Which semicircular canal is most commonly involved in BPPV?

Ans. is 'b' i.e., Posterior * BPPV is one of the most common cause of vertigo, the symptom that describes the feeling of intense spinning of the head. BPPV is characterized by vertigo when the head is placed in certain critical position, therefore is called positional. Vertigo is brought on by typical head movements, usually neck extension such as with looking up at a high shelf or at the sky; or rotation to one side. The vertigo will commonly be felt when going to lie down in bed or when rolling over to one side while in bed, and for this reason it is frequently first noticed at night or awakening.* BPPV describes the situation where the spinning sensation lasts only a few minutes and often stops by itself. There may be recurrent episodes without any specific reason or cause.* While there are many causes of vertigo, BPPV is the term that is used for vertigo that comes and goes (paroxysmal), without a specific associated illness (Benign). Episodes are frightening and difficult to predict. In some cases (20- 30%) BPPV has history of head trauma or ear infection.* BPPV is thought to be caused by displacement of otoconia (mineral crystals) from the vestibule of inner ear into the semicircular canals. The posterior semicircular canal is most commonly involved, though superior and horizontal canals canal can also be affected. Otoconia or ear rocks are small crystals of calcium carbonate derived structure in the utricle which migrate into semicircular canals and cause BPPV. While saccules also contains otoconia, they are not able to migrate into the semicircular canals.