderately loud and can be heard readily without much effort, yet they do not produce a thrill, which is a vibration felt on the chest wall and indicates a more significant underlying issue.

Grade 4 murmurs are loud, accompanied by a palpable thrill, indicating that the blood flow through the heart is turbulent enough to produce these sensations. Since the scenario describes a murmur that is moderately loud but lacks the thrill, it aligns perfectly with the characteristics of a grade 3 murmur. Thus, the most appropriate classification is grade 3.