MCQ – 87912

Correct Answer � B Explanation

Ans. is b i.e. Lateral semicircular canal 

Caloric Tests:

• Principle: To induce nystagmus by thermal stimulation of the vestibular system.

• Lateral semicircular canal  is commonly tested by all these tests.

• There are 3 methods of performing these tests:

1. Cold caloric test (modified Kobrak test):

• Patient position: patient is seated with head tilted 60°C backwards (to place horizontal canal in vertical position) 

• Temperature of water used – ice cold water.

2. Fitzgerald: (Hallpike test (bithermal caloric test)

• Patient position: patient lies supine with head tilted 30 degrees.

• Temperature of water = 30°C and 44°C.

3. Cold air caloric test:

• Done when there is perfora -tion of tympanic membrane (as irrigation with water is contraindicated in these cases).

• Air cooled by ethylchloride is blown into the ear by Dundas Grant tube.