What does a Type C tympanogram indicate about the Eustachian tube?

A Type C tympanogram indicates negative middle ear pressure, which is often a result of Eustachian tube dysfunction. This means that the air pressure in the middle ear is lower than the atmospheric pressure, suggesting that the Eustachian tube is not functioning properly to equalize the pressure. This can occur due to various reasons, such as allergies, colds, or sinus infections, which can lead to an inability of the Eustachian tube to open and allow air into the middle ear.

In contrast, other options reflect different conditions. Normal pressure in the middle ear would typically result in a Type A tympanogram, not Type C. A narrow ear canal volume might indicate other issues, such as earwax blockage or congenital anomalies, and it does not specifically relate to Eustachian tube function. Increased tympanic membrane mobility is associated with a Type Ad tympanogram, indicating a different kind of tympanic membrane condition, such as a flaccid tympanic membrane, which is also unrelated to the negative pressure described by a Type C tympanogram. Thus, the identification of the Type C tympanogram as indicative of negative pressure due to dysfunction is a key diagnostic aspect of understanding middle ear health and Eustach