A 40-year-old male shows the following on impedance audiometry: tympanogram type B (flat) with normal ear canal volume. This is most consistent with:
- A Tympanic membrane perforation
- B Otosclerosis with stapes fixation
- C Serous otitis media (middle ear effusion) ✓
- D Ossicular chain disruption
Correct answer: C. Serous otitis media (middle ear effusion)
Explanation
A Type B (flat) tympanogram with a normal ear canal volume indicates absent tympanic membrane mobility due to middle ear effusion. Normal ear canal volume excludes a perforated TM (which would show abnormally large ear canal volume with Type B curve). Otosclerosis shows a Type As (shallow) tympanogram due to reduced compliance from stapes fixation, not a flat trace. Ossicular chain disruption (ossicular discontinuity) classically produces a Type Ad (deep/high-compliance) tympanogram.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.