About Nystagmus Transformation in a Case of Apogeotropic Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo
Figure 3
(a) When the patient in supine position rolls his/her head by 180° from the right side to the left side (outer arrow), the endolymphatic flow (dashed arrow) pushes the debris localized in the anterior arm of the canal towards the cupula and those in the posterior arm towards the lowermost part of the canal (thin arrows). (b) Therefore, when the head is still in this position, the debris in the anterior arm of the canal moves away from the ampulla due to gravity (thin arrow), provoking an ampullofugal flow and a right beating apogeotropic nystagmus (head arrow), while the debris in the posterior arm does not provoke any flow.
