9/10/2013

9/10/2013

Answers:

This tympanogram is type...?

A) Type A 

B) Type As 

C) Type Ad 

D) Type B 

E) Type C

Type B tympanograms are flat and indicate nonmobility of the TM due to middle ear effusion or perforation.

How can you differentiate a type B tympanogram due to middle ear effusion from a type B tympanogram due to perforation?

The ear canal volume will be large if a perforation is present because the middle ear space is included in that volume, however if an effusion is present then EAC volume should be within normal limits (.5cm^3 in kids, 3cm^3 in adults)

MC Questions:
Wave IV of an auditory brain stem response corresponds to what structure?
A) Olivary complex 
B) Cochlear nucleus 
C)Inferior colliculus 
D) Lateral lemniscus 
E) Eight nerve action potential

Free Response Question:
With regards to the acoustic reflex, which pathway (ipsilateral or contralateral) contain the majority of neurons? Describe the path of that pathway.

Quick Facts:
Stapedius Muscle: 
-attached to posterior crus of stapes 
-contracts reflexively at loud noise. 
-always contracts bilaterally even if only one ear stimulated. 
-protects inner ear from damaging intense sound