Otology/Audiology Flashcards

Question

Describe the orientation of the IAC nerves?

Answer 1

Bills bar Falciform crest

Answer 2

Two (usually) vertical fissures in the anterior portion of the cartilaginous external auditory canal, filled with fibrous tissue. Can lead to spread of malignancy from parotid to EAC, and vice versa

Answer 3

Transient anatomic landmark in petrous temporal bone and usually closes by 24th week of gestation. Located between the **otic capsule and the jugular bulb** Can persist, and cause a perilabyrinthine CSF fistula

Answer 4

Also known as the Foramen Tympanicum Located at the anteroinferior aspect of the EAC, posteromedial to the TMJ, in the tympanic portion of temporal bone If persists after 5 years of age, may lead to TMJ pathology or salivary discharge into the EAC with mastication May also predispose to spread of infection or tumor from EAC to infratemporal fossa or vice versa.

Answer 5

Concha cymba, concha cavum

Answer 6

Bordered laterally by **Shrapnell's membrane**, superiorly by the **scutum** and **lateral malleal ligament**, inferiorly by the **short process** of the **malleus**, and medially by the **neck** of the **malleus** Important because it is a site for pars flaccida acquired cholesteatoma

Answer 7

**65-80 mm²**

Answer 8

anatomical spaces between the malleolar folds and the tympanic membrane

Answer 9

**Herpes Zoster Oticus** essentially herpes zoster with a facial nerve palsy, may also affect other cranial nerves **Pathophysiology** primary infection or reactivation of herpes simplex virus (HSV), remains dormant in the cranial nerves and the cervical plexus **30–50%** risk of residual facial weakness after an acute episode (higher risk than Bell’s palsy) **Symptoms** acute peripheral facial palsy, painful vesicular lesions in the concha or EAC (**often misdiagnosed as external otitis media**), alterations in taste, may have hearing loss and vertigo, may involve other cranial nerves **Diagnosis** clinical history and physical exam, complement fixation and serum titers confirm diagnosis **Treatment** antivirals (acyclovir) and corticosteroids for 10 days, analgesics, and eye protection, rare to consider surgical facial nerve decompression

Answer 10

Scala tympani

Answer 11

1. Furosemide 2. Aspirin 3. Beta-blockers 4. Quinine 5. Aminoglycosides (e.g. gentamicin)

Answer 12

**Meningitis**

Answer 13

**Mastoiditis**

Answer 14

Otitis media

Answer 15

Most cases of genetic hearing loss are **autosomal recessive and nonsyndromic**. Hearing loss that results from abnormalities in **connexin** **26 and connexin 30** proteins likely account for 50% of cases of autosomal recessive nonsyndromic deafness in American children.

Answer 16

**Usher syndrome** is the most common cause of autosomal recessive hearing loss. The incidence of Usher syndrome is approximately 3-5 per 100,000 in the general population and 1-10% among profoundly deaf children.

Answer 17

**Blue mantles of manasseh**

Answer 18

AKA **Skull base osteomyelitis** Progressive **Pseudomonas** osteomyelitis in the temporal bone Diabetes mellitus remains most important associated condition Infection from the EAC spreads to the skull base via **fissures of Santorini**. Leads to bony destruction, can lead to cranial neuropathies (**FN** most common at stylomastoid foramen) Will see granulation tissue, purulence, even bone at inferior EAC at **bony-cartilaginous junction**. TM not involved.

Answer 19

**Osteoma** of the EAC is singular **Exostosis** is multiple (aka surfers ear in picture below) Facial nerve injury very common in aggressive removal of exostosis\*