Another evidence for pressure transfer mechanism in incomplete partition two anomaly via enlarged vestibular aqueduct.

A female patient with unilateral enlarged vestibular aqueduct (EVA) demonstrated scala vestibuli dilatation on that side while on the contralateral side both vestibular aqueduct and scala vestibuli were normal. This important radiological finding demonstrates that modiolar defects (hence 'cystic apex') observed in Incomplete partition-II is due to pressure transfer via EVA during embryological development. Therefore, it supports the previous histopathological ideas radiologically. Depending on the patency of EVA, variety of modiolar defects may arise.