Question
| A. | Cochlea |
| B. |
Lateral semicircular canal |
| C. |
Posterior semicircular canal |
| D. |
All |
|
Correct Answer � B Explanation |
 |
Ans. is b i.e. Lateral semicircular canal
Caloric Tests:
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Principle: To induce nystagmus by thermal stimulation of the vestibular system.
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Lateral semicircular canal is commonly tested by all these tests.
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There are 3 methods of performing these tests:
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Cold caloric test (modified Kobrak test):
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Patient position: patient is seated with head tilted 60°C backwards (to place horizontal canal in vertical position)
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Temperature of water used – ice cold water.
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Fitzgerald: (Hallpike test (bithermal caloric test)
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Patient position: patient lies supine with head tilted 30 degrees.
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Temperature of water = 30°C and 44°C.
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Cold air caloric test:
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Done when there is perfora -tion of tympanic membrane (as irrigation with water is contraindicated in these cases).
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Air cooled by ethylchloride is blown into the ear by Dundas Grant tube.