A young man presents with an accident leading to loss of hearing in the right ear. On otoscopic examination, the tympanic membrane was intact. Pure tone audiometry shows an Air – Bone gap of 55 dB in the right ear with normal cochlear reserve. Which of the following will be the likely tympanometry finding?

Okay, let's tackle this question. The patient has a right ear hearing loss after an accident. The tympanic membrane is intact, so maybe it's not a conductive issue from the ear drum. They mention an air-bone gap of 55 dB, which is significant. Normal cochlear reserve suggests sensorineural function is okay, so the problem is conductive. But since the TM is intact, it's not a perforation. So possible causes could be otosclerosis or a middle ear issue like a fixation in the ossicles. Tympanometry would help here. If the ossicles are fixed, like in otosclerosis, the tympanogram might show a normal or reduced compliance, but the key is the air-bone gap. Wait, tympanometry measures middle ear compliance. If the ossicles are fixed, the tympanic membrane might not move properly. But if the TM is intact, maybe tympanometry would show a normal type A curve if the middle ear is normal except for ossicular chain issues. Wait, no. If there's a fixation, like stapedial fixation, the compliance curve might be normal in shape but with reduced amplitude. Alternatively, if there's a fluid, the tympanogram would be flat. But the TM is intact, so fluid might not be the case here. The air-bone gap is large, so it's conductive. The correct answer is probably a normal tympanogram because the TM is intact and the issue is in the ossicular chain. The tympanometry would show a normal shape but maybe reduced mobility. So the answer is a normal type A tympanogram. So the correct answer is C if the options include that. The distractors might include flat tympanogram (like with fluid or TM perforation) which are incorrect here. The key is that the TM is intact and the problem is in the ossicles, not the middle ear space.

**Core Concept**
This question tests the understanding of conductive hearing loss (CHL) pathophysiology, specifically distinguishing middle ear pathology from cochlear dysfunction. A significant air-bone gap (>10 dB) with normal cochlear function (confirmed by normal speech discrimination or cochlear reserve) points to a conductive mechanism. Tympanometry evaluates middle ear mechanics, including tympanic membrane mobility and ossicular chain integrity.

**Why the Correct Answer is Right**
The intact tympanic membrane rules out perforation or external auditory canal obstruction. A 55 dB air-bone gap with normal cochlear function suggests ossicular chain disruption (e.g., otosclerosis, trauma-induced fixation). Tympanometry in such cases typically shows a **normal type A curve** (normal compliance and mobility) because the tympanic membrane is intact but the ossicles are fixed. This contrasts with fluid-filled middle ear (flat tympanogram) or TM perforation (low or absent compliance). The key is that the tympanogram reflects TM compliance, not ossicular function.

**Why Each Wrong Option is Incorrect**
**Option A:** A flat tympanogram (e.g., type B) suggests middle ear effusion or TM perforation, both excluded here by the intact TM.
**Option B:** A hypomobile curve (e.g., type As) indicates Eustachian tube dysfunction or otosclerosis. However, otosclerosis typically does not cause hypom

✓ Correct Answer: B. Ad type tympanogram