What is the defining feature of a Type B tympanogram?

A Type B tympanogram is characterized by no distinct peak and low compliance. This indicates that the middle ear space is not functioning properly, typically due to fluid accumulation, perforation of the eardrum, or significant dysfunction of the ossicular chain. In a healthy ear, a tympanogram usually has a clear peak where compliance is at its maximum, reflecting good mobility of the tympanic membrane. In contrast, a Type B tympanogram suggests that the eardrum is not able to move effectively, which is a significant indicator of middle ear pathology.

The presence of low compliance in this scenario further supports the concept that there is a blockage or restriction in the movement, leading to a flat line on the tympanogram. This scenario explains why the defining feature of a Type B tympanogram is the absence of a peak and indicates the need for further evaluation to determine the underlying cause of the middle ear dysfunction.