Incomplete Partition

Congenital malformations of the inner ear can be divided into two types of incomplete partition:

Incomplete partition type I, also known as cystic cochleovestibular malformation, is a condition where the cochlea lacks the entire modiolus and cribriform area, resulting in a cystic appearance. This is accompanied by a large cystic vestibule. On CT, there is an empty, cystic cochlea, a dilated vestibule, and absence of any partition within the cochlea. The vestibular aqueduct is not enlarged.

Incomplete partition type II is the classic Mondini deformity. The cochlea consists of 1.5 turns, in which the middle and apical turns coalesce to form a cystic apex, accompanied by a dilated vestibule and enlarged vestibular aqueduct. CT shows a dilated vestibule, an enlarged vestibular aqueduct, and confluence of middle and apical turns of the cochlea.

References

Sennaroglu L, Saatci I. A new classification for cochleovestibular malformations. Laryngoscope. 2002 Dec;112(12):2230-41.