NBCE Exam 2026 – 400 Free Practice Questions to Pass the National Board of Chiropractic Examiners

A nonmobile retracted tympanic membrane typically occurs due to Eustachian tube obstruction. When the Eustachian tube is obstructed, it prevents the equalization of pressure in the middle ear. As a result, the negative pressure that develops within the middle ear can cause the tympanic membrane (eardrum) to retract, resulting in a decreased mobility of the membrane during physical examination.

In contrast, acute otitis media can lead to a bulging or inflamed tympanic membrane rather than a retracted one. Cholesteatoma may cause retraction of the membrane, but it usually presents with additional complications such as infection, and the primary issue often stems from a chronic condition rather than an acute obstruction. Otitis externa primarily involves the external ear canal and does not directly cause retraction of the tympanic membrane. Understanding these conditions can help clarify why Eustachian tube obstruction is the most fitting explanation for a nonmobile retracted tympanic membrane.