A patient with hearing loss shows that bone conduction is greater than air conduction on the left side. What condition is most likely?

The observation that bone conduction is greater than air conduction on the affected side is a classic indication of conductive hearing loss. In this case, the finding suggests that there is likely an issue with the outer or middle ear that is obstructing or diminishing sound transmission through air conduction.

Otosclerosis, particularly on the left side, is a condition characterized by abnormal bone growth in the middle ear, which can impair the function of the ossicles – the tiny bones responsible for transmitting sound. This results in a scenario where the vibrations received through bone conduction (via the skull) are perceived more strongly than those acquired through air conduction, aligning perfectly with the described situation.

This patient's conductive hearing loss, indicated by the significant difference favoring bone conduction, aligns with otosclerosis affecting the left ear. In contrast, otosclerosis of the right ear or other conditions like cholesteatoma would not typically result in greater bone conduction on the left side, as they would either affect a different ear or involve conductive mechanisms that compromise bone conduction as well. Normal hearing would not present with this pattern at all, as it would exhibit equal or greater air conduction.